CCND1 and cancer: Cyclin-D1 plays the key role in regulation of the cell cycle progression of cancer cells and in HTB-35 cells exposed to Met the two-fold decrease of CCND1 transcript level was found under normoxia (p < 0.05 vs. untreated control) and under hypoxia as well (Figure 8B, p < 0.05 vs. untreated control).