Cancer is pervasive across multicellular species, but what explains the differences
in cancer prevalence across species? Using 16,049 necropsy records for 292 species
spanning three clades of tetrapods (amphibians, sauropsids, and mammals), we found
that neoplasia and malignancy prevalence increases with adult mass (contrary to Peto’s
paradox) and somatic mutation rate but decreases with gestation time. The relationship
between adult mass and malignancy prevalence was only apparent when we controlled
for gestation time. Evolution of cancer susceptibility appears to have undergone sudden
shifts followed by stabilizing selection. Outliers for neoplasia prevalence include
the common porpoise (<1.3%), the Rodrigues fruit bat (<1.6%), the black-footed penguin
(<0.4%), ferrets (63%), and opossums (35%). Discovering why some species have particularly
high or low levels of cancer may lead to a better understanding of cancer syndromes
and novel strategies for the management and prevention of cancer.
