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Keywords:

  • estrogen receptor (ER);
  • radioligand;
  • immunohistochemical;
  • estrogen receptor-β;
  • fibromatosis;
  • desmoid

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

BACKGROUND

Early experiments using ligand-binding assays demonstrated the presence of estrogen receptor (ER) in fibromatoses. These findings were not confirmed by later studies using immunohistochemical analysis.

METHODS

To verify the expression of ERs in fibromatosis as well as to clarify the inconsistency between radioligand and early immunohistochemical studies, the authors examined a series of 40 extraabdominal fibromatoses using antibodies raised against ERβ.

RESULTS

All 40 cases of extraabdominal fibromatosis were at least focally positive for ERβ. Thirty-three of 40 (83%) displayed 3+ (>50%) expression, 5 of 40 (12%) were 2+ (11–50%), and 2 of 40 (5%) cases showed 1+ (<10%) expression. All cases were negative for ERα.

CONCLUSIONS

Although extraabdominal fibromatosis does not express ERα, there appears to be nearly uniform expression of ERβ. This finding clarifies discrepancies in the literature regarding estrogen expression in fibromatosis, and provides a biological mechanism for the action of antiestrogenic compounds in the treatment of fibromatosis. Estrogen antagonists may have a role in the treatment of refractory or recurrent extraabdominal fibromatoses. Cancer 2006. © 2005 American Cancer Society.

Extraabdominal fibromatosis (desmoid tumor) is an infiltrative tumor composed of fibroblasts and myofibroblasts that, despite a significant risk for local recurrence, does not metastasize. Clinical observations including a high incidence of these tumors in young women and tumor growth during pregnancy have suggested a role for sex hormones, particularly estrogen, in tumor growth. Early experiments using ligand-binding assays confirmed the presence of estrogen receptors in some tumors1, 2; however, more recent experiments using immunohistochemical assays contradicted these biochemical findings.

A second estrogen receptor gene was identified in 1996 and designated estrogen receptor β (ERβ)3 to distinguish it from the earlier receptor, now designated estrogen receptor α (ERα). The ER receptors show a high degree of homology in the DNA binding region, but much less in the ligand binding domain. Antibodies to ERα have been available for some years, and recently antibodies specific to ERβ have become commercially available. The tissue distribution of ERβ is broader than that of ERα, including prostate, thyroid, and connective tissue.4 Although ERα has been assessed immunohistochemically in extraabdominal fibromatoses and found to be absent in most cases, to our knowledge ERβ has not been previously characterized in these entities. To verify the expression of ER in these tumors as well as to clarify the inconsistency between radioligand and early immunohistochemical studies, we examined a series of 40 cases of extraabdominal fibromatoses for expression of ERα and ERβ.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Forty cases of extraabdominal fibromatosis were retrieved from the paraffin archives of the University of Chicago and Emory University and reviewed to confirm that the diagnosis was consistent with published World Health Organization (WHO) criteria.5 Formalin-fixed paraffin-embedded specimens were cut into 4-μm sections and mounted on positively charged slides. Sections were deparaffinized, rehydrated, then washed in Tris-buffered saline (TBS) and subjected to heat epitope retrieval in a microwave. Slides were then incubated in 1% hydrogen peroxide in methanol for 5 minutes to block endogenous peroxidase activity, followed by incubation for 20 minutes in a protein blocking solution to reduce nonspecific antibody binding. The primary anti-ERβ (Polyclonal Erb88; Biogenex, San Ramon, CA) (dilution of 1:50) and anti-ERα (Mouse monoclonal clone 6F11; Novocastra, Newcastle-upon-Tyne, UK) antibodies were applied for 1 hour at room temperature. Slides were then incubated for 30 minutes at room temperature with the respective antimouse or antirabbit immunoglobulin (Ig) G antisera conjugated to a horseradish peroxidase (HRP)-labeled polymer (Dako Envision System; Dako Corporation, Carpenteria, CA), treated for 5 minutes with 3-3′-diaminobenzidine (DAB) chromogen, counterstained with hematoxylin, and coverslipped. Negative controls received a nonimmune polyclonal rabbit antiserum or monoclonal mouse antibody as appropriate.

Only definite nuclear staining was regarded as positive; cases were scored by the percentage of tumor cells staining as 1+ (<10%), 2+ (11–50%), or 3+ (>50%) by two pathologists (A.T.D. and A.G.M.). Normal breast served as normal control for ERα; ovarian follicles or granulosa cell tumors served as positive controls for ERβ.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Clinical

Extraabdominal fibromatosis affected primarily adults (age range, 5–74 yrs; mean age of 33.4 yrs and median age of 32 yrs) and occurred predominantly in women (29 females, compared with 11 males). Lesions were located in: buttock (seven patients), lower extremity (seven patients), upper extremity (seven patients), flank (three patients), chest wall (three patients), shoulder (seven patients), back (two patients), and face (one patient) and neck (three patients). One case was associated with pregnancy. Nine cases were recurrent.

Immunohistochemistry

All 40 cases displayed expression of ERβ (Table 1) (Fig. 1). Thirty-three of 40 (83%) displayed 3+ expression, 5 of 40 (12%) were 2+, and 2 of 40 cases (5%) showed 1+ expression (i.e., < 10% of nuclei staining). Stains for ERα were uniformly negative. There was no significant correlation noted between degree of ERβ staining and gender, age, location of the tumor, or history of recurrence.

Table 1. Estrogen Receptor-α and ER-β Expression in Extraabdominal Fibromatoses
Case no.Staining for ER-βStaining for ER-αalphaAge in yrs/genderSite
  1. F: female; M: male.

12050 FForearm
23019 MButtock
33029 FArm
43025 FButtock
53058 MButtock
63033 FCalf
73029 MThigh
83029 FThigh
9309 MChest wall
103034 FCalf
111015 MHand
123032 FFlank
131040 FButtock
143019 FFoot
152022 FArm
16305 FFace
173034 FFlank
182015 MThigh
193043 FButtock
203030 FShoulder
213025 FLeg
223048 MShoulder
233055 FButtock
243014 FShoulder
253032 FChest wall
263032 FChest wall
272046 FButtock
283037 FFlank
293040 FArm
303015 FBack
313028 FShoulder
323045 FArm
333033 MNeck
343072 FShoulder
353034 FBack
363037 MNeck
373017 MArm
383074 FNeck
392048 FShoulder
403054 MShoulder
thumbnail image

Figure 1. Microscopic appearance of fibromatosis. (A) Hematoxylin and eosin-stained section displaying long, sweeping fascicles of bland spindled cells. (B) Immunohistochemical stain for estrogen receptor-β showing strong nuclear positivity in the majority of cells.

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DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES

Fibromatoses can be classified as superficial (fascial) or deep (musculoaponeurotic); the latter category includes extraabdominal fibromatosis, abdominal fibromatosis, and intraabdominal fibromatosis. All consist of low cellularity proliferations of fibroblastic or myofibroblastic cells and may be locally aggressive with a tendency to recur. Patients with familial adenomatous polyposis (FAP) syndrome have a 1000-fold increased risk of developing desmoid tumor, and account for approximately 2% of all cases.6

The observation that some fibromatosis cases, particularly abdominal fibromatosis, occur in association with pregnancy has suggested that these tumors might be hormonally responsive. Women have over a threefold greater risk of developing fibromatosis than men6 and tend to have more rapidly growing tumors. Anecdotal cases have involuted with the withdrawal of hormonal replacement therapy, and in familial polyposis coli patients the use of contraceptives increases the risk of developing abdominal fibromatosis.7

In the 1970s, studies using radioligand binding or fluorescent hormone binding supported this hypothesis. Hayry et al.1 identified ERs in 3 of 4 patients, whereas Weiss et al.,8 Lim et al.,9 and Maddalozzo et al.10 found 1 of 3, 5 of 15, and 2 of 4 desmoid tumors with ERs, respectively (Table 2). After the advent of immunohistochemistry in the 1980s, the majority of immunohistochemical analyses using antibodies raised against the ER contradicted these earlier studies11–13 and, despite clinical findings which suggested a role for ER in the pathogenesis of desmoid tumors, it has been accepted that if estrogen had a role in fibromatosis, it was not by signaling through the ER pathway.14, 15

Table 2. Estrogen Receptor Expression in Patients with Aggressive Fibromatosis from Literature Review: Comparison of Ligand Binding and IHC Methods
ReferenceCases positive/total casesMethodology
  1. IHC: immunohistochemical.

Hayry et al., 198213/4Ligand binding
Weiss et al., 198681/3Ligand binding
Lim et al., 198695/15Ligand binding
Maddalozo et al., 1993102/4Ligand binding
Rasbridge et al., 1993110/6IHC
Moffatt et al., 19971715/52IHC
Devouassoux-Shisheboran et al., 2000120/33IHC
Sorensen et al., 2002130/72IHC

Although initial comparisons of immunohistochemical and biochemical assay methods found a good correlation between ligand binding and immunohistochemical techniques in breast carcinoma, no systematic comparison was made in mesenchymal lesions.16 Because ligand binding assays assess binding of a radiolabeled or fluorescein-labeled ligand, this technique measures both ERα and ERβ. Today, virtually all ER determinations are performed with an antibody-based method, typically using a monoclonal antibody against the ERα protein which, due to the specificity of the antibody, does not detect ERβ. Assays of tissues containing only ERβ will result in a false-negative result, accounting for the historical discrepancy in the literature regarding ER in extraabdominal fibromatoses and other tumors.

Of note is the outlier among the immunohistochemical studies: the study by Moffatt et al.17 (Table 2), which used the Ventana automated staining kit for ER, found staining in 15 of 52 cases. The antibody in this kit was provided by Novocastra (Clone CC4-5) and was raised using whole ERα protein as the immunogen. To our knowledge, no studies assessing cross-reactivity of this antibody with ERβ have been performed to date (verbal confirmation received from Novocastra June 20, 2005). In contrast, the study by Rasbridge et al. used the H222 clone marketed by Abbott Laboratories (North Chicago, IL), which demonstrated no cross-reactivity with ERβ,18 whereas the studies by Devouassoux-Shisheboran et al. and Sorensen et al. used the 1D5 clone from Dako Corporation, which also has been shown to have no cross-reactivity with ERα (Dakocytomation web site, available from URL: http://www.dakocytomation.us/prod_downloadpackageinsert.pdf?objectid=104482002 [accessed June 20, 2005]). The ERα antibody used in the current study, ER-6F11, has been shown to react only with the α form of the ER molecule by Western blot analysis (verbal confirmation received from Novacastra). It is possible that the positive staining noted by Moffatt et al.17 can be attributed to partial cross-reactivity of the CC4-5 clone with ERβ.

The use of systemic therapy in deep fibromatoses has evolved somewhat haphazardly; most reports are retrospective or prospective single-arm trials. Brooks et al.19 found 65% of 20 patients treated with tamoxifen or toremifene achieved a response ranging from stable disease to occasional complete disease remission. A metaanalysis by Serpell et al. in 1996 of 55 patients with desmoid tumors who were treated with tamoxifen and toremifene showed a response rate of 51% with no significant difference noted between patients with FAP versus sporadic tumors. Tonelli et al.20 reported on the treatment of desmoid tumors diagnosed in patients with FAP using raloxifene, an estrogen antagonist, or SERM (selective estrogen receptor modulator). Of 13 patients, 8 demonstrated complete disease remission whereas 5 patients achieved a partial response. To our knowledge, all the ER antagonists used to date act on both ERβ and ERα. In 2003, after the observation that a patient's intraabdominal fibromatosis regressed once hormone replacement therapy was withdrawn, Klemi et al.21 reported a partial response achieved with use of an aromatase inhibitor in a patient with abdominal fibromatosis. Other studies have reported responses to goserelin acetate, a luteinizing-hormone releasing hormone (LNFH) analog, or with medroxyprogesterone acetate.22, 23 Lanari24 reported complete disease remission in 6 of 11 patients with retroperitoneal fibromatosis who were treated with progesterone. In general, the literature regarding hormonal treatment of fibromatosis suggests that the tumors respond to manipulation of ER signaling.

Subsequent to a case report of complete regression of a fibromatosis tumor in a patient treated with a nonsteroidal antiinflammatory drug (NSAID) for another condition,25 NSAIDs have been reported in the treatment of both syndromic and sporadic cases of abdominal and extraabdominal fibromatosis. In what to our knowledge was the largest series reported to date,26 14 patients were treated, with 1 complete response and 7 partial responses reported, and 4 cases of stable disease. Waddel and Gerner25 found similar results for eight cases, with three patients achieving a partial disease remission and three patients reported to have stable disease. Hansmann et al. reported using tamoxifen together with sulindac, an NSAID agent, as primary treatment for 16 patients; a partial or complete disease remission was noted in 10 of 13 FAP-associated cases and stable disease was reported in 3 of 3 sporadic cases. Waddell and Kirsch27 reported a response rate of 40% to an aromatase inhibitor, compared with 70% when used in conjunction with an NSAID agent. The addition of estrogen blockade to inhibition of the adenomatous polyposis coli (APC) beta catenin pathway by NSAIDs appears to be additive.

We have shown that fibromatosis does express ER, accounting for the clinical effectiveness of antiestrogen therapy. However, there are additional pathways through which tamoxifen and other ER antagonists may be therapeutic, even in ER-negative disease. Nonsteroidal antiestrogen compounds appear to also be bound by intracellular antiestrogen-binding sites (AEBS) that are estrogen independent.28, 29 In one study of human melanoma cell lines, the synergistic effect of tamoxifen on cisplatin cytotoxic effect was mediated, not through estrogen receptors, but through AEBS.30 Although a similar study using desmoid fibroblast cell lines suggested an ER-independent pathway for the effect of toremifene, the exclusion of ER expression was based on immunohistochemistry with an antibody to ERα.31 It remains possible but unestablished that the effect of ER antagonists on fibromatosis may be mediated through an alternative pathway.

Deep fibromatoses, particularly intraabdominal fibromatosis, are associated with the familial polyposis syndrome and mutation of the APC gene. Decreased APC-mediated degradation of β-catenin leads to accumulation of the latter in the nucleus, which complexes with a transcription factor that up-regulates several cell cycle-related genes. Rather than mutations of the APC gene, most cases of sporadic fibromatosis are associated with mutations of the β-catenin gene that inhibit its degradation.32, 33 Superficial fibromatoses appear to have mutations of neither gene, but have a lesser degree of nuclear β-catenin accumulation, indicating a possible role of abnormal β-catenin regulation in those lesions, and indicating a role for an APC\β-catenin\wnt pathway signaling in most cases of fibromatosis.34

Evidence for interaction of the estrogen receptor pathway with the APC beta catenin pathway is circumstantial. In endometrial carcinoma, nuclear β-catenin expression is associated with endometrioid histology and positive staining for ERs.35 Optically clear nuclei in several tumor types are associated with accumulation of both ERβ and β-catenin.36 Functional interaction of the Wnt/APC/β-catenin and estrogen signaling pathways has recently been reported in human tumor cell lines and in Drosophila, in which estrogen signaling appears to potentiate the effects of nuclear β-catenin.37

Although there has been abundant empirical data suggesting the efficacy of antiestrogens in the treatment of fibromatosis, the use of such drugs is not common in clinical practice, perhaps due to the perceived lack of a biologic basis. Our findings suggest that ERβ provides a physiologic mechanism for the pharmacologic response of fibromatosis to antiestrogen therapy. Although surgery remains the treatment of choice when possible, antiestrogenic compounds are a logical avenue for further research in the therapy of fibromatosis.

REFERENCES

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. REFERENCES