A growing understanding of genetic variation both between histologically similar tumors from different patients and within individual tumors themselves is shedding light on the difficulties in treating cancer and developing biomarkers to diagnose it. It has long been known that a single tumor displays differences in morphology, nuclear shape, proliferation, and proportions of constituent cell types. However, these differences may be only be the “tip of the iceberg” as vast genetic and epigenetic variations that underlie them have been discovered between and within tumors. Continue reading →