STUDY AND SURVEY OF BCR-ABL TRANSCRIPT TYPES IN CHRONIC MYELOID LEUKEMIA (CML) YOUNG EGYPTIAN PATIENTS.

Abstract

Chronic myeloid leukaemia (CML) is a myeloproliferative disorder characterized by the presence of Philadelphia chromosome.

The other important risk factors are high doses of ionizing radiation, alcohol, obesity and occupational exposure to benzene.

The disease has three phases, chronic phase (CP), accelerated phase (AP) and blastic crisis (BC).

CML has a worldwide incidence of 1-1.5 cases per 100,000 inhabitants.

CML constitutes 15-20% of all leukemias.

The median age at diagnosis is 40-60 years.

CML incidence rates in western countries vary from 0.6 to 2 cases per 100,000 inhabitants

Reliable epidemiological information on chronic myeloproliferative disorders is rare. Geographic and ethnic variations contribute to the variability of incidences among CML registries. (Oehler, 2013)

BCR-ABL gene codes for a protein tyrosine kinase (PTK) that is the recognized cause of the leukemic transformation of hematopoietic stem cells (Quintas-Cardama A and Cortes J.2009).

This hybrid gene is generated by a reciprocal translocation between chromosome 9 (ABL) and chromosome 22 (BCR), to a fusion gene that is located on chromosome 22 (Philadelphia chromosome). In CML, the breakpoints in chromosome 22 are located in major breakpoint cluster region (M-BCR), leading to origin to two transcripts, e14a2 (B3A2) or e13a2 (B2A2) coding for PTK of slightly different length (P210) (Melo J 1996). Much more rarely, the breakpoint is located outside the M-BCR, either in the minor BCR (mBCR), leading to a