Metastasis mechanism and gene/protein expression in gastric cancer with distant organs metastasis

Metastasis is the most fatal characteristics of malignancy tumor, which accounted for more than 90% of tumor-related mortality. Distant organ or tissue metastasis is a sign of poor prognosis in patients with gastric cancer. Tumor cells metastasis is a very complex process including tumor cell transformation, growth, angiogenesis, invasion, dissemination and survival in the circulation, and subsequent adhesion and colonization the secondary organ or tissue. The origin of tumor cell, genetic variation, the circulatory mode and the physiological structure of the metastatic organ determines the specific sites of distant metastasis. In theory, the metastatic lesion is originated from their primary tumor, so they should have the same molecular profile with the primary tumor. But this view has been confirmed to be wrong in various tumors, including gastric cancer. The gene expression of primary gastric cancer and its metastasis have differences, which may contribute to the early diagnosis and individualized treatment of metastasis. However, the heterogeneity of tumor cells is still unclear in different metastasis lesion of gastric cancer, which will be a major focus of future research. In this review, we discuss the basic principles of cancer metastasis, the unique physiological characteristics of the various metastasis organs and the expression of different functions of gene/protein in primary and metastasis of gastric cancer. In addition, we also discuss the diagnosis, prognosis and treatment in various organ metastasis of gastric cancer.