CD47 and bone neoplasm: Because spontaneous lung metastases occur only in mice that have established tumors from intratibially xenografted KRIB cells, the incidence of lung metastasis occurring in mice with established bone tumors was 2 of 15 (13%) in anti-CD47-treated mice and 12 of 16 (75%) in IgG-treated mice (Wilcoxon's rank-sum P < 0.0001 for both comparisons).