Expression patterns of apoptosis related proteins bcl-2 and bak in endometrial hyperplasia and carcinoma and their correlation to estrogen and progesterone receptor status

Abstract EN

-Background : The expression pattern of bcl-2 gene in the endometrium is at least partially regulated by ovarian sex steroids.

Some studies suggest that the development of endometrial adenocarcinoma is linked to inadequate activation of cell death program.

Aim of the work: The purpose of this study was to evaluate the distribution and frequency of apoptosis-related proteins bcl-2 & bak & their correlation with estrogen, & progesterone receptors in endometrial hyperplasia & carcinoma.

Material & Methods: Immunohistochemical analyses of bcl-2, bak, and steroid receptors were performed in 25 endometrial carcinomas, and 25 endometrial hyperplasia.

Results : Bcl-2 was expressed in 48 % of carcinomas and 88 % of hyperplasia.

Bak immunostaining was found in 76 % of carcinomas and 80 % of hyperplasia.

Thirteen carcinomas (52 %), and 22 hyperplasia (88%), were positive for estrogen receptor (ER) and progesterone receptor (PR).

A highly significant positive correlation between ER & PR scores in hyperplasia and carcinoma groups (p < 0.

01) ; as well as a highly significant positive correlation between ER and PR expression and bcl-2 & bak immunoreactivity within the same groups was observed (p < 0.

01).

There was a significant positive correlation between bcl-2 and bak.

There was a statistically significant difference for bcl-2 (p=0.005) between the hyperplasia and carcinoma groups.

There was significant decreased expression of bcl-2, and bak proteins in advanced endometrial carcinomas (p=0.05 & 0.01 respectively).

Conclusions: Therefore the expression of bcl-2 & bak may occur more frequently in estrogen-related, low grade endometrial carcinomas.

Thus, bcl-2 & bak may be used as an additional biological marker for prognosis of patients with endometrial carcinoma.

Targeting bcl-2 and/or bak hormone receptor-positive endometrial cancer might improve the therapeutic ratio of adjuvant therapy in this population.