Several tumor markers, including serum β-human chorionic gonadotropin (β-hCG) and α-fetoprotien (AFP), were applied for the diagnosis and prognosis of recurrences of sacrococcygeal teratoma; however, this application was limited in the mature teratomas as the recurrence may have originated from non-secreting parts of the previous lesion (32). The gene discussed is AFP; the disease is neoplasm.