PALB2 and breast cancer: To test this hypothesis, women were classified as low risk if they met both criteria: (1) absence of P variants and variants of uncertain significance (VUS) in breast cancer genes (BRCA1, BRCA2, PALB2, ATM, and CHEK2),3,6,7,8,9 and (2) having a low (bottom 10%) polygenic risk score (PRS) using a validated 313–single-nucleotide variants (SNVs) model.10 Using these criteria, we compared breast cancer incidence among those considered at low risk with their average-risk counterparts.