Previous studies used to enumerate
circulating tumor cells to predict prognosis and
therapeutic effect of
colorectal cancer. However, increasing studies have shown that only
circulating tumor cells enumeration was not enough to reflect the heterogeneous condition of
tumor. In this study, we classified different metastatic-potential
circulating tumor cells from
colorectal cancer patients and measured FAM172A expression in
circulating tumor cells to improve accuracy of clinical diagnosis and treatment of
colorectal cancer. Blood samples were collected from 45 primary
colorectal cancer patients.
Circulating tumor cells were enriched by blood filtration using isolation by size of epithelial
tumor cells, and in situ hybridization with
RNA method was used to identify and discriminate subgroups of
circulating tumor cells. Afterwards, FAM172A expression in individual
circulating tumor cells was measured. Three
circulating tumor cell subgroups (epithelial/biophenotypic/mesenchymal
circulating tumor cells) were identified using epithelial-mesenchymal transition markers. In our research, mesenchymal
circulating tumor cells significantly increased along with
tumor progression, development of distant
metastasis, and vascular invasion. Furthermore, FAM172A expression rate in mesenchymal
circulating tumor cells was significantly higher than that in epithelial
circulating tumor cells, which suggested that FAM172A may correlate with malignant degree of
tumor. This hypothesis was further verified by FAM172A expression in mesenchymal
circulating tumor cells, which was strictly related to
tumor aggressiveness factors. Mesenchymal
circulating tumor cells and FAM172A detection may predict highrisk stage II
colorectal cancer. Our research proved that
circulating tumor cells were feasible surrogate samples to detect gene expression and could serve as a predictive
biomarker for
tumor evaluation.