TF and gastric cancer: Using the SNA-positive TF-specific antibody avidity value equal to 72.45% as a cut-off limit, which allows the best discrimination between cancer patients and controls (calculated by ROC curve analysis), the sensitivity and specificity for gastric cancer were 73.53% and 73.08%, respectively, with a 73.2% accuracy of diagnostics (ROC statistics: the area under a curve 0.776, P < 0.0001) (Figure 5).