Exploring the link between low germline mutational load and low breast cancer incidence: Lessons from the Xavante...

The study of cancer, its initiation, and its mechanisms of progression has been a focal point in science for more than a century. Despite controversies among scientists, there is a growing consensus to determine the moment when a cell gains the capacity to be transformed and whether this mechanism is to be attributed to germinal or somatic events, or possibly both. The case of the Xavante Indians is a beacon for this journey, pointing toward the importance of genetic diversity in shaping our approach to cancer research and treatment. As we incorporated these lessons into clinical practice, we embarked on a new era of personalized preventative healthcare strategies against cancer. Based on recent data, we comment on the low germinal mutational load and low cancer incidence. Statistical analyses reveal a significantly lower mutation burden in Xavante women compared to global populations (p < 0.0001), including rare deleterious variants in cancer-associated genes. Additionally, polygenic risk scores (PRS) for breast cancer are markedly lower in Xavante (mean PRS ∼35) compared to TCGA cohorts (∼80-90) (p < 0.0001). The absence of breast cancer cases in Xavante is statistically significant when compared to expected rates (p < 0.001), reinforcing the hypothesis of a protective genetic landscape.