In this study tumor cell P-170 expression was assessed in 29 patients suffering from acute leukemia (17 acute myeloid leukemia (AML) and 12 acute lymphoblastic leukemia (ALL)) using three different techniques: flow cytometry measuring rhodamine 123 (Rh123) efflux (functional level), immunocytochemistry (protein level) and RT-PCR (mRNA level).
Immunocytochemical detection of the multidrug resistance (MDR)-associated membrane protein (P-170) was performed at time of diagnosis in a series of 36 children and 23 adults with acute lymphoblastic leukemia (ALL) using two monoclonal antibodies JSB1 and C219.
From these observations it appears that overexpression without gene amplification of mdr-1/P-170 may be one mechanism of clinical drug resistance in ALL.