S100A9 and primary cutaneous T-cell non-Hodgkin lymphoma: In cutaneous T-cell lymphoma (CTCL), CCL13+ monocytes/macrophages play a role in mediating immunosuppression by interacting with malignant T cells, and blocking the S100A9-TLR4 interaction with tasquinimod has been shown to inactivate the NF-κB pathway, leading to inhibition of CTCL tumor cell growth and induction of apoptosis (22).