In Sudan, CML is the most common cancer among males and the second most common cancer among females. Differences in the site of BCR breakpoint and the types of BCR/ABL transcripts suggest that subtypes of CML may have different prognosis and clinical course. This book therefore, aimed to determine the common frequencies of BCR/ABL fusion transcripts, and to quantify the BCR/ABL fusion transcripts and to correlate the obtained findings with hematological and clinical course findings of the disease at diagnosis. Our finding in this book showed distinct genetic profile of CML in Sudan in contrast with what have been reported in other population including those of Europe. This has been demonstrated in different frequencies of BCR-ABL rearrangements suggesting that the transcripts frequencies among Sudanese patients may be due to the ethnically different target populations. The results may explain also the distinct CML clinical course observed in Sudanese patients compared with the natural history observed in Caucasian population and also distinctive genetic profile at molecular level. That book may be of interest for molecular Scientist who are studying genetic polymorphism in cancer.