YY1 and colorectal cancer: The transcription factor YY1 is involved in the progression of a variety of tumours, such as prostate cancer, ovarian cancer and colorectal cancer.31–33 The overexpression of YY1 in pancreatic cancer can inhibit the invasion and migration of pancreatic cancer.10 Using luciferase and ChIP assays, we demonstrated that YY1 binds to the promoter region of TPPP and inhibits the transcription of TPPP in vivo.