Birthweight, height, and body mass index in relation to the expression of stem cell markers among women with benign breast biopsies in the Nurses' Health Study II
BACKGROUND: The amount and activity of breast stem cell population may play an important role in breast carcinogenesis. However, little is known about whether early-life and adult anthropometric measures, including body mass index (BMI), birthweight, and height, are associated with stem cell marker expressions in non-cancerous breast tissue. METHODS: Among 730 women with biopsy-confirmed benign breast disease (BBD) in the Nurses' Health Study II, we quantified immunohistochemical staining of stem cell markers (CD44, CD24, ALDH1A1) in histopathologically normal epithelial and stromal breast tissue. Linear regression was conducted to estimate the associations of anthropometric measures with stem cell marker expression, adjusting for potential confounders. RESULTS: BMI at age 18 (≥23.0 vs. <19.0 kg/m2), BMI at benign breast biopsy (≥30.0 vs. <21.0 kg/m2), and change in BMI since age 18 (>7.0 vs. ≤0 kg/m2) were inversely associated with CD44 expression levels in epithelium and stroma combined (β [95% CI]= -0.30 [-0.55, -0.04]; -0.34 [-0.59, -0.08]; -0.38 [-0.65, -0.10]; respectively). Change in BMI since age 18 (>7.0 vs. ≤0 kg/m2) was also inversely associated with ALDH1A1 expression in epithelium (-0.31 [-0.62, -0.001]) and stroma (-0.63 [-1.18, -0.08]). Birthweight and height were not associated. CONCLUSION: Adiposity measures may be associated with stem cell marker expression among cancer-free women.