PTPRC and acute lymphoblastic leukemia: Expression of CD27, CD34, CD45 and CD66c antigens has already been reported to be associated with prognosis of ALL.11,12,13,14,15,16,17,18 Additionally, expression of CD66c strongly correlates with BCR/ABL rearrangement.17 To our knowledge there is no data about the influence of chemotherapeutic drugs on expression of these prognostic markers in the literature.