If researchers in Siena, Italy, are right, measurement of Inhibin, a hormone molecule produced by the ovary, could be an effective ovarian cancer screening test.
In a study published this month in The Journal of Clinical Endocrinology and Metabolism, the researchers measured total Inhibin levels using an Elisa-based assay, comparing results in women with ovarian cancers to those of normals and those with benign ovarian tumors and other cancers. Total Inhibin levels were highly sensitive and specific in detecting ovarian cancers. When combined with Ca125 levels, the results were superior to either test alone. (See graph above).
The percentage of cancers detected at 95% specificity varied according to the histological subtype but was always improved by the combination of total inhibin and CA-125. In detail, the detection rate of all tumors raised from 84–87% with single markers to 99% with combined markers (P < .05). The addition of total inhibin increased the CA-125 detection rate for mucinous tumors from 14 of 17 (82%) to 17 of 17 cases (100%) without loosing specificity (95%). Remarkably, the detection rate of clear cell adenocarcinomas increased from 59–68% with single markers to 96% with combined markers (P < .05)
The next step is a large multicenter trial.
Inhibin has been on the radar as a potential ovarian cancer marker for some years now. The problem has been that there are various Inhibin molecules, and the different kinds of ovarian cancers make one or more of these in any combination. Most Inhibin assays are specific to one or more of the subtypes, which limits them in detecting all ovarian cancers. It seems that the total Inhibin assay used in this study may have worked so well because of its lack of specificity, making it more useful as a screening test.
What I found most exciting is that the inhibin assay used is one that is already commercially available, meaning that, if these results hold true, then we won’t have to wait very long to implement screening.