Predictive biomarkers for immunotherapy response in extensive-stage SCLC

Area of Science:

• Oncology
• Immunotherapy
• Biomarker Discovery

Background:

• Small cell lung cancer (SCLC) is highly malignant with frequent metastasis.
• Extensive-stage SCLC (ES-SCLC) is diagnosed in 70% of patients.
• Immunotherapy plus chemotherapy is standard first-line treatment for ES-SCLC, but response is limited.

Purpose of the Study:

• To identify predictive biomarkers for immunotherapy in ES-SCLC.
• To review traditional biomarkers like PD-L1 and TMB.
• To explore potential biomarkers including molecular subtypes, gene expression, MHC classes, TIME, and ctDNA.

Main Methods:

• Literature review of traditional and potential biomarkers for ES-SCLC immunotherapy.
• Analysis of research progress on programmed cell death ligand 1 (PD-L1) and tumor mutation burden (TMB).
• Investigation of molecular subtypes, gene expression, MHC I/II, TIME, and ctDNA as prognostic biomarkers.

Main Results:

• Conventional biomarkers like PD-L1 and TMB are not suitable for SCLC.
• Molecular subtypes based on transcription factors may offer guidance.
• Circulating tumor DNA (ctDNA) shows high positivity rates and dynamic changes, aiding in tissue accessibility and treatment prediction.

Conclusions:

• Biomarker exploration for SCLC immunotherapy remains challenging.
• Molecular subtypes require prospective clinical validation.
• ctDNA presents a promising avenue for SCLC biomarker development due to accessibility and dynamic predictive potential.