Family members of patients with FA who are heterozygous carriers of PV in genes from the fourth module FANCD1 (BRCA2), FANCJ (BRIP1), FANCN (PALB2), FANCO (RAD51C) and FANCS (BRCA1) (Figure 1) are at increased risk to develop cancer [2,21]. Here, BRCA1 is linked to acquired polycythemia vera.