Table 5:

Risk Factors for Male Breast Cancer

Risk Factor Category	Examples of Risk Factors
High estrogen level	Exogenous estrogen exposure, Klinefelter syndrome, body mass index ≥ 30, cirrhosis, pituitary adenoma
Low androgen level	Cryptorchidism, orchitis, orchiectomy
Genetic mutations	BRCA2, BRCA1, CHEK2, CYP17A1, PTEN
Exposures	Radiation, electromagnetic fields, polycyclic aromatic hydrocarbons, high ambient temperature, exhaust
Family history	First-degree relative with breast or ovarian cancer
Personal history	Breast cancer
Race and ethnicity	Ashkenazi Jew, African American, Saharan African

Note.—BRCA1 = BRCA1, DNA repair associated gene; BRCA2 = BRCA2, DNA repair associated gene; CHEK2 = checkpoint kinase 2 gene; CYP17A1 = cytochrome P450 family 17 subfamily A member 1 gene; PTEN = phosphatase and tensin homolog gene.