Circulating tumor cells （CTCs） represent a submicroscopic fraction detached from a primary tumor and in transit to a secondary site. The prognostic significance of CTCs in metastatic cancer patients was demonstrated...Circulating tumor cells （CTCs） represent a submicroscopic fraction detached from a primary tumor and in transit to a secondary site. The prognostic significance of CTCs in metastatic cancer patients was demonstrated for the first time more than ten years ago. To date, it seems clear enough that CTCs are highly heterogeneous and dynamically change their shape. Thus, the inadequacy of epithelial cell adhesion molecule （EpCAM） as universal marker for CTCs detection seems unquestionable and alternative methods able to recognize a broader spectrum of phenotypes are definitely needed. In this review the pleiotropic functions of EpCAM are discussed in detail and the role of the molecule in the biology of CTCs is critically dissected.展开更多
Background： Circulating tumor cells （CTCs） are often undetected through the immunomagnetic epithelial cell adhesion molecule （EpCAM）-based CellSearch~ System in breast and colorectal cancer （CRC） patients treat...Background： Circulating tumor cells （CTCs） are often undetected through the immunomagnetic epithelial cell adhesion molecule （EpCAM）-based CellSearch~ System in breast and colorectal cancer （CRC） patients treated with bevacizumab （BEV）, where low CTC numbers have been reported even in patients with evidence of progression of disease. To date, the reasons for this discrepancy have not been clarified. This study was carried out to investigate the molecular and phenotypic changes in CRC cells after chronic exposure to BEV in vitro. Methods： The human CRC cell line WiDr was exposed to a clinically relevant dose of BEV for 3 months in vitro. The expression of epithelial and mesenchymal markers and EpCAM isoforms was determined by western blotting and immunofluorescence. To evaluate the impact of EpCAM variant isoforms expression on CTC enumeration by CellSearch, untreated and treated colon cancer cells were spiked into 7.5 mL of blood from a healthy donor and enumerated by CellSearch. Results： Chronic exposure of CRC cell line to BEV induced decreased expression of EpCAM 40 kDa isoform and increased expression EpCAM 42 kDa isoform, together with a decreased expression of cytokeratins （CK）, while no evidence of epithelial to mesenchymal transition （EMT） in treated cells was observed. The recovery rate of cells through CellSearch was gradually reduced in course of treatment with BEV, being 84% , 70% and 40% at l, 2 and 3 months, respectively. Conclusions： We hypothesize that BEV may prevent CellSearch from capturing CTCs through altering EpCAM isoforms.展开更多
文摘Circulating tumor cells （CTCs） represent a submicroscopic fraction detached from a primary tumor and in transit to a secondary site. The prognostic significance of CTCs in metastatic cancer patients was demonstrated for the first time more than ten years ago. To date, it seems clear enough that CTCs are highly heterogeneous and dynamically change their shape. Thus, the inadequacy of epithelial cell adhesion molecule （EpCAM） as universal marker for CTCs detection seems unquestionable and alternative methods able to recognize a broader spectrum of phenotypes are definitely needed. In this review the pleiotropic functions of EpCAM are discussed in detail and the role of the molecule in the biology of CTCs is critically dissected.
文摘Background： Circulating tumor cells （CTCs） are often undetected through the immunomagnetic epithelial cell adhesion molecule （EpCAM）-based CellSearch~ System in breast and colorectal cancer （CRC） patients treated with bevacizumab （BEV）, where low CTC numbers have been reported even in patients with evidence of progression of disease. To date, the reasons for this discrepancy have not been clarified. This study was carried out to investigate the molecular and phenotypic changes in CRC cells after chronic exposure to BEV in vitro. Methods： The human CRC cell line WiDr was exposed to a clinically relevant dose of BEV for 3 months in vitro. The expression of epithelial and mesenchymal markers and EpCAM isoforms was determined by western blotting and immunofluorescence. To evaluate the impact of EpCAM variant isoforms expression on CTC enumeration by CellSearch, untreated and treated colon cancer cells were spiked into 7.5 mL of blood from a healthy donor and enumerated by CellSearch. Results： Chronic exposure of CRC cell line to BEV induced decreased expression of EpCAM 40 kDa isoform and increased expression EpCAM 42 kDa isoform, together with a decreased expression of cytokeratins （CK）, while no evidence of epithelial to mesenchymal transition （EMT） in treated cells was observed. The recovery rate of cells through CellSearch was gradually reduced in course of treatment with BEV, being 84% , 70% and 40% at l, 2 and 3 months, respectively. Conclusions： We hypothesize that BEV may prevent CellSearch from capturing CTCs through altering EpCAM isoforms.
