PALB2 and breast cancer: The most common protein-truncating genetic variant in Western European populations is the frame shift c.1100delC (p.Thr367MetfsTer15, rs555607708); a recent analysis by the Breast Cancer Association Consortium (BCAC) estimated a relative risk of 2.26 for this variant.10 Truncations of PALB2, the partner and localiser of BRCA2, have been associated with a fivefold relative risk,4 though studies in different populations have produced divergent estimates.11–14 XRCC2 encodes a protein in the Rad51 family that participates in homologous recombination repair of double-stranded DNA breaks.