However, our query of the Oncomine database indicated that PER3 and to a lesser extent PER1 and PER2 expression was reduced among adenomas compared to normal mucosa, which is consistent with previous studies that observed a reduction in PER1 and PER3 expression in human colorectal tumors relative to adjacent normal tissue (32,36,56,57). This evidence concerns the gene PER2 and colorectal neoplasm.