Subtypes of breast cancer and fast life history strategy

Hidaka, B. H., & Boddy, A. M. (2016). Is estrogen receptor negative breast cancer risk associated with a fast life history strategy? Evolution, Medicine, and Public Health, 2016(1), 17–20. http://doi.org/10.1093/emph/eov034  Open access

Risk factors for breast cancer are often confusing and contradictory. Discrepancies are likely due to different subtypes having divergent risk factors. An important distinction between breast cancer subtypes is hormone-receptor status. Compared to women diagnosed with estrogen receptor positive (ER+) breast cancer, those with estrogen receptor negative (ER−) tumors are usually diagnosed at a younger age and have a higher mortality [1]. Few studies have attempted to explain ‘why’ breast cancer subtypes have different risk factors. buy generic zovirax

In a recent meta-analysis, Aktipis et al. [2] demonstrated that modern reproductive behaviors are more strongly associated with the development of ER+ than ER− breast cancer. The systematic review specifically reported the following: (a) fewer total offspring is a risk factor for ER+, but not ER−, tumors; (b) older age at first birth is associated with risk for ER+, but not ER−, tumors and (c) lower age of menarche is a risk factor for both ER+ and ER− tumors buy levaquin 500mg. These results support the evolutionary mismatch hypothesis for ER+ breast cancer susceptibility; that is, modern women have a higher risk from more menstrual cycles and greater cumulative exposure to estrogen compared to ancestral humans. However, modern reproductive patterns seem to have little influence on hormone-independent breast cancer risk. Breast cancer susceptibility may require complementary evolutionary explanations. In this article, we propose that the risk factors for ER− breast cancer, low socioeconomic status (SES), poor diet and early age of menarche are features of a faster life history strategy. buy Lasix 20mg

Life history theory provides a framework for understanding how, when and why organisms allocate their resources [3]. To maximize reproductive success, organisms must strategically distribute resources toward growth, reproduction and somatic maintenance. This process of phenotypic development is largely determined by trade-offs. Three of the most important trade-offs include reproduction versus  Full article here