Human TACI is alternatively spliced, thus in breast cancer two isoforms are found (short: uc002gqt.1, coding exon count: 4 and long: uc002gqs.1, coding exon count: 5) which display one and two ligand binding domains, respectively, and may alter in receptor functionality (23, 24). Here, TNFRSF13B is linked to breast carcinoma.