PIK3CA and neoplasm: Remarkably, despite the clearly distinct transcriptional landscapes observed according to PDS classification, outside of enrichment for BRAF mutations and fewer APC mutations, in the PDS2 group (these are expected within the CMS1 and CMS4 groups, respectively), mutational and copy number profiles across all key genes assessed within the WNT, MAPK, PIK3CA, cell cycle, or TGF-β pathways were identical in PDS1 and PDS3, again, the two groups that contained equal proportions of CMS2 tumours.