Fig. 1.

Timeline of the discovery of the contagious cancers CTVT, DFT1, DFT2 and BTNs. The images presented were originally published as follows: CTVT—Siddle et al. (2015); DFT1—Siddle et al. (2015); DFT2—Pye et al. (2016b); clam leukaemia—Metzger et al. (2015); BTNs—Metzger et al. (2016)