This developmental perspective for TGCT origin and progression has led to the discovery of several biomarkers of the disease, both tissue-based (pluripotency factors, such as OCT3/4, SOX2, and SOX17) and liquid biopsy-based (including the ‘classical’ serum markers alpha fetoprotein (AFP) and human chorionic gonadotropin subunit beta (β-HCG)). Here, AFP is linked to testicular germ cell tumor.