The potential of platelet TGF-β and Smad2 mRNAs as biomarkers for colon cancer diagnosis and grading

Currently, liquid biopsy has been widely investigated for improving the diagnosis and monitoring of colon cancer. As a potential sample type, platelets are abundant in the circulation and provide multiple types of information closely related to tumors. In this study, we investigated the associations between patients’ platelet TGF-β/Smad2 mRNA levels and colon cancer pathologic type and explored their potential value as biomarkers for diagnosis and grading. We performed a bioinformatics study on the GSE68086 dataset to identify differentially expressed platelet mRNAs, followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. For the 104 participants, including colon cancer patients and healthy individuals, the expression of the TGF-β and Smad2 mRNAs in platelets and tissues was quantified. We analyzed the correlations of platelet mRNAs with local tumors and pathological characteristics. We also established cutoff values for platelet TGF-β and Smad2 mRNA levels for colon cancer diagnosis. KEGG analysis revealed high enrichment of platelet-derived TGF-β and SMAD2 in colon cancer. TGF-β and Smad2 mRNAs were upregulated in patient platelets and tumors ( P < 0.05). Platelet Smad2 was expressed at higher levels in high-grade tumors than in low-grade tumors ( P < 0.05). The diagnostic performance of platelet TGF-β and Smad2 mRNA levels had a sensitivity and area under the curve (AUC) of 86.36% and 0.8947, respectively ( P < 0.05). Platelet TGF-β and Smad2 mRNAs are potentially valuable biomarkers for detecting and grading colon cancer.