Fig. 2 |. Tumour evolution with emergence of distinct tumour subtypes.

a | Schematic of the occurrence of tumour subclones over time. Genomic differences between subclones might result in different expression patterns and thereby different tumour subtypes. Chemotherapy can cause contraction of subtypes and isolation of a specific subtype, which becomes the dominant clone after chemotherapy (subtype 4 in this example). b | The fractions of different subtypes can vary over time and under the selection pressure of treatments, resulting in inconsistent subtype calling even if the entire tumour is analysed. Sampling of only parts of a tumour would be expected to further complicate consistent subtype calling.