Image: Mathias Appel / Wikimedia Commons
The realization that such contagious cancers may be more widespread than previously thought has intensified efforts to understand their biology—not just for the sake of the species they affect, but also to understand how cancer can become an infectious disease. Many questions remain unanswered, including how these diseases emerge and in what populations. But in the last few years, genetic and immunological studies have provided some insight into these cancers’ interactions with their hosts. The findings have led researchers to view them as independent parasites, with the survival of their host species depending on a delicate interplay between the animals’ immune systems and the cancers’ ability to evade them.