Common cancer-associated PIK3CA activating mutations rarely occur in Langerhans cell histiocytosis

To the editor: Langerhans cell histiocytosis (LCH) can be a multisystem disease with an unpredictable outcome, from autoregressive to vital organ damage and sometimes fatal evolution. In 2010, Badalian-Very et al reported the BRAF V600E somatic activating mutation was present in 57% of LCH cases