The clinical relevance of the expression of several multidrug-resistant-related genes in patients with primary acute myeloid leukemia

Multidrug resistance (MDR) is a complex phenomenon that includes the expression of many different genes regulating drug transport or metabolism, cellular repair or detoxification mechanisms. The co-expression of several genes could be at the basis of the resistant phenotype in vivo. In order to test a possible prognostic role of the expression and co-expression of several MDR-related genes (MDR1, topoisomerase IIalpha, topoisomerase lip, MRP, GSTpi, LRP), 35 patients affected by acute myeloid leukemia (AML) were tested by RT-PCR assays. In our series, topoisomerase 110 was significantly co-expressed with MRP ( p=0.05), GSTpi (p=0.017) and LRP (p=0.005). GSTpi was co-expressed with LRP (p=0.03) and MRP (p=0.007); on the other hand, 53.8% of patients were LRP and MRP-positive (p=0.02). The PCR-positivity did not differ according to biological/clinical characteristics of patients, including age; this latter was the only parameter conditioning the response and overall survival. Neither the expression nor the co-expression of the tested genes was significantly correlated with the response to the induction treatment and long-term outcome.