Differential expression of clusterin according to histological type of endometrial carcinoma

Clusterin expression has been associated with various malignancies. Endometrial carcinoma is divided into endometrioid and papillary serous type carcinoma according to the histological characteristics and regarding to the unopposed estrogenic stimulation. In this study, we investigated the expression profiles of clusterin according to the histological types and the effect of estrogen stimulation on its expression in endometrial carcinoma.

Clusterin expression in endometrial carcinoma tissues was examined by RT-PCR, Western blot analysis, and immunohistochemistry. 63 endometrioid and 10 papillary serous types of fresh cases and 81 endometrioid and 7 papillary serous types of paraffin-embedded cases were studied. Regulation of clusterin expression by beta-estradiol in HEC-1B and HEC-1A cells was investigated using RT-PCR and Western blot analysis. Cell proliferative function of clusterin was examined in 293T cells.

We found higher expression of clusterin in endometrioid compared to papillary serous carcinoma using both immunohistochemistry (p=0.033) and Western blot analysis (p=0.024). The mRNA and protein expressions of clusterin in endometrioid carcinoma were higher than in benign endometrium (p=0.002). Forced expression of clusterin promoted 293T cell survival in a concentration-dependent manner, and estradiol treatment increased clusterin expression in HEC-1B but not in HEC-1A cells.

These data suggest that clusterin expression is related to endometrioid carcinoma of endometrium, in which estrogen is involved in the regulatory network of clusterin.