Decreased expression of miR-34a can occur as a result of p53 mutation and/or miR-34a gene promoter methylation (both of which are known to occur in MI-BC cells [26,29]) and restoring miR-34a levels has been shown to reduce the impact of the loss of p53 and/or miR-34a function in several cancer types [30]. The gene discussed is TP53; the disease is breast cancer.