Immunotherapy and lung cytopathology: Overview and possibilities

Area of Science:

• Oncology and Pathology
• Cancer Immunotherapy Research

Background:

• Immunotherapy has emerged as a significant cancer treatment modality.
• Immunohistochemistry (IHC) is the standard for Programmed Death-Ligand 1 (PD-L1) and Programmed Death 1 (PD1) evaluation.
• PD-L1 assays are applicable to both formalin-fixed paraffin-embedded (FFPE) tissues and cytological samples, but validation on smears is ongoing.

Purpose of the Study:

• To review the role of cytopathology in analyzing PD-L1 expression using immunocytochemistry (ICC).
• To explore future directions for cytopathology in the context of cancer immunotherapy.
• To highlight the potential of advanced imaging and algorithms for PD-L1 interpretation in cytological specimens.

Main Methods:

• Review of existing literature on PD-L1 testing in cytological samples.
• Discussion of immunohistochemistry (IHC) and immunocytochemistry (ICC) techniques for PD-L1 evaluation.
• Exploration of multiplexed immunofluorescence (mIF) assays on minimally invasive cytological samples.

Main Results:

• While IHC is established, the application of PD-L1 assays on cytological smears requires further validation.
• Digital imaging and algorithms offer potential for improved interpretation of PD-L1 in cytological samples.
• Multiplexed immunofluorescence (mIF) on cytological samples is a promising approach for studying the tumor immune microenvironment in non-small cell lung cancer (NSCLC).

Conclusions:

• Cytopathology plays an increasingly important role in evaluating biomarkers for immunotherapy.
• Further research and validation are needed to optimize PD-L1 testing on cytological specimens.
• Advanced techniques like mIF hold promise for comprehensive immune profiling in NSCLC.