Background: Gastric cancer (GC) is a significant global health concern, often diagnosed at advanced stages. While lincRNA-p21 has emerged as a potential biomarker in various cancers, its precise role in GC remains elusive.
Materials and Methods: This case-control study analyzed 40 matched pairs of tumor and non-tumor gastric samples, alongside gastric cancer cell lines. Total RNA extraction, cDNA synthesis, and real-time PCR were performed. Various cell lines, including NTERA2, AGS, MKN45, MDA-MB-231, FLO-1, OE-19, hiPSCs NP-40-8 and NP-41-17, and MSCs, were cultured to explore lincRNA-p21 expression across cancers and stem cells. Key cell cycle regulatory genes, including STAT3, CDK2, and E2F, were analyzed in gastric adenoma samples across various p53 statuses using the TCGA dataset via UALCAN database.
Results: Our findings indicate a significant decrease in lincRNA-p21 expression in tumor samples compared to non-tumor counterparts (P=0.01). LincRNA-p21 showed reduced expression across different malignancy grades. Additionally, analysis of gene expression in various cancer and stem cell lines consistently showed low levels of lincRNA-p21 expression rather than normal samples, suggesting its potential role in suppressing stemness and tumorigenesis. Further investigation into the lincRNA-p21-P21-P53 axis-regulated genes using TCGA data revealed a significant increase in their expression in both P53-mutated and non-mutated gastric adenocarcinoma compared to non-tumor samples.
Conclusion: The reduced levels of lincRNA-p21 and P21, along with elevated STAT3, CDK2, and E2F, indicate disrupted cell cycle control and tumorigenesis in gastric cancer. Consistent lincRNA-p21 downregulation across malignancy stages suggests its potential as an early prognostic biomarker for gastric cancer detection.