Molecular analysis of the Imatinib-induced complete cytogenetic response in chronic myelogenous leukemia.

The aim of this study was to elucidate the relationship between clonal and normal haematopoiesis in chronic myelogenous leukemia (CML). Thirteen female patients who reached complete cytogenetic response (CCR) after Imatinib treatment were studied. Although all the study patients exhibited a polyclonal pattern of X inactivation, p210 BCR/ABL transcript remained detectable in all cases by nested RT-PCR. This study also demonstrated the presence of p190 transcript in nine out of 13 study patients. A longer follow-up analysis is needed to clarify the prognostic value of these results. The recent observation that clonal cytogenetic abnormalities may occur in CML patients in polyclonal remission after imatinib suggests that a neoplastic stem cell lacking BCR/ABL rearrangement may acquire further cytogenetic alterations other than Philadelphia chromosome.