From Cronaca I learned of this cancer killing Tasmanian devils.

A BIZARRE infectious cancer seems to be the cause of the fatal facial tumours that are wiping out Tasmanian devils, the world's largest surviving carnivorous marsupial. The disease, which has killed at least a third of the wild population since the mid-1990s, had now infected devils across more than half the island.

Early analysis of the tumours suggested that the animals may be passing on cancerous cells during fights (New Scientist, 6 July 2005). Now a team led by Anne-Maree Pearse of Tasmania's department of primary industries has performed a genetic analysis of tumour cells from 37 animals.

Results from the first 11 animals reveal that all the tumours contain cells with 13 grossly abnormal chromosomes, instead of the usual 14 healthy ones (Nature, DOI:10.1038/439549a). They were genetically identical whatever their stage of development, suggesting they did not arise in the animals' own tissue. "The cancerous cell line is leading a sort of independent existence," Pearse says.

The idea of this cancer leading an existence as a parasitic but nevertheless somehow separate entity reminds me of HeLa cells.

HeLa cells have proven difficult to control. They sometimes contaminate other cell cultures growing in the same laboratory, interfering with biological research. The degree of contamination is unknown, because few researchers test the identity or purity of already-established cell lines. It has been claimed that a substantial fraction of in vitro cell lines are actually HeLa, their original cells having been overwhelmed by a rapidly growing population derived from HeLa contaminant cells. Walter Nelson-Rees was the first to publish on the contamination of cell lines by HeLa. It has been estimated that the total mass of HeLa cells today far exceeds that of the rest of Henrietta Lacks' body.

Life is stranger than we think.