Purpose: Matrix metalloproteinases are responsible for proteolytic degradation of basement membrane and extracellular matrix. In tumor tissues, elevated expression of matrix metalloproteinase-1 (MMP-1) has been associated with tumor invasion and metastasis. However, little is known about the expression of MMP-1 in peripheral blood (PB) and bone marrow (BM) in gastric cancer patients. Thus, the aim of the present study is to determine MMP-1 messenger RNA (mRNA) expression levels in BM and PB of patients with gastric cancer.
Methods: The study group consisted of 857 patients with gastric cancer (577 males and 280 females) ranging in age from 27 to 87 years (average 61.6 years). MMP-1 mRNA expression levels in BM and PB were evaluated quantitatively by real-time reverse-transcription polymerase chain reaction (RT-PCR).
Results: Expression of MMP-1 mRNA in BM and PB of patients with gastric cancer was significantly higher than in noncancer patients. High levels of MMP-1 mRNA expression were significantly associated with differentiated histology, tumor size, tumor invasiveness, lymph node metastasis, liver metastasis, and clinical stage. Particularly importantly, MMP-1 mRNA expression in PB was an independent factor of distant metastasis.
Conclusions: We disclosed that MMP-1 mRNA expression in peripheral blood and bone marrow of gastric cancer patients was very high, precisely reflecting staging of gastric cancer. MMP-1 mRNA expression in peripheral blood may be a useful marker for distant metastasis in gastric cancer.