A trend toward younger median age at cancer diagnosis was observed in biallelic CHEK2 PV carriers as compared to monoallelic carriers for all evaluated categories (≥ 1, ≥ 2, or ≥ 3 cancer diagnoses of any kind; 1 or ≥ 2 breast cancer diagnosis), though this trend was generally not statistically significant (Fig. 2). Here, CHEK2 is linked to breast cancer.