The results revealed that radiation increased the ratio of MAP1LC3-II/MAP1LC3-I in MDA-MB-231-2A cells (PTTG1-knockdown MDA-MB-231 cells) and MCF-7 cells (low PTTG1 expression), but not in the parental MDA-MB-231 cells, suggesting that radiation induced autophagy in PTTG1-depleted cancer cells. Here, PTTG1 is linked to cancer.