TOKYO—In cancer treatment, the correlation of pharmacogenomics and drug efficacy requires genetic sampling directly from tumors, but this presents difficulties in terms of invasiveness and sample preparation. Recently, however, researchers at Tokyo's National Cancer Center, Ishikawa's Kanazawa University Hospital and AstraZeneca in Cheshire, U.K. applied Scorpion-based PCR to blood samples, looking for mutations that would indicate the efficacy of the tyrosine kinase inhibitor Iressa (gefitinib).
They presented their work in Clinical Cancer Research.
Using the EGFR Scorpion kit from DxS, the researchers were able to detect and identify clear mutation signals in real and spiked blood samples even when the mutation was diluted 105-fold in wildtype sequences. They also noted specific EGFR mutations that correlated closely with response to Iressa treatment and cancer patient survival. They then compared serum and tumor samples and found the two analyses correlated more than 72 percent of the time.
The researchers suggest that one limitation to the method is that it relies on the availability of Scorpion primers for each of the possible EGFR mutations, but DxS is quick to point out that it has developed assays for 26 different mutations and more are on the way.