BRCA2 and breast cancer: They also revealed that individuals with monoallelic PALB2-mutations had a 2.3-fold increased risk of breast cancer compared with controls (95% confidence interval [CI], 1.4–3.9; p = 0.0025) (6), hinting that monoallelic PALB2 mutations may have a more moderate role in breast cancer predisposition than monoallelic BRCA2 variants (58, 59).