Many studies report that a genomic amplification of the ABCB1-containing chromosomal region 7q21.12 occurs in MD-resistant cancers and that overexpression of genes of such region contributes to MDR (Figure 5) [51,73,119,120,121,122,123,124,125,126,127,128,129,130,131]. This evidence concerns the gene ABCB1 and cancer.