WT1 Staining Research Articles

Prognostic significance of specific anti‐WT1 IgG antibody level in plasma in patients with ovarian carcinoma

Ovarian carcinoma (OC) has a poor prognosis and lack early effective screening markers. Wilm's tumor gene 1 (WT1) is overexpressed in OCs. Therefore, it is of great interest to investigate whether WT1-specific antibody (Ab) measurements in plasma can serve as a biomarker of anti-OC response, and is of importance in relation to patient prognosis. Peripheral blood samples were obtained from a total of 103 women with ovarian tumors with median being 1 day (range 0–48 days) before operation. WT1 IgG Ab levels were evaluated using enzyme-linked immunosorbent assay (ELISA). Immunohistochemical analysis of WT1 protein expression was performed on OC tissue samples. We found that low-WT1 Ab level in plasma was related to improved survival in patients diagnosed at stages III–IV and grade 3 carcinomas. Positive WT1 protein staining on OC tissue samples had a negative impact on survival in the entire cohort, both overall survival (OS) (P = 0.046) and progression-free survival (PFS) (P = 0.006), but not in the serous OC subtype. Combining WT1 IgG Ab levels and WT1 staining, patients with high-WT1 IgG Ab levels in plasma and positive WT1 protein staining in cancer tissues had shorter survival, with a significant association in PFS (P = 0.016). These results indicated that WT1 Ab measurements in plasma and WT1 staining in tissue specimens could be useful as biomarkers for patient outcome in the high-risk subtypes of OCs for postoperative individualized therapy.

Ovarian low grade serous carcinoma: A case report

<h3>Case report</h3> We present a case of a 76-year-old woman with bilateral ovarian masses and a right upper quadrant cyst detected on imaging. Histology of the solid tumour component in both ovaries showed a low grade serous carcinoma with sheets and irregular nests of cells with uniform round to oval nuclei and evenly distributed chromatin. The solid component merged with a cystic component, showing variable features of serous cystadenoma and borderline serous change. The cells showed positive staining for WT-1, and were negative for p53. The right upper quadrant cyst showed similar features. <h3>Discussion</h3> Low grade and high grade ovarian serous carcinomas are two distinct tumour types with different underlying pathogenesis, molecular events, and prognosis. Low grade serous carcinomas are hypothesised to evolve from adenofibromas or borderline tumours, and have frequent mutations of the KRAS, BRAF, or ERBB2 genes, and lack TP53 mutations. This is termed the Type I pathway. The progression to invasive carcinoma is a slow step-wise process. Low-grade tumours are indolent and have better outcome than high-grade tumours. In contrast, high grade serous carcinomas arise via the Type II pathway and the vast majority are characterised by TP53 mutations and lack mutations in KRAS, BRAF, or ERBB2. Immunohistochemical stains for p53, pl6, p53 and Ki-67 for distinction of low- from high-grade tumours can be helpful in selected instances. This case is presented to show the spectrum of histological appearances in a low grade ovarian serous carcinoma, for instance areas resembling serous cystadenoma through to borderline serous change.

Mice are unable to endogenously regenerate podocytes during the repair of immunotoxin-induced glomerular injury

Recent studies have reported that podocytes are postnatally generated from progenitor cells localized in Bowman's capsule or in the bone marrow. In the present study, we investigated whether or not podocyte regeneration is important in the repair of injured glomeruli after mild podocyte injury in mice. Mild podocyte injury was induced in NEP25 mice (n = 8) by injecting an immunotoxin, LMB2 (0.625 ng/g body weight). Control mice, not injured by LMB2 injection (n = 7) was used as a comparison. Proliferating cells were labeled by continuous infusion of bromodeoxyuridine (BrdU). Podocytes, identified by nephrin, WT1 or podocin staining, that had incorporated BrdU were enumerated 4 weeks later. A total of 742 corpuscles were inspected in serial sections stained for BrdU and nephrin; 19% showed sclerosis. BrdU(+) cells were observed in both the glomeruli and Bowman's capsules, averaging 2.5 ± 3.1 in non-sclerotic corpuscles and 7.0 ± 5.8 in sclerotic corpuscles. Only one BrdU(+) cell was also positive for nephrin. Another cell, localized at a position consistent with its potential identification as a podocyte, was nephrin negative but had incorporated BrdU. WT1 staining similarly revealed that only two nuclei were doubly positive for BrdU and WT1. Additional 1676 corpuscles were inspected by double staining for BrdU and podocin; none were doubly positive. Podocytes are not replenished by proliferation of endogenous progenitor cells in mice with glomerular injury.

Case report: Papillary mesothelioma of the peritoneum with foamy cell lining

A 34-year-old female, with a history of continued asbestos exposure, presented with a papillary peritoneal mesothelioma with a diffuse, prominent clear foamy cell change, with microvacuolation in its papillary lining, that expressed cytokeratins 7, 5/6 and calretinin as well as nuclear WT-1 and apical membrane staining for thrombomodulin, podoplanin D2-40 and HBME-1. In contrast, lining cells were CD68 negative. Foamy cell change has been reported in isolated cases as solid cords but not as a diffuse change in the mesothelial papillary lining. This phenomenon prompts differential diagnoses with abdominal and renal papillary clear cell tumours, which were discarded after a characteristic mesothelial immunophenotype was demonstrated.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4679576081031834.

Clinically Occult Tubal and Ovarian High-grade Serous Carcinomas Presenting in Uterine Samples

We report the clinicopathologic and immunohistochemical features in 8 patients with tubal or ovarian high-grade serous carcinoma that was present in uterine samples, in which there was the potential for clinical and morphologic misinterpretation as a primary uterine lesion before hysterectomy/bilateral salpingo-oophorectomy. Patients ranged in age from 45 to 70 yr (mean, 57 yr). The initial presentation was variable, ranging from incidental findings on routine Pap smears to pleural effusion. During the preoperative clinical investigation, 7 of 8 patients did not have evidence of an adnexal tumor based on physical examination and radiologic imaging, and serum CA-125 levels were normal to low in 4 of 5 patients. Six patients required multiple rounds of uterine samples, and the preoperative uterine specimens that contained lesional tissue and were available for rereview in all 8 patients included endometrial biopsies/curettages (n=6), endocervical curettages (n=3), Pap smears (n=2), and a hysteroscopic myomectomy specimen (n=1). The amount of carcinoma in these specimens was typically scanty. The lesions in most cases were characterized by detached and minute epithelial clusters, small papillae, and/or individual cells. The constituent glandular cells exhibited notable atypia. Psammoma bodies were identified in only 2 cases. Immunostains for WT-1 were positive in 3 of 4 preoperative specimens. All patients ultimately underwent a hysterectomy/bilateral salpingo-oophorectomy, which revealed an invasive high-grade serous carcinoma of tubal (n=6) or ovarian (n=2) origin. The mean/median tumor size was 3.2/1.7 cm. Transtubal spread was considered the most likely mechanism resulting in tubal/ovarian carcinoma being found in the preoperative uterine samples. These findings highlight the deceptive clinical features of some tubal/ovarian high-grade serous carcinomas, and demonstrate that small and clinically undetectable adnexal high-grade serous carcinomas can initially present in uterine biopsies/curettages. To guide clinical evaluation more accurately and prevent histologic misdiagnosis/misclassification, a possible adnexal origin should be considered in the differential diagnosis of small, detached, and markedly atypical glandular fragments in endometrial or cervical specimens, and immunohistochemical staining for WT-1 is recommended in this setting.

PP034. Renal histology in preeclampsia: A special role for the podocyte

In preeclampsia (PE), the kidney is one of the major target organs. Growing evidence suggests PE increases the risk of subsequent microalbuminuria and end-stage renal disease (ESRD). Endotheliosis and podocyte changes due to anti-angiogenic factors seem to be salient features of PE. However, it is unknown whether chronic lesions are present in PE patients that could contribute to this increased risk. We hypothesized that women with PE and young women with chronic hypertension might show similarity in renal lesions. Furthermore, we investigated if the number of podocytes within the kidney is decreased under these different circumstances. Methods We performed a search for renal autopsy-tissues using a nationwide computerized database (PALGA) to collect a unique large cohort of preeclamptic patients (n=11). Three control groups were included consisting of young women who died during pregnancy without hypertension (n=25) and non-pregnant controls with (n=14) and without (n=13) chronic hypertension. WT-1 staining was used to quantify the number of podocytes. Results Women with PE had MPGN-like lesions without immune-deposits. Tram tracking and podocyte changes were exclusively observed in these patients. Endotheliosis was significantly more present in PE, but sporadically seen in pregnant- and hypertensive controls. Chronic ischaemic lesions were predominantly found in young women with chronic hypertension, and not in PE and other controls. No differences were found in glomerular podocyte number between the study groups. All women with PE had MPGN-like lesions in their kidneys which was therefore regarded characteristic for PE. In contrast, no chronic lesions were observed in PE which could explain the increased risk of impaired renal function later in life. Interestingly, we demonstrated no difference in podocyte number between study groups. These results might suggest that neither persistent hypertension or dysbalance in angiogenic factors (i.e. preeclampsia) cause an observable change in podocyte number within the kidney.

Low-grade Smooth Muscle Tumors of the Primary and the Secondary Mullerian System

Some patients with bland smooth muscle tumors in the uterus have synchronous or asynchronous smooth muscle tumors in the peritoneum and/or the retroperitoneum. It is usually assumed that the uterine tumor is the primary lesion, and the extrauterine neoplasm represents its metastasis. Thus, they are designated as low-grade leiomyosarcomas because they lack the diagnostic features of a conventional spindle cell leiomyosarcoma. Nineteen such cases were retrieved from the files of the Department of Pathology at The University of Texas M.D. Anderson Cancer Center, covering a period of 18 yr. Institutional Review Board approval was obtained before the initiation of this study. In addition, 31 cases of conventional uterine leiomyosarcomas of a high grade were reviewed for comparison. Clinicopathologic features such as patients' age, tumor location, histologic features, stage, treatment, and follow-up were recorded. Immunohistochemical stains for estrogen receptor (ER), progesterone receptor (PR), p53, Ki-67, and WT-1 were performed in the initially detected tumor and the subsequent neoplasm of all cases with available material in the low-grade group and selected cases in the high-grade group. Compared with high-grade leiomyosarcomas, the low-grade group cases were found at an early age (45 vs. 52.8 yr), had a longer median time of "recurrence" (42 mo for the low-grade group vs. 12 mo for high-grade leiomyosarcomas), longer median survival (165 mo for the low-grade group vs. 41 mo for the high-grade group), and a much better overall survival (84% vs. 13%). Three (16%) patients died of disease in the low-grade group versus 27 (87%) patients in the high-grade leiomyosarcoma group. We also found a difference in the location of the extrauterine tumors. Most cases of low-grade tumors were found in the pelvis, abdomen, or retroperitoneum, whereas most high-grade leiomyosarcomas involved the lung. In the low-grade tumors, there were some differences in the immunophenotype between the uterine and the extrauterine neoplasms, but in the high-grade tumors, there were no differences in the immunohistochemistry between the primary tumor and the metastasis. In addition to these differences between the 2 groups in the age of the patients, sites of recurrences, and the immunophenotype of the uterine and extrauterine tumor, neither the uterine nor the extrauterine low-grade lesions had histologic features of malignancy. On the basis of these differences, the possibility that the extrauterine lesions in the low-grade group represent independent primaries involving the secondary mullerian system is proposed.

Abstract 1303: The Wilms’ tumor gene, WT1, regulates E-cadherin expression and migration of prostate cancer cells.

Abstract Carcinoma of the prostate is one of the most common malignancies and second leading cause of death among American men. Even though patients with localized disease have high survival rates, patients with detectable metastasis have a median survival of only 12-15 months. One key step in the metastatic process is the loss of E-cadherin expression associated with tumor invasion. However the regulation of E-cadherin gene expression in prostate cancer (PrCa) cells is not well understood. Recently, the zinc finger transcription factor, WT1 was shown to regulate E-cadherin in NIH 3T3 cells and epicardial cells. We have previously reported the presence of WT1 protein in high grade prostate tumor sections, with little or no WT1 staining in non-neoplastic or benign prostatic hyperplasia (BPH) tissues. However, the significance of WT1 expression in prostate cancer has not been established. The objective of this study was to determine whether WT1 might contribute to increase migration of PrCa cells by repressing E-cadherin expression. Using quantitative real-time PCR (QRTPCR), WT1 and E-cadherin mRNA levels were measured and found to be inversely related in PrCa cells. Similarly, QRTPCR results showed a decrease in E-cadherin mRNA in GFP/WT1 transfected PrCa cells, while E-cadherin levels were increased in PrCa cells with suppressed WT1 expression. Titration of WT1 levels also affected the migration of PrCa cells in wound healing and transwell migration assays. Silencing of WT1 by siWT1 RNA decreased the migratory potential of PC3 cells and the overexpression of GFP/WT1 increased the migration of LNCaP cells. A bioinformatics approach was used to identify potential WT1 binding sites in E-cadherin promoter, then direct in vivo binding of WT1 to the E-cadherin promoter in the chromatin of PrCa cells was confirmed by Chromatin Immunoprecipitation. Transcriptional control was quantified by co-transfection of a GFP/WT1 expression construct with E-cadherin promoter constructs. Results showed that WT1 decreased the activity of the proximal E-cadherin promoter in PC3 cells and DU145 cells. Using site directed mutagenesis, a newly identified WT1 binding site located 146 bp from the transcription start site was shown to be required for the repression of the E-cadherin proximal promoter by WT1. Overall these results demonstrate that WT1 transcriptionally down-regulates E-cadherin expression and thereby increases migration of PrCa cells. This finding suggests that the biological significance of WT1 expression in high grade prostate cancer lies in its contribution to cell migration and potentially to the promotion of metastasis. Supported by NIHR15CA11360 and the Ohio Board of Regents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1303. doi:1538-7445.AM2012-1303

Advanced Papillary Serous Carcinoma of the Uterine Cervix: A Case with a Remarkable Response to Paclitaxel and Carboplatin Combination Chemotherapy

Papillary serous carcinoma of the uterine cervix (PSCC) is a very rare, recently described variant of cervical adenocarcinoma. This review, describes a case of stage IV PSCC whose main tumor existed in the uterine cervix and invaded one third of the inferior part of the anterior and posterior vaginal walls. Furthermore, it had metastasized from the para-aortic lymph nodes to bilateral neck lymph nodes. Immnoreactivity for CA125 was positive, whereas the staining for p53 and WT-1 were negative in both the original tumor and the metastatic lymph nodes. Six cycles of paclitaxel and carboplatin combination chemotherapy were administered and the PSCC dramatically decreased in size. The main tumor of the uterine cervix showed a complete response by magnetic resonance imaging (MRI), and on rebiopsy, more than 95% of the tumor cells in the cervix had microscopically disapperared. This is the first report of PSCC in which combination chemotherapy was used and showed a remarkable response.

WT1-Specific Immune Responses in Patients with High-Risk Multiple Myeloma Undergoing Allogeneic T Cell-Depleted Hematopoietic Stem Cell Transplantation Followed by Donor Lymphocyte Infusions

Abstract 1993Wilm's tumor protein-1 (WT1) is over-expressed in a number of solid and hematologic malignancies including multiple myeloma (MM). The emergence of WT1-specific T cells has been shown to correlate with better relapse-free survival after allogeneic stem cell transplantation in patients (pts) with hematologic malignancies, such as leukemia. In MM, the expression of WT1 in the bone marrow has been shown to correlate with numerous negative prognostic factors, including disease stage and M protein ratio. Taken together, these findings suggest that immunotherapeutic augmentation of WT1-specific immune responses, such as adoptive transfer of WT1-specific T cells, may be capable of eradicating minimal residual disease and preventing relapse in MM.Thus, we examined the significance of WT1-specific cellular immune responses in pts with relapsed MM and high-risk cytogenetics who are undergoing allogeneic T cell-depleted hematopoietic stem cell transplantation (TCD HSCT). In this study, pts were eligible to receive low doses of donor lymphocyte infusions (DLI, 5×105-1×106 CD3+/kg) no earlier than 5 months post TCD HSCT. WT1-specific T-cell frequencies were measured in freshly isolated peripheral blood and bone marrow specimens. Frequencies were detected by staining for intracellular IFN-γ production in response to WT1 peptides, and/or by tetramer analysis, where available.Of 17 pts evaluated, all pts exhibited low frequencies of WT1-specific T-cell responses pre TCD HSCT. Ten of these pts received DLI post TCD HSCT. All 10 pts developed WT1-specific T cell responses post DLI. These increments in WT1-specific T-cell frequencies were associated with reduction in circulating myeloma proteins in all pts. Long-term evaluation demonstrated fluctuations in persisting WT1-specific T-cell frequencies following DLI.In one representative patient, a peak of 3.5% (72/ml) WT1-specific CD8+ T cells were detected in the peripheral blood by staining with the tetramer HLA-A*0201 RMF. This peak T-cell response occurred post TCD HSCT and DLI, and coincided with disease regression. This patient has remained in complete remission for more than 3 years post transplant, with fluctuating levels of WT1-specific CD8+ T cells ranging from 0.3–1.5% still persisting. Findings from concurrent molecular chimerism studies conducted on isolated T cells post TCD HSCT suggest that the WT1-specific T cells are of donor origin.Immunohistochemical analyses of WT1 and CD138 staining in MM bone marrow specimens demonstrated consistent co-expression within malignant plasma cells. WT1 expression in the bone marrow of all 6 pts tested correlated with the extent of malignant plasma cell infiltration. In contrast, no WT1 expression was observed when disease was low or absent.Taken together, our findings suggest a correlation between the emergence of WT1-specific T cells post DLI, and disease regression in pts being treated for relapsed MM. The present data support the development of adoptive immunotherapeutic approaches utilizing WT1-specific T cells for pts with MM. Disclosures:No relevant conflicts of interest to declare.

Ovarian Low-grade Serous Carcinoma Involving the Cervix Mimicking a Cervical Primary

We describe the clinicopathologic and immunohistochemical features of the first reported case of an ovarian low-grade serous carcinoma metastatic to the cervix mimicking a cervical primary. The patient, a 55-year-old woman, was found to have an abnormal cervix and an abnormal Pap smear during a preoperative workup for a rectocele repair. A subsequent cervical biopsy contained moderately differentiated adenocarcinoma and the patient underwent a cold knife conization. An infiltrating adenocarcinoma was found in the anterior cervical lip, the neoplasm reached the surface of the endocervical canal and was composed of mildly to moderately atypical, eosinophilic or amphophilic columnar cells arranged in glands and papillae. Mitotic figures were rare and no apoptotic bodies were seen. Psammoma bodies and intraglandular mucinous material were also noted. There was extensive vascular/lymphatic invasion. The tumor extended to all margins and was interpreted as a moderately differentiated (grade 2) adenocarcinoma of the uterine cervix with a linear spread of at least 1.4 cm and a depth of at least 0.6 cm (FIGO stage 1B1). The patient was treated with radiotherapy and cisplatin. Six months later, surveillance imaging studies showed that the patient's ovaries seemed to be enlarging. The patient underwent exploratory laparotomy, bilateral salpingo-oophorectomy, right pelvic lymph node sampling, omentectomy, peritoneal biopsies, and pelvic washings. The ovaries contained bilateral cystic tumors. There was gross tumor involving multiple peritoneal sites. Microscopic examination of the ovaries showed the typical features of low-grade serous carcinoma associated with a serous neoplasm of low malignant potential with a cribriform pattern. Metastatic low-grade serous carcinoma was detected in multiple peritoneal sites and in the pelvic washings. A consultation was obtained, with the consultant concurring that the tumors represented independent primaries. The patient received carboplatin and taxol. Two and 4 years after the initial diagnosis, she experienced recurrences and was treated with carboplatin and taxol each time. After the second recurrence, the patient decided to seek additional advice about treatment options. The latter prompted a re-review of her histologic material. Upon this re-review, it was noted that the tumor in the cervix had some rather unusual features for a primary cervical adenocarcinoma, such as the lack of conspicuous mitotic activity, extensive vascular/lymphatic invasion in the context of a tumor with no solid areas, and only mild-to-moderate cytologic atypia. In addition, the tumor in the cervix had areas that were similar to the metastatic tumor present in the omentum. Immunoperoxidase staining for WT-1, estrogen receptor, and p16 was performed on the tumor in the cervix and on the ovarian tumor. The neoplastic cells in both tumors stained in a similar manner; the tumor cells were diffusely positive for WT-1 and estrogen receptor (90%) and focally positive for p16. No detectable signal for high-risk human papillomavirus was seen in the in-situ hybridization performed on the section of the tumor in the cervix. In summary, the histologic and immunohistochemical features and the in-situ hybridization results were in keeping with a diagnosis of metastatic ovarian low-grade serous carcinoma involving the cervix. This case underscores the importance of attentive histopathologic examination and the use of ancillary tests to ensure the recognition of the site of origin of a neoplasm involving the cervix.

Impact of proliferative indices and tumor suppressor genes on treatment response in marginal zone lymphomas

Firstly, increased Ki67 and MUM-1 staining has been associated with worse prognosis in marginal zone B cell lymphomas (MZL). However, ours is the first study to assess the impact of proliferative indices on chemotherapy response. Secondly, loss of p53 and p16 tumor suppressor genes (TSG) has traditionally been associated with cancer progression. The significance of these markers in MZL was investigated. Thirdly, we explored the role of proliferative indices and tumor suppressor genes in identifying MZLs with significant plasmacytic differentiation (PD). Consecutive MZL cases (2006–2008) were identified. Slides were reviewed to confirm the diagnosis; immunohistochemical stains for Ki67, MUM-1, WT-1, p53, and p16 were subsequently performed and graded for percentage staining. Wilcoxon two-sample test and Pearson correlation coefficient were performed. Twenty-nine cases were analyzed. None of the assayed markers were correlated with treatment response. Ki67 and MUM1 expression, however, were correlated with PD (p = 0.0136 and p = 0.0042). A correlation between MUM1 and p16 staining was also seen (p = 0.0006). IHC assay for TSGs, p53 and p16, and proliferative indices (Ki67, MUM1, WT1) is unlikely to predict treatment response in low-grade MZL. Ki67 and MUM1 staining, however, may serve as a useful adjunct in ascribing PD.

Chronic sphingosine 1-phosphate 1 receptor activation attenuates early-stage diabetic nephropathy independent of lymphocytes

Sphingosine 1-phosphate (S1P), a pleiotropic lipid mediator, binds to five related G-protein-coupled receptors to exert its effects. As S1P1 receptor (S1P1R) activation blocks kidney inflammation in acute renal injury, we tested whether activation of S1P1Rs ameliorates renal injury in early-stage diabetic nephropathy (DN) in rats. Urinary albumin excretion increased in vehicle-treated diabetic rats (single injection of streptozotocin), compared with controls, and was associated with tubule injury and increased urinary tumor necrosis factor-α (TNF-α) at 9 weeks. These effects were significantly reduced by FTY720, a non-selective, or SEW2871, a selective S1P1R agonist. Interestingly, only FTY720 was associated with reduced total lymphocyte levels. Albuminuria was reduced by SEW2871 in both Rag-1 (T- and B-cell deficient) and wild-type diabetic mice after 6 weeks, suggesting that the effect was independent of lymphocytes. Another receptor, S1P3R, did not contribute to the FTY720-mediated protection, as albuminuria was also reduced in diabetic S1P3R knockout mice. Further, both agonists restored WT-1 staining along with podocin and nephrin mRNA expression, suggesting podocyte protection. This was corroborated in vitro, as SEW2871 reduced TNF-α and vascular endothelial growth factor mRNA expression in immortalized podocytes grown in media containing high glucose. Whether targeting kidney S1P1Rs will be a useful therapeutic measure in DN will need direct testing.

Abstract 2169: The effect of WT1 on E-cadherin expression in prostate cancer cells

Abstract Prostate carcinoma is the most common malignancy and second leading cause of death among American men. The molecular mechanisms that control the progression of this type of cancer are still poorly understood. One of the genes expressed in prostate cancer epithelium is the zinc finger transcription factor Wilms’ Tumor 1, WT1. Previous studies in our lab have shown WT1 protein in a majority of high grade prostate tumor sections with little or no WT1 staining in non-neoplastic or benign prostatic hyperplasia (BPH) tissues. However, a mechanistic role for WT1 in prostate cancer has not been established. Recently, WT1 has been associated with the regulation of cell adhesion molecules such as E-cadherin in NIH 3T3 cells and epicardial cells. Loss of E-cadherin expression is frequently associated with increased cellular motility and tumor invasion. Several regulatory mechanisms controlling E-cadherin gene expression have been proposed in breast cancer cells, however the mechanisms of regulation of E-cadherin gene expression in prostate cancer cells are not yet understood. The objective of this study was to determine whether WT1 might regulate E-cadherin expression and contribute to cancer progression in prostate cancer cells. First, potential WT1 binding sites were identified in the promoter of the E-cadherin gene using a bioinformatics approach. Chromatin Immunoprecipitation (ChIP) showed direct in vivo binding of WT1 to the E-cadherin promoter in the chromatin of LNCaP and PC3 cells. The effect of transfection of prostate cancer cells with a GFP/WT1 expression construct was then tested by quantitative real-time PCR (QRT-PCR). QRT-PCR results showed a decrease in E-cadherin transcripts in GFP/WT1 transfected prostate cancer cells. Conversely, knockdown of WT1 mRNA in siWT1 transfected LNCaP cells, showed increased levels of E-cadherin mRNA. Moreover, co-transfection of WT1 expression construct with an E-cadherin promoter reporter construct showed that WT1 decreased the activity of the proximal E-cadherin promoter in PC3 cells. Overall these results demonstrated that WT1 modulated E-cadherin expression in prostate cancer cells and suggests a novel mechanism whereby WT1 may increase migration by decreasing E-cadherin levels, a novel role for WT1 mediated prostate cancer progression. This work was supported by NIHR15CA11360 and Ohio Board of Regents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2169. doi:10.1158/1538-7445.AM2011-2169

Tumor Suppressor Menin Represses Paired Box Gene 2 Expression via Wilms Tumor Suppressor Protein-Polycomb Group Complex

Tumor suppressor menin, the product of the MEN1 gene, plays a key role in controlling histone 3 lysine 4 trimethylation (H3K4me3) and gene transcription, which can regulate proliferation, apoptosis, and differentiation. However, little is known as to whether menin controls gene expression and cell proliferation and survival via regulating Polycomb group (PcG) protein complex/H3K27me3. Here we show that menin specifically represses transcription factor Paired box gene 2 (Pax2) through PcG-mediated H3K27me3 and Wilms tumor suppressor protein (WT1), a zinc finger domain-containing DNA-binding protein. Menin does not directly bind to the Pax2 locus, instead, it up-regulates WT1 expression. WT1 recruits PcG complex to the Pax2 promoter and represses expression of Pax2 through PcG-dependent H3K27me3. Moreover, WT1 also interacts with DNA methyltransferase 1 (DNMT1), and recruits DNMT1 to the Pax2 promoter, resulting in hypermethylation of CpG in the Pax2 promoter. Together, these studies have uncovered a novel epigenetic mechanism whereby menin regulates H3K27me3 and promoter DNA methylation via WT1 and suggest that WT1 protein plays an important, yet previously unappreciated role in regulating the function of the menin/PcG axis, H3K27 methylation, and DNA methylation, resulting in repression of gene transcription.

WT1 expression in salivary gland pleomorphic adenomas: a reliable marker of the neoplastic myoepithelium

Pleomorphic adenoma is a benign salivary gland neoplasm with a diverse morphology. This is considered to be a function of the neoplastic myoepithelium, which shows histological and immunophenotypical variability. Wilms' tumor 1 gene (WT1) protein, involved in bidirectional mesenchymal–epithelial transition, has been detected by reverse transcription PCR in salivary gland tumors showing myoepithelial–epithelial differentiation. The aim of this study was to investigate the immunoreactivity of WT1 in pleomorphic adenomas and to compare the pattern of staining with p63 and calponin, two reliable markers of myoepithelial cells. A total of 31 cases of pleomorphic adenoma were selected. The myoepithelium was classified as myoepithelial-like (juxtatubular and spindled), modified myoepithelium (myxoid, chondroid and plasmacytoid) and transformed myoepithelium (solid epithelioid, squamous and basaloid cribriform). Immunohistochemistry for WT1, p63 and calponin was assessed in each myoepithelial component, as well as in nonneoplastic myoepithelial cells and inner tubular epithelial cells. There was no immunostaining of tubular epithelial cells by any of the markers. In contrast to p63 and calponin, WT1 did not react with normal myoepithelial cells. Cytoplasmic WT1 staining was present in all pleomorphic adenomas, and in 29 cases (94%), >50% of neoplastic myoepithelial cells were highlighted. p63 and calponin stained the myoepithelium in 30 tumors. In comparison, 50% of cells were positive in 21 (68%) and 9 (29%) cases of p63 and calponin, respectively. Staining with WT1 showed less variability across the spectrum of myoepithelial differentiation with the difference most marked in the transformed myoepithelium. WT1 is a sensitive marker of the neoplastic myoepithelial cell in pleomorphic adenomas. The role of this protein in influencing the mesenchymal–epithelial state of cells suggests that WT1 and the myoepithelial cell have an important role in the histogenesis of pleomorphic adenomas.

WT1 Is Not a Reliable Marker to Distinguish Reactive from Neoplastic Astrocyte Populations in the Central Nervous System

A diagnostic difficulty in neuropathology practice is distinguishing reactive from neoplastic astrocyte populations. This is particularly true in small biopsy samples that lack evidence of increased cellularity or mitotic activity, microvascular proliferation, or necrosis. We performed the current study to validate the previously reported finding that in the central nervous system, the expression of WT1 is limited to neoplastic astrocytes. We retrospectively studied WT1 protein expression by immunohistochemistry (IHC) in 100 formalin-fixed, paraffin-embedded brain tissue samples consisting of 3 normal control tissues, 44 cases of reactive gliosis, 49 gliomas and 4 lesions suspicious for glioma. In normal human cortex, WT1 staining was restricted to vascular endothelium. Most cases of reactive gliosis (82%) showed at least focal WT1 positivity, and analysis of specimens with electrode monitoring lesions showed an inverse relationship between WT1 expression intensity and the number of days from electrode placement to tissue resection. All glioma samples (100%) and all cases suspicious for glioma (100%) showed at least focal WT1 positivity. Our results likely differ from those in the prior report because of differences in tissue fixation and IHC methodology. Thus, our findings indicate that WT1 expression alone is not a reliable feature to distinguish reactive from neoplastic astrocytes.

Metastatic Carcinomas in the Cervix Mimicking Primary Cervical Adenocarcinoma and Adenocarcinoma In Situ

Metastatic tumors within the cervix are uncommon if one excludes endometrial carcinoma, which involves the cervix by direct spread. A variety of other neoplasms rarely metastasize to the cervix and, in most cases, the diagnosis is straightforward because of a combination of clinical and pathologic parameters, common features of metastatic carcinoma within the cervix including predominant involvement of the deep stroma, absence of surface involvement and of an in situ component, and prominent lymphovascular permeation. We describe 6 cases of metastatic adenocarcinoma involving the cervix with superficial "mucosal" involvement mimicking primary cervical adenocarcinoma or adenocarcinoma in situ. In 5 cases, the primary adenocarcinoma was in the ovary or peritoneum and was of serous (4 cases) or clear-cell (1 case) type. In the other case, the primary neoplasm was in the pancreas and this was initially interpreted as a primary cervical adenocarcinoma. In the cases of primary ovarian or peritoneal carcinoma, the mucosal tumor within the cervix, which was discovered at the same time as the ovarian or peritoneal neoplasm, raised the possibility of synchronous independent lesions or metastasis from the cervix to the ovary or peritoneum. Positive staining for WT1, p53, and estrogen receptor in the cases of serous carcinoma and an absence of human papillomavirus by linear array genotyping in all cases was of value in excluding a primary cervical neoplasm, although these ancillary studies are supplementary to microscopic examination. In those cases with an ovarian or peritoneal primary, the likely pathogenesis of the cervical involvement is transtubal and intrauterine spread. It is important for the pathologist to be aware of the possibility of cervical mucosal metastasis to avoid an erroneous diagnosis of a primary cervical adenocarcinoma or adenocarcinoma in situ.

Abstract 1237: WT1, Wnt signaling and E-cadherin in prostate cancer

Abstract Prostate carcinoma is the most common malignancy and second leading cause of death among American men. The molecular mechanisms that control the progression of this type of cancer are still poorly understood. Among the genes proposed to play a role in prostate cancer is the zinc finger transcription factor, WT1. Previous studies in our lab have shown WT1 protein in a majority of high grade prostate tumor sections with little or no WT1 staining in non-neoplastic or benign prostatic hyperplasia (BPH) tissues. However, a mechanistic role for WT1 in prostate cancer has not been established. Recently, WT1 has been associated with the Wnt signaling pathway and Beta catenin, the central molecule in the pathway. The cytoplasmic levels of Beta catenin can be regulated through the canonical Wnt signaling or through the intracellular adhesion complex where it binds to E-cadherin. Importantly, E-cadherin has previously been identified as a WT1 target gene in NIH 3T3 cells. The objective of this study was to determine whether WT1 might regulate genes that, in turn, regulate the levels of Beta catenin in prostate cancer cells. First potential WT1 binding sites were identified in the promoters of two candidate genes, GSK3 Beta and E-cadherin, using a bioinformatics approach. Then the effect of transfection of LNCaP prostate cancer cells with GFP-tagged WT1 expression constructs was tested by quantitative real time PCR (QRT-PCR). In vivo evidence of direct binding of these gene promoters by WT1 protein was obtained by Chromatin immunoprecipitation (ChIP) of GFP/WT1 transfected LNCaP cells. Using evolutionary conservation analysis we identified two WT1 binding sites in the E-cadherin promoter conserved among primate species and one that was conserved among primates, rodents and dog. QRT- PCR results showed a decrease in E-cadherin transcripts in GFP/WT1 transfected LNCaP cells, compared with untransfected cells. ChIP was used to demonstrate that this effect on E-cadherin expression was direct and mediated by DNA binding to the E-cadherin promoter in vivo. Overall these results suggest that WT1 modulates E-cadherin and the Wnt signaling pathway in LNCaP cells. These findings suggest a novel mechanism for proliferation and migration of prostate cancer cells and ultimately may contribute towards an improved cancer therapy. This work was supported by NIHR15CA11360 (GF) and GSS KSU grant(AB) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1237.

WT 1 expression in nevi and melanomas: a marker of melanocytic invasion into the dermis

WT1, first recognized as a tumor suppressor gene involved in the development of Wilms' tumor, may have apparently contradictory findings and functions. As WT1 has been identified as a molecular target for cancer immunotherapy, immunodetection of WT1 in tumor cells has become an essential step in cancer studies. We compare the expression of this protein among different types of melanocytic nevi and among stages in primary melanoma progression. Tissue microarrays containing normal tissues and 271 primary melanocytic lesion samples (163 primary melanomas and 108 nevi) were studied by immunohistochemistry using monoclonal antibody against WT1. The present study shows these: 1. WT1 protein is predominantly expressed in the cytoplasm of the neoplastic cells. 2. A higher rate of WT1 staining in melanocytic nevi against melanomas has been observed. 3. WT1 expression is increased in advanced stages of melanoma progression: a significant (p < 0.05) increase of expression of WT1 was detected in vertical cases 46.5% vs. radial cases 16.0%, in high levels of Clark (IV, V) 57.4% vs. low levels (I, II, III) 33.0% and when comparing depth of invasion within thickness subgroups. 4. Finally, this study establishes an association of WT1 protein expression with shorter overall survival in melanoma.