Besides well-known cystatins C, D, E/M, F, S, SA, SN this group contains the male reproductive tract cystatins 8 (CRES, cystatin-related epididymal spermatogenic protein), 9 (testatin), 11 and 12 (cystatin T), the bone marrow-derived cystatin-like molecule CLM (cystatin 13) and the secreted phosphoprotein ssp24 (cystatin 14) .