In addition, the expression levels of five clock genes (REV-ERBα, PER1, PER2, BMAL1, and CRY1) and three clock-controlled genes (D-Box binding PAR BZIP transcription factor or DBP, p21, and WEE1) were determined by qRT-PCR in colorectal liver metastases [50]. This evidence concerns the gene CLOCK and medical procedure.