The ability of the immune system to reocgnize exogenous elements is one of the factors preventing the development of transmissible tumors. However, two particular tumors are contagious and also naturally: the transmissible venereal tumor in the dog (TVT) and devil facial tumor disease (DFTD). Normally, the immune system effector cells or self antigens would prevent transmission of neoplastic cells. However, either through mutations or by generating immune tolerance, some neoplasms have evolved mechanisms to evade the immune system response. This review describes this process in the case of TVT and DFTD.
Immunology of naturally transmisible tumours. Siddle HV. Immunology. 2015. 114 (1): 11-20