Human epidermal growth factor receptor 2 expression in gastric carcinoma and its association with histopathological...

Gastric carcinoma is a leading cause of death worldwide with a five year survival of 10-15% even after curative resection. Trastuzumab has emerged as a potential targeted therapy in treatment of Her 2 positive gastric cancer. Her2 positivity ranges from 7-34% in studies across the world. There is a paucity of Indian studies hence a need for determination of Her2 expression in Indian population for better patient management. This study was carried out to determine the frequency of Her 2 expression in gastric carcinoma by immunohistochemistry (IHC) technique and to evaluate its association with histopathological parameters.

A total of 110 cases of gastric adenocarcinoma diagnosed on histopathological examination from July 2013 to June 2015 were included. Of these, 40 cases were resection specimens and 70 were biopsies. Histological typing of gastric carcinoma was done on the basis of Lauren classification. IHC for Her2 was done in all 110 cases. Her 2 expression was correlated with various histopathological parameters.

Positive Her 2 expression (IHC 3+) was seen in 24.5% cases of gastric carcinoma. Patients in older age group(> 60 years) showed higher Her 2 positivity rate as compared to middle age (40-60 years) and younger population (<40 years). Higher percentage of Her 2 positivity was noted in male patients as compared to female patients. Her 2 positivity was seen more commonly in intestinal type of tumor as compared to diffuse and mixed types. Her 2 positivity was seen more in well differentiated carcinoma and higher stage tumors (pT3 and pT4). However, out of all, a statistically significant association of Her2 expression was found only with (intestinal) type of tumors (p= 0.005) and no significant association was seen with age, gender, site of tumor, tumor stage, lymph node status, lymphovascular, perineural and perinodal invasion or survival.

Inspired by promising results of Trastuzumab therapy in Her 2 positive gastric carcinoma worldwide, it is recommended to routinely test all cases of gastric carcinoma for Her 2 expression and to use the targeted therapy with curative intentions in Indian population.