These mechanisms of emergence have been implicated in both DFTD and CTVT (Murchison et al., 2014; Siddle, Sanderson, Sanderson, & Belov, 2007), although the absence of MHC molecules from circulating tumours indicates that the host immune system has exerted pressure on the cancer cells during their evolution, as has been observed in single‐organism cancer (McGranahan et al., 2017). This evidence concerns the gene HLA-C and cancer.