PROGNOSTIC SIGNIFICANCE OF GLUTATHIONE S-TRANSFERASE µ3 mRNA EXPRESSION IN ACUTE LYMPHOBLASTIC LEUKEMIA

Glutathione S-transferase μ3 (GSTμ3) is one of the isoforms of the μ class of the glutathione S-transferase (GST) multigene family of enzymes implicated in intracellular detoxification mechanisms. It has been linked to various types of carcinogenesis. To investigate the pattern of GSTμ3 expression and its prognostic impact in childhood acute lymphoblastic leukemia (ALL), peripheral blood (PB) and bone marrow (BM) aspirate samples were obtained from 25 patients. They were 13 males and 12 females, with age ranging from 6 to 159 months, and were subjected to complete blood count (CBC), BM examination, cytochemistry, immunophenotyping and detection of GSTμ3 mRNA expression by polymerase chain reaction (PCR). According to the immunophenotyping findings samples were clas- sified into 21 B-lineage ALL and 4 T- lineage ALL. GSTμ3 was expressed in 14 (67%) of B-lineage ALL and 3 (75%) of T-lineage ALL samples, sharing no significant relation with established prog- nostic indicators (age, sex, white blood cell count). A positive correlation between lymphoblast expres- sion of GSTμ3 and prognosis was demonstrated with a better overall clinical outcome. These findings suggest that GSTμ3 mRNA expression may convey a positive prognostic impact in childhood ALL, making it possible to stratify patients and exploit new therapeutic strategies.