To investigate the effects of dyskerin overexpression in tumors in vitro, we induced a stable DKC1 overexpression through the retroviral transduction of DKC1 cDNA in three cell lines with different basal dyskerin expression (Figure S2), thus recapitulating distinct levels of transformation in vitro: From lowest to highest, MCF10A (immortalized untransformed mammary epithelium cells), MCF7 (estrogen-positive invasive breast ductal carcinoma-derived cells), and MDA-MB-231 (triple negative invasive breast ductal carcinoma-derived cells). This evidence concerns the gene DKC1 and invasive ductal breast carcinoma.