Tumor cells release mutant gene fragments into circulation, providing highly specific markers that can be used to detect tumor activity. The number of circulating tumor DNA (ctDNA) fragments, however, can be very small, making ctDNA difficult to detect.
OncoBEAM™ overcomes this difficulty thanks to the highly-sensitive BEAMing technology, which combines digital polymerase chain reactions (PCR) with magnetic beads and flow cytometry to deliver clinical assays for the accurate detection of ctDNA.
The BEAMing process begins with the isolation of circulating DNA from a patient’s blood or plasma sample.
Target regions of the purified DNA undergo a pre-amplification step with conventional PCR utilizing primers of known sequences to amplify the genetic regions of interest.
These amplified DNA fragments are then compartmentalized in a water-in-oil emulsion consisting of millions of individual water droplets, each of which containing one target DNA fragment and one magnetic beads. During the digital emulsion PCR process, each single DNA fragment is amplified utilizing primers covalently bound to the bead surface resulting in the conversion of a single DNA fragment into a DNA-covered bead.
Following emulsion PCR, the emulsion is broken and the beads are magnetically purified. Fluorescent probes are then attached (hybridized) to the DNA fragments on the beads to distinguish between wild-type and mutant DNA fragments. One fluorescent probe binds specifically to the wild-type DNA and the other probe is specific for mutant DNA.
Each individual fluorescently labelled bead is analyzed in a flow cytometer resulting in the precise separation of beads carrying mutant from those carrying wild-type DNA. The ratio of wild-type and mutant beads accurately represents the ratio of wild-type and mutant DNA in the patient’s blood sample.
Use of OncoBEAM™ and BEAMing technology for the testing of various mutations related to non-small cell lung cancer (NSCLC), colorectal cancer (CRC), and melanoma has been studied in multiple clinical studies.Review studies