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Test Code P53CA Hematologic Neoplasms, TP53 Somatic Mutation, DNA Sequencing Exons 4-9, Varies

Useful For

Evaluating chronic lymphocytic leukemia patients at diagnosis or during disease course for the presence of TP53 gene variants indicating high risk of disease progression and adverse outcomes

 

This test is not intended for the evaluation of patients suspected of having an inherited or germline TP53 cancer syndrome (eg, Li Fraumeni syndrome)

Testing Algorithm

Flow cytometry will be performed on peripheral blood samples to verify diagnosis of chronic lymphocytic leukemia (CLL) and to selectively enrich for B-cells in samples with a clonal population.

 

See TP53 Sequencing Testing Algorithm in Special Instructions.

Reporting Name

TP53 gene somatic mutation analysis

Specimen Type

Varies


Advisory Information


For the evaluation of patients suspected of having an inherited or germline TP53 cancer syndrome (eg, Li Fraumeni syndrome), order TP53Z / TP53 Gene, Li Fraumeni Syndrome, Full Gene Analysis, Varies.



Shipping Instructions


Blood and bone marrow specimens must arrive within 10 days of collection.



Necessary Information


The following information is required:

1. Pertinent clinical history

2. Clinical or morphologic suspicion

3. Date of collection

4. Specimen source



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Blood (preferred)

Container/Tube: Lavender top (EDTA) or yellow top (ACD solution B)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

Specimen Stability Information: Ambient/Refrigerate <10 days

 

Specimen Type: Bone marrow

Container/Tube: Lavender top (EDTA), yellow top (ACD solution B), or green top (heparin)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.

Specimen Stability Information: Ambient/Refrigerate <10 days

 

Specimen Type: Tissue

Container/Tube: Plastic container

Specimen Volume: 100 mg

Collection Instructions: Stabilize fresh tissue in tissue culture medium or freeze immediately after collection.

Specimen Stability Information: Refrigerate 24 hours/ Frozen


Specimen Minimum Volume

Blood, bone marrow: 1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies 10 days

Reject Due To

Gross hemolysis Reject
Extracted DNA Moderately to severely clotted Reject

Clinical Information

Patients with chronic lymphocytic leukemia (CLL) have variable disease course influenced by a series of tumor biologic factors. The presence of chromosomal 17p- or a TP53 gene variant confers a very poor prognosis to a subset of CLL patients, both at time of initial diagnosis, as well as at disease progression, or in the setting of therapeutic resistance. TP53 gene variant status in CLL has emerged as the single most predictive tumor genetic abnormality associated with adverse outcome and poor response to standard immunochemotherapy; however, patients can be managed with alternative therapeutic options.

 

Although the prognostic relevance of an acquired TP53 gene variant is best studied for CLL, similar findings are also reported for other hematologic malignancies including low-grade B-cell lymphoma, diffuse large B-cell lymphoma, and some types of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Therefore, while this test has been developed to be primarily focused on high-risk CLL patients, TP53 gene sequencing analysis can also be performed in additional neoplasms, as clinically indicated.

Reference Values

Genetic variants present or absent as compared to a reference sequence of the normal TP53 gene

Day(s) and Time(s) Performed

Monday through Friday

Analytic Time

7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81405-TP53 (tumor protein 53) (eg, tumor samples), full gene sequence or targeted sequence analysis of >5 exons

LOINC Code Information

Test ID Test Order Name Order LOINC Value
P53CA TP53 gene somatic mutation analysis 21739-8

 

Result ID Test Result Name Result LOINC Value
MP018 Specimen Type: 31208-2
607075 Signing Pathologist 19139-5
35759 Final Diagnosis: 34574-4

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CSP53 TP53 Pre-Analysis Cell Sorting, V No No

NY State Approved

Yes

Method Name

Polymerase Chain Reaction (PCR) and Sanger Sequencing

Forms

1. Molecular Hematopathology Patient Information: B-Cell Chronic Lymphocytic Leukemia (CLL) for IGVH and/or TP53 Somatic Mutation Testing in Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.