Fig. 2
From: Cancer heterogeneity: converting a limitation into a source of biologic information
Schematic representation of somatic cancer evolution as a phylogenetic tree. Different colors represent subclones and indicate genetic heterogeneity in the primary tumor and its metastases. a, b, c, d indicate sampling of cancer specimens. Spatial heterogeneity is detected by sampling and analyzing either a and b or c and d and will result in an enhanced sensitivity for detection of subclones and mutations. Analyzing a or b together with c or d will reveal temporal heterogeneity. X indicates extinction of a subclone