CD4 and acute myeloid leukemia: In our study, the aberrant expression of lymphocytic markers on AML blasts was observed in a small number of cases: CD56 expression was observed in 13% of t(15;17) AML cases; the coexpression of CD19 and CD56 was observed in 28% of t(8;21) AML cases; the partial and low expression of CD19 was observed in 42% of t(8;21) AML cases; CD4 expression was observed in 7% of inv(16)/t(16;16) AML cases and in 18% of MLL-r AML cases; and CD7 expression was observed in 9% of all AML cases.