The continuing discovery and characterization of genomic biomarkers which may predict the onset of disease have the potential to greatly improve the capabilities of clinical diagnostics and disease prognosis. A specific malignant disorder to which molecular diagnostics can offer vast improvement in is lung cancer, as current detection methods typically lead to detection in the later stages of disease progression, resulting in poor prognosis and survival rates. Coupling knowledge of biomarkers available from non-invasive patient samples with the high-throughput screening capabilities of DNA biochips potentially offers a new tool for early diagnosis, enabling early treatment options for patients and improved outcomes likely. A primary limitation associated with this technology involves the specific detection of low copy number polynucleotide sequences using clinically suitable detection instrumentation, requiring target amplification with PCR-based methods or through signal amplification methods. This research involves developing a novel, rapid, and specific detection method that utilizes a free radical photopolymerization reaction for signal amplification, enabling the sensitive detection of genetic biomarkers while eliminating reliance on expensive detection instrumentation. This approach involves coupling photoinitiators to complementary DNA hybrids on a biosensor surface using an allele-specific primer extension reaction. These molecules catalyze the polymerization of detectable monomers exclusively from DNA hybrids on a biochip surface. Rapid propagation rates characteristic of acrylate monomers enable thick polymer films to be generated on the biosensor surface in a matter of minutes from minute amounts of targeted genetic material, allowing for direct visual detection of polynucleotide sequences upon inspection of the biosensor surface. Such an amplification system has advantages of being rapid, inexpensive, and robust, meeting requirements inherent for use at a doctor's office or at point of care settings. We are currently using this method for the direct visual detection of single base mutations present in codon 12 of the K-Ras oncogene, known to play a role in the onset of lung, pancreatic, and colorectal cancers.

Second AACR International Conference on Molecular Diagnostics in Cancer Therapeutic Development-- Sep 17-20, 2007; Atlanta, GA