IGF1R and cancer: From a biological standpoint, it is worth noting that, given the ubiquitous expression of the Insulin receptor and its fetal variant’s increased levels in cancer cells, coupled with the variable expression patterns of the IGF-IR, the simple IGF-II transcript detection via available molecular detection methods identifies, bona fide, an autocrine IGF-II loop and, therefore, an IGF-II secreting tumor (IGF-IIsT).