Using a self-collected vaginal fluid test for endometrial cancer detection

A 2-marker panel of methylated DNA markers (MDMs) detected endometrial cancer (EC) in self-collected vaginal fluid with 96% sensitivity (84–99%) and 82% specificity (67–91%) in an independent test set, according to data published in the May 2026 edition of Gynecologic Oncology. The findings from the study “Optimization of methylated DNA markers to rule out endometrial cancer in patients with abnormal uterine bleeding,” support continued development of a minimally invasive alternative to endometrial biopsy for patients presenting with abnormal uterine bleeding (AUB) or postmenopausal bleeding (PMB).¹

Elle Kielar Grevstad, PhD, Director, Product Strategy, Abbott Cancer Diagnostics, University of Wisconsin–Madison, and co-author of the study, described the project's scope.

"This study was really the foundational effort to find the best marker panel that could essentially detect endometrial cancer via vaginal fluid," she said. "Vaginal fluid, in this case, was self-collected via an over-the-counter tampon."

The study began with 19 previously identified MDMs and narrowed that set through a marker reduction process to a panel of 12, from which a final 2-MDM model was selected and validated using a random forest model in an independent test set. According to results, the 19-MDM model achieved 91% sensitivity (83–96%) and 87% specificity (80–92%) for EC versus benign endometrium in marker reduction; the downstream 2-MDM model achieved an AUC of 0.97 (0.94–1) in marker selection.

"We used about 29 methylated DNA markers and then went through a series of experiments over the course of about 3 years to narrow those markers down to the ones that gave the most information and had the highest sensitivity for all forms of endometrial cancer," she said, including early-stage disease and the more aggressive type 2 cancers.

"We ultimately found that 2 methylated DNA markers gave a sensitivity of about 96% overall, 100% sensitivity in cancers that are grade 2 and above, and 100% sensitivity in type 2 cancers," Kielar Grevstad said.

Addressing limitations of current diagnostic approaches

Current standard-of-care evaluation for PMB and AUB relies on endometrial biopsy, an invasive, often painful procedure performed in-office without sedation, or transvaginal ultrasound in select patients per recently updated ACOG guidance. Kielar Grevstad pointed to limitations in both approaches.

"About 25% of women who experience these things find them excruciating in pain," she said of an endometrial biopsy. Ultrasound, meanwhile, "really doesn't work in a very diverse patient population," she said, citing reduced sensitivity in patients with structural causes of bleeding, such as uterine fibroids, as well as evidence suggesting limited utility in detecting type 2 endometrial cancers.

Kielar Grevstad explained the conceptual advantage of a molecular marker approach.

"You're actually detecting shedding of those molecular markers vs a structural change that could be associated with endometrial cancer," she said, describing the test as both minimally invasive and adaptable to patient preference.

"In the ASCO abstract, we also show almost identical performance in physician-collected swabs, so we really are taking a patient-centric approach here and looking for opportunities to meet the patient where they are and how they want their sample collected," she said.²

She also framed the test's potential triage value in terms of avoided procedures.

"If you think about [the] specificity of 82 to 85%, you're looking at a false positive rate of 15%. That means 85% of the patients that don't need a biopsy would actually be saved from having to have one with this device," Kielar Grevstad said.

What is next for the endometrial cancer test?

The current findings stem from case-control studies, and Kielar Grevstad emphasized that broader clinical validation is still required before the test can be adopted in practice.

"The next step for us is going to be a large clinical validation study," she said, referencing a forthcoming trial called Envision. "That study... is now open and will enroll across 50 sites around the United States and potentially ex-US. We are going to be enrolling over 4,200 patients who have abnormal uterine bleeding and hopefully, down the line, engaging with regulatory agencies such as the FDA to receive approval for this test."

Editor’s note: Elle Kielar Grevstad reported a relevant disclosure to Abbott.

References:

1. Bakkum-Gamez J, Harrington SP, Slettedahl SW, et al. Optimization of methylated DNA markers to rule out endometrial cancer in patients with abnormal uterine bleeding. Gynecologic Oncology. May 2026. Accessed June 22, 2026. https://www.sciencedirect.com/science/article/abs/pii/S0090825826019335
2. Gagrat B, Bakkum-Gamez J, Krockenberger M, et al. Development of an endometrial cancer test from a vaginal swab. Abstract. Presented at: American Society of Clinical Oncology. May 29 to June 2, 2026. Chicago, Illinois.