Through classifying B-cell phenotypes and localizing them within renal cell carcinoma (RCC) patient samples, they suggested that TLSs serve as sites for maturation, clonal amplification and isotype switching of B cells and for harboring PCs before they disseminate along CXCL12-positive fibroblastic cell tracks (Fig. 2). The gene discussed is CXCL12; the disease is renal cell carcinoma.