CHEK2 and breast cancer: The CHEK2 c.1100delC PV was identified in only 2/379 (0.53%) compared with 1.7% (55/3177) in women with breast cancer aged >30 years (p=0.0835) seen at the MCGM and 2.3% in the POSH study aged ≤40% and 1% in POSH cases≤30 years (table 1).