Epigenetics and cancer

Although this chapter focuses primarily on how mutations cause a cancer phenotype, it’s important to remember that the changes in gene expression and protein function are what are more directly relevant. Epigenetic modification of genes can have as much effect on cellular phenotype as a mutation. For example, about half of all familial breast cancers are linked with mutations in BRCA1, but only about 10% of breast cancers are familial – the remainder are sporadic. Only some of those sporadic cancers have mutations in BRCA111. However, other sporadic cancers show methylation of BRCA1, suggesting that epigenetic silencing may play a role in cancer progression.^[1]

Recent work even suggests that epigenetic changes alone are enough to trigger oncogenesis! ^[2]