HER2 Abnormalities and IHC Scores: Insights from Samsung Seoul Hospital Research Team

2023-08-07 23:00:54

Samsung Seoul Hospital research team published a paper in the journal of the American Society of Clinical Oncology
Discordance between HER2 abnormalities and HER2 IHC scores by NGS in many patients

[메디컬투데이=이재혁 기자] It was suggested that it would be reasonable to perform both next-generation sequencing (NGS) and immunohistochemistry (IHC) on patients receiving treatment in the study of HER2-targeted therapy.

Recently, a research team at Samsung Medical Center published a paper titled ‘Clinical Implication of HER2 Aberration in Patients With Metastatic Cancer Using Next-Generation Sequencing: A Pan-Tumor Analysis’ in the Journal of the American Society of Clinical Oncology (JCO Precision Oncology).

In general, overexpression of human epidermal growth factor receptor (HER)2 protein is an important predictive biomarker for identifying cancer patients who may benefit from HER2-targeted therapy.

At this time, it is well known that the incidence of HER2 overexpression varies according to various types of carcinoma. However, HER2 gene abnormalities such as amplification, somatic mutation, and fusion have rarely been reported in various solid carcinomas.

Accordingly, the research team investigated the incidence of HER2 abnormalities such as mutations, amplifications, and fusions through NGS for cancer patients at Samsung Seoul Hospital.

As a result, HER2 abnormalities were found in tumor specimens of 189 (8.9%) of 2119 cancer patients. Of the 189 patients, 113 (5.3%) had HER2 amplification, 82 (3.9%) had a HER2 mutation, and 11 (0.5%) had a HER2 fusion.

It should be noted that 10 patients (0.5%) had both HER2 amplification and HER2 fusion. All of these patients showed very strong HER2 overexpression.

The research team then investigated the correlation between HER2 positivity by IHC and HER2 aberrations detected by NGS. As a result, most HER2 amplified tumors had HER2 overexpression by IHC.

However, only 2 (3.9%) of 51 patients with HER2 mutations alone (no amplification) showed HER2 overexpression by IHC. Additionally, of the 55 HER2(-) cohorts, 10 patients had only HER2 amplification and 2 patients had both HER2 fusion and HER2 amplification. There were 42 patients with only HER2 mutations.

The research team said, “Since there was a discrepancy between NGS-induced HER2 abnormalities and HER2 IHC scores in a significant proportion of patients, we performed both NGS and IHC in all patients receiving HER2-targeted therapy, especially in the context of clinical trials, to better understand tumor biology.” It would be reasonable to do so.”

Reporter Lee Jae-hyeok of Medical Today ([email protected])

[저작권자ⓒ 메디컬투데이. 무단전재-재배포 금지]

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