乳房X线照相密度与乳腺癌风险相关，并受到已确定的乳腺癌风险因素的调节，例如生殖和激素史以及生活方式。最近的流行病学和生物学研究结果强调了母乳喂养在降低乳腺癌风险方面的公认益处，特别是对于侵袭性亚型。目前探索乳房 X 光密度、母乳喂养和乳腺癌之间关系的研究很少。怀孕期间乳房会发生变化，为哺乳做准备，其特点是乳腺组织增殖和乳腺泡发育。在哺乳期间，肺泡充满乳汁，随后的断奶会引发这些组织的复旧和重塑。母乳喂养会影响乳房微环境，可能会改变乳房X光密度。当出生后未开始母乳喂养，或在出生后不久突然停止母乳喂养时，乳房组织会经历强制和突然的复旧。相反，当母乳喂养持续较长时间并逐渐结束时，乳房组织会经历缓慢的重塑过程，称为逐渐复旧。经历突然退化的乳腺组织显示出更致密的基质、改变的胶原蛋白成分、加剧的炎症和增殖，以及雌激素受体α (ERα)和黄体酮受体的表达增加。此外，在突然复旧期间，妊娠相关血浆蛋白 A (PAPP-A) 水平升高超过其抑制剂，从而增强胰岛素样生长因子 (IGF) 信号传导和胶原蛋白沉积。母乳中的催乳素和小分子也可能调节 DNA 甲基化水平。我们的综述从当代流行病学和分子生物学研究中汲取见解，阐明了母乳喂养如何影响乳房X光密度，并探讨了其在影响乳腺癌中的作用。这篇综述强调了母乳喂养与通过乳房X光密度变化降低乳腺癌风险之间存在明确的保护性联系。未来的研究应该调查母乳喂养对不同种族群体的乳房X光密度和乳腺癌风险的影响，并阐明这些关联背后的分子机制。这种全面的研究将增强我们的理解并促进有针对性的乳腺癌预防和治疗策略的制定。© 2024。作者。

Mammographic density has been associated with breast cancer risk, and is modulated by established breast cancer risk factors, such as reproductive and hormonal history, as well as lifestyle. Recent epidemiological and biological findings underscore the recognized benefits of breastfeeding in reducing breast cancer risk, especially for aggressive subtypes. Current research exploring the association among mammographic density, breastfeeding, and breast cancer is sparse.Changes occur in the breasts during pregnancy in preparation for lactation, characterized by the proliferation of mammary gland tissues and the development of mammary alveoli. During lactation, the alveoli fill with milk, and subsequent weaning triggers the involution and remodeling of these tissues. Breastfeeding influences the breast microenvironment, potentially altering mammographic density. When breastfeeding is not initiated after birth, or is abruptly discontinued shortly after, the breast tissue undergoes forced and abrupt involution. Conversely, when breastfeeding is sustained over an extended period and concludes gradually, the breast tissue undergoes slow remodeling process known as gradual involution. Breast tissue undergoing abrupt involution displays denser stroma, altered collagen composition, heightened inflammation and proliferation, along with increased expression of estrogen receptor α (ERα) and progesterone receptor. Furthermore, elevated levels of pregnancy-associated plasma protein-A (PAPP-A) surpass those of its inhibitors during abrupt involution, enhancing insulin-like growth factor (IGF) signaling and collagen deposition. Prolactin and small molecules in breast milk may also modulate DNA methylation levels. Drawing insights from contemporary epidemiological and molecular biology studies, our review sheds light on how breastfeeding impacts mammographic density and explores its role in influencing breast cancer.This review highlights a clear protective link between breastfeeding and reduced breast cancer risk via changes in mammographic density. Future research should investigate the effects of breastfeeding on mammographic density and breast cancer risk among various ethnic groups and elucidate the molecular mechanisms underlying these associations. Such comprehensive research will enhance our understanding and facilitate the development of targeted breast cancer prevention and treatment strategies.© 2024. The Author(s).