A woman asks about the risk for developing breast cancer. Which of the following are considered as risk factors? Select all that apply.

Breast cancer involves the uncontrolled proliferation of malignant epithelial cells within the mammary ducts or lobules. Risk increases with prolonged estrogen exposure, genetic mutations like BRCA1/BRCA2, and high breast tissue density. Early detection through regular screening and identifying modifiable risk factors is essential for improving clinical outcomes. Rationale: A. Lactation is actually considered a protective factor rather than a risk factor for breast cancer. Breastfeeding reduces the total number of ovulatory cycles and promotes the terminal differentiation of mammary cells, which lowers the overall risk of malignant transformation in the breast tissue. B. A positive family history, particularly among first-degree relatives, significantly elevates an individual's risk profile. This suggests a potential genetic predisposition or shared environmental triggers that increase the likelihood of developing adenocarcinoma of the breast compared to the general population. C. Late-onset menopause, occurring at age 55 or older, increases the total lifetime exposure to endogenous estrogens. This prolonged hormonal stimulation of the mammary epithelium promotes cellular hyperplasia, which is a primary driver in the development of hormone-sensitive breast malignancies. D. Giving birth to a first child at age 20 is a protective factor against breast cancer development. A full-term pregnancy before age 30 results in long-term changes in the breast tissue that make the cells more resistant to carcinogenic influences compared to nulliparous individuals