PER2 and familial pancreatic carcinoma: The core circadian clock gene BMAL1 acts as a potential anti-oncogene in pancreatic cancer [25]; the loss of BMAL1 with PER2 accelerates lung tumorigenesis [26], and BMAL1 inhibits tumorigenesis and further increases the sensitivity of tongue squamous cell carcinoma to paclitaxel [24].