ARNT and colorectal neoplasm: In addition to HIF-1α, p53 was also reported to reduce the levels of HIF-1β; p53 transcriptionally induces the expression of miRNA-107, which targets HIF-1β at its 3′-UTR to repress its expression, inhibiting the HIF-1 signaling in colorectal tumor cells (Yamakuchi et al., 2010).