Dados do Resumo

Título

EVALUATION OF THE FREQUENCY OF HER2 PROTEIN OVEREXPRESSION IN PRIMARY OVARIAN CARCINOMAS AND COMPARISON BETWEEN TWO DIFFERENT SCORING SYSTEMS: A SINGLE ONCOLOGICAL CENTER EXPERIENCE

Introdução

Recent studies have demonstrated promising results in the use of anti-HER2 therapy in a subset of gynecologic malignancies, most of them related to endometrial carcinoma. The initial studies on this parameter in gynecological tumors adopted the scoring system used in gastric cancer (ToGA-SS) for quantification of HER2 staining and eligibility for targeted therapy. However, the College of American Pathologists recently published specific guidelines intended for the evaluation of endometrial serous carcinomas (CAP-HER2), with important analytical differences compared to the ToGA-SS.

Objetivo

Since fewer studies were conducted specifically regarding HER2 status in primary ovarian tumors, with wide variability in HER2 expression rates, we aimed to identify the prevalence of HER2 expression in a cohort of patients with ovarian carcinoma, and to verify whether there are significant stratification differences between the two mentioned systems that could impact the clinical management of these cases.

Métodos

552 cases of primary ovarian carcinomas of varied histological types were evaluated for HER2 staining on tissue microarray samples (TMA). The slides were reviewed and the HER2 score of each case was stratified according to both the ToGa (biopsy criteria) and CAP-HER2 systems.

Resultados

Of the 552 cases studied, 21 (3.8%) demonstrated any HER2 expression by immunohistochemistry. Five of these cases (23.8%) showed differences in graduation depending on the scoring system used. Using ToGa-SS, 10 cases (1.81%) were HER2 positive (3+), while only 6 (1.08%) were classified as such by the CAP-HER2 criteria; the four remaining cases were classified as equivocal (2+) by the latter. The ToGa-SS positive cases were histologically classified as serous (n=4), endometrioid (n=3), mucinous (n=2) and carcinosarcoma (n=1). Only 1 case classified as equivocal (2+) by the ToGa-SS was classified as negative (1+) on CAP-HER2, and therefore would not be referred to reflex testing by in situ hibridization. This was the only case in which there was a difference with major clinical impact between the two scoring systems.

Conclusões

Although HER-2 overexpression appears to be less frequent in primary ovarian tumors when compared to endometrial carcinoma, anti-HER-2 therapy may be useful in cases with HER2 expression. Even though minimal differences were observed when comparing the two classification systems, further studies with larger and multi-institutional cohorts are warranted to verify whether there are more significant differences in tumors from other sites in the gynecological tract and their correlation with the reflex testing.

Financiador do resumo

ovary; her2; ovarian carcinoma