Although miR-34 family was discovered early in miRNA biology as the major component of the p53 tumour suppressor network [16], we only recently have begun to decipher its physiological function, and it may play very different roles in different tissues [24, 40], including osteoclastogenenesis [41], ciliogenesis [42], or cardiac aging [43]. The gene discussed is TP53; the disease is neoplasm.