In renal cell carcinoma, IgA- and IgG-positive plasma cells derived from the TLS appear to disseminate into the tumor through CXCL-12-expressing fibroblast tracts, with TLS+ tumors exhibiting high frequencies of IgG-stained and apoptotic malignant cells, suggestive of anti-tumor effector activity [40]. This evidence concerns the gene CXCL12 and neoplasm.