USC trial tests blood biomarkers for earlier breast cancer detection

A clinical trial initiated by researchers at the USC Norris Comprehensive Cancer Center, affiliated with Keck Medicine of USC, seeks to determine if a specific blood test can identify breast cancer sooner than standard mammography. The study focuses on evaluating a liquid biopsy method intended to work in conjunction with existing screening tools to spot cellular and molecular indicators of early-stage disease.

Liquid biopsy targets rare cells and vesicles

The diagnostic tool was developed at the USC Michelson Center Convergent Science Institute in Cancer. It aims to detect two specific markers: rare cancer-associated cells and tumor-associated large extracellular vesicles (L-EVs). These L-EVs are tiny particles released by cancer cells that enter the bloodstream during the initial onset of the disease. While liquid biopsies currently serve post-diagnosis roles, such as monitoring treatment or checking for recurrence, most existing versions search for small DNA fragments. Those genetic markers often prove difficult to isolate when tumors remain small or in early stages.

This new approach diverges from traditional methods by targeting both rare cells and L-EVs. Preliminary data indicate these elements appear at the earliest phases of breast cancer. Research suggests they may also reflect communication between cancer cells and their surrounding environment as the disease progresses. "These particles could potentially give doctors an additional sign of cancer, especially at early stages when other tests might not be able to detect it," stated Anastasia Martynova, MD, a breast cancer specialist and medical oncologist at USC Norris who serves as the trial’s principal investigator.

Addressing gaps in current screening protocols

Mammograms remain the primary instrument for breast cancer screening in the United States, where more than 300,000 women receive diagnoses annually. However, abnormal mammogram results frequently necessitate further testing before clinicians can confirm the presence of cancer. Patients often undergo additional imaging or biopsies, and some cases require repeat imaging six months later. This waiting period generates significant anxiety and can delay treatment if a diagnosis is eventually confirmed.

"Our hope is to determine whether this test can provide more information about breast cancer screening and detection, particularly during the stages of the disease when it may be easier to treat," Martynova said. Beyond improving detection timing, investigators are assessing whether the test could expand access to screening for populations facing barriers to mammography. Amanda M. Woodworth, MD, director of breast health at Keck Medicine and Henry Mayo Newhall Hospital in Santa Clarita, noted that the technology might assist women in remote areas with limited screening services. She added that it could also benefit patients who have undergone mastectomies, for whom mammograms are no longer viable options.

Trial methodology and future applications

During the study, researchers will collect two blood samples from participants one year apart. They will compare these results against patient diagnoses to assess the test's accuracy. Officials emphasize that this experimental tool does not replace mammograms or breast biopsies. The underlying technology was created by Peter Kuhn, PhD, University Professor and Dean's Professor of Biological Sciences at the USC Dornsife College of Letters, Arts and Sciences. Kuhn developed a method capable of identifying several common breast cancer-associated rare-cell and extracellular-vesicle signals in the blood.

If the phase 1 trial yields positive results, the team plans to launch a larger phase 2 study involving a broader group of patients. The same technological framework holds potential for future application in screening for other solid tumor cancers, including lung and colon cancer.