CXCL13 and neoplasm: However, the animals that developed R- or BCBL-1-derived tumors (n = 2 /group) all showed greatly elevated serum levels of murine CXCL13 (ranging from about 10,000 to 40,000 pg/ml), and in tumor ascites fluid (ranging from about 25,000 to 100,000 pg/ml).