Great advances in DNA sequencing technology have made it possible for us to fully sequence the genomes of thousands of tumors along with the normal healthy genome of patients. By comparing the tumor genome with the normal healthy genome of patients, we are able to see all the mutations that have helped chance health cells into cancer. Additionally, we can use the same sequencing technology to examine gene expression and epigenetic state of tumors. These views on individual tumor show how disease is completely unique, in ways that are not visible without genomic sequencing. With such insights we hope to more precisely apply existing treatments and be able to develop therapies designed to target the weaknesses of individual cancers.