Sarcoma is the index diagnosis of Li-Fraumeni syndrome (LFS), a familial predisposition to cancer that also includes brain cancer, breast cancer, and adrenal cortical carcinoma. Germline mutations in the TP53 gene are detected in approximately 80% of families that fulfill LFS criteria and in 15% to 25% of families that fulfill criteria for Li-Fraumeni-like syndrome (LFS), a group of related syndromes with broader clinical criteria.
The authors of this report used the International Agency for Research on Cancer TP53 database to analyze the types, age at onset and mutation patterns of sarcoma in TP53 mutation carriers. Those data were compared with sarcoma types in the general population of Caucasians using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program.
Overall, sarcomas represented 25% of tumors in TP53 mutation carriers, and 95.6% occurred before age 50 years compared with 38.3% before age 50 years in the SEER data set. Sarcomas were more likely to be rhabdomyosarcoma in carriers aged <5 years (odds ratio [OR], 11.6; 95% confidence interval [CI], 6.1-21.9) and osteosarcoma in carriers at any age (aged <20 years: OR, 1.41; 95% CI, 1.02-1.94; age >20 years: OR, 4.61; 95% CI, 2.72-7.83). Early sarcoma (at age <20 years) was associated with missense mutations in exons encoding the DNA-binding domain of p53 protein. Conversely, p53 null mutations (frameshift, splice sites, nonsense) and mutations outside the DNA-binding domain were associated with leiomyosarcoma (OR, 10.1; 95% CI, 3.4-29.9), a type of sarcoma that occurred after age 20 years.
The current results further demonstrated genotype-phenotype correlations and age-dependent variations in sarcoma types in carriers of germline TP53 mutations.