ERK5 is also implicated as having a role in tumor cell invasion,with its activity in triple-negative breast cancer cell lines maintainingthe expression of the transcription factor Slug, which represses genesinvolved in an epithelial-to-mesenchymal transition.34 Furthermore, ERK5 has been shown to induce the phosphorylationof FAK to promote cell motility but in an ERK5 kinase-independentmanner.31 Consistent with these findings,ERK5 silencing has been shown to reduce the invasion of breast tumorcell lines in vitro and the metastasis of breast cancer xenograftsin vivo.34,31,35. The gene discussed is MAPK7; the disease is breast cancer.