Clinical implications of conventional cytogenetics, fuorescence in situ hybridization (FISH) and molecular testing in chronic myeloid leukaemia patients in the tyrosine kinase inhibitor era - A review

Despite the excellent treatment results obtained after the introduction of LKI drugs, especially Imatinib mesylate (IM), resistance to LKIs develops in approximately 35% - 40% of CML patients on LKI therapy. Since point mutations in BCR-ABL1 are a common cause of IM resistance, mutation analysis is important in IM resistant patients. Keywords: CML, cytogenetics, FISH, molecular testing, tyrosine kinase inhibitors INTRODUCTION The myeloproliferative neoplasm, chronic myeloid leukaemia (CML) which originates in a pluripotent stem cell in the bone marrow1, presents with leukocytosis, a left shift in the differential count and splenomegaly as the major clinical hallmarks.2 CML is a triphasic disease which starts with an initial chronic phase (CP), an intermediate accelerated phase (AP), and a final, fatal blastic phase (BP). For the estimated 1500 CML patients in Malaysia, lifelong treatment with TKIs remains the current standard of care.7 Cytogenetic analysis, fluorescence in situ hybridization (FISH) and molecular tests especially involving polymerase chain reaction (PCR), have emerged as important tests that play important roles in the management of CML by helping to establish the diagnosis as well as predict prognosis, monitor response to treatment and disease progression. [...]this review is aimed to give a conspectus of these laboratory approaches which are clinically useful and important in the management of adult CML patients.