Guidance for Fluorescence in Situ Hybridization Testing in Hematologic Disorders

Abstract

Fluorescence in situ hybridization (FISH) provides an important adjunct to conventional cytogenetics and molecular studies in the evaluation of chromosome abnormalities associated with hematologic malignancies. FISH employs DNA probes and methods that are generally not Food and Drug Administration-approved, and therefore, their use as analyte-specific reagents involves unique pre-and postanalytical requirements. We provide an overview of the technical parameters influencing a reliable FISH result and encourage laboratories to adopt specific procedures and policies in implementing metaphase and interphase The World Health Organization recent classification of tumors of hematopoietic and lymphoid tissues emphasizes the importance of chromosome abnormalities for accurate diagnosis, appropriate treatment, and monitoring response to therapy.1 In certain scenarios, fluorescence in situ hybridization (FISH) analysis offers one of the most sensitive, specific, and reliable strategies for identifying acquired chromosomal changes associated with hematologic disorders. With the growth in the understanding of the importance of cytogenetic abnormalities associated with these diseases and the availability of commercial FISH probes, this area of clinical laboratory testing is rapidly expanding. Here, we offer guidance for initiating, validating, routinely performing, and reporting FISH studies for hematologic disorders. The recommendations in this article provide detailed assistance for implementing FISH testing and are meant to assist laboratories with complying with existing

ERG Rearrangement for Predicting Subsequent Cancer Diagnosis in High-Grade Prostatic Intraepithelial Neoplasia and Lymph Node Metastasis

“…Therefore, in our previous study, the optimal operation point was established as the proportion of cells with abnormal signal patterns greater than 1.6% in a count of at least 400 cells for scoring positive ERG rearrangements; this cutoff value was also used in the present study. Noteworthy, the cutoff value at 1.6% even appeared low, but it was convincing because break-apart probes normally generate very low background due to the design nature of these probes as well as a larger amount of cells and samples used for the establishment of cutoff values (22). In addition, based on the 143 patients undergoing pelvic lymph node dissection (56 positive and 87 negative), the optimal cutoff value by ERG rearrangement for assessing the risk of lymph node metastasis was established in the present study, being 2.6% with a high detection sensitivity and specificity.…”

Assessing RET/PTC in thyroid nodule fine-needle aspirates: the FISH point of view

“…Dual-color, dual-fusion probes (Wolff et al 2007) (BAC RP11-351D16, containing the RET gene labeled with Spectrum Red, and BAC RP11-481A12, containing the NCOA4 gene labeled with Spectrum Green) (Abbott Molecular/Vysis) were used to test the possible presence of a RET/PTC3 rearrangement in instances of conflicting results between FISH and RT-PCR for RET/PTC. Cells with RET/PTC3 have one red (RET) and one green (NCOA4) signal plus two fused red/green signals (rearranged RET/NCOA4).…”

“…BACs were selected from the UCSC Human Genome Browser (http://genome.cse.ucsc.edu) and obtained from BAC/PAC Resources (http://www.chori.org/). Two different fluorophores were used to prepare a dual-color, break-apart probe (Wolff et al 2007): BAC clones RP11-686A03 and RP11-290I03 (for the proximal breakpoint), spanning 272.9 kb, labeled by nick translation with Spectrum Red (Abbott Molecular/Vysis, Downers Grove, IL, USA), and two BAC clones RP11-818P01 and RP11-696N03 (for the distal breakpoint), spanning 351.5 kb, labeled by Spectrum Green (Abbott Molecular/Vysis) were pooled to yield strong FISH signals. The two differently labeled sets were co-hybridized as described (Frau et al 2010), resulting in two pairs of adjacent/overlapping red and green FISH signals in cells with unbroken RET and red and green split-apart FISH signals in cells with gene breakage .…”

State‐of‐the‐art FISHing: Automated analysis of cytogenetic aberrations in interphase nuclei

“…According to the recommendation of the European Cytogeneticists Association (ECA), and the concerted standpoint of the Clinical Laboratory Improvement Amendments, the American College of Medical Genetics (ACMG), and the College of American Pathologists, samples should be evaluated by two independent, trained investigators. If the two primary scores differ significantly then a third person should be called in to provide a resolution (6,7). ECAs recommendation on the minimum number of cells that should be analyzed varies depending on the field of application.…”