Background: According to the stem cell hypothesis, breast carcinogenesis may be related to the breast stem cell pool size. However, little is known about associations of breast cancer risk factors, such as anthropometric measures, with the expression of stem cell markers in non-cancerous breast tissue.
Methods: The analysis included 414 women with biopsy-confirmed benign breast disease (BBD) in the Nurses' Health Study (NHS) and NHSII. Birthweight, weight at age 18, current weight, and current height were reported via self-administered questionnaire. Immunohistochemical staining of stem cell markers (CD44, CD24, ALDH1A1) in histopathologically normal epithelial and stromal breast tissue was quantified with an automated computational image analysis system. Linear regression was used to examine the associations of early-life and adult anthropometric measures with log-transformed stem cell marker expression, adjusting for potential confounders.
Results: Birthweight (≥10.0 vs. <5.5 lbs: β [95% CI]=4.29 [1.02, 7.56]; p-trend=0.001 in stroma) and adult height (≥67.0 vs. <63.0 inch: 0.86 [0.14, 1.58]; p-trend=0.02 in epithelium and stroma combined) were positively associated with CD44 expression. Childhood body fatness was inversely (p-trend=0.03) and adult height was positively associated with CD24 expression in combined stroma and epithelium (p-trend=0.03).
Conclusion: Our data suggest that anthropometric measures, such as birthweight, adult height, and childhood body fatness, may be associated with the stem cell expression among women with BBD.
Impact: Anthropometric measures, such as birthweight, height, and childhood body fatness, may have long-term impacts on stem cell population in the breast.