Cancer Genes, Tumor Suppressors, and Regulation of IGF1-R Gene Expression in Cancer

The IGF1-R displays potent antiapoptotic, prosurvival activities and has an important role in cell cycle progression. In addition, activation of the IGF1-R signaling pathway is a crucial prerequisite for malignant transformation. Overexpression of the IGF1-R has been identified as a typical hallmark of many, but definitely not all, types of tumors. The level of expression of the IGF1-R gene is determined by the concerted action of positively acting and negatively acting transcription factors. Loss-of-function mutation of tumor suppressors, a characteristic feature of many human cancers, leads to IGF1-R expression, with ensuing activation of cell-surface receptors by circulating and/or locally produced IGF-1 and IGF-2.