Conventional Cytogenetic Analysis of Solid Tumor Abnormalities: A 25-Year Review of Proficiency Test Results from the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.

The joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee works to ensure the competency and proficiency of clinical cytogenetic testing laboratories through proficiency testing (PT) programs for various clinical tests offered by such laboratories, including the evaluation of cytogenetic abnormalities in solid tumors. Review and analyze 25 years (1999-2023) of solid tumor chromosome analysis PT results, utilizing G-banded karyograms. A retrospective review of results from 1999 to 2023 was performed, identifying the challenges addressing solid tumors.

Conventional Cytogenetic Analysis of Constitutional Abnormalities: A 20-Year Review of Proficiency Test Results From the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.

Context.—: The joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee works to ensure competency and proficiency of clinical cytogenetics testing laboratories through proficiency testing programs for various clinical tests offered by such laboratories, including the evaluation of constitutional abnormalities.

Objective.

Immunohistochemistry and alternative FISH testing in breast cancer with HER2 equivocal amplification.

Purpose: While HER2 testing is well established in directing appropriate treatment for breast cancer, a small percentage of cases show equivocal results by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Alternative probes may be used in equivocal cases. We present a single community-based institution's experience in further evaluating these cases.