While this could be due to intrinsic differences in the tumour biology in the setting of HIV-DLBCL (due to low IL-6R tumour expression for instance), it more likely reflects the fact that high IL-6 levels are less often tumour-derived in this setting, and are therefore a less clear biomarker of the underlying tumour biology. The gene discussed is IL6R; the disease is diffuse large B-cell lymphoma.