Breast Cancer Blood Test Flags Early Tumours in Weizmann Study

Researchers at the Weizmann Institute of Science and the Hebrew University of Jerusalem have reported a breast cancer blood test that, in their study, distinguished early-stage tumours from samples from healthy women and also flagged a higher risk of the disease returning. The Weizmann Institute released the findings on 11 November 2026, alongside a peer-reviewed paper in Nature published the same day. The work is at the research stage, on small retrospective cohorts, and is not a clinical test in use.

The method looks at epigenetic tags on cell-free nucleosomes in the blood, using single-molecule microscopy developed in Prof. Efrat Shema’s laboratory, rather than relying only on scarce genetic fragments of tumour DNA. The Nature paper, “Epigenetic heterogeneity in breast tumours informs diagnosis and prognosis,” by Furth, Riemenschneider, Arieli and colleagues, with Guy Ron and Shema as senior authors, describes “the potential of concomitant single-molecule profiling of histone modifications on cell-free nucleosomes in blood as an epigenetic liquid biopsy approach for early diagnosis of breast cancer.” That “potential” wording is the journal paper’s own.

The breast cancer blood test, on small cohorts

Weizmann says the scientists tested the method on blood from “77 breast cancer patients who had been followed for at least five years at the Mayo Clinic in Florida, along with samples from 30 healthy women.” Artificial intelligence models, the institute says, achieved “95 percent accuracy in detecting early-stage breast cancer, when the tumor was still confined to the breast and measured no more than two centimeters.” Performance, it adds, held “regardless of breast density,” and when the samples were expanded “to 188 with the help of Sheba and Kaplan medical centers.”

Those accuracy figures are the study’s results on those cohorts, not the outcome of a screening trial in the general population. Prof. Shema is quoted as saying: “Breast cancer screening saves lives. Regular mammograms reduce the risk of dying from the disease by 22 percent, but the denser the breast tissue, the easier it is for a tumor to ‘hide’ in the image. Our blood test showed strong diagnostic performance regardless of breast density.” The 22 percent figure is Shema’s, about mammograms, not a claim that the new test has been shown to cut deaths by that amount.

On recurrence, Weizmann says the team could “distinguish with 81 percent accuracy between patients whose cancer returned during follow-up and those who didn’t.” Prof. Ron is quoted as saying: “The test even flagged a risk of recurrence in patients considered low risk by conventional measures.” The institute also says the test “outperforms conventional tissue biopsies in assessing the risk of recurrence after treatment.” That comparison is the researchers’ claim, made in the Weizmann release, not an independent clinical evaluation.

The paper and the release describe a rare, aggressive, basal-like cell population inside luminal tumours, with differences that Shema says “appear to be mainly epigenetic.” The Nature abstract links an epigenetic basal signature measured in blood to prognosis, “which enables the identification of patients at increased risk for disease relapse.”

Who took part, including Epivision Genetics

The Weizmann release lists clinical collaborators at Kaplan Medical Center in Rehovot, Sheba Medical Center, the Mayo Clinic in Jacksonville, and groups in Milan, Paris, Baltimore and Berlin, among others. It also lists four co-authors at Epivision Genetics in Boston, Massachusetts: Dr Ekaterina Andreishcheva, Abhijeet Shinde, Dr Jiaren Zhang and Dr Daniel Jones.

The Nature paper’s competing-interests statement records that Yeda Research and Development has filed a US provisional patent application related to the isolation and imaging of cell-free nucleosomes from plasma, that E. Shema, N. Erez and named colleagues, including D. Jones, are named inventors, and that “Epivision Genetics holds exclusive licence to the patent application related to this work.” That is a disclosure about the paper’s authors and licensing, not a claim about the company’s products or a timetable for a commercial test.

Other recent TSN coverage of tools aimed at breast-cancer risk includes the FDA clearance of an MRI-based AI score for 10-year return risk, a different, regulator-cleared approach, and an ESMO study that used routine health data to flag a higher risk of 20 cancers. A separate laboratory effort, the Sanger and CRG protein maps, is further upstream, on drug-binding sites rather than a blood test.

A research result, not a screening programme

The numbers that will travel with this paper — 95 percent, 81 percent, 77 patients and 30 healthy women, later 188 samples — are real results from the cohorts the researchers assembled. They are not evidence that a breast cancer blood test is ready to replace mammograms, or that it has been proven, in a prospective screening trial, to outperform today’s diagnostic path. The Nature paper itself speaks of potential for early diagnosis. Weizmann’s comparison with tissue biopsies, and Shema’s 22 percent figure for mammograms, should stay attached to those speakers.

Breast density is the practical problem the quotes are aimed at. Mammograms miss some tumours in dense tissue; a blood test that, in this study, did not lose accuracy when density changed is an interesting laboratory signal. It still has to be tested in larger, clearly defined populations, with the false-positive and false-negative rates that a screening programme would have to live with, before anyone could treat it as a clinical test.

The Epivision Genetics co-authorship and the exclusive licence sit in plain view in the official materials, which is how they should be read: as a relationship to the underlying method, not as proof that a product is on the market. What to watch next is whether a larger, prospective study, run with a pre-specified clinical question, can repeat the early-detection and recurrence signals on cohorts this size.

Sources

• Weizmann Institute of Science, 11 November 2026. “Cancer Leaves Its Mark: New Blood Test Detects Early Breast Cancer and Helps Predict Its Return.”
• Furth, Noa, Christina Riemenschneider, Yishai Arieli et al., 11 November 2026. “Epigenetic heterogeneity in breast tumours informs diagnosis and prognosis.” Nature.

Related stories

• FDA Clears MRI-Based AI That Scores 10-Year Breast Cancer Return Risk is the nearest TSN account of a breast-cancer risk tool that has already been cleared for clinical use, a different method from this research-stage blood test.
• ESMO Study: Routine Health Data Flags Higher Risk of 20 Cancers
• Sanger and CRG Map Hidden Drug Sites on Two Protein Families