When PHB1 expression was downregulated, the expression level of MAT1A decreased, and the expression levels of c-Myc, MAF bZIP transcription factor G (MAFG) and cellular musculoaponeurotic fibrosarcoma (c-MAF) increased; these proteins then bound to the E-box promoter region of the MAT1A blocker, negatively regulating the transcription of MAT1A and ultimately promoting the proliferation of tumor cells. This evidence concerns the gene MAF and fibrosarcoma.