Using genetics and genomics strategies to personalize therapy for cancer: focus on melanoma

Individualizing therapeutic selection for patients is a major goal in cancer treatment today. This goal is best facilitated by understanding both an individual's inherited genetic variation and the somatic genetic changes arising during cancer development. Clinical decision making based on inherited genetic variation is done for those patients with cancer susceptibility syndromes and more generally to personalize drug dosing. Personalized medicine based on genetic and genomic changes within tumors is being applied more widely, with increased use of therapies targeted to somatic mutations and amplifications. Somatic mutations associated with resistance also are being used to select against therapies. Somatic point mutation testing being used clinically includes direct sequencing, short sequencing and single nucleotide interrogation. Single amplifications are commonly assessed using FISH or CISH; high throughput assessment of amplifications and deletions is done mainly on a research basis. Melanomas contain complex mutational profiles that allow them to be sub-grouped by their genetic and genomic profile, each of which then can be evaluated pre-clinically to determine their response to targeted therapies. BRAF V600E mutations are the most common found in melanoma; specific inhibitors of mutant BRAF have been developed and are currently in clinical trials. In addition, other melanoma sub-groups have been identified genetically, which respond to other inhibitors. These studies focus on somatic genetic changes in cancer, which can be targeted directly by therapies. However in the future, personalized medicine will use a combination of inherited and somatic genetics to select the optimal tailored therapy for each patient.