Dysregulation of the C/EBPα Differentiation Pathway in Human Cancer

While much is known about aberrant pathways affecting cell growth and apoptosis, our understanding of another critical step of neoplastic transformation, differentiation arrest, remains poor. The differentiation-inducing transcription factor CCAAT enhancer binding protein alpha (C/EBP alpha) is required for proper control of adipogenesis, glucose metabolism, granulocytic differentiation, and lung development. Studies investigating the function of this protein in hematopoietic malignancies as well as in lung and skin cancer have revealed numerous ways how tumor cells abrogate C/EBP alpha function. Genetic and global expression analysis of acute myeloid leukemia (AML) cases identifies C/EBP alpha-deficient AML as a separate entity yielding novel classification schemes. In patients with a dysfunctional C/EBP alpha pathway, targeted therapies may overcome the block in differentiation, and in combination with conventional chemotherapy, may lead to complete eradication of the malignant clone. Overall, a better understanding of the mechanisms of how C/EBP alpha dysregulation participates in the neoplastic process has opened new gateways for differentiation biology research.