Apoptosis is a distinct mode of cell death that is responsible for the deletion of cells in tumors and in normal tissues. We pursued a pathway-based approach to investigate the association of potentially functional genetic polymorphisms of the corresponding genes with the outcomes of platinum-based chemotherapy in advanced non-small-cell lung cancer (NSCLC). A MALDI-TOF mass spectrometer was used for genotyping 10 polymorphisms of eight apoptosis-related genes, including BCL2 rs1801018, rs1564483, rs2279115, BAX rs4645878, caspase (CASP3) rs6948, CASP8 rs3834129, CASP10 rs13006529, rs3900115, tumor necrosis factor α (TNFα) rs1800629, and macrophage migration inhibitory factor (MIF) rs755622. The associations between these single nucleotide polymorphisms and the outcomes of 445 advanced NSCLC patients treated with platinum-based chemotherapy were evaluated. The CASP3 rs6948 polymorphism was most significantly associated with hematologic toxicity in a dose-dependent manner. The incidence of severe hematologic toxicity was significantly lower in C allele carriers (P = 0.005; odds ratio = 0.524; 95% confidence interval = 0.333–0.824) and still significant after a Bonferroni correction. The function of this single nucleotide polymorphism in gene expression was also investigated. Quantitative PCR showed that individuals with the C allele had lower levels of CASP3 transcripts in peripheral blood lymphocytes. Luciferase reporter assays showed that the minor C allele significantly decreased the reporter gene expression level. In addition, the TNFα rs1800629 mutant allele significantly elevated gastrointestinal toxicity (P = 0.020; odds ratio = 3.020; 95% confidence interval = 1.188–7.676), when compared to the wild-type homozygote. No other association was found. In conclusion, for the first time, our study suggests that CASP3 rs6948 might influence CASP3 expression and be associated with severe hematologic toxicity risk. (Cancer Sci, doi: 10.1111/j.1349-7006.2012.02323.x, 2012)
Platinum-based regimens are used as the standard first-line chemotherapy in NSCLC patients.[1, 2] Incidence and severity of toxicities vary greatly between individuals.[3, 4] Thus, the development of predictive markers to identify patients who will significantly benefit from chemotherapy with minimal toxicity is a continuing challenge in lung cancer research.
Most platinum compounds induce damage to tumors through the induction of apoptosis. Apoptosis is responsible for the characteristic hematologic toxicity, gastrointestinal toxicity, and most other drug toxicities. Apoptosis is a distinct mode of cell death that is responsible for the deletion of cells in tumors and in normal tissues. Apoptotic cell death is orchestrated by the activation of a cascade of enzymes called caspases (CASP).[6-8] Two distinct but converging pathways for CASP activation have been delineated: the extrinsic or receptor-mediated pathway; and the intrinsic or mitochondrial pathway.[6-10] The extrinsic pathway is triggered by the activation of cell surface death receptors following the binding of their specific ligands, such as tumor necrosis factor α (TNFα), and Fas ligand.[6-10] Ligand–receptor binding recruits the adaptor molecule Fas-associated protein with death domain, resulting in the activation of the initiator CASP8 and/or CASP10 and the formation of a death-inducing signaling complex. The activated initiator CASPs subsequently activate the downstream effector CASPs.[11, 12] The other principal death-signaling pathway, the intrinsic or mitochondrial pathway, is initiated by the release of cytochrome c from mitochondria in response to a variety of cytotoxic signals, including DNA damage, hypoxia, and growth factor deprivation.[6-8, 11] Released cytochrome c interacts with apoptotic protease activating factor 1, proCASP9, and dATP to form a multiprotein complex called the apoptosome. Once bound to the apoptosome, CASP9 is activated, which subsequently triggers a cascade of effector CASPs.[12-14] Another group of molecular importance in apoptosis is Bcl-2. This family is subdivided into two major classes: antiapoptotic members, such as Bcl-2 and Bcl-xL, which protect cells from apoptosis; and proapoptotic members, such as Bax and Bak.[15-17]
Macrophage migration inhibitory factor (MIF) participates in the immunological reaction and in apoptosis.[18-20] It may bind to p53 and inhibit it. Macrophage migration inhibitory factor also interacted with Bcl-2-interacting mediator (BIM)[21, 22] and inhibited BIM-induced cell apoptosis. Knockdown assays indicated that cells without MIF will arrest in G0 /G1.
Therefore, apoptosis-related molecules are potential predictive markers for platinum treatment. Several studies have suggested that functional differences between the polymorphic variants in apoptosis-related genes may alter the ability to bind components of the transcriptional machinery, activate transcription, induce apoptosis, and repress the transformation of primary cells.[25-27]
In this study, using DNA samples obtained from a series of patients with advanced non-small-cell lung cancer (NSCLC) treated with chemotherapy, we investigated the association between the apoptosis-related gene polymorphisms, grade 3 or 4 toxicities, and the objective response.
Materials and Methods
Patient recruitment and follow-up
Patients with advanced NSCLC (n = 445), newly diagnosed between March 2005 and September 2007, were from Shanghai Chest Hospital (Shanghai, China). These patients had inoperable stage IIIA–IV cancer and the presence of a measurable or assessable lesion. An additional 52 patients were enrolled from Changzheng Hospital (Shanghai, China), between February 2009 and April 2010. All of the patients with histologically confirmed lung cancer were eligible for the study if they fulfilled all of the following criteria: aged 18–80 years; no prior history of malignancy except non-melanoma skin cancer, in situ carcinoma of the cervix, or “cured” malignant tumor (>5-year disease-free survival); no prior chemotherapy; Eastern Cooperative Oncology Group Performance Status Scale 0~2, with laboratory values for inclusion of neutrophil count ≥1.5 × 109/L, platelet count ≥100 × 109/L, serum creatinine ≤1.5 × upper limit normal, estimated creatinine clearance ≥60 mL/min, ALAT and ASAT ≤1.5 × upper limit normal; no recent (<3 months before the date of treatment) myocardial infarction and no active congestive heart failure or cardiac arrhythmia requiring medical treatment; no uncontrolled infectious disease; and no other serious medical or psychological factors that might prevent adherence to the treatment schedule. Patients had to be available for follow-up, and informed consent was provided. The study protocols were approved by the Ethical Review Committees of the respective hospitals.
Clinical data were systematically recorded at entry. Before starting any treatment, all patients underwent a complete medical history interview, physical examination, and laboratory testing, including routine hematology and biochemistry analyses, staging with chest radiographs and computed tomography of the thorax and abdomen, and magnetic resonance imaging of the brain and a bone scan.
The incidence of grade 3 or 4 toxicity was assessed twice a week during first-line chemotherapy, according to the National Cancer Institute Common Toxicity Criteria version 3.0 (http://ctep.cancer.gov). Toxicities included neutropenia, leukocytopenia, anemia, thrombocytopenia, nausea, and vomiting. Severe hematologic toxicity consisted of grade 3 or 4 neutropenia, leukocytopenia, anemia, or thrombocytopenia. Severe gastrointestinal toxicity consisted of grade 3 or 4 nausea or vomiting. Response was assessed after two cycles of chemotherapy and every two cycles thereafter, using Response Evaluation Criteria in Solid Tumor Group guidelines. Patient charts were reviewed to extract data on toxicities experienced during chemotherapy. The complete medical record, including progress notes of the treating oncologist and treating nurses, chemotherapy infusion orders and infusion flow sheets, was reviewed to collect these data. The investigators were blinded to the polymorphism status of the patients.
All of the patients enrolled in the study were given first-line platinum-based chemotherapy. The detailed chemotherapeutic regimens were described previously. All chemotherapeutic drugs were given intravenously, and patients were treated for two to six cycles.
Patient group 1: 445 blood samples were collected at the time of recruitment. Genomic DNA was prepared using QIAamp DNA Maxi Kit (Qiagen, Hilden, Germany). Single nucleotide polymorphisms (SNPs) were typed using iPLEX chemistry on a MALDI-TOF mass spectrometer (Sequenom, San Diego, CA, USA). Detailed procedures were described in our previous report. The assay was arrayed with two no-template controls and four duplicated samples in each 384-well format as quality controls.
Patient group 2: Blood samples of 52 patients were collected at the end of the first or second cycle of chemotherapy treatment. The genomic DNA was prepared from peripheral leukocytes using a genomic DNA purification Kit (Fermentas Life Sciences, Burlington, Canada). The entire 3′-untranslated region (UTR) of CASP3 was sequenced with the following primers: forward, 5′-CTAAAGAAATGGTTGGTTGGTGG-3′; and reverse, 5′-GGCACAACATCAAAAACAACAGCA-3′. The SNP rs6948 was typed by direct sequencing with the primers 5′-TTCTAAAGGTGGTGAGGCAAT-3′ and 5′-TGAGACTTGGTGCAGTGACG-3′.
All genotyping results were generated and checked by laboratory staff unaware of the status of the patient.
Quantitative analysis of CASP3 mRNA
Fifty-two subjects with known genotypes from the second patient group were included for a quantitative RNA expression assay. RNA from peripheral leukocytes was extracted and converted to cDNA using TRIzol (Invitrogen, Carlsbad, CA, USA) and RevertAid First Strand cDNA Synthesis Kit (Fermentas, Leon-Rot, Germany). The SYBR PCR system (Toyobo, Osaka, Japan) was used for the amplification of cDNA. The CASP3 and the internal standard β-actin mRNA were measured by real-time quantitative RT-PCR in triplicate on a Bio-Rad CFX96 Real-Time PCR machine (Bio-Rad, Hercules, CA, USA) with primers as follows: for β-actin, sense, 5′-AGCCAACTGTGAGAAGATGAC-3′, antisense, 5′-AGTGAGGATCTCCATGAGGTAG-3′; and for CASP3, sense, 5′-GAACTGGACTGTGGCATTGAGA-3′, antisense, 5′-CACAAAGCGACTGGATGAACC-3′. The fold changes were calculated using the Ct method.
Construction of luciferase reporter plasmids
To determine whether the CASP3 rs6948 SNP influences expression of the CASP3 gene in cells, a 1625 bp fragment, from 4 bp upstream of the CASP3 3′-UTR to 46 bp downstream of the CASP3 3′-UTR, was amplified using forward and reverse primers with the indicated sequences (forward primer, 5′-GGGCTAGCCTAAAGAAATGGTTGGTTGGTGG -3′; reverse primer, 5′- GG-GGATCCGGCACAACATCAAAAACAACAGCA -3′). The two targeted alleles were obtained by PCR amplification from patient samples with different genotypes. The 3′-UTR fragments containing each allele of CASP3 rs6948 were cloned into the pGL3-promoter vector (Promega, Madison, WI, USA) instead of the SV40 late poly(A) signal, just after the firefly luciferase gene, between the XbaI and BamHI restriction sites. DNA sequences of the 3′-UTR constructs were validated before use (validation primers, 5′-TGTGGACGAAGTACCGAAAGG-3′ and 5′-GACGATAGTCATGCCCCGCG-3′).
Cell culture, transfection, and luciferase assays
All the cell lines were from ATCC (Rockville, MD, USA). HEK293 (human embryonic kidney 293), H1299 (human lung cancer cell), and HeLa (human epithelial cervical cancer) cells were cultured in DMEM (Gibco, Los Angeles, CA, USA) supplemented with 10% FBS (Sijiqing, Hangzhou, China) in a humidified incubator with 5% CO2 at 37°C. The culture medium was renewed every 2–3 days. One day before transfection, the cells were subcultured in a 24-well plate in 600 μL growth medium, and the cells were 90% confluent at the time of transfection. Cells were transfected by using Lipofectamine 2000 reagent according to the manufacturer's protocol (Invitrogen). One microgram of the pGL3 vector containing a CASP3 3′-UTR fragment coupled to the firefly luciferase reporter gene was used for transfection of each well. pGL3-Basic was used as a negative control. In each transfection, 20 ng pRL-TK (Promega), a reference plasmid expressing Renilla reniformis luciferase, was used to normalize for transfection efficiency. Media was changed 6 h post-transfection, and the cultures were continued for an additional 42 h before the luciferase assays. The transfected cells were then lysed in lysis buffer, and 100 μL aliquots of supernatant were assayed for luciferase activity by using the Dual-Luciferase Reporter Assay System in a GloMaxTM 96 Microplate luminometer (Promega). Promoter activities were expressed as the ratio between firefly luciferase and Renilla luciferase activities.
Toxicity outcome in 445 patients from Shanghai Chest Hospital was dichotomized by the presence or absence of grade 3 or 4 toxicity during the first-line treatment. Response outcome was also dichotomized by objective response (CR, complete response; PR, partial response) or poor response (SD, stable disease; PD, progressive disease). The associations between each genetic polymorphism and toxicity or response were estimated by odds ratios (OR) and their 95% confidence intervals (CI), which were calculated by unconditional logistic regression. Tests for trend were carried out by including genotypes as an ordinal variable in regression models. Individual haplotypes were estimated from the genotype data using the PHASE 2.0 program (version 2.0.2). TargetScan software (www.targetscan.org) was used for searching for predicted microRNA targets. All P-values reported were two-sided, and a level of 0.05 was considered statistically significant. A Bonferroni correction was carried out for each P-value of any SNP by multiplying the number of SNPs tested. Statistical differences between test and control values were analyzed by means of a Student's t-test. All statistical analyses used spss version 16.0 (SPSS Inc., Chicago, IL, USA).
The clinical and pathological characteristics of 445 patients from Shanghai Chest Hospital are shown in Table 1. All study patients had inoperable advanced NSCLC diagnosed histologically; adenocarcinoma represented the majority of cases, equaling 269 (60.5%) patients. The median age at diagnosis was 57 years (range, 18–80 years), with 219 subjects (49.2%) older than 57 years (older patient group). Overall, 317 patients (71.2%) were male. Among all patients, 145 (32.6%) subjects had severe hematologic toxicity, 27 (6.1%) had severe gastrointestinal toxicity, and 76 (17.1%) patients had objective response.
Table 1. Clinical characteristics of patients with non-small-cell lung cancer classified to group 1
Stratification of patients
Total n (%)
Grade 0, 1, or 2
Grade 3 or 4
Grade 0, 1, or 2
Grade 3 or 4
CR or PR
SD or PD
Other carcinomas include mixed cell, neuroendocrine carcinoma, or undifferentiated carcinoma. CR, complete response; NSCLC, non-small-cell lung cancer; PR, partial response; PD, progressive disease; PS, performance status; SD, stable disease.
Thirteen polymorphisms from eight genes were selected. They were either reported to be functional or located in an important region of the genes, including the promoter, 5′-UTR, 3′-UTR, and open reading frame. Detailed information of these SNPs is listed in Table 2. Genotyping was carried out on a MALDI-TOF mass spectrometer. The functional SNP from CASP9, rs1052576, failed at the design stage. The remaining 12 SNPs were genotyped successfully with a genotyping rate over 95%. However, rs4647600 of CASP3 and rs1045485 of CASP8 were not polymorphic in our study population. The genotype distributions of the other 10 SNPs (Table 2) were all under the Hardy–Weinberg equilibrium (P > 0.05).
Table 2. Genotype distribution of single nucleotide polymorphisms (SNP)
NCBI SNP ID
del, deletion; ins, insertion; MAF, minor allele frequency; NCBI, National Center for Biotechnology Information; UTR, untranslated region.
Promoter, −652 6 N ins>del
Failed at the design stage
Promoter, −308 A/G
Promoter, −173 G>C
Association between apoptosis gene polymorphisms and grade 3 or 4 toxicity and objective response rate
Logistic regression was carried out to reveal the association between apoptosis gene polymorphisms and patient outcomes. The incidence of grade 3 or 4 hematologic toxicity (27.3%) was significantly lower in C allele carriers of the CASP3 rs6948 polymorphism (P = 0.005; OR = 0.524; 95%CI = 0.333–0.824) compared to wild-type homozygotes AA (40.2%). The significance levels of the increasing trend were apparent, indicating a dose-dependent relationship between the polymorphism and grade 3 or 4 hematologic toxicity risk (P for trend = 0.010). The variant C allele, compared to the A allele, significantly reduced the risk of severe hematologic toxicity (P = 0.002; OR = 0.727; 95%CI = 0.596–0.885). This association was still significant after Bonferroni correction. There was no significant association between the risk of grade 3 or 4 hematologic toxicity and other polymorphisms (Table 3).
Table 3. Association analysis of single nucleotide polymorphisms (SNP) and hematologic toxicity in patients with advanced non-small-cell lung carcinoma treated with platinum-based chemotherapy
Genotypes or alleles
Grade 0, 1, or 2 hematologic toxicity/Grade 3 or 4 hematologic toxicity, n (%)/n (%)
When gastrointestinal toxicity was considered, the TNFα rs1800629 mutant allele significantly elevated grade 3 or 4 gastrointestinal toxicity risk (P = 0.041; OR = 1.555; 95%CI = 1.019–2.373) in a dose-dependent manner. The P-value for the trend was 0.043. The OR of heterozygotes was 3.354 (95%CI = 1.302–8.64; P = 0.012), compared to homozygotes for the wild-type allele. Additionally, the homozygotes for the mutant allele were not found in grade 3 or 4 gastrointestinal toxicity patients. A allele carriers had a 3.02-fold possibility to experience grade 3 or 4 gastrointestinal toxicity (95%CI = 1.188–7.676; P = 0.020). No other significant association between genotype and gastrointestinal toxicity was observed for the polymorphisms (Table 4).
Table 4. Association analysis of single nucleotide polymorphisms (SNP) and gastrointestinal toxicity in patients with advanced non-small-cell lung carcinoma treated with platinum-based chemotherapy
Genotypes or alleles
Grade 0, 1 or 2 gastrointestinal toxicity/Grade 3 or 4 hematologic toxicity, n (%)/n (%)
Data were calculated by unconditional logistic regression, adjusting covariates for age, gender, smoking status, type of treatment regimen, TNM stage, performance status, and histological type.
P for trend by unconditional logistic regression, adjusting covariates for age, gender, smoking status, type of treatment regimen, TNM stage, performance status, and histological type. CI, confidence interval; del, deletion; ins, insertion; NA, not applicable; OR, odds ratio.
The relationship between the polymorphisms and response was also evaluated by logistic regression. However, there was no significant association between the objective response rate and these polymorphisms (Table S1).
CASP3 rs6948 C allele might cause decreased mRNA levels
As rs6948 significantly affected hematologic toxicity, this polymorphism might regulate the response to platinum regimens through influencing the expression of CASP3. Therefore, we examined the relative CASP3 mRNA levels by real-time PCR in peripheral blood leukocytes of 52 platinum-treated lung cancer patients (clinical information in Table S2) whose CASP3 rs6948 SNP genotypes were determined. We found that the CASP3 rs6948 C variant in the 3′-UTR was associated with a relatively lower mRNA level (Fig. 1); platinum-treated lung cancer patients with AC and CC genotypes had a CASP3 mRNA level equal to 72.5% of patients with an AA genotype. Although the difference was not significant, the results still gave us a clue that the major A allele might elevate the transcription of this apoptosis gene.
A>C variation of CASP3 rs6948 decreased reporter gene expression
Whole 3′-UTR sequencing was carried out to determine the polymorphisms in the 3′-UTR of CASP3. Twenty patients from group 2 were selected. The entire 3′-UTR of CASP3 of those patients was amplified and sequenced. After careful analysis, we found that in addition to rs6948, there was another SNP at rs1049216 (3′-UTR, 337C>T). The results of individual genotypes of both SNPs are listed in Table S3. After phase analysis, we found that these two polymorphisms were completely linked, with haplotypes (rs6948/rs1049216) of 28 A/C and 12 C/T. Our result was consistent with that of the report by Hosgood et al. To further investigate the effect of CASP3 rs6948 and rs1049216 polymorphisms on CASP3 gene expression, luciferase assays were carried out. Because rs6948 and rs1049216 were highly linked, two haplotypes were included in this assay. A statistical difference was detected in reporter expression levels between the major A/C (rs6948/rs1049216) and minor C/T (rs6948/rs1049216) haplotypes of the CASP3 3′-UTR in three cell lines, including tumor cells (Fig. 2). The pGL3 vector with the C/T haplotype significantly decreased the luciferase level, compared to the A/C haplotype in all three cell lines examined. The protein level decreased by 23.1%, 43.1%, and 68.3% in HEK293, H1299, and HeLa cells, respectively.
In the present study, we investigated whether 10 putatively functional polymorphisms of apoptosis genes were associated with severe toxicity or objective response rate among platinum-based chemotherapy-treated advanced NSCLC patients. We found some significant associations.
Patients with CASP3 rs6948 mutant allele C have reduced hematologic toxicity response to the platinum treatment. Additionally, this association was dose-dependent. Several studies of this SNP were reported recently. Lan et al. found that the AA genotype significantly reduced the risk of female non-Hodgkins lymphoma compared to the CC genotype, especially in B-cell lymphoma. They presumed that the A allele elevated the expression level of CASP3 and inhibited the overproliferation of B cells, reducing the susceptibility to non-Hodgkins lymphoma. In a research of female patients with multiple myeloma, Hosgood et al. reported that rs6948 was not related to susceptibility. In both of these studies, another SNP located in the 3′-UTR was also reported. rs1049216 (3′-UTR, 337T>C) was found to be associated with both non-Hodgkins lymphoma and multiple myeloma. Additionally, Hosgood et al. reported that rs6948 and rs1049216 were highly linked (D' 0.98).
However, the functions of rs6948 and rs1049216 have not yet been investigated. The 3′-UTR has multiple functional elements: cytoplasmic polyadenylation element; adenylation control element; and microRNA binding site.[33-35] rs6948 in the CASP3 3′-UTR may influence the expression of CASP3, further affecting the clinical outcome. It is also possible that rs6948 was linked to a functional SNP that can influence the function or expression of CASP3. Therefore, a functional study was important to confirm the relationship between rs6948 and hematologic toxicity. TargetScan software was initially used to predict the potential function of this SNP. We found that rs6948 was located in a predicted miR-24 binding site (position 1290–1296 of the 3′-UTR of CASP3). The sequence of mutant allele C has a 7-nt binding site of miR-24, whereas the wild-type allele A only has 6-nt. According to our results from expression assays, consistent with our hypothesis, the C allele might reduce the mRNA level in peripheral blood lymphocytes from platinum-treated patients. However, this decrease of CASP3 mRNA was not significant after statistical testing, which might be an effect of the sample size or the timing of sample collection. CASP3 expression may be decreased immediately in response to chemotherapy then slowly recover to a normal level. Therefore, early and multiple time points of blood collection are required in future validation. Our further results revealed that the C allele also reduced the expression level in a luciferase reporter gene assay. Of course, the decrease of CASP3 would cause the reduction of apoptosis, further reducing the risk of severe toxicity. However, we could not confirm that these influences were from rs6948 because another SNP of the 3′-UTR rs1049216 was included in all of our assays, and it was shown completely linked with rs6948. TargetScan also suggested that a predicted miR-664 binding site (position 335–341 of CASP3 3′-UTR) was around this SNP, rs1049216. Thus, there are three possibilities: the functional SNP may be rs6948; or rs1049216; or both. Further experiments are needed to reveal the detailed molecular mechanisms.
In the analysis of the association with gastrointestinal toxicity, the TNFα rs1800629 mutant allele A was shown to increase the risk of gastrointestinal toxicity. Platinum causes the apoptosis of small intestinal crypt-like cells, ileal mucosal architecture, and villus epithelial cell influx, leading to prolonged nausea, vomiting, and anorexia.
Binding of TNF to TNFR1 induces the recruitment of the signaling proteins, further initiating apoptosis.[6-10]
The TNFα rs1800629 was located 308 nucleotides upstream of the translation initiation site in the TNFα promoter. The G to A transition is considered to be an important enhancer of transcriptional activation associated with elevated levels of TNFα, which have been shown to be involved in increased susceptibility to different diseases, including Alzheimer's disease, Parkinson's disease, non-Hodgkin's lymphoma, breast cancer, and diabetes. In our study, the mutant A allele significantly increased the risk of gastrointestinal toxicity. It was a reasonable result of the following procedure: the A allele elevated the mRNA level, increased the apoptosis of small intestinal crypt-like cells, caused prolonged nausea, vomiting and anorexia, and finally increased the toxicity outcome.
This investigation had some advantages and some disadvantages. Our 445 association-study subjects were all recruited from the same hospital, diagnosed with advanced NSCLC, and consistently treated with platinum anticancer therapies without surgery. The relatively homogeneous therapeutic standard limits the potential confounding effect of differences across various hospitals. The associations between CASP3 rs6948 and hematologic toxicity was still significant after Bonferroni correction. However, gastrointestinal toxicity and TNFα rs1800629 were no longer significantly associated after correction. In addition, platinum-based chemotherapy in our study still had different combination regimens, for which SNPs might play different roles. However, statistical power for stratified analysis requires more samples. Therefore, further studies with larger groups of study subjects, or other independent samples and functional studies, are warranted to address these questions.
In conclusion, CASP3 rs6948 may influence the expression of CASP3 and associate with severe hematologic toxicity risk. The TNFα rs1800629 mutant allele elevated gastrointestinal toxicity risk. Patients with TNFα rs1800629 mutant allele potentially have high gastrointestinal toxicity risk to chemotherapy. These genetic polymorphisms may become useful biomarkers to predict severe toxicity response in the future in NSCLC patients after platinum-based chemotherapy.
This work was supported by the Shanghai Science and Technology Research Program 06DZ19501, Shanghai Key Project 09JC1402200, Shanghai Project of International Cooperation 10410709100, and Shanghai Chenguang Scholar foundation 2007CG32.