TP53 and neoplasm: Noticeably, the introduction of two mutant TP53 proteins (R175H and R248W) into HCT116 TP53−/− cells, which have been shown to exert oncogenic instead of tumor suppressive activity (Liu et al. 2010), significantly reduced the association between let-7 and AGO2 (Fig. 2G), while a third TP53 mutant (R273H) lost its capacity to affect this association.