In contrast, CXCL16 exists in both membrane-bound and secreted forms.16 Immunohistochemical staining of pRCC tissue (Figure 3c) and cultured pRCC cells (Figure 3d) for CXCL16 confirmed the expression of this protein in the tumor cells, displaying a membranous localization. The gene discussed is CXCL16; the disease is neoplasm.