BAG-1 expression in normal endometrium, endometrial hyperplasia and endometrial cancer.

Background: BAG-1 (Bcl-2-associated athanogene 1) is a BCL-2 binding anti-apoptotic protein that may play a role in carcinogenesis. The purpose of this study is to compare the expression rate of BAG-1 in normal endometrium, endometrial hyperplasia and endometrial cancer, and further to determine a correlation between BAG-1 expression and clinicopathological parameters, and overall survival.

Methods: Tissue samples from 43 patients who were diagnosed with endometrial cancer, tissue samples from 20 patients with endometrial hyperplasia and tissue samples from 20 normal patients were included in the study. Immunohistochemical analyses were performed using a polyclonal anti-BAG-1 antibody from paraffin-embedded blocks.

Results: Cytoplasmic BAG-1 expression of the normal endometrium, endometrial hyperplasia and endometrial cancer samples was 4/20 (20%), 3/20 (15%) and 27/43 (62%), respectively. Nuclear BAG-1 expression was 17/20 (85%), 12/20 (60%) and 16/43 (37%), respectively. Cytoplasmic BAG-1 expression correlated with cancer grade (p=0.02). The mean survival of patients with positive/negative cytoplasmic BAG-1 expression and nuclear BAG-1 expression was 49.4/45.4 and 54.0/41.1 months, respectively, but there was no statistical difference for survival (log-rank p=0.31, p=0.55).

Conclusion: Cytoplasmic BAG-1 is more frequently expressed in endometrial cancer tissues than in normal and endometrial hyperplasia tissues (p=0.0007), and its expression correlates with cancer grade. Nuclear BAG-1 is more frequently expressed in the normal endometrium and hyperplasia tissues than in endometrial cancer tissues (p=0.002). Neither cytoplasmic nor nuclear BAG-1 expression is associated with survival.