Fig. 3.

Consensus clustering matrices without reordering for data from leukemia samples averaged over 50 connectivity matrices using 5,000 of the most highly varying genes according to their coefficient of variation. (a) Consensus matrix for a two-centroid SOM shows superposition of two clustering solutions, ALL-AML and ALLB-[ALLT+AML]. A relative probability of about two-thirds is estimated by looking at the color-coded consensus: yellow (≈70%) for the first pattern and light blue (≈30%) for the second. Metastability of the two-centroid SOM with respect to random initial conditions is illustrated by the motion of a rolling ball on a double-well potential. (b) Consensus matrix for a rank-2 NMF. The 0–1 pattern indicates highly robust classification. NMF stable attractor leads to ALL-AML partition irrespective of random initial condition. The lack of reordering ordering highlights the two ALL samples that consistently cluster with the AMLs (discussed in more detail in ref. 5).