To determine whether MPXV infection in vivo induces phosphorylation of ERK1/2 in the epidermis and translocation of this protein into the nucleus, we quantified ERK1/2 and ERK1/2_pY204 expression in the nuclei and cytoplasm of epithelial cells in MPXV-lesioned and adjacent epidermal tissues. This evidence concerns the gene MAPK3 and infection.