Hematologic Neoplasms, TP53 Somatic Mutation, DNA Sequencing Exons 4-9
Method Description Describes how the test is performed and provides a method-specific reference
This is a laboratory-developed test using analyte specific reagents and research use only reagents. Peripheral blood specimens of chronic lymphocytic leukemia only (but not other hematologic tumor samples) will be analyzed by a screening flow cytometry method to determine B-cell content and confirm the presence of a clonal B-cell population. The B-cell population in blood samples will then be subjected to immunomagnetic bead enrichment (Robosep, Vancouver Canada) and high-quality DNA extracted from the isolated B-cell fraction. DNA is otherwise routinely extracted directly from peripheral blood, bone marrow or fresh/frozen tissue of other specimens without prior enrichment. DNA is amplified by PCR technique targeting exons 4-9 of the TP53 (p53) gene and the PCR product is assessed for adequacy by capillary gel electrophoresis and then subjected to dideoxynucleotide automated Sanger cycle sequencing. Analysis of the sequenced DNA regions is performed using Mutation Surveyor and Alamut software and the sequence data is compared to a reference TP53 gene sequence to identify single nucleotide variants (SNV) or other types of small insertion/deletion nucleobase changes. The presence of a detected mutation is then assessed using a web-based public database of known p53 gene mutations. (http://p53.free.fr/index.html). Results are reported in standard nomenclature according to the most recent Human Genome Variation Society (HGVS) recommendations and an interpretive comment regarding the nature of the mutation (eg, known deleterious, suspected deleterious, synonymous change, etc) will be included to complete the clinical report.(The TP53 Web Site entry UMD TP53 Mutation Database. Available from http://p53.free.fr/index.html Retrieved 12/3/2013; den Dunnen JT, Antonarakis SE: Mutation nomenclature extensions and suggestions to describe complex mutations: a discussion. Hum Mutat 2000;15:7-12)
PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
DNA 3 months
Performing Laboratory Location The location of the laboratory that performs the test