Comparison of mutation prevalence in PIK3CA domains from colon and breast cancer Depiction of the mutation prevalence in colon and breast cancer for domains occurring on the PIK3CA gene. Each box represents a distinct domain from the PIK3CA gene. The color of the domain reflects the mutation prevalence for the domain – a mutation prevalence color scale is shown on the right. The mutation prevalence is calculated as the number of mutations occurring in the domain divided by the number of patients in either the colon (100) or breast (522) cancer sets. Each domain is labelled with the count of mutations found within the domain in the PIK3CA gene, with the mutation prevalence in parenthesis.