PIK3CA and skin cancer: Surprisingly, we found enrichment for six genes including FGFR3 especially among HNSCC with 20% corresponding to AID composite mutations, and lower lineage-specific proportions for EGFR (8.9% in Glioma), PIK3CA (~4% in Breast, Endometrial, Cervical, and Skin cancers), FBXW7 (~7% in Colorectal and Esophagogastric cancers); PTEN (2.5 and 4% in Endometrial and Cervical cancers) but not TP53 since it was present across different tumor types (Q < 0.01; Fig. 5a and Supplementary Fig. 17, Supplementary Table 6).