Activating mutations in the guanine‐nucleotide proteins GNAQ and GNA11 occur in the great majority of tumours (a combined frequency of ∼85–92.5%), and in CYSLTR2 (4%) and PLCB4 (2.5%), all in a mutually exclusive manner 4, 56, as these may all activate the MAPK pathway 56, 109 (Figure 2, Table 1). This evidence concerns the gene GNA11 and neoplasm.