Editor—The history of Li-Fraumeni syndrome (LFS) is a good illustration of the delineation of dominantly inherited family cancer syndromes. The identification of this syndrome is the result of the combination of two kinds of evidence, firstly, a number of reports on particular familial aggregations1 ,2 and, secondly, systematic family studies of childhood sarcomas.3-6 Among these studies, the decisive contribution came from Li and Fraumeni3 who were the first to publish the results of a family study on 641 children with rhabdomyosarcoma which led to the identification of four families in which a sib or a cousin was affected by rhabdomyosarcoma or another soft tissue sarcoma (STS). These families also had several members who were affected by diverse types of malignant tumours, in particular sarcomas and breast cancer at a very young age. This prompted the authors to propose the existence of a new familial syndrome.7 A prospective study on these families over 12 years provided evidence of a strong predisposition to cancer with a strikingly high frequency of multiple tumours.8 The term “Li-Fraumeni syndrome” was used for the first time in 19829 and the criteria, which subsequently became the classical definition of the syndrome, were proposed by Li and Fraumeni in 1988.10 These were a proband with a sarcoma before 45 years of age, a first degree relative with cancer before this age, and another close (first or second degree) relative in the lineage with either cancer before this age or a sarcoma at any age. These criteria led to the selection of 24 families which exhibited a wide variety of tumours including bone sarcomas, STS, breast cancer, brain tumours, leukaemia, adrenocortical carcinoma, lymphoma, lung, stomach, pancreas, and prostate cancer, but only the first six types were significantly in excess …