C-MYC Involvement in Chronic Lymphocytic Leukemia (CLL): A Molecular and Cytogenetic Update

Chronic lymphocytic leukemia (CLL) is a disorder entailing the slow proliferation of B-cell lymphocytes in the bone marrow and blood. In 2015, it is estimated that 14,620 patients will be diagnosed with CLL, and approximately 4,650 patients will die due to disease progression. CLL typically presents in patients about 71 years of age. Initially, the patients exhibit leukocytosis; however, as the disease progresses, they experience splenomegaly, lymphadenopathy, hepatomegaly, anemia, and infections. Although about 84% of CLL patients will survive for five years or more, CLL cases that report MYC (8q24) translocations with IGH, IGK, IGL, and TCR genes have poor prognoses and low survival rates. Recent studies have shown data supporting both a positive correlation and no correlation between disease progression and MYC expression. Nonetheless, other studies have revealed new information on multiple MYC-dependent pathways responsible for leukemogenesis and tumorigenesis. Herein, we summarize the current molecular nd cytogenetic findings in MYC-associated CLL, with focus on the underlying MYC-dependent mechanisms of leukemogenesis and MYC-associated CLL progression and treatment regimen.