Gene expression in r/r cHL compared with treatment-naive patients. (A) Volcano plot showing the most significant changes in gene expression comparing r/r cHL before and after anti-PD1 treatment, using the NanoString PanCancer Immune Profiling Panel. The fold change in gene expression (FC) is plotted against the P value. Genes highlighted in red have an FC < −2 and a P value < .05, whereas genes highlighted in yellow have an FC higher > 2 and a P value < .05. The graph also shows the expression changes in a group of known HRSC genes (MS4A1 = CD20B). (B) Analysis of TNFRSF8 (CD30) gene expression in samples from reactive lymph nodes (LN), first-line cHL pretreatment samples (blue), on-treatment rebiopsies (yellow), and in pretreatment (violet) and relapse (red) samples from a r/r cHL cohort.¹²  (C) The same analysis, as in (B), in samples from a cHL cohort that relapsed under conventional therapy (pretreatment: light blue, relapse: orange).¹³  *P < .05, **P < .005, Student t test. ns, not significant.