Identification and validation of the association of Janus kinase 2 mutations with the response to immune checkpoint inhibitor therapy

Janus kinase 2 (JAK2) mutation plays an important role in T cell immunity. However, the effect of JAK2 mutation on immunotherapy is largely uncharacterized.

In this study, we analyzed the effect of JAK2 mutation on the efficacy and outcomes of immune checkpoint inhibitor (ICI) therapy in the discovery cohort (n = 662) and the verification cohort (n = 1423). Furthermore, we explored the association of JAK2 mutation with the tumor immune microenvironment in a multiomics cohort.

In the discovery cohort (n = 662), JAK2 mutant-type patients had a better objective response rate (58.8% vs. 26.7%, P = 0.010), durable clinical benefit (64.7% vs. 38.9%, P = 0.043), progression-free survival (hazard ratio [HR] = 0.431, P = 0.015), and overall survival (HR = 0.378, P = 0.025), relative to JAK2 wild-type patients. Moreover, we further verified the prognostic significance of JAK2 mutation in an independent ICI treatment cohort with a larger sample size (n = 1423). In addition, we discovered that the JAK2 mutation was remarkably related to increased immunogenicity, such as a higher TMB, higher expression of costimulatory molecules and stimulation of antigen processing mechanisms. In addition, JAK2 mutation was positively correlated with activated anticancer immunity, such as infiltration of various immune cells and higher expression of chemokines.

Our study demonstrates that JAK2 mutation is a novel marker that can be used to effectively predict prognosis and response to ICI therapy.