'Some skin cancers will spontaneously regress while others will continue to grow (which may be fatal),' said Byrne.

Scientists don't yet understand why some tumours undergo regression and others continue to grow, but Byrne's team has discovered that the immune system is critically involved in the recognition of tumours and their destruction, said a Sydney release.

'This is why transplant patients on immune suppressive therapy are more prone to getting skin cancers,' he noted.

These findings have been published by the Nature Publishing Group (NPG).