Download p53 Sequencing for Li-Fraumeni Syndrome

p53 Sequencing for Li-Fraumeni Syndrome
Li-Fraumeni Syndrome (LFS) is a rare, autosomal
dominant familial cancer syndrome with a gene
frequency of approximately 1/50,000. The disease
was first described in 1969 by Li and Fraumeni,
who,
during
a
study
of
childhood
rhabdomyosarcomas, identified five pedigrees with
an unusually large number of family members
affected by diverse cancer types. Cancers in these
families included soft tissue sarcomas, early-onset
breast cancer, acute leukemias, brain tumors,
carcinoma of the lung, pancreas and skin, and
adrenocortical carcinoma.
In 1988, Li and
colleagues defined “classic” LFS kindreds as
families who met the following criteria: (1) a
proband with bone or soft tissue sarcoma
diagnosed before the age of 45, (2) one first degree
relative of the proband with cancer before the age
of 45 and (3) one first or second degree relative
(same lineage) of the proband with cancer before
the age of 45 or sarcoma at any age. More recently
it has been recognized that some families are
affected with tumors not previously included in the
definition of LFS such as germ cell tumors,
melanoma, prostate, and pancreatic cancer. These
families have been referred to as extended LFS. In
addition to extended LFS, a group of investigators
has also defined Li-Fraumeni-syndrome-like (LFSL), in which families demonstrate clustering of
tumors typical of LFS families, but do not meet the
criteria for classical LFS. Studies which should
help to clarify distinctions between LFS, extended
LFS, and LFS-L are currently underway.
In 1990, Malkin et al. demonstrated
germline p53 mutations in families with LFS
(Science 250:1233, 1990). The p53 protein is a
transcription factor which regulates growth factor
expression; the p53 protein exerts antiproliferative
effects via control at G1/S and G2/M checkpoints
and also plays a role in apoptosis and cellular
responses to DNA damage. The p53 gene was
investigated as a candidate for LFS because
somatic p53 mutations had been previously
identified in many sporadic malignancies including
rhabdomyosarcomas, osteosarcomas, soft-tissue
sarcomas, brain tumors, and carcinoma of the lung
and breast. Recent studies have demonstrated that
50-70% of classic LFS families have germline p53
mutations; explanations for the lack of identifiable
p53 mutations in 30-50% of classic LFS families
have yet to be elucidated. It is also important to
note that germline p53 mutations have also been
identified in LFS-L families and in a small
percentage of patients with cancers not typically
associated with LFS.
Physicians should be aware:
1. Approximately 30-50% of LFS families do not
have an identifiable germline mutation within
the p53 gene. For those LFS families in which
a p53 mutation is present, the vast majority of
these mutations will be located within exons 410. However, for certain cases, sequencing of
additional p53 exons may be indicated. These
cases should be discussed with the director of
the Molecular Diagnostics Lab.
2. For predictive and prenatal testing, it is
important to first document the presence of a
mutation in an affected family member.
3. Test results should be interpreted in the context
of clinical findings, family history, and other
laboratory results.
4. Genetic counseling is recommended for all
cases.
Testing offered:
Molecular genetic testing for LFS involves
sequence-based analysis for the detection of p53
mutations. DNA is extracted from the patient
specimen and four PCR reactions are used to
amplify exons 4-10 of the p53 gene. PCR
amplified DNA fragments, including intron/exon
boundaries, are then sequenced completely in both
the forward and reverse directions.
Patient
sequences are compared to wild type p53
sequences.
Turnaround Time:
Results are routinely available within 12 weeks.
Indications for Testing:
 Individuals with clinical features of LFS.
 Individuals with a family consistent with LFS.
Sample requirements:
Samples should be accompanied by a completed
University of Minnesota Outreach Laboratories
Molecular requisition.
Blood: 5-10 cc blood collected in a yellow top
(ACD solution A) or purple top (EDTA) tube sent
overnight at room temperature.
Isolated DNA: At least 5 µg of purified genomic
DNA will be accepted for analysis
Cultured cells: 1-2 T-25 flasks of cultured cells
may be sent overnight at room temperature in a
flask filled completely with media. Some of the
sample should be cultured separately in your lab as
a backup.
Prices effective 1/1/2013-6/30/2014:
 $1,156.68 for one gene by Next Generation
Sequencing; $2,332.45 for 2 genes
 $270.87 for known mutation
 In addition, $436.72 for Maternal Cell
Contamination (MCC) for prenatal testing
Billing:
 The University of Minnesota Physicians will
only bill the sending facility
 Pre-payment by the patient is also acceptable
 We DO NOT bill insurance
Payment:
 Make checks payable to the University of
Minnesota Physicians Outreach Labs
 We do not accept credit cards
CPT Codes:
 Full sequencing: 81479
 Level II testing for known mutations: 81479
 MCC: 81265
Send specimen to:
U of MN Physicians Outreach Lab
Attn: Specimen Management
Mayo Building, Room D293
420 Delaware St S.E. (MMC 198)
Minneapolis, MN 55455
Sample requirements:
Samples should be accompanied by a completed
University of Minnesota Physicians Outreach
Laboratory Molecular requisition.
Blood: 5-10 cc blood collected into a yellow top
(ACD Solution A) or purple top (EDTA) tube sent
overnight at room temperature.
Isolated DNA: At least 5g of purified genomic
DNA will be accepted for analysis.
Cultured cells: 1-2 T-25 flasks of cultured cells
may be sent overnight at room temperature in a
flask filled completely with media. Some of the
sample should be cultured separately in your lab as
a backup.
For more information contact:
Molecular Diagnostics Laboratory
Lab phone: (612)273-8445
Coordinator phone: (612)624-8948
Lab FAX: (612)273-8959