Similar studies followed, using both germ cell alkaline phosphatase [142], AFP and HCG [143,144], and combinations of markers (HCG, fibronectin, EGFR, CD44, alkaline phosphatase, human endogenous retrovirus type K and XIST) [145]; however, sensitivity for identifying CTCs was rather low (<60%), and not always associating with tumor burden. This evidence concerns the gene AFP and neoplasm.