Our results indicate that including TP53 in the setting of BRCA1/2 testing might be cost-effective, since adding a single TP53 multiplex PCR to a BRCA1/2 assay resulted in the detection of four TP53 PV/LPV carriers (Fig. 1), which represents 9.7% of all PV/LPV carriers in the present study. Here, BRCA1 is linked to acquired polycythemia vera.