TGFB1 and breast cancer: In both basal and luminal breast cancer cells, linc00668 acts by binding to SND1, which recognizes conserved motifs from the SMAD2/3/4 promoters and induces the expression of its target genes, which are well known to induce the TGF-β signaling pathway, essential for maintaining stemness (Figure 2J) (Qian W. et al., 2020).