HotSpotter identification of potential mutation hotspot sites/regions in the TCGA UCEC data set. The y-axis demarcates the names of genes and frequency of mutations within each gene. The x-axis demarcates the amino acid position within the protein product for each mutation. Orange dots (intentionally large for quick visualization) and their vertical position represent the frequency of mutation at a specific site in the UCEC test set. Blue dots (intentionally smaller) and their vertical position represent the frequency of mutations at specific sites in the COSMIC dataset. For non-substitution mutations, the first amino acid at which the alteration occurs is used as the “position”.