The circadian rhythm-related genes BHLHE40/DEC1 and BHLHE41/DEC2 have various functions under different cell and tissue conditions. BHLHE41/DEC2 has been reported to be both a cancer-suppressive and an oncogenic gene during cancer development. The effects of BHLHE41/DEC2 on differentiation have been examined using Bhlhe41/Dec2 knockout mice and/or in vitro differentiation models, and research has been conducted using genetic analysis of tumor cells, in vitro analysis of cancer cell lines, and immunohistochemical studies of the clinical samples. We summarize some of these studies, detail several problems, and consider possible reasons for contradictory results and the needs for further research.
Keywords: BHLHE41/DEC2; cancer; circadian rhythm; differentiation.