April 9, 2024
Until recently, tissue biopsy has been the most common method of cancer diagnosis. However, the possibility of metastasis that comes with this invasive process has led to the adoption of a new strategy for cancer diagnosis and prognosis prediction, according to findings of research conducted by a team at Jiangsu University in China and published in the journal, Molecular Cancer, in 2022.
Now, that same study suggests, liquid biopsy—characterized by minimally invasive detection through biofluids such as blood, saliva, and urine—has emerged as a revolutionary strategy for cancer diagnosis and prognosis prediction. Exosomes are a subset of extracellular vesicles (EVs) that shuttle molecular cargoes from donor cells to recipient cells and play a crucial role in mediating intercellular communication. Exosomes are thought to hold great promise to serve as novel biomarkers in liquid biopsy.
Indeed, an investigational exosome-based liquid biopsy accurately detected 97% of stage 1-2 pancreatic cancers when combined with the biomarker CA 19-9, according to research presented at the American Association for Cancer Research (AACR) Annual Meeting 2024, held April 5-10, reports EurekAlert.
“Pancreatic cancer is one of the most fatal malignancies, in large part because the majority of patients are diagnosed only after the cancer has already metastasized,” says Ajay Goel, PhD, senior author of the study and the chair of the Department of Molecular Diagnostics and Experimental Therapeutics at City of Hope.
While the five-year relative survival rate for patients diagnosed at the earliest stages—before the cancer has spread from the pancreas—is 44.3%; it is only 3.2% for those diagnosed with metastatic disease.
“It is of utmost importance to diagnose patients as early as possible so they have the opportunity to receive potentially curative surgery and treatment,” Goel says.
Furthermore, existing biomarkers, such as CA19-9, are not reliable on their own to detect early-stage pancreatic cancer.
“Exosomes retain the cytoplasmic content of the cell from which they were shed—essentially replicating the biology of their tissue of origin,” Xu explained.
The researchers previously tested the performance of their exosome-based liquid biopsy signature in a cohort of 95 individuals from either the United States or Japan—reporting a 98% pancreatic cancer detection rate. The latest study sought to evaluate the liquid biopsy in large, prospective cohorts from multiple institutions and countries.
The study enrolled individuals from:
- Japan (150 with pancreatic cancer; 102 healthy donors);
- USA (139 with pancreatic cancer; 193 healthy donors);
- South Korea (184 with pancreatic cancer; 86 healthy donors); and
- China (50 with pancreatic cancer; 80 healthy donors).
The liquid biopsy signature was trained on information from the Japanese cohort and validated in the cohorts from the United States, South Korea, and China.
Goel, Xu, and colleagues reported that their liquid biopsy approach detected:
- 93% of pancreatic cancers in the U.S. cohort;
- 91% of pancreatic cancers in the South Korean cohort; and
- 88% of pancreatic cancers in the Chinese cohort.
Further, when they combined their signature with the pancreatic cancer marker CA19-9, the liquid biopsy test accurately detected 97% of stage 1-2 pancreatic cancers in the USA cohort. Stage 1 pancreatic cancers are confined to the pancreas; some stage 2 cancers have spread to nearby lymph nodes but have not spread to distant sites.
“We have established an exosome-based signature that combines exosomal microRNAs and cell-free DNA to robustly identify patients with early-stage pancreatic cancer,” said Xu.
“Our approach offers a liquid biopsy test superior to CA19-9 measurement alone for early-stage disease,” Goel added. “Moreover, we evaluated the effectiveness of our assay in several different populations, including populations of different ethnic and geographical backgrounds.”
Research contact: @EurekAlert
