PIK3CA and Langerhans cell histiocytosis: Non-Langerhans cell histiocytosis shares a high incidence similar to that of BRAF V600E mutations, along with genetic alterations in ARAF, MAP2K1, PIK3CA, K/NRAS, and gene fusions involving BRAF, ALK, NTRK1, and ETV3-NCOA2 [6].