Multidrug resistance 1 gene expression in Indian patients with gastric carcinoma.

BACKGROUND: Gastric carcinoma is frequently refractory to chemotherapy. The multidrug resistance 1 gene (MDR1) encodes for a protein (p-glycoprotein) that functions as a drug efflux pump and thus contributes to resistance to chemotherapeutic agents. METHODS: We studied gastric tissues from 28 patients with gastric cancer for MDR1 expression, using immunohistochemistry. RESULTS: Sixteen (57%) of 28 cases showed MDR1 expression. Sections of normal mucosa away from the tumor showed perinuclear staining for MDR1 in surface epithelial cells, whereas tumor cells showed diffuse cytoplasmic positivity. CONCLUSIONS: Over one half of gastric carcinoma specimens at our center show MDR1 gene expression.