In addition, downregulation of MAD2 in MKN45 cells significantly reduces the growth of xenografts in immunocompromised mice, concomitant with a decrease in MMP1 and SNAI2. Based on this, we hypothesize, what is known in breast cancer 33, that SNAI2 controls MMP1 expression in GCSCs. This evidence concerns the gene MMP1 and breast cancer.