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Keywords:

  • gene polymorphisms;
  • toxicity;
  • rectal cancer;
  • neoadjuvant chemoradiation.

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

BACKGROUND

Toxicity from neoadjuvant chemoradiation therapy (NT) increases morbidity and limits therapeutic efficacy in patients with rectal cancer. The objective of this study was to determine whether specific polymorphisms in genes associated with rectal cancer response to NT were correlated with NT-related toxicity.

METHODS

One hundred thirty-two patients with locally advanced rectal cancer received NT followed by surgery. All patients received 5-fluorouracil (5-FU) and radiation (RT), and 80 patients also received modified infusional 5-FU, folinic acid, and oxaliplatin chemotherapy (mFOLFOX-6). Grade ≥3 adverse events (AEs) that occurred during 5-FU/RT and during combined 5-FU/RT + mFOLFOX-6 were recorded. Pretreatment biopsy specimens and normal rectal tissues were collected from all patients. DNA was extracted and screened for 22 polymorphisms in 17 genes that have been associated with response to NT. Polymorphisms were correlated with treatment-related grade ≥3 AEs.

RESULTS

Overall, 27 of 132 patients (20%) had grade ≥3 AEs; 18 patients had a complication associated only with 5-FU/RT, 3 patients experienced toxicity only during mFOLFOX-6, and 6 patients had grade ≥3 AEs associated with both treatments before surgery. Polymorphisms in the genes x-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1), xeroderma pigmentosum group D (XPD), and tumor protein 53 (TP53) were associated with grade ≥3 AEs during NT (P < .05). Specifically, 2 polymorphisms—an arginine-to-glutamine substitution at codon 399 (Q399R) in XRCC1 and a lysine-to-glutamine substitution at codon 751 (K751Q) in XPD—were associated with increased toxicity to 5-FU/RT (P < .05), and an arginine-to-proline substitution at codon 72 (R72P) in TP53 was associated with increased toxicity to mFOLFOX-6 (P = .008).

CONCLUSIONS

Specific polymorphisms in XRCC1, XPD, and TP53 were associated with increased toxicity to NT in patients with rectal cancer. The current results indicated that polymorphism screening may help tailor treatment for patients by selecting therapies with the lowest risk of toxicity, thus increasing patient compliance. Cancer 2013. © 2012 American Cancer Society.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

Neoadjuvant chemoradiation therapy (NT), including 5-fluorouracil (5-FU) and radiation therapy (RT), followed by total mesorectal excision (TME) is the standard of care for patients with locally advanced rectal cancer.1 The oncologic benefits of this treatment approach have been well established, and patients who respond to NT achieve excellent local tumor control and low rates of recurrence.1–4 However, not all patients respond equally to NT. Approximately 33% of patients will have no viable cancer cells in the resected surgical specimen after treatment and will have a pathologic complete response (pCR). However, other patients will have only a partial response or no response at all.3

An important limiting factor that can impede the efficacy of NT is the development of treatment-related toxicity. Some patients tolerate therapy well with few complications, but others experience severe (grade ≥3) adverse events (AEs) that cause significant morbidity. This can lead to a truncated course of therapy, limiting the full efficacy of treatment.5,6 Therefore, the ability to identify those patients most likely to develop toxicity to NT has clinical importance.

Gene polymorphisms are genetic variations that contribute to the genetic diversity observed between individuals. They can alter the expression and function of the encoded protein by changing a single amino acid.7,8 Recent studies suggest that specific polymorphisms in genes related to DNA repair, drug metabolism, cell cycle progression, cell growth, and inflammation are associated with response to NT and that patients with different polymorphisms in these genes have different tumor responses.9–14 We recently demonstrated that patients with rectal cancer who harbor select polymorphisms in the methylenetetrahydrofolate reductase (NAD(P)H) (MTHFR) gene, which functions in the metabolism of 5-FU, and in the cyclin D1 (CCND1) gene, which regulates cell cycle progression, are unlikely to achieve a pCR to NT.15 Studies in breast, ovarian, prostate, lung, esophageal, gastric, and colorectal cancers also have demonstrated that specific polymorphisms associated with response to NT also predict toxicity to treatment.9,11,14,16–21 However, few studies have examined this association in patients with rectal cancer.22,23

We studied a large cohort of rectal cancer patients who received treatment with NT 5-FU/RT, with or without modified infusional 5-FU, folinic acid, and oxaliplatin (mFOLFOX-6) chemotherapy, to determine whether specific polymorphisms correlate with NT-related toxicity.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

Patients and Treatment

This study included 132 patients with stage II/III rectal cancer who were enrolled in a multicenter clinical trial investigating the effect of increasing the chemoradiation-to-surgery time interval and adding chemotherapy (mFOLFOX-6) during the waiting period on tumor response (clinicaltrials.org identifier: NCT00335816). This study was designed as a series of sequential phase 2 trials or study groups (SGs), each with a progressively longer chemoradiation-to-surgery time interval and increasing cycles of preoperative mFOLFOX-6. This study was approved by an institutional review board at each participating institution, and by a central institutional review board. Informed written consent was obtained from each patient before enrollment in the trial. Patients in the current study were from 3 SGs: SG1 (n = 52), SG2 (n = 58), and SG3 (n = 22). Further details of patient eligibility for this trial are presented elsewhere.24

All patients received 5-FU/RT as described previously.24 Patients in SG1 (n = 52) then underwent TME an average of 6 weeks after completing 5-FU/RT. The remaining patients (SG2 and SG3, n = 80) received 2 (SG2) or 4 (SG3) cycles of additional chemotherapy (mFOLFOX-6) as described previously.24 These patients underwent TME an average of 11 weeks (SG2) and 16 weeks (SG3) after completing 5-FU/RT.

Assessment of Neoadjuvant Chemoradiation Therapy-Related Adverse Events

An AE was defined as a complication that occurred during 5-FU/RT or mFOLFOX-6 treatment. AEs were graded according to the Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. A severe AE was defined as any grade ≥3 toxicity (grade ≥3 AEs) that occurred during 5-FU/RT or mFOLFOX-6 treatment. Severe AEs were recorded prospectively for all patients and were compiled in a central database.

Sample Preparation and Polymorphism Screening

Unstained, formalin-fixed, paraffin-embedded tissue blocks were retrieved from all participating institutions. Benign colonic epithelial cells were microdissected from the proximal resection margins of the surgical specimen a distance >10 cm from the primary tumor. DNA was extracted using the QIAamp DNA FFPE Tissue Kit (Qiagen Inc., Valencia, Calif) according to the manufacturer's instructions as previously decribed.15 Standard polymerase chain reaction (PCR) and direct Sanger sequencing were performed to detect gene polymorphisms. We examined 22 polymorphisms in 17 genes associated with DNA repair (excision repair cross-complementing rodent repair deficiency, complementation group 1 [ERCC1]; x-ray repair complementing defective repair in Chinese hamster cells 1 [XRCC1]; RAD23B homolog [RAD23B]; xeroderma pigmentosum, complementation group A [XPA]; xeroderma pigmentosum, complementation group D [XPD]; 8-oxoguanine DNA glycosylase [OGG1]; and poly(ADP-ribose) polymerase 1 [PARP]), drug metabolism (MTHFR, thymidylate synthase [TS], dihydropyrimidine dehydrogenase [DPD], and uridine monophosphate synthetase [OPRT]), cell cycle progression (CCND1 and tumor protein 53 [TP53]), cell growth (epidermal growth factor receptor [EGFR]), and inflammation (vascular epidermal growth factor [VEGF], interleukin 6 [IL6], and toll-like receptor 2 [TLR2]). Primers were used to amplify genomic sequences using established conditions (Table 1).15 All polymorphisms were confirmed by 2 independently derived PCR products.

Table 1. Primers and Annealing Temperatures for Gene Polymorphisms Included in the Analysis
PolymorphismForward PrimerReverse PrimerSize, Base PairsTm, °C
  • Abbreviations: CCND1 G870A, glycine-to-alanine substitution at codon 780 in the cyclin D1 gene; DPD F632F, polymorphism with conserved phenylalanine at codon 632 in the dihydropyrimidine dehydrogenase gene; EGFR R497K, arginine-to-lysine substitution at codon 497 in the epidermal growth factor receptor gene; ERCC1 N118N, polymorphism with conserved asparagine at codon 118 in the excision repair cross-complementing rodent repair deficiency, complementation group 1 gene; IL6, interleukin 6; MTHFR A1298C, alanine-to-cysteine substitution at codon 1297 of the methylenetetrahydrofolate reductase (NAD(P)H) gene; MTHFR C677T, cysteine-to-threonine substitution at codon 677 of the methylenetetrahydrofolate reductase (NAD(P)H) gene; OGG1 S326C, serine-to-cysteine substitution at codon 326 of the 8-oxoguanine DNA glycosylase gene; OPRT G213A, glycine-to-alanine substitution at codon 213 in the uridine monophosphate synthetase gene; PARP1 V762A, valine-to-alanine substitution at codon 762 in the poly(ADP-ribose) polymerase 1 gene; RAD23B A249V, alanine-to-valine substitution at codon 249 in the RAD23B homolog gene; TLR2 R753Q, arginine-to-glutamine substitution at codon 753 in the toll-like receptor 2 gene; Tm, annealing temperature; TP53 R72P, arginine-to-proline substitution at codon 72 in the tumor protein 53 gene; TS Del6bp, 6-base-pair deletion in the 3′-untranslated region of the thymidylate synthase gene; VEGF, vascular endothelial growth factor; XPA R23G, arginine-to-glycine substitution at codon 23 in the xeroderma pigmentosum, complementation group A gene; XPD K751Q, lysine-to-glutamine substitution at codon 751 in the xeroderma pigmentosum group D gene; XRCC1 R194Y, arginine-to-tyrosine substitution at codon 194 in the x-ray repair complementing defective repair in Chinese hamster cells 1 gene; XRCC1 R399Q, arginine-to-glutamine substitution at codon 399 in the x-ray repair complementing defective repair in Chinese hamster cells 1 gene.

  • a

    Numbers indicate amino acid codons.

CCND1 G870A5′-TGAAGTTCATTTCCAATC-3′5′-TCAGTAAGTTCTAGGAGCAG-3′33748
DPD F632F5′-ATCAGTGAGAAAACGGCTGC-3′5′-TGCATCAGCAAAGCAACTGG-3′20560
EGFR R497K5′-TCTGTCACTGACTGCTGTGAC-3′5′-CAACGCAAGGGGATTAAAG-3′20464
ERCC1 N118N5′-GTGGTTATCAAGGGTCATCC-3′5′-TGCCCTTCCTGAAGTCTG-3′19760
TP53 R72P5′-CGTTCTGGTAAGGACAAGGGT-3′5′-AAGAAATGCAGGGGGATACGG-3′44664
IL6 572a5′-TGGAGACGCCTTGAAGTAAC-3′5′-TGACCAGATTAACAGGCTAG-3′23760
IL6 174a5′-ACTTCGTGCATGACTTCAGC-3′5′-GGGCTGATTGGAAACCTTAT-3′21160
MTHFR C677T5′-CCAAAGGCCACCCCGAAG-3′5′-GAAAGATCCCGGGGACGATG-3′18060
MTHFR A1298C5′-CTTTGGGGAGCTGAAGGACTACTAC-3′5′-CACTTTGTGACCATTCCGGTTTG-3′16376
OGG1 S326C5′-CAACACTGTCACTAGTCTCAC-3′5′-CCAAGGACTCTTCCACCTC-3′16662
OPRT G213A5′-TGAGACAGTTGGGAGAGTGA-3′5′-TGAGTTCTTTGGGTGCTTCCTT-3′10460
PARP1 V762A5′-TTGGACCTTCTCTGCATG-3′5′-TCCAGGAGATCCTAACACAC-3′31354
RAD23B A249V5′-ATTTTGCATGATGGGATATCT-3′5′-ATGAACGTCATTTCTGAAGTAT-3′27256
TLR2 R753Q5′-AGTGAGTGGTGCAAGTATG-3′5′-AAATATGGGAACCTAGGAC-3′24056
TS Del6bp5′-CAAATCTGAGGGAGCTGAGT-3′5′-GCAGATAAGTGGCAGTACAGA-3′14960
VEGF 634a5′-TGGAAACCAGCAGAAAGAGG-3′5′-TCAGCGCGACTGGTCAG-3′20360
VEGF 936a5′-TCACCATCGACAGAACAGTC-3′5′-TGTGTCTACAGGAATCCCAG-3′22860
VEGF 2578a5′-TGACTAGGTAAGCTCCCTG-3′5′-ATTCCTAGCTGGTTTCTGAC-3′22758
XPA R23G5′-TTAACTGCGCAGGCGCT-3′5′-TTCCGCTCGATACTCGC-3′22854
XRCC1 R194Y5′-GGACCTTAGAAGGTGAC-3′5′-AGGAGTCCAGGACTCCAC-3′25252
XRCC1 R399Q5′-TCAGATCACACCTAACTGG-3′5′-CAGGTCCTCCTTCCCTC-3′34156
XPD K751Q5′-CCTCTCCCTTTCCTCTGT-3′5′-AATGTCACCTGACTTCATAAGAC-3′22756

Statistical Analysis

Univariate analysis using the chi-square test was performed to determine the association between gene polymorphisms and grade ≥3 AEs resulting from 5-FU/RT, mFOLFOX-6, or both therapies and to determine the association between grade ≥3 AEs and clinical/pathologic factors. No adjustment for multiple comparisons was made. A 2-sided P value ≤ .05 indicated a significant association.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

Patient Characteristics and Tumor Response

Patient characteristics and tumor response to NT for all 132 patients are listed in Table 2. More than 50% of patients were men (n = 78; 59%), and the mean age was 57 years. Most patients (n = 102; 77%) had clinical stage III disease. Of the 132 patients who received NT, 52 patients received 5-FU/RT alone, and 80 patients received 5-FU/RT plus mFOLFOX-6. Final pathology revealed that 33 of 132 patients (25%) achieved a pCR to NT, including 10 patients (19%) who received 5-FU/RT alone and 23 patients (29%) who received 5-FU/RT plus mFOLFOX-6. There were no differences in clinical or pathologic characteristics between the treatment groups (P = .22).

Table 2. Patient Characteristics and Tumor Response
CharacteristicsNo. of Patients (%), n = 132
  1. Abbreviations: 5-FU, 5-flourouracil; mFOLFOX-6, modified infusional 5-fluorouracil, folinic acid, and oxaliplatin chemotherapy; pCR, pathologic complete response; RT, radiation therapy.

Sex 
Females54 (41)
Males78 (59)
Age: Mean [range], y57 [5–87]
Preoperative clinical stage 
II30 (23)
III102 (77)
Neoadjuvant treatment 
5-FU/RT52 (39)
5-FU/RT and mFOLFOX-680 (61)
Tumor response 
pCR33 (25)
Non-pCR99 (75)

Rate of Adverse Events

In total, 27 of 132 patients (20%) had 43 grade ≥3 AEs related to NT. Of the 27 patients who experienced an AE grade ≥3, 18 patients had a complication associated only with 5-FU/RT, 3 patients experienced toxicity only during mFOLFOX-6, and 6 patients had grade ≥3 AEs associated with both treatments (Table 3). The most common AEs observed were gastrointestinal symptoms, including diarrhea, rectal pain, severe nausea, and vomiting.

Table 3. Grade ≥3 Adverse Events Stratified by Treatment
 Treatment Arm: No. of Patients (%)
Grade ≥3 AEs5-FU/RT, n = 132mFOLFOX-6, n = 80
  1. Abbreviations: 5-FU, 5-fluorouracil; AEs, adverse events; mFOLFOX-6, modified infusional 5-fluorouracil, folinic acid, and oxaliplatin chemotherapy; RT, radiation therapy.

Patients with grade ≥3 AEs24 (18)9 (11)
Most common grade ≥3 AEs  
Gastrointestinal10 (8)0 (0)
Abdominal/rectal pain6 (5)1 (1)
Vascular0 (0)2 (3)
Infection2 (2)0 (0)
Hematologic3 (2)4 (5)
Constitutional symptoms3 (2)0 (0)
Cardiac event0 (0)1 (1)
Other: Allergy/skin/rash8 (6)3 (4)

To determine whether AE rates differed according to treatment response, we compared the rate of grade ≥3 AEs for patients who attained a pCR with the rate for patients who did not have a pCR (residual disease). In patients with a pCR (n = 33), 6 (18%) had a grade ≥3 AE after NT, whereas 21 of 99 patients (21%) with no pCR experienced toxicity from NT. There was no statistical difference in the rate of grade ≥3 AEs between patients with or without a pCR after NT (P = .81). There also was no difference in the rate of grade ≥3 AEs between patients who received 5-FU/RT alone (n = 11 of 52 patients; 21%) and patients who received 5-FU/RT plus mFOLFOX-6 (n = 17 of 80 patients; 21%; P = 1.0).

Association of Gene Polymorphisms With Treatment Toxicity

We examined the association of grade ≥3 AEs with gene polymorphisms during NT (Table 4). Gene polymorphisms in XRCC1 (arginine-to-glutamine substitution at codon 399 [Q399R]), XPD (arginine-to-lysine substitution at codon 751 [Q751K]), and TP53 (arginine-to-proline substitution at codon 72 [R72P]) were associated with grade ≥3 AEs during NT. Specifically, we observed that patients with the XRCC1 Q399 allele had an increased rate of toxicity to NT compared with patients who were homozygous for the XRCC1 R399 allele (27% vs 5%; P = .003). In addition, we observed that patients with the XPD Q751 allele had a lower rate of grade ≥3 AEs to NT compared with patients who had only the XPD K751 allele (14% vs 31%; P = .02). Finally, patients with the TP53 P72 allele had an increased rate of grade ≥3 AEs compared with patients who had only the TP53 R72 allele (32% vs 16%; P = .05).

Table 4. Association of Gene Polymorphisms With Treatment-Related Toxicity
 Treatment Arm
 Neoadjuvant CRT5-FU/RTmFOLFOX-6
Gene PolymorphismNo. of Patients, n = 132No. With Grade ≥3 AEs, n = 27PNo. of Patients, n = 132No. With Grade ≥3 AEs (%), n = 24PNo. of Patients, n = 80No. With Grade ≥3 AEs (%), n = 9P
  1. Abbreviations: 5-FU, 5-fluorouracil; AEs, adverse events; CRT, chemoradiation therapy; mFOLFOX-6, modified infusional 5-fluorouracil, folinic acid, and oxaliplatin chemotherapy; RT, radiotherapy; TP53 R72P, arginine-to-proline substitution at codon 72 in the tumor protein 53 gene; XPD K751Q, lysine-to-glutamine substitution at codon 751 in the xeroderma pigmentosum group D gene; XRCC1 R399Q, arginine-to-glutamine substitution at codon 399 in the x-ray repair complementing defective repair in Chinese hamster cells 1 gene.

XRCC1 R399Q         
R399 alone402 (5).003402 (5).01170 (0).10
Q3999225 (27) 9222 (24) 639 (14) 
XPD K751Q         
K751 alone5517 (31).025515 (27).02326 (19).08
Q7517711 (14) 779 (12) 483 (6) 
TP53 R72P         
R72 alone9515 (16).059514 (15).10573 (5).008
P723712 (32) 3710 (27) 236 (26) 

We next examined the association of gene polymorphisms with toxicity in each treatment arm (5-FU/RT and mFOLFOX-6) (Table 4). Among the patients who received 5-FU/RT (n = 132), those with the XRCC1 Q399 allele had a significantly higher rate of grade ≥3 AEs compared with patients who had only the XRCC1 R399 allele (24% vs 5%; P = .01). In addition, patients who had only the XPD K751 allele had an increased risk of developing grade ≥3 AEs to 5-FU/RT compared with patients who had the XPD Q751 allele (27% vs 12%; P = .02).

Finally, we determined whether gene polymorphisms correlated with toxicity specifically to mFOLFOX-6 (Table 4). Univariate analysis indicated that patients with the TP53 P72 allele had an increased risk of toxicity to mFOLFOX-6 compared with patients who had only the TP53 R72 allele (26% vs 5%; P = .008).

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

Severe toxicity from NT contributes to patient morbidity and may limit the delivery and efficacy of treatment. Predictive factors may help identify patients who are at risk for increased toxicity and, thus, guide multimodal therapy. We observed that specific polymorphisms in the XRCC1 (Q399R), XPD (Q751K), and TP53 (R72P) genes were associated with increased toxicity to NT in patients with locally advanced rectal cancer. The identification of these genetic polymorphisms as predictive factors is clinically relevant, because they may help identify patients who are more likely to develop severe AEs to NT. Treatment regimens with the lowest risk of toxicity, depending on these genetic factors, could then be selected, which may increase treatment compliance and efficacy.

Gene polymorphisms have been linked to differential response to neoadjuvant therapies in lung, colon, esophageal, breast, ovarian, and prostate cancers.9,11,13,14,16,19,20,25 Gene polymorphisms can affect protein function and alter biologic pathways that are integral in response to NT in tumor cells.7,8 Polymorphisms also can attenuate pathways, such as DNA damage repair, drug metabolism, and cell cycle progression, impairing the survival of normal cells under stress from treatment with either RT or chemotherapy.7,8 Thus, polymorphisms may contribute to significant treatment-related toxicity in patients.

Although little is known about the functional consequences of the XRCC1 R399Q polymorphism, previous reports have examined its association with toxicity to RT and/or chemotherapy in other malignancies.11,17,18,20,26 The XRCC1 protein acts as a scaffold that coordinates the base excision repair mechanism, which repairs DNA after damage from RT. Monaco et al described the effect of the XRCC1 R399Q gene polymorphism on XRCC1 protein function and observed that the R-to-Q amino acid substitution produces significant conformational changes at the BRCT1 binding domain, which interacts with the breast cancer 1 (BRCA1) gene during DNA damage, and decreases protein interaction. The overall effect may result in attenuated DNA repair, especially after RT.26 Chang-Claude et al observed that patients with breast cancer who harbored the XRCC1 R399 allele had increased acute toxicity from RT.17,18 Other studies have demonstrated that the XRCC1 R399 allele correlates with severe AEs after chemoradiation therapy and with an increased rate of grade 3 and 4 neutropenia in patients with ovarian cancer who receive cisplatin-based chemotherapy.11 In contrast, Giachino et al demonstrated that the XRCC1 Q399 allele was associated with a significantly increased risk of grade 3 and 4 complications in patients with lung cancer who received platinum-based chemotherapy.20 Our results support the later association of the XRCC1 Q399 allele with the development of severe toxicity to NT in patients with rectal cancer. In our study, the XRCC1 Q399 allele was strongly associated with toxicity during 5-FU/RT treatment.

The XPD protein is a DNA helicase involved in the nucleotide excision repair pathway. Monaco et al reported that the XPD K751Q polymorphism results in a conformational change in the C-terminal of the XPD protein.27 The C-terminal is responsible for the activation of XPD helicase during DNA repair, and it also affects the interaction with other proteins involved in DNA repair. Previous studies have demonstrated contrasting roles for the XPD K751 and Q751 alleles.28,29 Our results, which demonstrated an increased risk of AEs among patients with the XPD K751 allele, are in agreement with the results of Boige et al, who previously reported increased toxicity in patients with metastatic colorectal cancer who had the XPD K751 allele and received 5-FU-based regimens.16 Homozygosity of the XPD K751 allele may result in attenuated XPD function and diminished response to DNA damage. This may further lead to decreased DNA damage repair in normal cells after chemoradiation and may result in treatment toxicity. Other studies also support the association of the XPD K751 allele with an increased risk of toxicity from RT in patients with lung cancer.9,30

Mutations in the TP53 gene have been well studied, but genetic polymorphisms in the TP53 gene have only recently been evaluated and have been associated with an increased risk of cancers of the stomach, breast, lung, and esophagus.31–33 Studies have demonstrated that the TP53 R72 allele may encode a TP53 variant that increases the induction of programmed cell death.34 However, in cancer cells, the effectiveness of the TP53 R72 allele in promoting cell death may depend on the mutation status of the TP53 gene.35, 36 Specifically, the proapoptotic effects of the TP53 R72 allele may be lost when an inactivating TP53 gene mutation is present. This has been described in 70% of patients with nonmelanoma skin cancers.37 However, few studies have examined the role of the TP53 R72P polymorphism in determining toxicity to chemoradiation therapy. Khrunin et al observed an increased risk of severe neutropenia in women with ovarian cancer who were homozygous for the TP53 P72 allele and received platinum-based chemotherapy.11 These findings are consistent with our results, which demonstrate an association of the TP53 P72 allele with toxicity to NT, especially in patients who receive mFOLFOX-6. Further studies may be necessary to investigate the association of the TP53 R72P polymorphism with toxicity to platinum-based regimens.

Screening patients for specific gene polymorphisms that may predict toxicity to different components of NT could help tailor the management of patients with rectal cancer. Specifically, patients who carry polymorphisms associated with chemoradiation toxicity may benefit from a chemotherapy-based approach (mFOLFOX-6) and avoid RT. In addition, patients who harbor polymorphisms associated with platinum-based toxicity may be spared unnecessary morbidity by selecting nonplatinum-containing regimens. This potential impact on the clinical decision-making process must be weighed against the limitations of our study. First, our cohort size was relatively small with heterogeneity in the mFOLFOX-6 regimen. Consequently, we support validation of our results in a larger series of patients who are treated within the confines of a prospective trial. Second, our clinical trial consisted of 3 different treatment groups, and it is feasible that our current investigation was underpowered to detect small differences between groups. Finally, our list of polymorphisms was extensive, but not exhaustive. Other polymorphisms that were not assessed in this study also may be associated with treatment toxicity. Future sequencing of the whole genome may identify other polymorphisms associated with specific outcomes.

In conclusion, polymorphisms in the XRCC1, XPD, and TP53 genes may predict the development of severe AEs in patients with rectal cancer who are receiving NT. Screening for these polymorphisms before treatment may help identify patients who are at increased risk of developing toxicity to treatment. This may help guide clinicians in choosing the optimal treatment regimen by individualizing therapeutic regimens for maximum efficacy with minimal morbidity. By screening patients for the presence of these genetic markers, we may increase the likelihood that patients who are recommended for NT can tolerate and complete therapy and will receive the maximal benefit from treatment.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

We thank Nicola Solomon, PhD, for assistance in writing and editing the article. We also acknowledge the following participating investigators from the Timing of Rectal Cancer Consortium for providing the specimens that were used in the study: W. Donald Buie, MD (University of Calgary, Calgary, Alberta, Canada); Theodore Coutsoftides, MD (St. Joseph Hospital-Orange County Hospital, Orange, CA); David Dietz, MD (Cleveland Clinic Foundation, Cleveland, OH); Alessandro Fichera, MD (University of Chicago Medical Center, Chicago, IL); Daniel Herzig, MD (Oregon Health and Science University, Portland, OR); Steven Hunt, MD (Washington University, St. Louis, MO); Peter Cataldo, MD and Neil Hyman, MD (University of Vermont, Burlington, VT); Jorge Marcet, MD (University of South Florida, Tampa, FL); Samuel Oommen, MD (John Muir Health, Concord, CA); Thomas E. Read, MD (Lahey Clinic Medical Center, Burlington, MA); David Rothenberger, MD (University of Minnesota, Minneapolis, MN); Lee Smith, MD (Washington Hospital Center, Washington, DC); Michael J. Stamos, MD (University of California, Irvine, CA); Charles A. Ternent, MD, FACS (Colon and Rectal Surgery Inc., Omaha, NE); Madhulika G. Varma, MD (University of California, San Francisco, CA); and Charles R. Thomas, Jr., MD (Oregon Health and Science University, Portland, OR).

FUNDING SOURCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES

This study was supported by the National Institutes of Health, National Cancer Institute grant R01 CA090559 to Dr. Garcia-Aguilar (clinicaltrials.org identifier NT00335816)

CONFLICT OF INTEREST DISCLOSURES

The authors made no disclosures.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. MATERIALS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. FUNDING SOURCES
  9. REFERENCES
  • 1
    Sauer R, Becker H, Hohenberger W, et al. Preoperative versus postoperative chemoradiotherapy for rectal cancer. N Engl J Med. 2004; 351: 1731-1740.
  • 2
    Bosset JF, Collette L, Calais G, et al. Chemotherapy with preoperative radiotherapy in rectal cancer. N Engl J Med. 2006; 355: 1114-1123.
  • 3
    Maas M, Nelemans PJ, Valentini V, et al. Long-term outcome in patients with a pathological complete response after chemoradiation for rectal cancer: a pooled analysis of individual patient data. Lancet Oncol. 2010; 11: 835-844.
  • 4
    Pucciarelli S, Friso ML, Toppan P, et al. Preoperative combined radiotherapy and chemotherapy for middle and lower rectal cancer: preliminary results. Ann Surg Oncol. 2000; 7: 38-44.
  • 5
    Evans WE, Relling MV. Moving towards individualized medicine with pharmacogenomics. Nature. 2004; 429: 464-468.
  • 6
    Ulrich CM, Robien K, McLeod HL. Cancer pharmacogenetics: polymorphisms, pathways and beyond. Nat Rev Cancer. 2003; 3: 912-920.
  • 7
    International HapMap Consortium. The International HapMap Project. Nature. 2003; 426: 789-796.
  • 8
    Frazer KA, Ballinger DG, Consortium IH, Cox DR, Hinds DA, Stewart J. A second generation human haplotype map of over 3.1 million SNPs. Nature. 2007; 449: 851-861.
  • 9
    Booton R, Ward T, Heighway J, et al. Xeroderma pigmentosum group D haplotype predicts for response, survival, and toxicity after platinum-based chemotherapy in advanced nonsmall cell lung cancer. Cancer. 2006; 106: 2421-2427.
  • 10
    Cecchin E, Agostini M, Pucciarelli S, et al. Tumor response is predicted by patient genetic profile in rectal cancer patients treated with neo-adjuvant chemoradiotherapy. Pharmacogenomics J. 2011; 11: 214-226.
  • 11
    Khrunin AV, Moisseev A, Gorbunova V, Limborska S. Genetic polymorphisms and the efficacy and toxicity of cisplatin-based chemotherapy in ovarian cancer patients. Pharmacogenomics J. 2010; 10: 54-61.
  • 12
    Park DJ, Stoehlmacher J, Zhang W, Tsao-Wei DD, Groshen S, Lenz H. A xeroderma pigmentosum group D gene polymorphism predicts clinical outcome to platinum-based chemotherapy in patients with advanced colorectal cancer. Cancer Res. 2001; 61: 8654-8658.
  • 13
    Quintela-Fandino M, Hitt R, Medina PP, et al. DNA-repair gene polymorphisms predict favorable clinical outcome among patients with advanced squamous cell carcinoma of the head and neck treated with cisplatin-based induction chemotherapy. J Clin Oncol. 2006; 24: 4333-4339.
  • 14
    Wu X, Gu J, Wu T, et al. Genetic variations in radiation and chemotherapy drug action pathways predict clinical outcomes in esophageal cancer. J Clin Oncol. 2006; 24: 3789-3798.
  • 15
    Garcia-Aguilar J, Chen Z, Smith DD, et al. Identification of a biomarker profile associated with resistance to neoadjuvant chemoradiation therapy in rectal cancer. Ann Surg. 2011; 254: 486-493.
  • 16
    Boige V, Mendiboure J, Pignon J, et al. Pharmacogenetic assessment of toxicity and outcome in patients with metastatic colorectal cancer treated with LV5FU2, FOLFOX, and FOLFIRI: FFCD 2000-05. J Clin Oncol. 2010; 28: 2556-2564.
  • 17
    Chang-Claude J, Ambrosone CB, Lilla C, et al. Genetic polymorphisms in DNA repair and damage response genes and late normal tissue complications of radiotherapy for breast cancer. Br J Cancer. 2009; 100: 1680-1686.
  • 18
    Chang-Claude J, Popanda O, Tan X, et al. Association between polymorphisms in the DNA repair genes, XRCC1, APE1, and XPD and acute side effects of radiotherapy in breast cancer patients. Clin Cancer Res. 2005; 11: 4802-4809.
  • 19
    Damaraju S, Murray D, Dufour J, et al. Association of DNA repair and steroid metabolism gene polymorphisms with clinical late toxicity in patients treated with conformal radiotherapy for prostate cancer. Clin Cancer Res. 2006; 12: 2545-2554.
  • 20
    Giachino DF, Ghio P, Regazzoni S, et al. Prospective assessment of XPD Lys751Gln and XRCC1 Arg399Gln single nucleotide polymorphisms in lung cancer. Clin Cancer Res. 2007; 13: 2876-2881.
  • 21
    Keam B, Im S, Han S, et al. Modified FOLFOX-6 chemotherapy in advanced gastric cancer: results of phase II study and comprehensive analysis of polymorphisms as a predictive and prognostic marker [serial online]. BMC Cancer. 2008; 8: 148.
  • 22
    Schirmer MA, Nadine Mergler CP, Rave-Frank M, et al. Acute toxicity of radiochemotherapy in rectal cancer patients: a risk particularly for carriers of the TGFB1 Pro25 variant. Int J Radiat Oncol Biol Phys. 2012; 83: 149-157.
  • 23
    Thomas F, Motsinger-Reif AA, Hoskins JM, et al. Methylenetetrahydrofolate reductase genetic polymorphisms and toxicity to 5-FU-based chemoradiation in rectal cancer. Br J Cancer. 2011; 105: 1654-1662.
  • 24
    Garcia-Aguilar J, Smith DD, Avila K, Chen Z, Li W. Optimal timing of surgery after chemoradiation for advanced rectal cancer: preliminary results of a prospective trial. Ann Surg. 2011; 254: 97-102.
  • 25
    Biros E, Kalina I, Biros I, et al. Polymorphism of the p53 gene within the codon 72 in lung cancer patients. Neoplasma. 2001; 48: 407-411.
  • 26
    Monaco R, Rosal R, Dolan MA, Pincus MR, Brandt-Rauf PW. Conformational effects of a common codon 399 polymorphism on the BRCT1 domain of the XRCC1 protein. Protein J. 2007; 26: 541-546.
  • 27
    Monaco R, Rosal R, Dolan MA, Pincus MR, Freyer G, Brandt-Rauf PW. Conformational effects of a common codon 751 polymorphism on the C-terminal domain of the xeroderma pigmentosum D protein [serial online]. J Carcinog. 2009; 8: 12.
  • 28
    Spitz MR, Wu X, Wang Y, et al. Modulation of nucleotide excision repair capacity by XPD polymorphisms in lung cancer patients. Cancer Res. 2001; 61: 1354-1357.
  • 29
    Lunn RM, Helzlsouer KJ, Parshad R, et al. XPD polymorphisms: effects on DNA repair proficiency. Carcinogenesis. 2000; 21: 551-555.
  • 30
    Isla D, Sarries C, Rosell R, et al. Single nucleotide polymorphisms and outcome in docetaxel-cisplatin-treated advanced non-small-cell lung cancer. Ann Oncol. 2004; 15: 1194-1203.
  • 31
    Shen H, Solari A, Wang X, et al. P53 codon 72 polymorphism and risk of gastric cancer in a Chinese population. Oncol Rep. 2004; 11: 1115-1120.
  • 32
    Wu X, Zhao H, Amos CI, et al. P53 genotypes and haplotypes associated with lung cancer susceptibility and ethnicity. J Natl Cancer Inst. 2002; 94: 681-690.
  • 33
    Pim D, Banks L. P53 polymorphic variants at codon 72 exert different effects on cell cycle progression, Int J Cancer. 2004; 108: 196-199.
  • 34
    Bonafe M, Salvioli S, Barbi C, et al. P53 codon 72 genotype affects apoptosis by cytosine arabinoside in blood leukocytes. Biochem Biophys Res Commun. 2002; 299: 539-541.
  • 35
    Nelson HH, Wilkojmen M, Marsit CJ, Kelsey KT. TP53 mutation, allelism and survival in non-small cell lung cancer. Carcinogenesis. 2005; 26: 1770-1773.
  • 36
    Dumont P, Leu JI, Della Pietra AC 3rd, George DL, Murphy M. The codon 72 polymorphic variants of p53 have markedly different apoptotic potential. Nat Genet. 2003; 33: 357-365.
  • 37
    Marin MC, Jost CA, Brooks LA, et al. A common polymorphism acts as an intragenic modifier of mutant p53 behavior. Nat Genet. 2000; 25: 47-54.