Assessment of glutathione S-transferaseM1 (GSTM1) and its polymorphisms GSTM1 null in the response to treatment with chemotherapy in advanced ovarian carcinoma

Abstract

Objective: To assess if the genotype of the glutathione S-transferaseM1 (GSTM1) enzyme and its GSTM1 null polymorphism can influencethe response to chemotherapeutic treatment of advanced ovariancancer. Methods: Case-control study of 112 patients with advancedovarian cancer submitted to chemotherapy during the period fromJanuary 1995 to December 2005. The tissue to study the GSTM1genotype and its deletion came from surgical staging to treatovarian cancer. The PCR product generates two distinct genotypes,characterized as positive and null. The response to chemotherapywas evaluated using the World Health Organization (WHO) criteria.Patients were classified as having: a) no response, b) a response.Results: The presence of GSTM1 or its GSTM1 null polymorphismdid not influence the preoperative chemotherapy response. Amongthe patients who did respond, 88.9% presented with positive GSTM1and 11.1% with null GSTM1. Among the patients that did notrespond, 85.71% presented with positive GSTM1 and 14.29% withnull GSTM1 (p = 0.825). GSTM1 and its GSTM1 null polymorphismhad no influence on the postoperative response to chemotherapy.Among the patients who did respond, 80.65% presented with positiveGSTM1 and 19.35% with null GSTM1. Among the patients who didnot respond, 87.50% presented with positive GSTM1 and 12.5% withthe null polymorphism (p = 0.553). Conclusion: No difference wasobserved in the response to treatment with chemotherapy in patientswith advanced ovarian cancer, as to the GSTM1 genotype comparedto its GSTM1 null polymorphism.

Keywords

• Ovarian neoplasms/drug therapy
• Polymorphism
• genetic
• Glutathione transferase