The diagnosis of LFS can be established if the patient conforms to the classical diagnostic criteria and is family based on the germline variant of TP53. When LFS is clinically suspected, it is recommended to go for genetic testing of TP53. LFS is considered a syndrome of high penetrance, with reports of a lifetime cancer risk of more than 70% in men and 90% in women [5, 6] and an 80% risk of cancer by age 70 [7]. This evidence concerns the gene TP53 and Li-Fraumeni syndrome.