Detection of the value of C-MYC oncoprotein in relation to estrogen receptor status as a prognostic factor in cases of grade I endometroid carcinomas versus endometrial hyperplasias

ABSTRACT

The mechanism of progression from endometrial hyperplasia to carcinoma, together in association with estrogen receptor have not been fully elucidated, also, c-myc oncoprotein expression may play a role in this progress. The aim of this study was to evaluate the expression of c-myc oncoprotein sequentially during the menstrual cycle as well as in some cases of endometrial hyperplasias and carcinomas, correlating it to estrogen receptor status. This study included tissue specimens obtained from 30 female patients, classified as normal cycle cases [10], endometrial hyperplasias [10], and endometrial carcinoma cases [10]. Tissue blocks from all cases were examined by H and E, as well as by immunohistochemical techniques using c-myc and estrogen receptor antibodies. The obtained results were evaluated statistically. Ten cases of normal cyclic endometrium [5 proliferative and 5 secretory] showed distinct, diffuse nuclear immunoreactivity to ER in the proliferative cases, while only 2 of the secretory cases showed focal weak staining pattern. As for c-myc, staining was strong nuclear in proliferative cases and moderate cytoplasmic in secretory cases. Immunoreactivity to ER was seen in 8 cases of endometrial hyperplasia, it was diffuse and strong in 2 cases of simple hyperplasia, moderate in 4 cases of complex hyperplasia without atypia and weak in 2 cases of atypical biopsies. As for c-myc, all hyperplastic cases were positive and showed cytoplasmic staining, moderate in simple cases and weak in complex cases with or without atypia. ER immunostaining was seen in 6 cases of endometriod carcinoma of which 3 were of grade I, 2 were of grade II, and one case was of grade III. On the other hand, all cases of carcinoma were positively stained by c-myc. Strong nuclear and cytoplasmic staining was observed in grade III cases, whereas only cytoplasmic staining was seen in lower grades. C-myc expression in normal cyclic endometrium appeared to be altered according to phases. During progression from hyperplasia to carcinoma, c-myc played a role in the development of carcinoma with the induction by estrogen leading to neoplastic transformation