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| Purpose:Current CTC technologies in patients with colorectal cancer, such as Cellsearch, flow cytometry and RT-PCR, are all epithelial marker-depent method. While a number of researches have found that EMT was present in CTC, which undermined their authority in CTC detection and therefore hampered their wider application clinically. We aimed at exploring another approach to detect CTC circuvmenting the phenomenon of EMT and test its effectiveness in patients with metastatic colorectal cancer. Methods: Colorectal cell lines SW480, lung adenocarcinoma cell lines A549, and human skin cell lines Hacat were used to eastablish expeimental model in vitro. Peripheral blood from 14 patients with metastatic colorectal cancer were obtained and filtered though a filter with 8 um pore membrane to isolate CTC. Blood samples from 14 healthy voluteers were used as negative control. Immunofluorescence and in situ immunocytochemistry following Pap stain was proceed to directed at AE3/Vimentin and CDX-2 respectivelly. Results: In cell experiments, we verified that CDX-2 could be used as marker in differential diagnosis between SW480 cells and A549 cells or Hacat cells, while pan cytokeratin could not. In clinical detection, we found it effective in CTC isolation using ISET. Immunocytochemistry results showed that all the CHNCs-MF were postive for CDX-2 while part of CTCs were postive for pan-cytokeratin. Meanwhile, we found one CTC expressing vimentin only in a patients with metastatic colorectal cancer and a number of circulating cells without morphologically malignant feartures showing postive expression of pan-cytokeratin in peripheral blood of a healthy voluteer. Conclusion: We found a way to detect CTCs circumventing EMT in patients with metastatic colorectal cancer for the first time. Both the ISET and the CDX-2 marker are regardless of the EMT in the CTCs detection,showing advantage compared with current detection technology depending on epithelial marker. This method could be a promising way to detect CTCs in patients with colorectal cancer. |
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| Keywords:oncology; colorectal cancer; circulating tumor cells; CDX-2; |
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