It is then not surprising that regulation of HIF-1α and its target genes is essential in CRC cells, which display high energy demands and are controlled by an intricate network of signaling pathways (PI3K/PTEN/Akt, JNK cascade, Wnt, p53, K-ras, LB1/AMPK, TGF-β). Here, KRAS is linked to colorectal carcinoma.