Expression of WT1 and PAX8 in the epithelial tumours of Malaysian women with ovarian cancer

Background: Ovarian cancer is particularly lethal due to late stage at presentation. The subtypes behave differently with respect to their biology and response to treatment. Two recent markers reported to be useful in assisting in the diagnosis are WT1 and PAX8. Malaysia, with its multi-ethnic population provides an opportunity to study the expression of these biomarkers in ovarian cancer in the three most populous ethnicities in Asia and ascertain their usefulness in the diagnosis of ovarian carcinoma.Materials and methods: Tissues from ovarian epithelial neoplasms diagnosed between 2004 and 2012 were tested using antibodies to WT1 and PAX8. The slides were assessed to determine levels of marker expression and related to ethnicity, ovarian tumour type, grade and stage.Results: Serous tumours were the main histological type (n=44), the remaining being endometrioid (n=15), mucinous (n=15) and clear cell tumours (n=7). Late stage at diagnosis was significantly associated with serous (p<0.001) and endometrioid (p 0.026) tumours. The vast majority of serous tumours were positive for WT1 (87%, p<0.001) and PAX8 expression (86%, p<0.001) whilst 40% of endometrioid tumours were positive for PAX8 and 13% for WT1. Few mucinous carcinomas (n=1) and clear cell carcinomas (n=2) expressed PAX8, and none expressed WT1. There was no significant difference in the tumour expression of either WT1 or PAX8 between the three Malaysian ethnicities.Conclusions: In an Asian setting, PAX8 and WT1 are expressed in the vast majority of serous ovarian cancers and may be useful in distinguishing serous ovarian carcinomas from other poorly differentiated tumours.