Investigations on nonmammary tumour types gave partly controversial results regarding the prognostic significance of ERK expression: in salivary gland mucoepidermoid carcinomas, high levels of phosphorylated ERK1/2 in tumour cells were associated with early progression (Handra-Luca et al, 2003). Here, MAPK3 is linked to salivary gland mucoepidermoid carcinoma.