AFP and esophageal squamous cell carcinoma: Within the NS tumor cohort, CRIPTO concentration out-performed classical serum markers AFP and β-HCG for the indication of disease stage (stage I vs. II and III; Figure 2A, Table 2), in line with the findings that the highest CRIPTO expression in glioblastoma patients (ELISA) [28] and esophageal squamous cell carcinoma (immunohistochemistry) [29] correlates strongly with poorer survival prognosis.