TP53 and Li-Fraumeni syndrome: Six of the 18 patients (33%) with positive findings in TP53 did not meet classic Li-Fraumeni syndrome,20 Li-Fraumeni-like,21 2009 Chompret,22,23 or National Comprehensive Cancer Network guideline criteria for TP53 testing,24 resulting in a frequency of 0.06% (6/9,605) unanticipated positive results.