Multiple downstream effector pathways have been reported to mediate RAS signaling, such as the RAF/MEK/ERK, PI3K/PDK1/AKT and TIAM1/RAC1 cascades, that regulate cell survival and proliferation, as well as cytoskeletal organization.9 In this study, we focused on the correlation between individual RAS/BRAF mutations, assessed by massive parallel sequencing technology, and actual MEK/ERK pathway activation, analyzed by immunohistochemistry for phosphorylated ERK1/2 as an activation marker in primary MM patient biopsies.10 The gene discussed is BRAF; the disease is Miyoshi myopathy.