Bone marrow and peripheral blood expression of ID1 in human gastric carcinoma patients is a bona fide indicator of lymph node and peritoneal metastasis

Recent studies have showed that the bone marrow-derived endothelial progenitor cells play critical roles in metastasis and that ID1 is required in metastasis as regulator of angiogenesis. Therefore, we investigated the clinical significance of ID1 mRNA expression in bone marrow and peripheral samples in patients with gastric cancer. Two hundred and eighty-nine bone marrow and 196 peripheral blood samples from gastric cancer patients were collected and analysed by quantitative RT-PCR for ID1. The ID1 protein expression in one bone marrow, three metastatic lymph nodes and three peritoneal disseminated tumours was examined by immunohistochemical methods. In both bone marrow and peripheral blood samples, ID1 mRNA expression in the metastatic group was significantly higher than in any other group (P = 0.003, P = 0.0001, respectively) and significantly associated with lymph node metastasis and peritoneal dissemination. The cells in bone marrow with metastatic cancer stained strongly with ID1 compared with those of healthy volunteers. The expression of ID1 mRNA in bone marrow and peripheral blood was significantly associated with lymph node metastasis and peritoneal dissemination, and therefore constitutes a predictable marker for lymph node metastasis and peritoneal dissemination. British Journal of Cancer (2009) 100, 1937-1942. doi: 10.1038/sj.bjc.6605085 www.bjcancer.com Published online 2 June 2009 (C) 2009 Cancer Research UK