In support of our BRCA1 and BRCA2 results, there was not an increased frequency of PV in LM cases compared to controls in the UKB for BRCA1 (0.2% in cases vs. 0.1% in controls) or BRCA2 (0.3% in cases vs. 0.3% in controls). The gene discussed is BRCA1; the disease is acquired polycythemia vera.