Automated Image Analysis of HER2 Fluorescence In Situ Hybridization to Refine Definitions of Genetic Heterogeneity in Breast Cancer Tissue

Abstract

Human epidermal growth factor receptor 2 gene- (HER2-) targeted therapy for breast cancer relies primarily on HER2 overexpression established by immunohistochemistry (IHC) with borderline cases being further tested for amplification by fluorescence in situ hybridization (FISH). Manual interpretation of HER2 FISH is based on a limited number of cells and rather complex definitions of equivocal, polysomic, and genetically heterogeneous (GH) cases. Image analysis (IA) can extract high-capacity data and potentially improve HER2 testing in borderline cases. We investigated statistically derived indicators of HER2 heterogeneity in HER2 FISH data obtained by automated IA of 50 IHC borderline (2+) cases of invasive ductal breast carcinoma. Overall, IA significantly underestimated the conventional HER2, CEP17 counts, and HER2/CEP17 ratio; however, it collected more amplified cells in some cases below the lower limit of GH definition by manual procedure. Indicators for amplification, polysomy, and bimodality were extracted by factor analysis and allowed clustering of the tumors into amplified, nonamplified, and equivocal/polysomy categories. The bimodality indicator provided independent cell diversity characteristics for all clusters. Tumors classified as bimodal only partially coincided with the conventional GH heterogeneity category. We conclude that automated high-capacity nonselective tumor cell assay can generate evidence-based HER2 intratumor heterogeneity indicators to refine GH definitions.

MET amplification assessed using optimized FISH reporting criteria predicts early distant metastasis in patients with non-small cell lung cancer

“…However, in such cases, the overall estimated copy numbers i.e. by FISH for the assessment of oncogene amplifications are often underestimated [ 26 ]. Using the definition of MET amp in this study, the results are in line with what have been reported.…”

Intratumoral Heterogeneity and Immune Response Indicators to Predict Overall Survival in a Retrospective Study of HER2-Borderline (IHC 2+) Breast Cancer Patients

“…HER2 FISH was performed on FFPE sections using the PathVysion HER2 DNA probe kit and Paraffin pretreatment kit (Abbott-Vysis, Inc., Downers Grove, IL, USA) as described in detail previously ( 87 ). Briefly, 4 µm thick sections were mounted on positively charged slides and dried overnight at 56°C.…”

Deep learning to automatically evaluate HER2 gene amplification status from fluorescence in situ hybridization images

“…In addition, studies have demonstrated that image analysis can be performed a significantly shorter evaluation time 17 , 33 . However, other studies have suggested that image analysis underestimates the HER2 and CEP17 data of FISH images compared with the results of the conventional method 34 , and manual intervention is always required during the image analysis process 17 . In this study, an automated detection method (the Aitrox AI model) for FISH images was constructed through a two-step deep learning pipeline.…”