HIF1A and rectal cancer: In a panel of six CRC cell lines (colon cancer: HT-29, DLD-1, HT55, and HCT116; rectal cancer: C80 and C99), HIF-1α and VEGF protein levels were detected in all cells cultured under hypoxic conditions (2% oxygen) for 24h (Figure 1A), however the biggest response was observed in HT-29 cells and was used as the reference model in subsequent experiments.