JAK2 and diffuse large B-cell lymphoma: Moreover, JAK2 was found to stimulate PD-L1/2 expression, which conferred immune escape of cancer cells.440–442 Furthermore, in activated B-cell-like (ABC) DLBCL, JAK1 was discovered to phosphorylate H3Y41, which in turn stimulated MYC, MYD88, and IRF4.