HIF1A and neoplasm: Specifically, because in the classical angiogenesis pathway the main driver of vascular development is VEGF (itself being upregulated by HIF-1A under hypoxic conditions [57]), we hypothesized that the use of endoscopic DRS and the longitudinal analysis of the levels of expression of Vegf and Hif-1a mRNA (and also the levels of mRNA from genes are known to upregulate VEGF and HIF-1A in an independent manner) would be able to provide a more comprehensive picture of the effect of MET and MTD NAC regimens in tumor angiogenesis in CRC.