# Plasma Lysophosphatidylcholine Levels Correlate with Prognosis and Immunotherapy Response in Squamous Cell Carcinoma

## TL;DR

Low levels of lysophosphatidylcholine in the blood are linked to worse outcomes and less response to immunotherapy in squamous cell carcinoma patients.

## Contribution

Identified plasma lysophosphatidylcholine as a novel biomarker for prognosis and immunotherapy response in SCC.

## Key findings

- Low plasma lysophosphatidylcholine levels correlate with poor overall survival in SCC patients.
- Plasma lysophosphatidylcholine levels are associated with response to immune checkpoint inhibitor therapy.
- Low LPC levels reflect systemic chronic inflammation marked by elevated inflammatory proteins and cytokines.

## Abstract

Cancer is a systemic disease rather than a localized pathology and is characterized by widespread effects, including whole-body exhaustion and chronic inflammation. A thorough understanding of cancer pathophysiology requires a systemic approach that accounts for the complex interactions between cancer cells and host tissues. To explore these dynamics, we employed a comprehensive metabolomic analysis of plasma samples from patients with either esophageal or head and neck squamous cell carcinoma (SCC). Plasma samples from 149 patients were metabolically profiled and correlated with clinical data. Among the metabolites identified, lysophosphatidylcholine (LPC) emerged as the sole biomarker strongly correlated with prognosis. A significant reduction in plasma LPC levels was linked to poorer overall survival. Plasma LPC levels demonstrated minimal correlation with patient-specific factors, such as tumor size and general condition, but showed significant association with the response to immune checkpoint inhibitor therapy. Proteomic and cytokine analyses revealed that low plasma LPC levels reflected systemic chronic inflammation, characterized by high levels of inflammatory proteins, the cytokines interleukin-6 and tumor necrosis factor-α, and coagulation-related proteins. These findings indicate that plasma LPC levels may be used as reliable biomarkers for predicting prognosis and evaluating the efficacy of immunotherapy in patients with SCC.