Tumor-infiltrating lymphocytes and outcome in Merkel cell carcinoma, a virus-associated cancer

An intense immune infiltrate, enriched in T cells, is associated with the presence of Merkel cell polyomavirus (MCPyV) DNA in Merkel cell carcinoma (MCC), a rare skin cancer. High tumor-infiltrating T-cell counts are associated with favorable survival regardless of the tumor MCPyV status. Hence, boosting host immune functions might constitute a new approach for the treatment of MCC.