Germline mutations of the p53 coding region are present in approximately 50-70% of patients with Li-Fraumeni Syndrome (LFS), a rare hereditary disorder of familial and intraindividual clustering of different malignancies such as sarcoma (index tumor), breast cancer, brain tumors, leukemias, and adrenocortical carcinomas, the latter usually in young children.
However, loss of heterozygosity at chromosomal locus 17p has been consistently observed in adrenocortical cancer. p53 is a recessive tumor suppressor gene located on chromosome 17p.
Children in southern Brazil that exhibit an elevated incidence of adrenocortical carcinoma (ACC) harbor an Arg 337 to His mutation within the tetramerization domain of p53 (p53-R337H; 35 of 36 patients).
According to the Chompret criteria for LFS, any patient with adrenocortical cancer (ACC), irrespective of age and family history, is at high risk for a TP53 germline mutation.
Recently, a characteristic TP53 mutation at codon 337 (R337H) has been identified in the germline of children with adrenocortical carcinoma in Southern Brazil.
These data suggest that mutational inactivation of the p53 gene occurs in a minority (20%) of sporadic adrenocortical carcinomas and that these mutations constitute a late event in the multi-step process of malignant transformation.
The authors here present a family with pR337P mutation in TP53 gene who had a child with acute lymphoblastic leukemia (ALL) and associated adrenocortical carcinoma as a case 1 and his cousin with brain tumor as a case 2.
Germline TP53 mutations predispose to a rare familial cancer syndrome, the Li-Fraumeni Syndrome (LFS), characterized by the early onset of multiple cancers including childhood adrenocortical carcinomas, sarcomas and brain tumors, and breast and colon cancer in young adults.
Germline p53 mutations carry an increased risk of development of breast cancer, soft tissue and osteosarcomas, brain tumors, leukemia and adrenocortical carcinomas.
The tetramerization domain for wild-type p53 (p53tet-wt) and a p53 mutant, R337H (p53tet-R337H), associated with adrenocortical carcinoma (ACC) in children, can be converted from the soluble native state to amyloid-like fibrils under certain conditions.
We found a statistically significant correlation between the expression of p53, p21, Ki67 and the differential diagnosis of adrenal cortical adenoma and adrenocortical carcinoma (for proteins: p53 p=0.010, for p21 p=0.010, for Ki67 p<0.001).
Clinically relevant TP53 germline mutations were identified in three of the four patients (75%) with a family history of at least two LFS-linked cancers (breast, bone or soft tissue sarcoma, brain tumors or adrenocortical cancer); 1 of the 17 patients (6%) with a family history of breast cancer only, and 1 of the 62 patients (< 2%) with no family history of breast or LFS-linked cancers.