Multispectral immunofluorescence with 6 markers plus 4′,6-diamidino-2-phenylindole (DAPI) using the Vectra platform in pretreatment biopsies from 9 patients. (A) Spatial definition of the tumor involvement in a biopsy of MF using the HALO software. (B) Representative mIF image from a biopsy of PTCL stained as indicated. (C) Phospho-S6 expression in tumor cells distinguished patients with CBR or no CBR from ruxolitinib (P = .05). Phospho-STAT3/5 expression in tumor cells did not differ between patients with CBR or no CBR (P = .9).