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Paediatric Laboratory Medicine

Cancer Related Testing: Li-Fraumeni Syndrome - TP53 Deletion/Duplication Analysis

Clinical Significance

Li Fraumeni syndrome (LFS) is a clinically and genetically heterogeneous cancer syndrome associated with a wide spectrum of tumours occurring in children and young adults. LFS is caused by mutations in the TP53 gene which has been localized to chromosome 17p13.1. Germline mutations in the TP53 gene predispose individuals to various tumours associated with LFS including early onset sarcomas and breast cancer, osteosarcomas, brain cancer, leukemia and adrenal cortical carcinoma. Other cancers that have been seen in LFS families include lymphoma, melanoma, and cancers of the lung, stomach, ovary, colon/rectum, endometrium, thyroid, pancreas, prostate, and cervix. For individuals with an identified TP53 mutation the risk of developing any invasive cancer is approximately 50% by age 30 and almost 90% by age 70.

LFS is diagnosed in individuals who meet the established clinical criteria and/or are found to carry a TP53 mutation. The “classic” clinical criteria used to diagnose LFS includes: one patient with sarcoma diagnosed under the age of 45, a first-degree relative under the age of 45 with cancer (type not specified) and a third affected first or second-degree relative with either sarcoma at any age or cancer (type not specified) under the age of 45.

Individuals who do not meet the classic criteria may meet one of the following, less stringent criteria. The modified inclusion criteria for Li-Fraumeni-like syndrome (Birch’s criteria) is a proband with any childhood cancer or sarcoma, brain tumor, or adrenal cortical tumor diagnosed before 45 years of age, a first or second-degree relative with a typical LFS cancer at any age, and a first- or second-degree relative with any cancer under the age of 60 years.

Incomplete LFS criteria (Chompret’s criteria) includes a child with adrenocortical carcinoma or choroid plexus carcinoma AND a 1st—or 2nd-degree relative with early onset cancer of any kind OR child with rhabdomyosarcoma diagnosed < 3 years of age OR child with osteosarcoma diagnosed < 10 years of age OR proband with early onset multiple synchronous or metachronous cancers, at least one of which is a typical LFS tumor OR patient with early-onset breast cancer (< 45 years) with at least 1 1st- or 2 2nd-degree relatives with cancer diagnosed under age 45 OR any family with numerous cancers in the same parental lineage that have a broad spectrum of cell type lineage (i.e. carcinomas, sarcomas, leukemias, neural crest tumors).

Germline mutations in the TP53 gene have been identified in 80% of families meeting the classic LFS clinical criteria and approximately 95% can be detected by sequencing analysis. Genetic testing can be used to identify relatives at high risk for developing cancer and allow for increased surveillance for LFS-related cancers in those identified to carry a mutation. An individual is at high risk for developing an invasive LFS-related cancer when s/he has inherited one copy of the altered TP53 gene.

Test Name

Cancer Related Testing: Li-Fraumeni Syndrome - TP53 Deletion/Duplication Analysis

Alternate Name/ Synonym

  • LFS

Gene Name

  • TP53

Alternate Gene Name

P53; LFS1

Test Code

LFS

Division

Molecular Genetics

Method

Deletion/duplication analysis via MLPA

External Proficiency Testing

CAP

Turn Around Time

2 weeks (Prenatal samples), 2-3 weeks (Pregnancy/Urgent samples), 4-6 weeks (Routine)

Protein

Tumour protein p53

Disease/Condition

Li-Fraumeni Syndrome

Specimen Type

Blood; we will not accept extracted DNA for this test.

If sending a prenatal sample, please contact the laboratory prior to sending sample to discuss sample requirements.

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Minimum Specimen Requirements

5-10 mL EDTA or ACD
0.5 mL EDTA (neonate)

Storage/Transportation

Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Approval is not required

CPT Codes

81479

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Interpretation

Interpretation is provided in report

Information Sheet: Li-Fraumeni Syndrome