Modern reproductive patterns associated with estrogen receptor positive but not negative breast cancer susceptibility.

C Athena Aktipis,Katherine K Nishimura,Robert A Hiatt,Bruce J Ellis

doi:10.1093/emph/eou028

Abstract

It has long been accepted that modern reproductive patterns are likely contributors to breast cancer susceptibility because of their influence on hormones such as estrogen and the importance of these hormones in breast cancer. We conducted a meta-analysis to assess whether this ‘evolutionary mismatch hypothesis’ can explain susceptibility to both estrogen receptor positive (ER-positive) and estrogen receptor negative (ER-negative) cancer. Our meta-analysis includes a total of 33 studies and examines parity, age of first birth and age of menarche broken down by estrogen receptor status. We found that modern reproductive patterns are more closely linked to ER-positive than ER-negative breast cancer. Thus, the evolutionary mismatch hypothesis for breast cancer can account for ER-positive breast cancer susceptibility but not ER-negative breast cancer.

Highlights

It has long been known that breast cancer is associated with reproductive factors such as age of menarche, parity and reproductive timing [1]
Parity was found to be protective against estrogen receptor (ER)-positive breast cancer (Fig. 1a; odds ratio (OR) = 0.77, 95% confidence interval (CI) = 0.71–0.82, P < 0.001) but not protective against ER-negative breast cancer (Fig. 1b; OR = 1.01, 95% CI = 0.95–1.08, P = 0.69)
Our meta-analysis indicated that late age of first birth was associated with higher odds of ER-positive breast cancer (Fig. 2a; OR = 1.42, 95% CI = 1.30–1.55, P < 0.001)

Summary

Introduction

It has long been known that breast cancer is associated with reproductive factors such as age of menarche, parity and reproductive timing [1]. Modern reproductive patterns not associated with ER-negative breast cancer different risk factors [2,3,4,5,6,7,8,9,10,11]. We take an evolutionary approach to examine how risk factors associated with modern reproductive patterns as opposed to those characteristic of ancestral peoples differ with regard to estrogen receptor (ER) status

Methods

Results

Discussion

Conclusion