PALB2 mutations are not as frequent in the population as BRCA1 and BRCA2 mutations; however, the role of PALB2 in breast cancer susceptibility is still significant, some studies suggesting that particular PALB2 mutations may predispose individuals to breast cancer to a similar extent as BRCA2. It therefore warrants knowing who should be tested. This evidence concerns the gene PALB2 and breast cancer.