AFP and neoplasm: When taking into consideration that both β-hCG and αFP may at the same time show positive levels (overlap factor), the total diagnostic sensitivity of tumor markers for the recent group increased from 34.6 % (9/26 cases) to 65.4 % (17/26 cases), among which the major proportion should be attributed to the CSF β-hCG levels (61.5, 94 % cases involved in recent group).