HER-2/neu amplification and overexpression in endometrial carcinoma

HER-2/neu is a proto-oncogene associated with poor prognosis in women with breast and ovarian carcinoma. The significance of HER-2/neu in endometrial carcinoma is less clearly established. The authors compared HER-2/neu gene amplification using fluorescence in situ hybridization and protein overexpression using immunohistochemistry with survival in patients with endometrial carcinoma. Fluorescence in situ hybridization and immunohistochemical staining were performed on 72 formalin-fixed, paraffin-embedded endometrial carcinoma specimens. Vysis combination HER-2/neu and centromere 17 probe mixture was applied to isolated tumor cell nuclei. A minimum of 200 nuclei were scored for each specimen using standard signal enumeration criteria. A specimen was considered amplified with 5% or greater amplified nuclei. Tissue sections were immunostained with polyclonal antibody against p185erb-2 transmembrane glycoprotein. Immunohistochemical reactivity was scored on a three-tiered scale. HER-2/neu gene amplification and protein overexpression were detected in 15 of 72 (21%) and 12 of 72 (17%) of the specimens, respectively, with 2 cases of normal copy overexpression and 5 cases of amplification without overexpression. Both amplification and overexpression were associated with higher grade tumors. Amplification was associated with clear cell and serous subtypes (p = 0.002), and overexpression with only clear cell type (p = 0.006). Using the proportional hazards model of survival, amplification was found to have significant negative predictive value beyond stage, grade, and cell type (p = 0.002). HER-2/neu gene amplification as detected by fluorescence in situ hybridization in archival material has significant prognostic value.