BRAF and Langerhans cell histiocytosis: Approximately 55% of the LCH cases were known to have the BRAFV600E [proto-oncogene B-Raf and v-Raf murine sarcoma viral oncogene homolog B where valine (V) is replaced by glutamic acid (E) in the 600th position] mutation which activated the MAPK signalling pathway.