Interferon-ε loss is elusive 9p21 link to immune-cold tumors, resistant to immune-checkpoint therapy and endogenous CXCL9/10 induction. (PubMed, J Thorac Oncol)
We identify IFNϵ loss as the elusive 9p21 link to human immune-cold, CXCL9/10-CXCR3 axis-depleted tumors. Extending mouse-model studies of IFN-I on TME immune-cell levels, we found that IFNϵ loss is the primary cell-intrinsic 9p21 immune signal to DC and macrophage subtype and subcluster expression of CXCL9 and CXCL10, the major sources of these chemokines. Larger deletions to 9p24 further restrict CXCL9/10 induction via loss of IFN-γ-pathway gene, JAK2. 9p-loss tumors with these distinct IFN defects operative in the TME, lack the capacity of endogenous CXCL9/10 induction in an immune-desert, ICT-resistant state. These data, the extensive 9p loss/ICT resistance body of evidence, and early NSCLC DC-chemokine vaccine trials, have led to a DC vaccine engineered with a CXCL9/10 payload, designed to bypass the specific, severe chemokine deficit in 9p loss tumors.