Matched detection of chemotaxis and activation markers such as CCL2, CCL5, CXCL12, CD3, CD4, CD8, CTLA-4, PD-1, and CXCR4 and nitration in melanoma tissue will establish the role of NOS and NOX in inhibiting the T cell infiltration/activation in melanoma. The gene discussed is CTLA4; the disease is melanoma.