Table 1.

Comparison of the topics included in the ‘genetic susceptibility: inherited syndromes’ chapter in the WHO classification, 4th edition (2012) and the ‘genetic tumour syndromes of the breast’ chapter in the WHO classification, 5th edition (2019). Of note, the association between Lynch syndrome and breast cancer is controversial, so the editorial board did not feel that there was sufficient evidence to include Lynch syndrome in the 2019 classification system. In the current classification system, Li–Fraumeni syndrome has also been split into two categories associated with variants in either TP53 or CHEK2. These classification systems may continue to evolve as more knowledge is accrued

WHO classification 4th edition (2012) 199	WHO classification 5th edition (2019) 37
BRCA1 and BRCA2 syndromes	BRCA1/2‐associated hereditary breast and ovarian cancer syndrome
Li–Fraumeni syndrome	Li–Fraumeni syndrome, TP53‐associated
	Li–Fraumeni syndrome, CHEK2‐associated
Ataxia–telangiectasia	Ataxia–telangiectasia
Cowden syndrome	Cowden syndrome
Lynch syndrome	Not included in new edition
Other breast cancer‐predisposing genes	CDH1‐associated breast cancer
	PALB2‐associated cancers
	Peutz–Jeghers syndrome
	Neurofibromatosis type 1
	The polygenic component of breast cancer susceptibility