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Ovarian cancer is the leading cause of gynecologic cancer-related morbidity and mortality owing to the difficulty in detecting early-stage disease. Despite advances in surgical and chemotherapeutic strategies, only marginal improvement in patient outcome has been achieved. Hence, understanding the biological mechanisms underlying ovarian cancer development and progression is critical for its treatment. We reported that CD157 (also known as BST-1), a NAD-metabolizing ectoenzyme regulating leukocyte diapedesis in inflammatory conditions, is expressed in approximately 90% of epithelial ovarian cancers and high CD157 expression is associated with poor outcome in patients. Our experimental results showed that CD157 controls ovarian cancer progression by promoting mesenchymal differentiation. The increased aggressiveness associated with tumors with high CD157 can be reverted in vitro by CD157 gene silencing, or by monoclonal antibodies that block CD157. The overall picture inferred from our experimental and clinical findings suggests that CD157 could aid diagnosis by classifying ovarian cancers into molecular subtypes with different outcomes, CD157 could also represent a novel candidate as a target of antibody-based therapies. This review summarizes and assesses recent research into the emerging functions of CD157 in the control of ovarian cancer progression.

CD31, an adhesion molecule expressed by endothelial cells, leukocytes, and platelets, is used in surgical pathology as a marker of normal and neoplastic vascularization. During the assessment of angiogenesis in breast carcinomas, CD31 expression was observed in a single case of large (5.2 cm diameter) high nuclear grade ductal carcinoma in situ (HG-DCIS) associated with poorly differentiated invasive ductal carcinoma (G3-IDC). Expression was limited to the cell membrane. This study focused on 32 HG-DCISor = 2 cm, either pure or associated with IDC. Cancer cells wereCD31(+) in 11 cases. Double staining using anti-CD31 monoclonal antibody (MAb) and anti-CD44 MAb, the anti-hyaluronate receptor, showed that foci of CD31(+) and CD44(-) tumour cells could be traced throughout the glandular tree, marking the intraductal diffusion of tumour up to Paget's cells at the nipple. The associated G3-IDC and their lymph node metastases were instead CD31(+) and CD44(+). CD31(+) tumours were oestrogen receptor (ER)(-), frequently p53(+) and c-erb-B2(+), and infiltrated by CD4(+) T lymphocytes. Normal and hyperplastic epithelia were constantly CD31(-). Other endothelial markers (e.g Factor VIII-RA and CD34) were not expressed by carcinoma cells, as was CD38, the CD31 ligand. In conclusion, CD31 expression is a feature acquired by breast cancer cells in the DCIS model. CD31 expression mainly correlates with tumour cells spreading within the ductal system. Finally, the invasive phenotype requires the co-expression of CD31 and CD44.

BACKGROUND: Intrinsic and/or acquired chemoresistance is the major obstacle to overcome in the treatment of patients with ovarian carcinoma. The aim of the present study was to investigate the prognostic value of drug resistance associated proteins P-glycoprotein (P-gp), multidrug resistance related protein (Mrp1), canalicular multispecific organic anion trans-porter (c-MOAT or Mrp2) and lung resistance protein (Lrp) in ovarian carcinoma. METHODS: Expression of P-gp, Mrp1, Mrp2 and Lrp was determined by immunohistochemistry of frozen tissue sections of 115 ovarian carcinoma patients and associated to clinico-pathological factors, response to chemotherapy and (progression free) survival. RESULTS: Expression of P-gp was observed in 20 out of 115 (17%), Mrp1 in 51 out of 115 (44%), Mrp2 in 19 out of 115 (16%) and Lrp in 85 out 115 (74%) tumors. Expression of Mrp1 was related to Mrp2 (p < 0.0001) and P-gp (p < 0.001) expression, while Lrp expression was more frequently observed in patients with stage I/II versus stage III/IV tumors (p < 0.01), grade I/II versus III tumors (p < 0.05) and residual tumor < 2 cm versus > 2 cm after laparotomy (p < 0.05). Lower stage (p < 0.001), small residual tumor after first laparotomy (p < 0.001) and lower differentiation grade (p < 0.05) were related to longer (progression free) survival. P-gp, Mrp1, Mrp2, and Lrp expression was neither related to response to first line chemotherapy (59 evaluable patients) nor to (progression free) survival (all patients). On multivariate analysis only stage and residual tumor after first laparotomy were independent prognostic factors for (progression free) survival. CONCLUSIONS: In ovarian carcinoma Mrp1 expression is associated with Mrp2 and P-gp expression, while Lrp expression is associated with favorable clinicopathological characteristics. Assessment of P-gp, Mrp1, Mrp2 or Lrp does not allow prediction of response to chemotherapy or (progression free) survival in ovarian carcinoma.