RESULTS

We measured hCGβ, intact hCG, and total hCG in 18, 15, and 19 serum samples from six patients, respectively. All patients were positive (i.e., above the detectable limit) with at least one of the hCG-related markers before treatment. hCGβ values ranged from <0.1 to 0.2 ng/mL, intact hCG ranged from <0.5 to 21.8 mIU/mL, and total hCG ranged from <1.2 to 20.5 mIU/mL.
The positivity rate of serum hCGβ, intact hCG, and total hCG was 6% (1/18), 47% (7/15), and 42% (8/19), respectively. Before treatment, only one case (case 5, 1/6, 17%) was positive for hCGβ, whereas five cases (case 2-6, 5/6, 83%) and six cases (case 1-6, 6/6, 100%) were positive for intact and total hCGs, respectively. The median value of hCGβ, intact hCG, and total hCG before treatment was 0.1 ng/mL, 4.6 mIU/mL, and 4.5 mIU/mL, respectively.
None of the patients showed AFP elevation above the standard limit (10 ng/mL), suggesting there is no nongerminomatous germ cell tumor component (Table 2). The positivity rates of intact and total hCGs were significantly higher than those of hCGβ (p = 0.041), whereas the difference between serum intact and total hCGs was very small (Figure 1).
The tumors responded completely to chemotherapy and radiotherapy in all patients, and all the hCG-related markers diminished below detectable values (Table 2). One patient experienced recurrence 2 years after the initial treatment with an increased total hCG value whereas hCGβ remained negative, which was the same pattern as that of the initial tumor. The patient received additional irradiation and chemotherapy, and he achieved a second complete response.