Abstract
Circulating tumor cells (CTCs) play a key role in tumor metastasis. CTCs have altered gene expression and can survive in the bloodstream. Finding the key genes whose expression are altered in CTCs could help explain the mechanism of tumor metastasis. We searched for genes differentially expressed in CTCs by analyzing four CTCs and primary tumor gene expression datasets in the GEO database. Key genes of clear cell renal cell carcinoma (ccRCC) CTCs were identified. The correlation between key genes and the immune microenvironment of ccRCC was explored. Finally, the CTCs cell model of ccRCC was constructed by in vivo screening method, and the expression of key genes was detected at the cell and tissue levels. A total of 771 DEGs were obtained. Gene enrichment analysis showed that DEGs of CTCs were mainly involved in the regulation of the tumor immune process and tumor cell apoptosis. Finally, we found 2 key genes, MMP9 and TYROBP in ccRCC CTCs. The high expression of these 2 genes predicted a poor prognosis of ccRCC, and the expression levels of these 2 genes were significantly increased in CTCs and ccRCC tissues. Our study suggested that genetic alterations in CTCs contribute to the ability of CTCs to survive in the blood by adapting to the tumor microenvironment. MMP9 and TYROBP are potential therapeutic and prognostic targets for ccRCC.