Expressions of E2F4 and E2F2 Transcription Factors in Breast Carcinoma

ABSTRACT

BACKGROUND: The E2F family (E2F1 to E2F6) of transcription factors plays a key role in cell cycle progression. Some act as oncogenes and others act as tumor suppressor genes (TSG) in a tissue-specific manner. E2F4 may function as a TSG. However, the role of E2F4 in breast carcinogenesis remains controversial. Also the clinical impact of E2F2 expression on breast cancer remains unknown. METHODS: Expressions of E2F4 and E2F2 were assessed immunohistochemically in 113 breast carcinomas and were compared with clinicopathological variables, expressions of G1/S checkpoint proteins (p16, cyclin D1 and Rb), and DNA ploidy to identify their possible role and to assess their prognostic value in breast cancer. RESULTS: Expressions of E2F4 and E2F2 were detected in 48 cases (42.5%) and 66 cases (58.4%), respectively. Expressions of E2F4 and E2F2 were significantly correlated with large tumor size (p<0.001) and lymph node metastasis (p<0.001). There was no correlation between expressions of E2F4 or E2F2 and any other variables, including age, histologic grade, DNA ploidy and expressions of p16, cyclin D1 and Rb. CONCLUSIONS: These results suggest that expressions of E2F4 and E2F2 are associated with growth and spread of breast cancer and indicate poor prognosis.