α-Subunit in Sera of Choriocarcinoma Patients in Remission*

Publisher Website
Google Scholar
Abstract
A small percentage of patients treated for choriocarcinoma and related gestational trophoblastic neoplasia (GTN) have recurrences after apparent complete remission. Serum samples obtained from 13 patients during periods of clinical and laboratory remission before their first definite recurrence were assayed in a homologous hCG-α RIA system. Ten of these patients were maintained on combined oral contraceptives, while 3 were not. To provide a basis for comparison, the following samples were also assayed: 104 from females without GTN and withnormal levels of LH and FSH, 26 from normal women taking combined oral contraceptives, and 48 fromwomen treated for GTN without recurrences (28 of these women were takingcombined oral contraceptives and 20 were not). In subjects maintained on oral contraceptives, immunoreactive α-subunit was detected in 40% of the GTN recurrence patients, 10.7% of the GTN nonrecurrence patients, and noneof the normal subjects. he increased incidence of detectability in the recurrence group was significant. Of the patients not maintained on oral contraceptives, 33.3% of the GTN recurrence group, 35% of the GTN nonrecurrence group, and 44.2% of the normal groups had detectable α-subunit immunoreactivity. There were no statistically significant differences among these groups. six serum samples from the GTN recurrence group were fractionated on a calibrated Sephadex G-100 column. Free asubunit was found in allfractionated GTN samples, demonstratingthat the immunoassayable α-subunit of the whole sera did not merely represent cross-reactivity with intact glycoprotein hormones. Although the α-subunit RIAspecific for hCG-αof trophoblastic tumor origin, the increased detectability of a-subunit in GTNpatients maintainedon oral contraceptives who later had recurrences might reflect secretion of hCG-α from persistent tumor. Routine measurement ofα-subunit during remission in patients on oral contraceptives may assist in selecting those patients at greater risk of recurrent GTN.