Comparison of cyclin expression between endometrioid-type endometrial cancer (EEC) and endometrioid ovarian cancer (EOC)

Abstract

5013 Background: The biological behavior of EEC and EOC differs despite their histologic similarity. While EEC is usually diagnosed at an early stage and has a good prognosis, EOC is generally advanced at diagnosis and shows a poor prognosis. Cyclins are reported to regulate the cell cycle and influence the prognosis of several cancers. We compared the pattern of cyclin expression between EEC and EOC, and evaluated the relationship among cyclin expression, estrogen receptor (ER) status, and the Ki67 labeling index (Ki67-LI). Methods: There were 36 EECs and 37 EOCs. Immunohistochemistry (IHC) was used to detect cyclin A, B1, D1, E and F (CNA, CNB1, CND1, CNE, CNF), Ki67, and ER. The percentage of positive nuclear staining for cyclins was calculated. Quantitative PCR was performed for CNA, CND1 and CNE. Results: (1) When EEC and EOC were compared, CNA expression was higher in EEC. In contrast, CND1 and CNE expression were higher in EOC. The Ki67-LI was also higher in EOC than EEC. Conversely, ER positivity was higher in EEC than EOC (80.6% vs 35.1%, p=0.0007). (2) EEC: Only CNA expression was significantly correlated with the Ki67-LI (r=0.55, p=0.0004). ER status was not related to cyclin expression. Protein and mRNA levels were significantly correlated for CNA and CNE. (3) EOC: Expression of CNA and CND1 was weakly correlated with the Ki67-LI (r=0.54, p=0.001; r=0.38, p=0.04). CNA expression was higher in ER-negative tumors than ER-positive tumors (23.7 vs 9.6, p=0.027). CND1 expression was also higher in ER-negative than ER-positive tumors (12.1 vs 0, p=0.065). CND1, and CNE protein and mRNA levels were significantly correlated. Conclusions: The pattern of cyclin expression differed between EEC and EOC. No significant financial relationships to disclose.