A Head-to-head Comparison of a Novel Silicon Microsieve Device Against a Cell Surface Marker-based Platform for the Isolation of Portal Vein Circulating Tumor Cells in Pancreatic Cancer

Circulating tumor cells (CTCs) aid prognostication of cancer by predicting the presence of microscopic metastases. This is important in pancreatic cancer, which is associated with a poor prognosis even in resectable disease, due to microscopic metastases that are not detectable on pre-operative cross-sectional imaging. In pancreatic cancer, blood is sampled from the portal circulation to overcome the "hepatic sieve" effect, where CTCs are filtered out in the capillary beds of the liver before entering the peripheral circulation. Minimally invasive blood sampling from the portal vein can now be done via endoscopic ultrasound (EUS) guidance, allowing CTC analyses to be done pre-operatively.

CTCs have traditionally been isolated in various cancers using a cell surface marker-based platform (CellSearch™). This involves the use of antibodies to identify, isolate and quantify CTCs based on presence of specific epithelial cell markers. However, CTCs are now known to undergo epithelial-mesenchymal transformation. The current epithelial cell surface marker-based method of CTC isolation is limited by its inability to detect mesenchymal-type CTCs, potentially under estimating the CTC count, affecting quantification and subsequent CTC molecular analyses.

The use of a novel silicon microsieve device will overcome these limitations. It will simplify the isolation of CTCs by its characteristic size, enable both epithelial and mesenchymal types of CTCs to be isolated and results in greater cell viability, aiding in subsequent cell culture and organoid growth.

The investigators will compare a novel silicon microsieve size-based cell filtration device against the cell surface marker label-based CellSearch™ platform for the identification of pancreatic cancer CTCs in portal venous blood obtained via an Endoscopic Ultrasound (EUS)-guided puncture. The investigators will compare the yield of epithelial-type CTCs isolated using both methods. The investigators will investigate whether the isolation of mesenchymal-type CTCs via a sized-based cell filtration device leads to a significant increase in total CTC yield.

The investigators expect our study to show that the new technique of size-based CTC isolation improves CTC yield in pancreatic cancer. This preliminary data would be crucial for future research into patient selection for neoadjuvant chemotherapy and individualized treatment from patient-specific tumor tissue, which the investigators intend to embark upon.