TP53 and breast cancer: Furthermore, the expression of lincRNA-p21 was also inhibited after knockdown of p53 in a pair of breast cancer cell lines, MCF7 (wild-type TP53) and MDA-MB-231 (mutant TP53), which indicated that regulation of lincRNA-p21 by p53 may be a common mechanism in different cancers (Additional file 2: Figure S1).