Testing DNA Could be the way Forward for Predicting Responses to Cancer Therapies

A paper published in an edition of Clinical Cancer Research indicates that testing DNA isolated from blood, rather than tumour tissue, could be the way forward for predicting responses to Gefitinib (Iressa),  Erlotinib (Tarceva) and other cancer therapies.

This is a far less invasive sample than the current practice of obtaining a tumour biopsy from patients with lung cancer.
 
Previously, tumour biopsies have been used, as it has been difficult to detect the low levels of specific mutations shed from the tumour into the blood against the high background of normal DNA.

However, the sensitivity afforded by DxS’ Epidermal Growth Factor Receptor (EGFR) Mutation Test kit allowed the National Cancer Centre in Tokyo to reliably measure mutations in serum and use these as a predictor of response to Gefitinib (Iressa).
 
The DxS EGFR Mutation Test Kit is a molecular assay combining ARMS (allele specific PCR) and Scorpions, a rapid fluorescent signaling system.
 
In addition to heralding the introduction of blood-based mutation detection, the paper also concluded that patients who were EGFR mutation positive appeared to have better outcomes with Gefitinib treatment in terms of progression-free survival, overall survival and response, than those patients who were EGFR mutation-negative.
 
Commenting on the publication of the paper, corresponding author Dr Kazuto Nishio said, "The DxS test kit detected mutations that were missed by direct sequencing techniques."

"We anticipate that the detection of EGFR mutations in serum DNA using the Scorpions ARMS assay will be useful as a feasible approach for predicting tumour response to gefitinib." 
 
DxS has already developed assays for the 26 next most common EGFR mutations which predict both drug response and also drug resistance (T790M).