Therefore, we speculate that in the deterioration of CRC, activation of MYC/HIF1 down-regulates the first rate-limiting enzyme in the polyamine synthesis pathway (ODC) and reduces the synthesis of endogenous polyamines, which makes the tumor tissue plunder the polyamines of intestinal mucosa to meet its metabolic needs (Figure 1). The gene discussed is HIF1A; the disease is colorectal carcinoma.