Association between Glutathione-S-Transferase and Gastric Carcinoma: A Case Control Study

ABSTRACT

Gastric carcinoma is the fourth most common cancer type and the second leading cause of cancer deaths worldwide. Every year, around 1 million new cases and 0.7 million deaths are caused due to gastric carcinoma. Gastrointestinal tract is involved in absorption and metabolism of toxic or potentially carcinogenic compounds which may be present in the food we eat. In this context, digestive tract may be considered as a major site of cancer in humans. Glutathione-S-Transferase (GST) is an important metabolizing enzyme, present in the epithelial cells of human GIT. As nearly all reactive, ultimate carcinogenic forms of chemicals are electrophiles, GST is substantially important as a mechanism for carcinogen detoxification. The present study was conducted to evaluate the role of GST in gastric carcinoma and analyse the level of serum GST in patients suffering from gastric carcinoma. METHODSThis is a case control study, conducted among 50 cases of gastric carcinoma and 50 age sex matched controls. Patients included in this study were diagnosed with gastric carcinoma, after clinical and histological examination. Circulating levels of GST were assayed in the in the serum of control group and in patients with gastric carcinoma, using standardized method. RESULTSMean GST activity in serum was significantly higher (p < 0001) in gastric carcinoma patients (8.24 ± 1.94) as compared to control (5.47 ± 0.52). After chemotherapy (12.34 ± 1.05) the activity of GST was significantly higher (p < 0001) than before chemotherapy (10.23 ± 2.12). The generation of free radicals is as reflected by increased GST and GST-π activity in carcinoma cases. CONCLUSIONSSerum GSTs measurement in plasma may be a useful tumour marker in stomach cancer and serum GSTs activity might be helpful in predicting the response of chemotherapy in advanced stages of cancer. GST values are helpful in predicting the radiation response. Overexpression of GST in neoplasia may be causal, allowing replicative advantage, or casual, accompanying clonal expansion. The major limitation to its widespread use is the time needed for doing the assay and until this is overcome it will remain primarily a research tool.