ABCC4/MRP4 contributes to the aggressiveness of Myc-associated epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is a complex disease comprising discrete histological and molecular subtypes, for which survival rates remain unacceptably low. Tailored approaches for this deadly heterogeneous disease are urgently needed. Efflux pumps belonging to the ATP-binding cassette (ABC) family of transporters are known for roles in both drug resistance and cancer biology and are also highly targetable. Here we have investigated the association of ABCC4/MRP4 expression to clinical outcome and its biological function in endometrioid and serous tumors, common histological subtypes of EOC. We found high expression of ABCC4/MRP4, previously shown to be directly regulated by c-Myc/N-Myc, was associated with poor prognosis in endometrioid EOC (P = .001) as well as in a subset of serous EOC with a “high-MYCN” profile (C5/proliferative; P = .019). Transient siRNA-mediated suppression of MRP4 in EOC cells led to reduced growth, migration and invasion, with the effects being most pronounced in endometrioid and C5-like serous cells compared to non-C5 serous EOC cells. Sustained knockdown of MRP4 also sensitized endometrioid cells to MRP4 substrate drugs. Furthermore, suppression of MRP4 decreased the growth of patient-derived EOC cells in vivo. Together, our findings provide the first evidence that MRP4 plays an important role in the biology of Myc-associated ovarian tumors and highlight this transporter as a potential therapeutic target for EOC.     

Overexpression of the p53 protein and allele loss at 17p13 in ovarian carcinoma.

Mouse monoclonal antibodies PAb 240 and PAb 1801 which specifically immunoprecipitate p53 protein, were used to examine 27 fresh ovarian tumours (16 serous adenocarcinomas, six endometrioid carcinomas, one mucinous adenocarcinoma, one mucinous borderline tumour and three benign adenomas). Eleven out of 16 (69%) serous adenocarcinomas and one endometrioid tumour showed positive staining with one or both antibodies and none of the mucinous or benign tumours stained with either antibody. DNA from tumour and peripheral blood leukocytes was used to identify allelic deletions on chromosome 17p in tumours. 11/12 positively staining tumours showed less of heterozygosity (LOH) on 17p at the nearest informative locus to the p53 gene. In this series of ovarian tumours, LOH on 17p correlates closely with the aberrant expression of the p53 protein in a high proportion of advanced stage serous adenocarcinomas. This observation suggests that the p53 tumour suppressor gene is involved in the evolution of epithelial ovarian cancer (EOC) and may have prognostic significance.     

Comparative immunohistochemical studies of bcl-2 and p53 proteins in benign and malignant ovarian endometriotic cysts

BACKGROUND: A number of histologic and epidemiologic studies have suggested an association between endometriosis and ovarian carcinoma. Some reports have described a transition from endometriosis to atypical endometriosis to carcinoma. Using immunohistochemistry, the authors compared staining patterns in benign endometriotic cysts with ovarian tumors and the endometriotic cyst lining from which they arose, in an attempt to identify sequential or etiologic correlations. METHODS: One hundred thirteen formalin-fixed, paraffin-embedded sections were studied (30 benign ovarian endometriotic cysts, 24 endometriotic cysts containing endometrioid carcinomas, 19 endometriotic cysts harboring clear cell carcinomas, and 40 ovarian papillary serous cystadenocarcinomas). All sections were immunostained with anti-bcl-2 and anti-p53 antibodies using the streptavidin-biotin method. RESULTS: bcl-2 was reported to stain 23% of benign endometriotic cysts, 67% of endometrioid carcinomas, 73% of clear cell carcinomas, and 50% of papillary serous carcinomas. Approximately 42% of benign endometriotic lesions adjacent to the endometrioid carcinoma and 73% adjacent to clear cell carcinomas were found to stain for bcl-2 (p = 0.274 [not significant (NS)] and P = 0.008, respectively). p53 staining was negative in the benign endometriotic cyst group and was positive in 37-55% of the group with tumors. p53 staining was positive in 25% of the benign endometriotic lesions next to the endometrioid carcinoma and in 9% of the benign endometriotic lesions next to clear cell carcinoma (P = 0.014 and P = 0.239 [NS], respectively). CONCLUSIONS: The results of the current study suggest that alterations in bcl-2 and p53 may be associated with the malignant transformation of endometriotic cysts.     

Expression of c-ABL,c-KIT,and platelet-derived growth factor receptor-beta in ovarian serous carcinoma and normal ovarian surface epithelium

BACKGROUND: Tyrosine kinases, such as c-KIT, c-ABL, and platelet-derived growth factor-beta (PDGFR-beta), are important regulators of cell growth. Highly potent and selective inhibitors of tyrosine kinases are being investigated as alternatives to standard chemotherapy. One such inhibitor, imatinib mesylate, is being used to treat gastrointestinal stromal tumors and chronic myelogenous leukemia. Ovarian carcinomas frequently develop resistance to conventional chemotherapeutic agents. Immunohistochemical expression of c-ABL, PDGFR-beta, and c-KIT was evaluated in ovarian carcinomas to determine whether treatment with imatinib mesylate might be feasible. METHODS: The expression of c-ABL, c-KIT, and PDGFR-beta in tumors was evaluated by immunohistochemical analysis of 52 ovarian serous carcinomas, including 21 low-grade (well differentiated) and 31 high-grade (poorly differentiated) tumors. Fourteen normal ovaries were also evaluated. RESULTS: In normal ovarian surface epithelium, c-ABL was expressed universally. PDGFR-beta was expressed in the majority (93%) of samples of normal ovarian epithelium, whereas the c-KIT protein was undetectable in normal ovarian surface epithelium. Overall, c-ABL was expressed in 71% of serous carcinomas. c-ABL was expressed more frequently in the low-grade serous carcinomas (81%) compared with the high-grade serous carcinomas (65%). PDGFR-beta expression was observed in 81% of serous carcinomas overall and was observed more frequently in higher-grade tumors. c-KIT immunohistochemical staining was absent in low-grade tumors but was present in 26% of high-grade serous carcinomas. CONCLUSIONS: The majority of ovarian serous carcinomas express one or more of the kinases targeted by the tyrosine kinase inhibitor, imatinib mesylate, suggesting the potential usefulness of this drug in the treatment of ovarian carcinoma.     

TFF3 Expression as Stratification Marker in Borderline Epithelial Tumors of the Ovary

Borderline tumors (BOT) of the ovary account for 10% to 20% of ovarian neoplasms. Like ovarian cancer, BOT encompass several different histological subtypes (serous, mucinous, endometrioid, clear cell, transitional cell and mixed) with serous (SBOT) and mucinous (MBOT) the most common. Current hypotheses suggest low-grade serous carcinoma may develop in a stepwise fashion from SBOT whereas the majority of high grade serous carcinomas develop rapidly presumably from inclusion cysts or ovarian surface epithelium. The pathogenesis of mucinous ovarian tumors is still puzzling. Molecular markers could help to better define relationships between such entities. Trefoil factor-3 (TFF3) is an estrogen-regulated gene associated with prognosis in different types of cancer. It has also been included in a recent marker panel predicting subtypes of ovarian carcinoma. We analyzed the expression of TFF3 by immunohistochemistry in a cohort of 137 BOT and its association with histopathological features. Overall expression rate of TFF3 was 21.9%. None of the BOT with serous and endometrioid histology displayed strong TFF3 expression. On the other hand, TFF3 was highly expressed in 61.4% of MBOT cases and 33.3% of BOT with mixed histology (P < 0.001) suggesting a potential function of the protein in that subtypes. Associations of TFF3 expression with FIGO stage and micropapillary pattern were significant in the overall cohort but confounded by their correlation with histological subtypes. The highly specific expression of TFF3 in MBOT may help to further clarify potential relationships of tumors with mucinous histology and warrants further studies.     

NPPB is a novel candidate biomarker expressed by cancer‐associated fibroblasts in epithelial ovarian cancer

Most solid tumors contain cancer‐associated fibroblasts (CAFs) that support tumorigenesis and malignant progression. However, the cellular origins of CAFs in epithelial ovarian cancers (EOCs) remain poorly understood, and their utility as a source of clinical biomarkers for cancer diagnosis has not been explored in great depth. Here, we report establishing in vitro and in vivo models of CAFs in ovarian cancer development. Normal ovarian fibroblasts and mesenchymal stem cells cultured in the presence of EOC cells acquired a CAF‐like phenotype, and promoted EOC cell migration in vitro. CAFs also promoted ovarian cancer growth in vivo in both subcutaneous and intraperitoneal murine xenograft assays. Molecular profiling of CAFs identified gene expression signatures that were highly enriched for extracellular and secreted proteins. We identified novel candidate CAF‐specific biomarkers for ovarian cancer including NPPB, which was expressed in the stroma of 60% primary ovarian cancer tissues (n = 145) but not in the stroma of normal ovaries (n = 4). NPPB is a secreted protein that was also elevated in the blood of 50% of women with ovarian cancer (n = 8). Taken together, these data suggest that the tumor stroma is a novel source of biomarkers, including NPPB, that may be of clinical utility for detection of EOC.     

Decreased expression of BTG3 was linked to carcinogenesis, aggressiveness, and prognosis of ovarian carcinoma

B-cell translocation gene 3 (BTG3) is a member of the BTG family which inhibits cell proliferation, metastasis, and angiogenesis, and also regulates cell-cycle progression and differentiation in a variety of cell types. However, there is no study to analyze BTG3 expression in epithelial ovarian carcinoma (EOC). Here, we investigated the expression of BTG3 in EOC carcinogenesis and subsequent progression. BTG3 mRNA expression was detected by real-time RT–PCR in ovarian benign and malignant tumors. The expression of BTG3 protein was examined by immunohistochemistry on tissue microarrays containing ovarian normal tissue, benign and borderline epithelial ovarian tumors, and EOCs. Relationships of BTG3 with both EOC clinicopathology and prognosis were analyzed statistically. The expression of BTG3 protein was also evaluated in ovarian normal tissue, benign tumors, and EOCs by western blot. The BTG3 mRNA expression level was higher in ovarian normal tissue and benign tumors than that in borderline, primary, and metastatic carcinoma (p?<?0.05), and was negatively correlated with dedifferentiation and FIGO staging of EOC (p?<?0.05). Using western blot, BTG3 protein was found lower in EOCs compared to the normal and benign tumors (p?<?0.05), and poorly differentiated EOCs showed lower BTG3 expression than well-differentiated and moderately differentiated EOCs (p?<?0.05). Immunohistochemically, BTG3 protein expression was statistically lower in EOCs than normal tissue and benign tumors (p?<?0.05). EOC patients with low BTG3 protein expression showed a higher incidence of metastasis (p?=?0.020), poor differentiation (p?=?0.030), and shorter disease-free time and overall survival time (p?<?0.05). By using Cox’s proportional hazard model, BTG3 protein expression and FIGO staging were independent prognostic factors for both disease-free time and overall survival time of EOCs (p?<?0.05). It was suggested that down-regulated BTG3 expression might play roles in the pathogenesis and aggressiveness of EOC. BTG3 protein expression may be considered as a good marker to indicate the favorable prognosis of EOCs.     

Induction of FGF receptor 2-IIIb expression and response to its ligands in epithelial ovarian cancer

Epithelial ovarian cancers (EOCs) arise in the Ovarian Surface Epithelium (OSE). This tissue is a simple, poorly committed mesothelium which exhibits characteristics of epithelial and mesenchymal cells when grown in culture. In contrast, EOCs frequently exhibit properties of complex epithelial tissues of the female reproductive tract, such as oviductal, endometrial and cervical epithelia, and show induction of expression of epithelial markers such as E-cadherin. Fibroblast Growth Factor Receptor 2 isoform IIIb (FGF receptor 2-IIIb) is a spliced variant of FGF receptor 2 that binds the ligands FGF-1 and FGF-7 with high affinity, and is expressed exclusively by epithelial cells. We have studied the expression of FGF receptor 2-IIIb and its ligands in primary cultures of normal human OSE, EOC cell lines and snap frozen tissue from EOCs. Expression of FGF receptor 2-IIIb mRNA is undetectable in normal OSE, but is expressed in 16/20 (80%) of EOCs. FGFs 1 and 7 mRNAs are expressed in normal OSE, whilst only 4/20 (20%) and 12/20 (60%) of EOCs demonstrated expression for these ligands respectively. However, FGF-7 protein was detected in 70% (mean level=0.7 ng/ml) of ascitic fluids obtained from patients with EOC. FGFs 1 and 7 stimulate DNA synthesis in EOC cell lines that express FGF receptor 2-IIIb. Moreover, DNA synthesis in these cell lines can be partially blocked by blocking antisera to FGFs 1 and 7. It is suggested that induction of expression of FGF receptor 2-IIIb may play a role in the development of EOCs by rendering the OSE susceptible to paracrine and/or autocrine stimulation by its requisite FGF ligands.     

The HE4 (WFDC2) protein is a biomarker for ovarian carcinoma

The WFDC2 (HE4) gene is amplified in ovarian carcinomas, whereas its expression in normal tissues, including ovary, is low. Although the function of the HE4 protein is unknown,it is a member of a family of stable 4-disulfide core proteins that are secreted at high levels. We therefore performed experiments to explore whether quantitation of HE4 protein levels in serum can be used as a biomarker for ovarian carcinoma. A fusion gene was constructed encoding the HE4 protein fused to a gene encoding the murine IgG2a Fc domain. Subsequently, protein produced in mammalian cells was purified by affinity chromatography and used to immunize mice to generate hybridomas specific for HE4. Hybridoma supernatants were screened for binding to a similar fusion protein that, instead, had a human immunoglobulin tail. Two hybridomas, 2H5 and 3D8, were selected that produce monoclonal antibodies to different HE4 epitopes, and a double determinant ("Sandwich") ELISA was constructed and shown to detect a signal at the 160-pg level. Blinded studies on sera from postmenopausal patients with ovarian carcinoma and controls indicate that the specificity and sensitivity of the HE4-based ELISA is equivalent to that of the CA125 assay. However, the HE4 assay may have an advantage over the CA125 assay in that it is less frequently positive in patients with nonmalignant disease.     

卵巢癌组织中REG4与survivin的蛋白表达及临床意义

目的:研究REG4和survivin在卵巢癌组织中的蛋白表达与卵巢癌临床病理特征的关系和彼此间的相关性。方法:应用免疫组化法（EliVision二步法）分别检测REG4和survivin在39例原发性卵巢癌（包括浆液性癌27例，黏液性癌7例，透明细胞癌3例，子宫内膜样癌2例）和13例上皮来源的卵巢良性肿瘤组织中的蛋白表达水平，分析与卵巢癌临床病理特征的关系。结果:REG4和survivin在卵巢癌组织中蛋白表达均高于在上皮来源的卵巢良性肿瘤组织中的表达（P<0.01）；REG4和survivin的蛋白表达与卵巢癌的分期、分化有关，分期越高、分化程度越低，其在卵巢癌组织中的蛋白表达水平越高；REG4与survivin的蛋白表达呈正相关（r=0.375，P=0.019）。结论:REG4和survivin参与卵巢癌的发生发展，可能有共同促进的作用。     

MMP7蛋白及mRNA在卵巢上皮性肿瘤中的表达及意义

目的 探讨MMP7在上皮性卵巢癌组织中的表达及临床意义。方法 采用免疫组化方法及原位杂交方法检测10例正常卵巢组织、10例良性上皮性卵巢肿瘤组织和54例上皮性卵巢癌组织中MMP7蛋白的表达。结果 正常卵巢组织及良性卵巢肿瘤组织中,MMP7蛋白不表达;上皮性卵巢癌组织中,MMP7阳性表达率为88.89%。MMP7的表达与上皮性卵巢癌的临床分期和病理分级有关,与淋巴结转移无关。MMP7的mRNA与蛋白表达呈正相关(P＜0.0001)。结论 上皮性卵巢癌组织中,MMP7蛋白高度表达。MMP7蛋白在上皮性卵巢癌的发生过程中发挥着重要的作用,MMP7蛋白及mRNA表达水平可以作为判断卵巢癌预后的指标。     

Engagement of collagen-binding integrins promotes matrix metalloproteinase-9-dependent E-cadherin ectodomain shedding in ovarian carcinoma cells

Reversible modulation of cell-cell adhesion, cell-matrix adhesion, and proteolytic activity plays a critical role in remodeling of the neoplastic ovarian epithelium during metastasis, implicating cadherins, integrins, and proteinases in i.p. metastatic dissemination of epithelial ovarian carcinoma (EOC). Aberrant epithelial differentiation is an early event in ovarian carcinogenesis; thus, in contrast to most carcinomas that lose E-cadherin expression with progression, E-cadherin is abundant in primary EOC. Metastasizing EOCs engage in integrin-mediated adhesion to submesothelial interstitial collagens and express matrix metalloproteinases (MMP) that facilitate collagen invasion, thereby anchoring secondary lesions in the submesothelial matrix. As metalloproteinases have also been implicated in E-cadherin ectodomain shedding, the current study was undertaken to model the effects of matrix-induced integrin clustering on proteinase-catalyzed E-cadherin ectodomain shedding. Aggregation of collagen-binding integrins induced shedding of an 80-kDa E-cadherin ectodomain [soluble E-cadherin (sE-cad)] in a MMP- and Src kinase-dependent manner, and sE-cad was prevalent in ascites from ovarian cancer patients. Expression of MMP-9 was elevated by integrin aggregation, integrin-mediated ectodomain shedding was inhibited by a MMP-9 function blocking antibody, and incubation of cells with exogenous MMP-9 catalyzed E-cadherin ectodomain shedding. In contrast to other tumors wherein sE-cad is released into the circulation, EOC tumors maintain direct contact with sE-cad-rich ascites at high concentration, and incubation of EOC cells with physiologically relevant concentrations of recombinant sE-cad disrupted adherens junctions. These data support a novel mechanism for posttranslational modification of E-cadherin function via MMP-9 induction initiated by cell-matrix contact and suggest a mechanism for promotion of EOC metastatic dissemination.     

The BRK tyrosine kinase is expressed in high-grade serous carcinoma of the ovary

BACKGROUND: We identified the BRK tyrosine kinase in a PCR-based screen of tyrosine kinases expressed by ovarian tumors. BRK expression is restricted to normal differentiating epithelial cells and its overexpression may play a role in processes related to tumor development and growth. Its expression in normal ovary and ovarian tumors has not previously been described, and is the focus of this study. METHODS: BRK expression levels were determined in 14 normal ovaries and 138 high-grade, late stage serous carcinomas of the ovary by immunohistochemical analysis, and in 19 ovarian cancer cell lines and immortalized ovarian surface epithelium by Western blot analysis. Furthermore, BRK/PTK6 gene copy number was determined in seven primary serous carcinomas by fluorescence in situ hybridization. RESULTS: Immunohistochemical studies indicate that BRK is highly expressed in 97/138 (70%) of high-grade, serous carcinomas of the ovary, but is absent in normal ovarian surface epithelia. BRK is also expressed by 9/19 of ovarian cancer cell lines, but is undetectable in immortalized ovarian surface epithelium. Interestingly, the BRK gene has been mapped to chromosome 20q13.3, a site frequently amplified in ovarian cancers, and associated with poor prognosis. We have determined by fluorescence in situ hybridization (FISH) that BRK is specifically amplified at low levels in 6/7 primary ovarian carcinomas. CONCLUSIONS: The amplification of the BRK gene and overexpression of BRK protein in the majority of high-grade serous carcinomas and ovarian cancer cell lines suggest that BRK may play a role in the development and growth of ovarian tumors.     

Six new monoclonal antibodies to serous, mucinous, and poorly differentiated ovarian adenocarcinomas

Six monoclonal antibodies directed against ovarian adenocarcinoma were generated by use of 100,000 x g supernatants of Triton-X-100 solubilized extracts of ovarian serous adenocarcinoma as the antigen source. Immunoperoxidase preparation of frozen-sections and routinely processed paraffin section specimens revealed a highly restricted reactivity of these antibodies when tested with adult (n = 2) and fetal (n = 3) tissue types. Coreactivities were occasionally observed with epithelia of the kidney, mammary gland, and pancreas. One monoclonal antibody, Ki-OC I-6-2, cross-reacted only with epididymal epithelia. No coreaction occurred with normal tissue of the ovary, Fallopian tube, or uterus. All antibodies were additionally tested on 74 cases of nonovarian malignancies, 15 cases of ovarian metastases of nonovarian carcinomas, and 114 specimens of ovarian neoplasms other than carcinomas. Ki-OC I-6-2 had no cross-reactivity with these tumors except for one case of renal cell carcinoma. This monoclonal antibody recognized serous, mucinous, and poorly differentiated adenocarcinoma cell types. None of the six antibodies reacted with clear cell or endometrioid carcinoma. All were found to be of the IgG-1 subclass. The tumor antigen to which Ki-OC I-6-2 immunoreacted was estimated to have a molecular weight of 80 kilodaltons (KD).     

Tumor protein D52 (TPD52) is overexpressed and a gene amplification target in ovarian cancer

Recurrent chromosome 8q gain in ovarian carcinoma is likely to reflect the existence of multiple target loci, as the separate gain of chromosome bands 8q21 and 8q24 has been reported in independent studies. Since tumor protein D52 (TPD52) has been identified as a chromosome 8q21 amplification target in breast and prostate carcinoma, we compared TPD52 expression in normal ovarian epithelium (n = 9), benign serous adenomas (n = 11), serous borderline tumors (n = 6) and invasive carcinomas of the major histologic subtypes (n = 57) using immunohistochemistry. These analyses revealed that all normal ovarian epithelium samples and benign serous tumors were predominantly TPD52-negative, whereas TPD52 was overexpressed in most (44/57; 77%) ovarian carcinomas regardless of histologic subtype. TPD52 subcellular localization was predominantly cytoplasmic, although nuclear localization was also frequently observed in mucinous and clear cell carcinomas. In an independent cohort of stage III serous carcinomas (n = 18), we also directly compared in situ TPD52 expression using immunohistochemistry and TPD52 copy number using interphase FISH analyses. This revealed that TPD52 dosage and TPD52 expression were significantly positively correlated. TPD52 therefore represents a novel molecular marker in ovarian cancer, which is broadly expressed across the different histologic subtypes and whose upregulation frequently reflects increased TPD52 copy number.     

HE4在浆液性卵巢癌组织中的表达及与临床病理因素的关系

目的：探讨人附睾分泌蛋白4（ HE4）在浆液性卵巢癌组织中的表达及与临床病理因素之间的关系。方法应用免疫组化的方法检测HE4在140例浆液性卵巢癌组织中的表达情况及与临床病理因素的关系,并联合检测CA125在卵巢癌中的组织学表达情况,对比HE4与CA125的相关性。结果HE4和CA125在中低分化浆液性卵巢癌组织中的阳性表达率分别为89．76％和81．89％,在高分化者阳性率分别为46．61％和15．38％,中晚期卵巢癌者阳性率为92．44％和83．19％,早期卵巢癌者阳性率为47．62％和33．33％,有盆腔淋巴结转移者阳性率95．65％和84．35％,无盆腔淋巴结转移者40．00％和36．00％,有腹腔种植者阳性率90．00％和87．27％,无腹腔种植者70．00％和33．33％,卵巢癌合并腹水者阳性率89．76％和79．53％,无腹水者为46．15％和38．46％,另外,HE4和CA125在浆液性卵巢癌中的阳性表达率分别为86％和76％,差异均具有统计学意义（ P＜0．05）,两者在卵巢癌的阳性表达上存在相关性（P＜0．05）。 HE4和CA125的表达与卵巢癌患者是否绝经和产数无关,（P＞0．05）。结论 HE4在浆液性卵巢癌组织中的表达与FIGO分期、肿瘤分化程度、淋巴结有无转移、腹腔有无种植和是否合并腹水有关。     

Patterns of gene expression in different histotypes of epithelial ovarian cancer correlate with those in normal fallopian tube, endometrium, and colon.

PURPOSE: Epithelial ovarian cancers are thought to arise from flattened epithelial cells that cover the ovarian surface or that line inclusion cysts. During malignant transformation, different histotypes arise that resemble epithelial cells from normal fallopian tube, endometrium, and intestine. This study compares gene expression in serous, endometrioid, clear cell, and mucinous ovarian cancers with that in the normal tissues that they resemble. EXPERIMENTAL DESIGN: Expression of 63,000 probe sets was measured in 50 ovarian cancers, in 5 pools of normal ovarian epithelial brushings, and in mucosal scrapings from 4 normal fallopian tube, 5 endometrium, and 4 colon specimens. Using rank-sum analysis, genes whose expressions best differentiated the ovarian cancer histotypes and normal ovarian epithelium were used to determine whether a correlation based on gene expression existed between ovarian cancer histotypes and the normal tissues they resemble. RESULTS: When compared with normal ovarian epithelial brushings, alterations in serous tumors correlated with those in normal fallopian tube (P = 0.0042) but not in other normal tissues. Similarly, mucinous cancers correlated with those in normal colonic mucosa (P = 0.0003), and both endometrioid and clear cell histotypes correlated with changes in normal endometrium (P = 0.0172 and 0.0002, respectively). Mucinous cancers displayed the greatest number of alterations in gene expression when compared with normal ovarian epithelial cells. CONCLUSION: Studies at a molecular level show distinct expression profiles of different histologies of ovarian cancer and support the long-held belief that histotypes of ovarian cancers come to resemble normal fallopian tube, endometrial, and colonic epithelium. Several potential molecular markers for mucinous ovarian cancers have been identified.