Abstract
This study aimed to explore the combined detection of secreted frizzled-related protein-2 (SFRP2), Syndecan-2 (SDC2), and Fusobacterium nucleatum (Fn) in fecal samples for early colorectal cancer (CRC) screening. Public datasets were analyzed to evaluate the expression of SFRP2, SDC2, and Fn. The study included 30 pairs of tissue and 196 fecal samples. Gene expression of SFRP2, SDC2, F. nucleatum antigen adhesinA (fadA), and N-utilization substance G (nusG) was measured by qPCR. Correlations with Ki67, P53 expression, and immune infiltration were examined. The diagnostic performance of the combined markers was assessed using ROC curve analysis. SFRP2 and SDC2 were underexpressed (p < 0.001), while Fn was notably enriched in CRC (p < 0.0001). Expression of SFRP2 and SDC2 correlated with immune cell infiltration, whereas Fn abundance showed a negative correlation with immune infiltration. ROC analysis indicated that the combined detection of these markers outperformed single-gene tests, CEA, and FOBT in early CRC detection. This combined detection approach offers a promising, non-invasive, and cost-effective method for early CRC screening.