Does placental invasiveness lead to higher rates of malignant transformation in mammals?Response to: ‘Available data suggests positive relationship between placental invasion an malignancy’

Abstract

In our study, Lifetime cancer prevalence and life history traits in mammals, we reported the prevalence of neoplasia and malignancy in a select group of mammals housed at San Diego Zoo Global from 1964 to 1978 and 1987 to 2015 [1]. We also used these data to evaluate associations between life history traits and measures of population health. Our analysis showed placental invasiveness could not predict the proportion of animals diagnosed with neoplasia or malignancy. In a response to our article, Drs Wagner and colleagues describe a different calculation to test for a relationship between placental invasiveness and malignancy. They identified and included previously published veterinary neoplasia and malignancy data with our published dataset and suggest a positive relationship between placental invasiveness and development of malignancy (referred to as malignancy rate in Wagner and colleagues’ response). These data provided support for the Evolved Levels of Invasiveness (ELI) hypothesis [2]. We are pleased that other investigators find our data useful, and wholeheartedly agree with Drs Wagner and colleagues in the need to identify more data on cancer in a wide variety of species. Notwithstanding, this updated analysis brings up a number of topics that we would like to address....