Abstract
Serial serum determinations and cellular localization of AFP utilizing radioimmunoassay and immunocytochemical techniques have improved the diagnosis and therapy of testicular seminoma. Elevated level of serum AFP in patients with “pure seminoma” suggests the presence of non‐seminomatous elements or liver metastases. It appears that modest elevated serum alphafetoprotein may be encountered in liver metastases when active liver regeneration is present. These distinctions are pertinent and may play an important role in selecting therapeutic modalities. Two patients are reported to illustrate the interpretation of elevated AFP in patients with testicular seminoma.