การประเมินความสอดคล้องของการการประเมินความสอดคล้องของการกำหนดสถานะ HER2 โดยเทคนิค Fluorescence  in situ hybridization ด้วยหลักเกณฑ์ของ ASCO/CAP ของปี 2013 และ ปี 2018

Kanthida Jangyubol; Jutamas Yimnoon; Somboon Kittikongwat; Bongkod Petcharat; Thivaratana Sinthuwiwat; Priyavudh Herabutha

doi:10.14456/jmu.2026.17

Authors

Kanthida Jangyubol Bureau for Research and Innovation Management, Chulabhorn Royal Academy
Jutamas Yimnoon Bureau for Research and Innovation Management, Chulabhorn Royal Academy
Somboon Kittikongwat Institute of Pathology,Ministry of Public Health
Bongkod Petcharat Bureau for Research and Innovation Management, Chulabhorn Royal Academy
Thivaratana Sinthuwiwat Bureau for Research and Innovation Management, Chulabhorn Royal Academy
Priyavudh Herabutha Bureau for Research and Innovation Management, Chulabhorn Royal Academy

DOI:

https://doi.org/10.14456/jmu.2026.17

Keywords:

HER2, FISH, ASCO/CAP, breast cancer

Abstract

The human epidermal growth factor receptor 2 (HER2) gene plays a crucial role in breast cancer. Most breast cancer patients found overexpression of the HER2 protein or HER2 amplification in 15–20% of invasive breast cancers. Fluorescence in situ hybridization (FISH) is regarded as a standard method for determining the abnormality of HER2 overexpression in breast cancer. Assessment of HER2 status is an essential step for prognosis, managing the treatment, and choosing chemotherapy for breast cancer efficacy. In 2018, the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) was an improved version for testing HER2 in breast cancer in 2013. They try to decrease equivocal HER2 cases because equivocal case results are challenging for clinical treatment. After all, anti-HER2 therapy in equivocal patients is always unpredictable. Furthermore 2023, there will be ASCO-CAP HER2 testing guideline updates and no changes in the 2018 ASCO-CAP recommendations. This update affirms the 2018 ASCO-CAP guideline recommendations. This research assesses the concordant HER2 status using the FISH technique within the ASCO/CAP guideline between 2013 and 2018. Moreover, this research needs to compare HER2 status between different numbers of cells because the number of cells that should be counted and reported in this technique is controversial. The result found that in 71 cases (94.67%) of 75 cases, the HER2 status using the FISH technique within the ASCO/CAP guideline between 2013 and 2018 was concordant with 0.8886 kappa with showing a strong of not difference between HER2 status from both guidelines. Furthermore, 2 of 75 samples (2.67%) changed from equivocal to negative, making it easy to decide on treatment management. Moreover, the results of the number of cells for analysis between 200 and 60, followed by ASCO/CAP 2018, are similar, and we found 70 cases (93.33 %) in which decreasing the analyzed cell number did not affect the HER2 status. Even with a reduced number of cells used for analysis, the HER2 status interpretation was not affected. Although there were 5 cases (6.67%) with a change in status, but when looking at the kappa, it still shows strong concordant at 0.8567, indicates a high level of concordance. This study can conclude that our laboratory can use the ASCO/CAP 2018 guideline for FISH analysis, allowing the patient to receive potential treatment and reducing laboratory analysis time.

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