Circulating guanylyl cyclase C (GCC) mRNA is a reliable metastatic predictor and prognostic index of colorectal cancer.

Abstract

BackgroundCurrently, few specific biomarkers or standard cutoff values are available for circulating tumor cells (CTCs) detection and survival prediction in patients with early stage colorectal cancer (CRC). Guanylyl cyclase C (GCC) presents as a specific expression in intestinal tumor cells and during their metastases, indicating its potential application as a metastatic predictor of CRC.MethodsThe circulating GCC mRNA of 160 colorectal cancer patients at stage I–III was detected via quantitative real-time (qRT)-PCR in our study, and the correlation of GCC mRNA level with tumor metastasis and long-term survival was explored.ResultsGCC mRNA was found to be positive in 43 out of 160 CRC patients and negative in ten healthy controls. It was found that GCC mRNA over the baseline (>100 copies/µL and 200 copies/µL) showed a significant correlation with disease-free survival (DFS) and overall survival (OS) in the stage II subgroup. It was further revealed that GCC mRNA over 300 copies/µL or higher than the median value of copy numbers was significantly correlated with reduced OS and DFS in CRC patients. A nomogram model based on variables including GCC mRNA copy number was established for predicting the OS of CRC patients (AUC =0.98).ConclusionsCirculating GCC mRNA over baseline is a reliable predictor for tumor metastasis and can be a prognostic index in CRC patients.