My research aims to develop novel diagnostic tools for cancer, through the application of molecular and genomic technologies. Our research group's focus is on circulating tumour DNA (ctDNA) as a noninvasive modality to assess evolution of solid malignancies. The study of ctDNA is complicated by the presence of overwhelming amounts of germline (normal) DNA fragments in the blood: a typical sample (2 ml of plasma) may contain as many as 10,000 copies of germline DNA but only a few dozen copies of the tumour genome. We use a cutting edge methods such as next-generation sequencing and digital PCR that allow sensitive measurement of rare alleles. Changes in ctDNA levels may indicate disease progression and response to therapy. We've recently shown that ctDNA also allows noninvasive exploration of cancer genomics and clonal selection. We continue to develop better tools for ctDNA analysis. Translational projects explore the relationship between tumour changes and ctDNA levels, and their clinical implications.