BRCA1 and acquired polycythemia vera: The frequency of somatic variants (Table 1) in patients aged ≥70 years was 7% (n = 22) for BRCA1/2 and 1% (n = 2) for the 11 other HR-related genes combined and was not significantly different to those aged <70 years (i.e. somatic PV detected in 24 of 325 patients aged ≥70 years [7.38%] versus 81 of 881 patients aged <70 years [9.19%]; risk ratio of somatic PV status 0.80 [95% CI, 0.52 to 1.23]; risk difference of somatic PV status 1.81% [95% CI, −1.49% to 5.78%]; p = 0.36, Fisher's exact test).