BRCA1 and breast cancer: While this tumor phenotype is more typical of BRCA1 PGVs, TNTs  occur in 16% of BRCA2 associated breast cancers and at increasing ages as compared with BRCA1.23 In our data set, the mean age of the TNTs associated with a PALB2 PGV (46.6 years) was similar to that for TNTs associated with a BRCA2 PGV (46.8 years) and, while tending toward an older age than for BRCA1 PGVs (40.4 years), this was not significant.