RB1 and cancer: There is mounting evidence that the usual increase of ribosome biogenesis (one of the main functions of DKC1) in cancer cells is the consequence of frequent alterations of two major tumour suppressors, TP53 and retinoblastoma (RB) genes.55 In addition, tumours with altered p53 and/or retinoblastoma protein pRb functions are characterised by significantly larger/more conspicuous nucleoli than tumours with normally functioning p53 and pRb. 56