Diagnostic and Predictive Immunohistochemistry for Non-Small Cell Lung Carcinomas

Area of Science:

• Oncology
• Pathology
• Molecular Diagnostics

Background:

• Non-small cell lung carcinoma (NSCLC) is a leading cause of cancer-related death globally.
• Advanced stage diagnosis is common, necessitating targeted therapies and immunotherapy.
• Immunohistochemistry (IHC) plays a vital role in surgical pathology for NSCLC diagnosis and management.

Purpose of the Study:

• To review diagnostic and predictive immunohistochemical (IHC) markers in NSCLC.
• To highlight emerging diagnostic markers like NUT and SMARCA4.
• To discuss the utility of IHC for predictive biomarkers in advanced NSCLC.

Main Methods:

• Review of current literature on diagnostic and predictive IHC markers in NSCLC.
• Discussion of specific markers including NUT, SMARCA4, ALK, ROS1, PD-1, EGFR, BRAF V600E, RET, pan-TRK, LKB1, ERBB2, and MET.
• Analysis of the role of IHC versus molecular methods for biomarker detection.

Main Results:

• Emerging markers NUT and SMARCA4 are important for specific aggressive thoracic tumors.
• IHC is essential for "must-test" predictive biomarkers such as ALK, ROS1, PD-1, and EGFR.
• IHC serves as a screening or confirmation tool for BRAF V600E, RET, pan-TRK, and LKB1.
• Molecular methods are primary for ERBB2 and MET alterations, with limited IHC role.

Conclusions:

• IHC is indispensable in the integrated practice of surgical pathology and molecular diagnostics for NSCLC.
• IHC functions as a surrogate for molecular testing, enabling precision medicine.
• Accurate IHC marker interpretation is critical for optimal patient management and targeted therapy selection.