Blood RNA marker 'Tu-stroma' flagged early ovarian cancer and its precursor far better than CA125 in a Nature Medicine study
In serum samples from 506 people, an RNA molecule carried in extracellular vesicles distinguished the precursor lesion STIC and high-grade serous ovarian cancer from controls with an AUC of about 0.99, versus 0.59 for CA125 in STIC. The authors stress that prospective validation is still needed.
A study published in Nature Medicine on 10 November 2026 reports a candidate blood test for the most common and deadliest type of ovarian cancer, high-grade serous carcinoma (HGSC), and for its precursor, serous tubal intraepithelial carcinoma (STIC) — a non-invasive lesion that today can usually be seen only when fallopian tube tissue is removed and examined.
What was measured
The researchers measured Tu-stroma, a tumour-associated long non-coding RNA carried in tiny extracellular vesicles in blood serum, in 506 people: 143 controls with normal adnexa, 88 with benign lesions, 43 with isolated STIC and 232 with HGSC at stages I–IV.
Results
- Tu-stroma levels were higher in STIC and HGSC than in controls and benign lesions, including in premenopausal women.
- For STIC vs controls, discrimination (AUC) was 0.99 for Tu-stroma vs 0.59 for CA125, the standard blood marker; vs benign masses it was 0.99 vs 0.31.
- For HGSC vs controls, 0.99 vs 0.96.
- Tu-stroma was not systematically raised in inflammatory or physiological conditions (116 samples) or in 160 non-ovarian cancers.
Limitations
- This is a diagnostic accuracy study on selected samples with known diagnoses, not a screening trial; such designs often overestimate real-world performance.
- The STIC group was small (43 people).
- The authors themselves write that prospective evaluation in consecutively enrolled real-world cohorts is required before clinical use.
The test is not available to patients. Anyone with concerns about ovarian cancer risk should talk to their doctor.
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