HER-2/Neu Status in Gastric Carcinomas in a Series of Egyptian Patients and Its Relation to Ki-67 Expression

Objective: HER-2/neu status in gastric carcinomas (GCs) has not been studied before in the Egyptian population. Materials and Methods: Seventy-three GCs were evaluated for the expression of HER-2/neu and Ki-67 using immunohistochemistry (IHC). Fluorescence in situ Hybridization (FISH) was done for HER2/neu IHC score 2+ cases. Results: Out of the 73 gastric carcinomas, 23 (31.5%) were score 0, 17 (23.3%) were score 1+, 23 (31.5%) were score 2+, and 10 (13.7%) were score 3+. FISH analysis revealed that the HER-2/neu gene was amplified in 11 out of the 23 cases (47.8%) scored 2+ by IHC. Therefore, the overall HER-2/neu positivity rate was 28.8% and it was significantly associated with higher T-stage and lymphovascular invasion (LVI). The Ki-67 expression rate ranged between 10% and 100%, with 84.9% of the cases (n = 62) featuring high Ki-67 scores. High Ki-67 score was significantly associated with male sex, tumor grade, and number of positive nodes. HER-2/neu protein expression correlated significantly with Ki-67 score. Twenty tumors showed combined HER-2/neu positivity and high Ki-67 score and were significantly associated with higher T-stage and occurrence of LVI, implying a more aggressive behavior. Conclusions: The rate of HER-2/neu positive GCs in our series simulates universal rates, thereby mandating routine evaluation of HER-2/neu status in all GCs submitted to our laboratory to benefit from trastuzumab therapy. Further studies on a larger number of GCs are required to prove that the concurrent HER-2/neu positivity and high Ki-67 score are markers of worse prognosis.