In cases of VD deficiency and/or unresponsiveness such as advanced colorectal tumor lacking VDR expression due to transcriptional repression by SNAIL1/2 (Pálmer et al., 2004; Larriba et al., 2009), the activation of SIRT1 by compounds other than 1,25(OH)2D3 may be especially relevant. The gene discussed is SIRT1; the disease is colorectal neoplasm.