Divergent understandings in comparative oncology

Butler et al.'s recent exploration of the rates of species diversification and cancer is an important addition to the study of comparative oncology (1).Do lineages that tend to diversify more rapidly get more cancer?The authors hypothesize that a susceptibility to genomic rearrangements might lead to higher diversification and cancer rates.However, because deleterious rearrangements are swiftly eliminated, only lineages with robust, stabilized genomes can diversify (2).Diversification is a signature of genomic stability rather than instability.Therefore, species with more stable genomes might diversify more and have less cancer.Unfortunately, the statistical model, previously published in Butler et al.'s analysis of body size and cancer (3), is deeply flawed.Butler et al. treat tumor counts as additive, therefore, any apparent relationship between diversification and cancer prevalence may simply reflect differences in sample size rather than related to evolution.Their approach estimates a proportion of necropies