FAS mutations in patients with T- and NK-cell lymphoma. (A) Lollipop illustration of FAS mutations in protein coding sequence (modified from cBioPortal). Red circle represents nonsense mutations; black circle represents frameshift mutations; and green circle represents missense mutations. Red arrowed line represents mutations identified in patients with HLH (only 1 patient with D260N or N264K mutations had HLH). (B-C) 3-dimensional modeling showing the amino acid changes of several representative missense mutations (https://www.ncbi.nlm.nih.gov/Structure/pdb/3OQ9). (D) Graphic illustration of the frequency of FAS mutations in patients with HLH. (E) The distribution of patients with HLH related to FAS mutations and the types of T/NK-cell lymphoma. (F) Representative pictures of FAS immunohistochemical staining in patients with T-cell lymphoma with wild-type FAS (left) and mutant FAS (right). Original magnification, 400×; scale bar, 50 mm. (G) Summary of FAS immunohistochemical staining in 48 patients with and without FAS mutations. IHC, immunohistochemistry; Mut, mutated; N, no; neg, negative; pos, positive; Y, yes.