CPM, 12q15, for Well-Differentiated Liposarcoma/Atypical Lipomatous Tumor, FISH
Method Description Describes how the test is performed and provides a method-specific reference
Formalin-fixed, paraffin-embedded tissues are cut at 4 microns and mounted on positively-charged glass slides. Five slides are prepared, with 1 to 2 slides stained with hematoxylin and eosin (H and E); the other 3 are left as unstained slides. The selection of tissue and the identification of target areas on an H and E-stained slide are performed by a pathologist. Using the H and E slide as a reference, target areas are etched with a diamond-tipped etcher on the back of the unstained slide to be assayed. Abnormalities involving the CPM locus at 12q13-15 are detected using a FISH enumeration probe, CPM (Mayo Clinic developed), along with a reference probe, CEP 12 (Abbott Molecular). The probe design consists of DNA derived from bacterial artificial chromosomes (BACs) spanning the CPM locus region and labeled with Spectrum Orange (R) and CEP 12 (D12Z3), labeled in Spectrum Green (G). The probe set is applied to the appropriate target areas, denatured, and hybridized overnight. Two independent scorers analyze 100 interphase nuclei each (200 total). Normal interphase nuclei show 2R2G signals. Normal patterns also include 1R1G, 1R2G, and 2R1G. Abnormal nuclei will have 3 or more additional G with amplification of the R, meaning the R signals will be too many to count and indicating that CPM is amplified. If the cells have multiple copies of RG, but the ratio is 1:1, this is considered abnormal, but not positive. In cases of low level amplification, green and red signals of 100 cells are recorded. If the ratio of G:R is 1:>3 the sample is called positive, if the ratio G:R is 1:2-3 then it is called low level amplification, if the ratio of G:R is 1:<2 the sample is called negative. Rarely, cases cannot be classified as neither positive nor negative; for these cases, the sample is called indeterminate. If the results of the 2 observers are comparable, the result is reported as positive or negative for amplification of the CPM locus 12q13-15 according to the 2005 ISCN nomenclature. The results are interpreted and reported by a working group pathologist.(Unpublished Mayo method)
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.
Monday through Friday; 8 a.m.-4:30 p.m.
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
1 week/7 days
Performing Laboratory Location The location of the laboratory that performs the test