[1135] The Molecular Profile of Ovarian Transitional Cell Carcinoma

TL Mao, MI Hsieh, KT Kuo, MC Lin. National Taiwan University Hospital, Taipei, Taiwan

Background: Ovarian transitional cell carcinoma (TCC) is a distinct type of ovarian surface epithelial carcinoma as defined by WHO. Some studies had demonstrated differences in pathological and immunohistochemical features from those of ovarian Brenner tumor. However, the distinction of ovarian TCC from other types of ovarian carcinoma can be subjective and the morphological features of TCC often coexist with other types of ovarian carcinoma, especially high-grade serous carcinoma.
Design: To better classify ovarian TCC, we retrospectively retrieved 24 ovarian carcinomas with pure or partial features of TCC for immunohistochemical study and mutational analysis of genes frequently mutated in ovarian carcinomas. High density (250K) single nucleotide polymorphism (SNP) array was also performed in 5 cases using affinity purified samples from fresh specimens. The DNA copy number variation profiles were compared to those of 9 high-grade serous carcinomas.
Results: The 24 cases included 6 pure TCC and 18 mixed TCC and high-grade serous carcinoma. Immunostaining of p53 was either positive (>60% nuclear staining, n=16) or totally negative (n=8). Mutation of TP53 was found in 100% of informative cases (n=16). No mutation was found in PIK3CA, PTEN, BRAF and β-catenin. Kras mutation was detected in two cases. The pattern of DNA copy number variations was similar to that of high-grade serous carcinoma, with frequent DNA gains and losses. No significant molecular difference was found between pure TCC and mixed TCC and high-grade serous carcinoma.
Conclusions: Our result demonstrated that pure TCC and mixed TCC and high-grade serous carcinoma have similar molecular alterations. In conjunction with the observation that focal morphological feature of TCC is not uncommon in high-grade serous carcinoma, ovarian TCC can be regarded as a variant of high-grade serous carcinoma when making diagnostic and treatment decisions.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 157, Wednesday Afternoon

 

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