Guardant Health Unveils Compelling Data on Shield Multi-Cancer Detection Test at AACR 2025, Showcasing High Specificity and Sensitivity Across Ten Tumor Types
Guardant Health, Inc. (Nasdaq: GH), a prominent leader in precision oncology, has released new clinical data demonstrating the robust performance of its methylation-based Shield™ multi-cancer detection (MCD) test. The findings, which were presented during an oral session at the 2025 American Association for Cancer Research (AACR) Annual Meeting, underscore the test’s potential as a non-invasive tool for early cancer detection through a simple blood draw.
The data, gathered from a study designed to evaluate the accuracy and clinical value of the Shield test, show that the blood-based assay achieved a high specificity of 98.5% and an overall sensitivity of 60% in detecting cancer across ten distinct tumor types. Moreover, the test delivered a 74% sensitivity rate for detecting six of the most aggressive and deadly cancers, including esophageal-gastric, hepatocellular (liver), lung, ovarian, and pancreatic cancers—types that are often only discovered at an advanced stage when treatment options are limited.
These promising results have led to the Shield MCD test being selected by the National Cancer Institute (NCI) for inclusion in its highly anticipated Vanguard Study. This study is a large-scale, population-based initiative intended to assess emerging multi-cancer detection technologies that could transform cancer screening paradigms in the United States and beyond.
Groundbreaking Accuracy and Signal-of-Origin Detection
In addition to its impressive sensitivity and specificity, the Shield test demonstrated strong performance in identifying the signal of origin (CSO)—the likely primary or secondary source of a detected cancer signal. The test achieved an 89% accuracy rate in pinpointing the tissue or organ where the cancer is most likely to have originated. This feature is especially valuable in clinical settings, as it helps guide subsequent diagnostic workups and accelerates time to diagnosis and treatment.
The oral presentation, titled “Evaluation of a plasma cell-free DNA methylation-based multi-cancer detection test,” detailed the performance of the Shield assay in a cohort of patients with both cancer and non-cancer conditions. The study utilized a targeted methylation sequencing approach to analyze cell-free DNA (cfDNA) circulating in the bloodstream. By identifying specific methylation patterns associated with malignancies, the test could flag the presence of cancer with minimal invasiveness.
Methylation markers have emerged as a highly informative class of epigenetic signals for cancer detection. Unlike genetic mutations, which can vary significantly across patients and cancer types, methylation patterns offer consistent signals that can be used for both identifying cancer presence and inferring tumor origin. The Shield test capitalizes on this approach by analyzing hundreds of methylation regions simultaneously, enabling it to detect a wide spectrum of cancers from a single blood sample.
A Major Step Toward Population-Scale Screening
“There are still many types of cancer that are difficult to detect with existing technologies until the late stages,” said AmirAli Talasaz, co-founder and co-CEO of Guardant Health. “This strong data reinforces the potential of the Shield test to detect multiple cancers earlier through a simple blood draw. This study was a critical step in evaluating this innovative technology as a new screening option we can bring to patients to help reduce cancer deaths.”
Guardant’s Shield test is designed for early detection, a frontier in oncology that has the potential to save thousands of lives annually. Most current cancer screening programs—such as those for breast, colon, and cervical cancers—target individual cancers and require different testing methods, some of which are invasive, burdensome, or inconsistently utilized. In contrast, a multi-cancer detection blood test like Shield can screen for multiple types of cancer at once, using a single non-invasive sample.
This advancement is particularly important in the context of aggressive cancers that currently lack standard screening protocols. For example, cancers like pancreatic and ovarian are rarely diagnosed early because symptoms typically appear only at later stages. The Shield test, by detecting molecular signals in cfDNA early in the disease process, may offer a solution to this diagnostic blind spot.
Alignment with National Cancer Institute Goals
The inclusion of the Shield test in the NCI’s Vanguard Study marks a major validation of Guardant Health’s scientific approach and technological development. The Vanguard Study will serve as a precursor to a larger-scale randomized controlled trial and is part of the Cancer Moonshot initiative’s effort to accelerate progress in the early detection of cancer.
The NCI’s decision reflects a growing consensus within the oncology community that liquid biopsy technologies are approaching the performance thresholds needed for widescale population screening. As these tests continue to mature, they may be integrated into national health programs alongside or in place of existing single-cancer screening tools.
According to Guardant Health, Shield’s inclusion in the Vanguard Study was based on a combination of scientific rigor, reproducibility, and test performance, including the data presented at AACR 2025. The Shield test joins a short list of next-generation liquid biopsy technologies being considered for national deployment.
Guardant Health’s Vision for the Future of Oncology
Guardant Health has been at the forefront of developing liquid biopsy solutions, which have transformed how oncologists detect, monitor, and manage cancer. The company’s portfolio includes a range of genomic profiling tools used for therapy selection, residual disease detection, and now, early cancer screening.
The Shield test represents a major expansion of Guardant’s mission to make cancer detection more accessible and less invasive. With this new data, Guardant aims to accelerate commercial adoption and regulatory approval of the Shield test, targeting both clinical and at-home screening markets.
In parallel, the company is investing in educational efforts aimed at healthcare providers, patients, and policymakers to raise awareness of multi-cancer detection and its implications for public health. Guardant believes that as healthcare systems evolve to support preventative care, tools like Shield will become indispensable in the fight against cancer mortality.
Clinical and Public Health Implications
From a clinical perspective, the high specificity of the Shield test—98.5%—is particularly noteworthy. High specificity reduces the likelihood of false positives, which can lead to unnecessary anxiety, testing, and procedures for patients. At the same time, achieving 60% overall sensitivity—and 74% in the most lethal cancers—positions Shield as a powerful complement to current screening protocols.
If adopted at scale, Shield could significantly shift the cancer care paradigm from late-stage treatment to early intervention. Earlier detection generally correlates with higher survival rates, reduced treatment intensity, and lower healthcare costs.
The unveiling of these new data at AACR 2025 represents a milestone not only for Guardant Health but for the field of early cancer detection. With high specificity, meaningful sensitivity, and accurate signal-of-origin prediction, the Shield multi-cancer detection test stands out as a leading candidate for widespread clinical adoption.
As the Shield test progresses through validation studies and prepares for broader deployment, its impact could be profound—offering millions of individuals a chance to detect cancer earlier, when it is most treatable, and helping to fulfill the vision of a future where cancer is caught before it can advance beyond cure.
