Comparative Immunohistochemical Study of Endometrioid and Serous Papillary Carcinoma of Endometrium

Objective: The aim of this study was to determine whether immunohistochemical analysis of molecular parameters can provide an alternative method for classification of endometrial cancer cases according to their aggressiveness.

Methods: Sixty-four cases of endometrial carcinoma were assigned to three groups: group I--28 cases of endometrioid well and moderately differentiated (G1-G2) carcinoma; group II--14 cases of endometrioid poorly differentiated (G3) carcinoma; group III--22 cases of serous papillary endometrial cancer. Immunohistochemistry was used to determine the existence of estrogen receptors (ER), progesterone receptors (PR), and the expression of bcl-2, p53, HER-2/neu and Ki-67.

Results: There was a significant difference in the immunohistochemical profile of the studied molecular parameters comparing the three study groups. The endometrioid G1-G2 cases (group I) were characterized by increased immunoreactivity for ER and PR (85.7% and 78.6%, respectively), increased immunoreactivity for bcl-2 (42.8%) and low expression of p53 (14.3%) and HER-2/neu (14.3%). In contrast to group I cases, the serous papillary endometrial cancer cases (group III) were characterized by immunonegativity for ER, PR and bcl-2 and high immunoreactivity for p53 (81.8%) and HER-2/neu (45.4%). The endometrioid G3 cases (group II) demonstrated an intermediate immunoprofile, characterized by immunonegativity for ER, PR and HER-2/neu, low immunoreactivity for bcl-2 (7.1%) and high expression of p53 (57.1%). The expression of Ki-67 did not differ significantly comparing the different cases of endometrial cancer.

Conclusion: This study provides evidence that the immunohistochemical analysis of endometrial carcinoma differentiates between different grades and histological types, thus being useful in the distinction of high risk cases.