Bio-Rad's ddPCR Highlighted at AACR 2017
Emil Christensen, PhD Candidate, Aarhus University Hospital in Denmark (left) and Geoffrey Oxnard, MD, Dana-Farber Cancer Institute (right). Credit: Bio-Rad
New research demonstrating the pivotal role of Bio-Rad’s Droplet Digital PCR (ddPCR™) technology in detecting cell-free DNA and RNA biomarkers in cancer liquid biopsies has been presented at the American Association for Cancer Research (AACR) Annual Meeting, Washington D.C., April 1–5.
“Liquid biopsy as an application of ddPCR has become quite routine over the past few years,” said Viresh Patel, PhD, Bio-Rad Marketing Director, Digital Biology Group. “Wherever traces of cancerous DNA or RNA can be found, whether in the blood as cell-free nucleic acids, or in circulating tumor cells, or in urine or stool samples, research groups are applying ddPCR to detect and quantify these cancer biomarkers. Droplet Digital PCR is an ultra-sensitive and quantitative method for determining how genetic changes influence cancer development and response to treatment,” Patel said.
More than 50 scientists from around the world have presented their research on disease detection as well as tracking progression and treatment responses in patients with lung, bladder, colorectal, and other cancers using ddPCR.
Notable research highlights at the meeting include the following poster presentations:
Understanding Resistance Mechanisms in Lung Cancer Using ddPCR
Resistance to therapy by different cancers can take many forms and significantly impact prognosis. To better understand different resistance pathways, Geoffrey Oxnard, MD, and his team at Dana-Farber Cancer Institute and Harvard Medical School are using ddPCR to analyze the step-by-step genetic changes in non–small-cell lung cancer (NSCLC).
Oxnard’s team tested the plasma of patients whose NSCLC acquired resistance to the third-generation EGFR tyrosine kinase inhibitor osimertinib. They discovered that the loss of the T790M resistance mutation in tumor cells could be associated with occurrence of early resistance to the drug and emergence of alternate resistance mechanisms. The treatments failed twice as fast in patients who lost the T790M mutation compared with those whose cancers retained the mutation. The research team at Dana-Farber is using this liquid biopsy data to map mechanisms against outcomes and hope to eventually supplement the standard of care with serial monitoring of treatment effect in plasma.
“While liquid biopsy to test for EGFR T790M is now a standard approach for managing drug resistance in lung cancer, our data suggest a role for repeat testing after treatment of the T790M mutation to help guide the next steps in a patient’s care,” said Oxnard.
This poster (abstract #4112) was presented on Tuesday, April 4, from 1–5 PM during the Molecular Targeted Therapies 2 session.
Serial Monitoring of Bladder Cancer Using ddPCR
Serial disease monitoring in patients with bladder cancer is important for early diagnosis of progression and metastasis as well as for optimal therapeutic treatment. Traditionally, cystoscopy has been used as the primary diagnostic modality for bladder cancer. The invasive, painful, and awkward procedure motivated Emil Christensen, PhD Candidate, and his team at Aarhus University Hospital in Denmark to use liquid biopsy as a noninvasive and sensitive monitoring technique. The team developed and used ddPCR assays to screen for two hotspot mutations—FGFR3 and PIK3CA—during disease surveillance in patients with bladder cancer. Urine and plasma samples were collected over 10 years to gather relevant data. Their findings showed that high levels of tumor DNA were significantly associated with later disease progression and recurrence.
“Our liquid biopsy analysis revealed that FGFR3 and PIK3CA hotspot mutations are indicative of aggressive disease in bladder cancer patients,” said Christensen. “We believe these assays can provide an optimal supplement to current methods of monitoring disease progression and metastasis.”
This poster (abstract #2752) was presented on Monday, April 3, from 1–5 PM, during the Liquid Biopsies 2: cfDNA session.
ddPCR Technology Used for Research Across Multiple Cancer Types
Two additional noteworthy presentations will highlight the use of ddPCR technology to probe other cancer types:
• Pancreatic Cancer: Researchers from the University of Tokyo, Japan, have presented a highly sensitive procedure for detecting circulating repetitive RNA as a novel early marker of pancreatic cancer. This poster (abstract #730) was presented on Sunday, April 2 during the Early Detection session.
• Neuroblastoma: Researchers from Charité, Berlin, Germany, have presented on the use of ddPCR to analyze MYCN copy number plasma from patients with high-risk neuroblastoma. This poster (abstract #5679) was presented on Wednesday, April 5 during the Liquid Biopsies 5: cfDNA, MicroRNA, and Protein session.