[1,2,3] Its content has been found greatly diminished in cancer cells with respect to the corresponding normal line [1] and its exogenous administration to adenocarcinoma (HT29), [4] osteosarcoma (U2OS, [5] or SaOS [6]) cancer cell lines results in a significant inhibition of the proliferation rate, as well as a significant increase of p53-independent p21 expression. The gene discussed is CDKN1A; the disease is cancer.