In our study, it was discovered that BHLHE41 overexpression largely enhanced the levels of BHLHE41 and E-cadherin but repressed the levels of HIF-1α, N-cadherin, vimentin, and MMP9 in hypoxia-induced CC cells, which was consistent with the report of BHLHE41 in breast cancer [27]. This evidence concerns the gene MMP9 and breast carcinoma.