A novel, de novo germline TP53 mutation in a rare presentation of the Li-Fraumeni syndrome in the maxilla
Introduction
Cancer occurrence is principally sporadic; however, non-random clusters of tumours have been recognised to occur since the mid-nineteenth century, when Rokitansky and Virchow suggested the concept of constitutional predisposition for neoplasia [1]. The first report in English was by Warren in 1837, as a brief footnote on a familial cancer case [2]. Subsequently, Sir James Paget [3], [4] in England and Paul Broca in France [5] wrote and reported on cancer heredity, with Broca being the first to attempt statistical analysis on his cases and correlation with cancer incidence and patterns in the general population. Virtually every type of cancer has since been reported to occur in a familial form, with hereditary cancer syndromes accounting for a small but significant percentage. This percentage varies greatly amongst different types of cancer. Inherited mutations in the breast cancer genes BRCA1 and BRCA2 are responsible for approximately 7% of breast cancer and 10% of ovarian cancers, while 20–25% of all medullary thyroid carcinomas are due to inherited mutations in the RET (receptor protein tyrosine kinase) proto-oncogene [6].
Li-Fraumeni (LFS) syndrome, described in 1969 [7], [8], is a rare familial multicancer syndrome characterised by a striking aggregation of multiple tumours of early onset. It features five component tumours, namely sarcomas, breast cancer, adrenocortical carcinomas, leukaemias and brain tumours. A wide range of other tumours occasionally appears in the LFS phenotype. Studies on different family series confirmed that the familial clustering in LFS is due to inherited predisposition and not to environmental factors [9], [10], [11].
LFS is a highly penetrant autosomal dominant trait, with 40% reported risk for carriers to develop carcinoma (Ca) before the age of 16 [12], high mortality rates and increased frequency of second primaries [13]. Following systematic studies and collaboration between research groups, standard clinical criteria have been developed, and families are phenotypically classified as classic LFS (LFS-C) [14] and variant LFS (LFS-V) or LFS-like (LFL) [15], [16].
LFS was shown to be associated with germline TP53 mutations [17]. Although p53 is mutated in over 50% of sporadic human cancers, this is the only clinical condition described to date that features a high percentage of germline p53 mutations. However, in approximately 30% of classic LFS families no heritable p53 mutation can be detected after complete sequence of all exons including non-coding regions [18], [12], and TP53-negative families have been the subject of extensive research in the recent years.
Section snippets
Family history
The family we studied comprised of two adults and their three children. The pedigree featured five tumours (Fig. 1) in three of the five family members. The father (I.1, deceased) developed a maxillary chondrosarcoma at age 27. The second child (patient II.2, alive) developed a cluster of tumours that included an adrenocortical carcinoma with associated hermaphroditism at age 1, an osteosarcoma of the maxilla at age 26, and Bowen's disease at age 31. The son (II.3, deceased) died due to
DNA extraction and amplification
DNA extraction and purification was performed according to a modification of standard protocols [20], [21]. Purification by phenol-chloroform extraction was additionally performed on the paraffin tissue DNA [22].
PCR amplification followed. Sets of sense and antisense primers were used for the coding exons 2-11, including 10 base pairs of the intron sequences upstream and downstream of each exon, to include the splicing sites (Table 1) [23]. Exons 2 and 3 and 8 and 9 were amplified as single
Results
SSCP/HA screening indicated heteroduplex conformational shifts in the normal tissue of all affected members, indicative of a germline mutation located in exon 5 of the p53 gene. However, these were not of the same band pattern (Fig. 2, lanes 3, 5, 7). These conformations were consistently present in repeated screenings of exon 5 on products of separate PCR amplifications. Conformational shifts indicative of normal polymorphisms in exon 4 of patient I.2 and exon 6 of patients I.2, II.2 and the
Characteristics of the identified mutation
We identified a germline A>T transversion in codon 144, exon 5 of the TP53 gene in one of the three affected members (patient II.3). Analysis of the p53 and LFS mutational databases indicated that, at the germline level, the mutation we document has not been previously reported in the literature. To our knowledge, there are no reported germline mutational events of any type at position 144, rendering this a novel mutational site for Li-Fraumeni syndrome, even though identified in only one
Electronic database information
URLs for data in this article are as follows:
Institut Curie, http://perso.curie.fr/Thierry.Soussi/p53database.htm for somatic, germline and cell-line p53 mutation database
Charles University, Faculty of Medicine, Prague, http://www.lf2.cuni.cz/projects/germline_mut_p53.htm for LFS mutational database
UMD software, http://www.umd.necker.fr/ for position mutational analysis
EMBL database, http://www.ebi.ac.uk/cgi-bin/emblfetch for TP53 sequence
Acknowledgements
We would like to thank Professor Newell Johnson, Dr. Ann Gerling, Mr. Roger Rees, Dr. S. Sousha and Dr. Evan Reed for provision of clinical information and histology material, as well as Dr. Merrill Griffiths for her kind review of histopathogical material. Special thanks to Drs. Frederick Li and Joseph Fraumeni, Dr. Thierry Soussi and Dr. Diana Barnes for their comments and advice.
References (59)
The enigmatic chondrosarcoma of the maxilla
Oral Surg.
(1972)- et al.
Rapid and sensitive detection of DNA polymorphisms using the polymerase chain reaction
Genomics
(1989) - et al.
Abnormal expression of wild-type protein in normal cells of a cancer family patient
Lancet
(1992) - et al.
Li-Fraumeni syndrome and osteosarcoma of the maxilla
J. Oral Maxillofac. Surg.
(1998) - et al.
Are germ cell tumors part of the Li-Fraumeni cancer family syndrome?
Cancer Genet. Cytogenet.
(1989) - et al.
Identification of a novel PTEN intronic deletion in Li-Fraumeni syndrome and its effects on RNA processing
Cancer Genet. Cytogenet.
(2000) - et al.
Analysis of Li-Fraumeni syndrome and Li-Fraumeni-like families for germline mutations in Bcl10
Cancer Lett.
(1999) - et al.
Development of spontaneous mammary tumours in BALB/c p53 heterozygous mice: a model for Li-Fraumeni syndrome
Am. J. Pathol.
(2000) - et al.
A conceptual history of cancer
Semin. Oncol.
(1979) Surgical Observations on Tumours, with Cases and Operations
(1837)