Summary
A study in Nature Medicine assessed the RNA marker Tu-stroma in serum extracellular vesicles from 506 people, including people with STIC and high-grade serous ovarian cancer. The researchers report strong separation from control and benign-lesion groups, with prospective testing still needed to assess clinical use.
Researchers report that the RNA marker Tu-stroma, measured in blood serum, distinguished people with a pre-invasive ovarian cancer lesion or high-grade serous ovarian cancer from control and benign-lesion groups in a study published in Nature Medicine on 10 November 2026. The analysis included samples from 506 people. The authors say prospective studies in consecutively enrolled real-world cohorts are needed to evaluate diagnostic performance and clinical utility.
The study focused on high-grade serous carcinoma (HGSC), the most prevalent histotype of epithelial ovarian cancer, and serous tubal intraepithelial carcinoma (STIC), a non-invasive precursor lesion. STIC is typically identified by examining excised fallopian tube tissue under a microscope. A blood-based marker that can identify its presence could offer a different way to detect disease biology earlier in its course.
A marker carried in serum vesicles
Tu-stroma is a tumour-associated long noncoding RNA: an RNA molecule that does not provide instructions for making a protein. The researchers measured it in serum extracellular vesicles (EVs), small membrane-bound particles that can carry molecular material released by cells.
The team assessed samples from 143 controls with histologically normal adnexa, 88 people with benign adnexal lesions, 43 with isolated STIC and 232 with HGSC. The HGSC group covered International Federation of Gynecology and Obstetrics (FIGO) stages I–IV. The study also included a premenopausal subgroup, in which the reported pattern was similar.
The normalized EV Tu-stroma measure was higher in the STIC and HGSC groups than in the control and benign-lesion groups. In paired receiver operating characteristic analyses, Tu-stroma separated STIC from controls with an area under the curve (AUC) of 0.99, compared with 0.59 for the established blood marker CA125. Against benign adnexal masses, the respective AUCs were 0.99 and 0.31.
For HGSC, Tu-stroma had an AUC of 0.99 against controls, compared with 0.96 for CA125; against benign masses, the figures were 0.98 and 0.84. An AUC closer to 1 indicates stronger separation between the groups tested. The reported comparisons were statistically significant, with P values ranging from less than 0.001 to 0.001.
The next step is prospective evaluation
The researchers also assessed inflammatory or physiological comparators and non-ovarian malignancies against healthy controls. They report that Tu-stroma did not show systematic elevation across those comparison groups, a result consistent with the marker being associated with ovarian cancer-related disease contexts.
These findings make Tu-stroma a candidate biomarker for further study, including for STIC and HGSC. The reported discrimination comes from analyses of samples grouped by histological status; the authors identify prospective evaluation in consecutively enrolled real-world cohorts as the next step to validate performance, predictive value and clinical utility. They also report modelling risk-enriched contexts, but that is distinct from establishing how the marker performs in routine screening or diagnosis.