Can Fluorescent In Situ Hybridization (FISH) be performed on lymphocytes in both metaphase and interphase?

From the Guidelines

Fluorescent In Situ Hybridization (FISH) can indeed be performed on lymphocytes in both metaphase and interphase stages. This is supported by the European recommendations for cytogenomic analysis of haematological neoplasms, which highlight the utility of FISH in diagnosing and managing these conditions 1.

Key Points:

• FISH analysis can be used as a sole or first-line test for some neoplasms, particularly when metaphases are difficult to obtain or rapid diagnostic testing is required 1.
• Interphase FISH is useful for detecting numerical chromosome abnormalities and specific gene rearrangements without the need for cell culture, making it valuable for rapid screening 1.
• Metaphase FISH, on the other hand, offers better resolution for structural abnormalities and can provide high-resolution mapping of genetic loci 1.
• The choice between metaphase and interphase FISH depends on the specific diagnostic question, with each approach having its own advantages and limitations 1.
• It is essential to validate any FISH system used in a diagnostic setting, including establishing thresholds and confidence limits for all FISH probes and probe sets 1.
• A minimum analysis of 100 interphase nuclei is recommended for diagnostic samples, with at least 200 interphase nuclei required for follow-up of previously detected clonal anomalies 1. When considering the application of FISH on lymphocytes, it's crucial to understand the strengths and limitations of both metaphase and interphase analyses to ensure the most appropriate diagnostic approach is chosen.

From the Research

Fluorescent In Situ Hybridization (FISH) on Lymphocytes

• FISH can be performed on lymphocytes in both metaphase and interphase, as stated in 2 and 3.
• The technique is widely used to study numerical and structural genetic abnormalities in both metaphase and interphase cells 2.
• Interphase FISH is most often applied on cytologic material such as hematologic smears or imprints, but the method is also used to study genetic changes in tissue sections when morphology is important or when cytologic material is not available 2.
• FISH analysis has become standardized in its ability to detect characteristic chromosomal anomalies in association with genetic and neoplastic diseases, and can be used in the interphase and metaphase stages of the cell cycle 3.

Metaphase and Interphase FISH

• Metaphase FISH was performed on follow-up samples from patients suffering from haemopoietic malignancies, and was found to be reliable and sensitive for detection of minimal residual disease 4.
• Interphase FISH can provide estimates of numerical alterations which closely reflect those seen during metaphase analysis using either FISH or conventional approaches, but frequencies of aneuploid nuclei obtained using single label FISH should only be considered approximations of absolute frequencies 5.
• Multi-color FISH with two or more different probes can be used to increase accuracy 5.

Applications of FISH

• FISH is widely used in routine diagnostics to identify cancer-specific aberrations including lymphoma-associated translocations or gene copy number changes in single tumor cells 6.
• The technique is also used to study genetic changes in tissue sections when morphology is important or when cytologic material is not available 2.
• FISH technology provides essential information to the physician regarding the diagnosis, response to treatment, and ultimately the prognosis of their patients' disorder 3.