While these changes are important, it is now clear that the anti- or pro-tumourigenic nature of the lymphoid infiltrate is not only dependent on the specific type and ratio of various lymphocytes (CD4+ “helper” T cells, CD8+ cytotoxic T cells, cytotoxic NK cells, regulatory T cells), but also their location within the tumour, and the context of the surrounding cellular (e.g. myeloid cells, dendritic cells) and the cytokine milieu. The gene discussed is CD4; the disease is neoplasm.