# CHEK1 Expression Correlates with Tumor Progression in Lung Adenocarcinoma but Not in Squamous Cell Carcinoma

## TL;DR

CHEK1 expression is linked to worse outcomes in lung adenocarcinoma but not in squamous cell carcinoma, suggesting it could be a useful biomarker for the former.

## Contribution

Identifies CHEK1 as a subtype-specific prognostic biomarker for lung adenocarcinoma but not squamous cell carcinoma.

## Key findings

- High CHEK1 expression correlates with advanced tumor stage and shorter survival in lung adenocarcinoma.
- CHEK1 expression does not significantly affect survival outcomes in squamous cell carcinoma.
- CHEK1 overexpression reflects tumor aggressiveness in lung adenocarcinoma.

## Abstract

Background and Objectives: Non-small cell lung cancer (NSCLC) is histologically divided into adenocarcinoma (AD) and squamous cell carcinoma (SCC). While Checkpoint kinase 1 (CHEK1) regulates the DNA damage response, its subtype-specific clinical impact in NSCLC remains unclear. We investigated the association of CHEK1 expression with clinicopathologic features and prognosis in AD and SCC. Materials and Methods: Transcriptomic and clinical data from 980 patients (492 AD, 488 SCC) were analyzed using The Cancer Genome Atlas (TCGA). Patients were stratified by median CHEK1 mRNA expression. Relationships between expression and clinicopathologic variables were evaluated via Chi-square tests, and overall survival (OS) was assessed using Kaplan–Meier analysis. Results: In AD, high CHEK1 expression significantly correlated with advanced T stage (p < 0.001), lymph node metastasis (p = 0.025), younger age (p = 0.017), and shorter OS (p = 0.025). Conversely, CHEK1 expression in SCC did not reach statistical significance for survival outcomes, although a borderline trend was observed (p = 0.067). Conclusions: CHEK1 is a subtype-specific prognostic biomarker for AD but not for SCC. These findings suggest that CHEK1 overexpression reflects tumor aggressiveness in AD, highlighting its potential as a therapeutic target for this specific population.