Deciphering the genetic landscape of cancer--from genes to pathways.

Advances in genomic technologies have made it possible to screen the entire cancer genome for mutations, leading to a better understanding of the genetic landscape of cancer. Emerging results suggest that the cancer genome is composed of a few commonly mutated genes and many infrequently mutated genes. Although the number of mutated genes in any one tumor is limited, there is much heterogeneity in the genes mutated in two tumors of even the same class because of the large number of infrequently mutated genes. This could explain the wide variation in tumor behavior to chemotherapeutic intervention. Pathway analysis suggests this large collection of cancer genes functions in a few signaling pathways, providing a simplifying picture of cancer, and indicating the possibility of treating cancer using target-based therapeutics directed against the deregulated signaling pathways themselves rather than the individually mutated genes.