DNMT1 and breast cancer: Another example is represented by the DNMT1/miR-148a and miR-152 circuit [273]: DNMT1 catalyzes promoter hypermethylation and silencing of the two miRNAs in both BC cells and tissues, thus upregulating IGF-IR and IRS1 (which are also targeted by miR-148a and miR-152) and promoting tumor growth and angiogenesis [272].