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Inhibin forms in serum from postmenopausal women with ovarian cancers
Author(s) -
Robertson David M.,
Cahir Nicholas,
Burger Henry G.,
Mamers Pamela,
Groome Nigel
Publication year - 1999
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1999.00656.x
Subject(s) - radioimmunoassay , medicine , endocrinology , serous fluid , granulosa cell , ovary , ovarian cancer , mucinous cystadenocarcinoma , serous cystadenocarcinoma , cancer
BACKGROUND AND OBJECTIVE Previous studies have shown that serum inhibin as measured by α subunit‐directed radioimmunoassay (RIA) and inhibin A ELISA was elevated in postmenopausal women with mucinous and granulosa cell cancers, with the RIA showing a more frequent elevation than the inhibin A ELISA. It was thus hypothesised that these cancers may also produce inhibin B or the free α subunit. The aim of the study was to identify the forms of inhibin found in a range of ovarian cancers using a range of inhibin assays with varying specificities. DESIGN Serum samples obtained from women with ovarian cancer were assayed by inhibin B ELISA and Pro‐αC subunit ELISA and compared with inhibin RIA and inhibin A ELISA. PATIENTS Blood samples were obtained from 34 postmenopausal women (>55 years) with no history of endocrine disease and from women with ovarian serous cystadenocarcinomas ( n = 66), mucinous cystadenocarcinomas ( n = 20), granulosa cell tumours ( n = 9 − 11), miscellaneous ovarian cancers ( n = 46) and non ovarian cancers ( n = 23). MEASUREMENTS Inhibin B and inhibin Pro‐αC subunit levels were determined by ELISA and compared to values obtained by RIA and inhibin A ELISA. Cancers were discriminated from controls based on values obtained 2SD above the geometric mean of the control values. RESULTS Granulosa cell tumours were detected by RIA and inhibin B ELISA (100%), Pro‐αC ELISA (90%) and inhibin A ELISA (77%). Mucinous tumours were detected by RIA (70%), inhibin B ELISA (60%), Pro‐αC ELISA (55%) and inhibin A (20%). Serous tumours were detected by RIA (35%) and the other assays (<15%). Miscellaneous tumours were detected by RIA (41%) and other assays <30%. CONCLUSIONS Ovarian neoplasms may produce a variety of peptides related to the inhibins, including dimeric inhibin A and B. Inhibin B is detected in more ovarian cancers than inhibin A but does not discriminate as well as the α subunit directed assays. The higher discrimination index obtained with the RIA compared to the Pro‐αC ELISA suggests that assays detecting all inhibin forms containing the α subunit and not just those detecting the Pro‐αC subunit will provide the most useful detection method.