Comparison of fluorescence in situ hybridization and immunohistochemistry for assessment of HER-2 status in breast cancer patients

Abstract

The accurate assessment of a proto-oncogene, human epidermal growth factor receptor-2 gene (HER-2), is extremely important for the therapy and prognosis of breast cancer. Currently, immunohistochemistry (IHC) is the method widely used for the detection of HER-2 protein. Fluorescence in situ hybridization (FISH) has been suggested to be a golden standard assay for HER-2 amplification. This study examined the expression and amplification of HER-2 in paraffin-embedded sections of breast cancer tissues, and compared the two methods on the measurement of HER-2 status. HER-2 gene and protein were determined in breast cancer samples from 52 Chinese women by FISH and IHC respectively. The findings indicated that the HER-2 gene amplification was found in 18 cases (34.6%) by FISH and the HER-2 protein over-expression (score 3+) in 15 cases (28.8%) by IHC. Immunohistochemically, 28.6% of the cases scored as 2+ and 93.3% of the cases scored as 3+ were HER-2-positive by FISH. There was a significant correlation between the HER-2 gene amplification and HER-2 protein over-expression in breast cancer (P<0.005). No correlation was noted between the HER-2 gene amplification and any of the clinicopathological parameters examined, including age, menopausal status, menarche age, tumor size, histological tumor type, histological grade, lymph node status, and the expression of ER and PR. It was concluded that the detection of HER-2 gene amplification in breast cancer by FISH is valuable and can compare with HER-2 protein detection by IHC.

Assessment of Her‐2/neu status using immunocytochemistry and fluorescence in situ hybridization on fine‐needle aspiration cytology smears: Experience from a tertiary care centre in India

“…It has been suggested that IHC is appropriate for initial HER‐2/neu assessment; however, patients with tumors scores interpreted as 2+, would benefit from FISH to more accurately assess Her‐2/neu status and avoid unwarranted treatment and prognostication . To assess the feasibility and accuracy of FISH for Her‐2/neu on FNA, we chose 50 cases with 3+/2+ status (by IHC on histology) for performing FISH in corresponding MGG stained slide.…”

Assessment of Her-2/neu gene amplification status in breast carcinoma with equivocal 2+ Her-2/neu immunostaining

“…Despite some evidence that FISH testing predicts the therapeutically significant Her-2/neu status more accurately, the approach of primary immunohistochemistry screening with supplementary FISH molecular confirmation is widely used. Nevertheless, many centers recommend the initial assessment of cases of invasive breast cancer by IHC supplemented by FISH when IHC results are equivocal [17][18][19]. Several studies showed that score 2+ Her-2/neu by IHC is infrequently accompanied by true gene amplification [2,7,9], while others reported significant higher rates [8,15].…”

“…Such cases with score 2+ by IHC and with negative gene amplification are considered false positive by IHC. Possible explanations for these results could be attributed to variation in time fixation, processing conditions that can lead to variation in the intensity of staining especially with the use of heat inactivation epitope retrieval that can cause false positive results [18,21,22]. Tumor heterogeneity is another possible explanation which is documented in many tumors with the presence of a clone that is biologically different from nearby clones [23,24].…”

The paradox of seeking help: Socioeconomic inequality in medical crowdfunding in the era of the mobile internet

“…However, it still leaves many drugs and medical consumables needed for treating critical illnesses uncovered. Moreover, this program has a single source of funds, offers limited security, and suffers from low efficiency (Wu et al, 2019). Many families have had to forego treatment due to huge medical expenses (Shen and Li, 2013).…”