Fig. 6

Selected pairs of signatures of interest and with constant ratios of (softmax-transformed) \(\widehat{\varvec{\beta }}_1\). Each point represents a cancer type, and a tighter match along the identity line (the dashed line \(x=y\)) indicates a higher agreement in the differential abundance characteristics, i.e. a constant fold-change in their abundance. Only signatures which are shared between each pair of cancer types are shown in the plot. The mean squared error is shown for each pair of signatures. Note the very good agreement between SBS1 and SBS5 (signatures of proposed constant mutation rate) and the consistently lower values for the softmax-transformed \(\widehat{\varvec{\beta }}_1\) of SBS2 compared to SBS8