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

Useful For

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

Testing Algorithm

Flow cytometry CKP53 protocol may be performed on peripheral blood samples to verify diagnosis of chronic lymphocytic leukemia (CLL) and determine the percent B-cells in the sample prior to TP53 testing.

See TP53 Sequencing Testing Algorithm in Special Instructions.

Reporting Name

TP53 gene somatic mutation analysis

Specimen Type

Varies


Advisory Information


This test is not intended for the evaluation of patients suspected of having an inherited, or germline TP53 mutation cancer syndrome (eg, Li Fraumeni syndrome); if this is intended as a clinical indication, see TP53Z / TP53 Gene, Full Gene Analysis.



Additional Testing Requirements


This test is complementary to FISH analysis for the 17p- abnormality, but more appropriately identifies the presence of mutational alteration and gene inactivation in tumor cells. For hereditary (germline) TP53 mutation syndrome testing, an additional whole blood specimen is required. See TP53Z / TP53 Gene, Full Gene Analysis.



Shipping Instructions


Blood and bone marrow specimens must arrive within 4 days (96 hours) 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: EDTA (lavender top), ACD solution B (yellow top), or Heparin (green top)

Specimen Volume: 10 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 <96 hours

 

Specimen Type: Bone marrow

Container/Tube: EDTA (lavender top), ACD solution B (yellow top), or Heparin (green top)

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 <96 hours

 

Specimen Type: Tissue

Container/Tube: Plastic container

Specimen Volume: 100 mg

Collection Instructions: Freeze immediately after collection.

Specimen Stability Information: Frozen


Specimen Minimum Volume

5 mL peripheral blood
2 mL bone marrow

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred) 4 days
  Refrigerated  4 days

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 TP53 gene mutation 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 mutation 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 acquired TP53 gene mutation 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, p53 gene sequencing analysis can also be performed in additional neoplasms, as clinically indicated.

Reference Values

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

Day(s) and Time(s) Performed

Monday, Wednesday

Analytic Time

7 days

Performing Laboratory

Mayo Medical 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 In Process

 

Result ID Test Result Name Result LOINC Value
MP018 Specimen Type: 31208-2
35759 Final Diagnosis: 34574-4

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CKP53 CKP53 Protocol, B 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 Form (T726) with the specimen http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf