Evaluation of diagnostic performances of leptin and vitamin D for colorectal cancer diagnosis and follow-up

Globally, colorectal cancer (CRC) is one of the most often diagnosed solid tumors, with a significant death and morbidity rate. CRC biomarkers are desperately needed for early detection. Traditional CRC tumor markers do not have the best diagnostic performance. The levels of leptin and vitamin D were evaluated. CRC patients before treatment (n=16), CRC patients after treatment (n=14), and 20 patients with benign tumors were included in this case-control study. ELISA was used to determine the levels of traditional tumor markers (CA19.9 and CEA) as well as candidate markers (leptin and vitamin D). Using area receiver-operating characteristic analysis (AUC), the diagnostic performance of single and combination markers was assessed (ROC). The levels of CEA and CA 19.9 in the three groups studied were not significantly different. Vitamin D and leptin were significantly decreased (p= 0.03 and p= 0.02; respectively) in CRC patients than after benign patients. A novel combination, based on the combination of vitamin D and leptin was developed for CRC diagnosis using stepwise multivariate discriminant analysis (MDA). The combination can be represented as = (4.65 – vitamin D ((ng/ml)) × 0.009 + Leptin (ng/ml) × 0.441). AUCs were reported when leptin was used as a single biomarker for distinguishing CRC from benign (0.78) and non-treated CRC from treated CRC (0.67). When leptin and vitamin D were combined, the AUCs increased to 0.84 and0.72, respectively. Conclusion: Leptin and vitamin D were shown to be promising diagnostic and follow-up indicators for CRC in our investigation.