Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest malignancies. Most patients were diagnosed at advanced stages, and the median overall survival rate is 5 to 8 months. Surgical resection is the only possible curative option. It is feasible for a minority of patients. After that, the recurrence rates are 70%. These challenges highlight the need to improve diagnostic and prognostic methods that are capable of detecting disease early and monitoring response to treatment. Circulating tumor cells (CTCs) and circulating epithelial cells (CECs) are shed from primary or metastatic lesions and present in premalignant conditions like intraductal papillary mucinous neoplasms (IPMNs). It offers a minimally invasive window into tumor biology. Their rarity and phenotypic heterogeneity, specifically in the context of epithelial-to-mesenchymal transition, limit the effectiveness of conventional isolation methods. It relies on surface marker expression.
The aim of this study was to compare a size-based inertial microfluidic (iMF) isolation platform with an immunomagnetic negative selection system (EasySep™) to evaluate which method is more effective in capturing the label-free CTCs and CECs while preserving cell heterogeneity in pancreatic cancer patients.
They cultured PANC1 pancreatic cancer cells and injected known quantities into healthy donor blood and processed clinical blood samples, which were collected from the patients who had PDAC, IPMN, and neuroendocrine tumors in perioperative phases. The iMF system consisted of a straight polydimethylsiloxane microchannel that used inertial forces to separate cells by size, moving larger tumor cells to the central outlet and removing smaller white blood cells (WBCs). The EasySep™ system used immunomagnetic CD45-based depletion to eliminate hematopoietic cells. Recovered cells from both methods were placed on slides by cytocentrifugation, fixed, and stained using Hoechst, cytokeratin (CK), and CD45 to detect tumor-derived cells. In surging methods, the iMF device continuously recovered 28 to 44% of PANC1 cells in spike in levels from a range of 50 to 10,000 cells/mL, after adjusting for cytocentrifugation-induced losses, which made for about 50% of total cell loss. The adjusted recovery of the iMF device reached 59 to 79% on the basis of spike concentration. The device showed significant enrichment, generating 6.5-to-8.6-fold elevation in the CTC-to-WBC ratios.
EasySep™ produced substitutionally lower recoveries of about 3 to 10% in the whole or lysed blood with modest enrichment ratios of 1 to 1.8. These disparities stem from many handling and magnetic separation steps in the EasySep™ method. It increases the risk of cell loosening. When it was applied to patient samples, the iMF device outperformed EasySep™ and detected 390 CECs/mL in an IPMN patient as compared to 14 CECs/mL recovered by EasySep™. Â
CTCs were found in all remaining patients who used the iMF device, with counts ranging from 28 to 189 CTCs/mL. Post-operative samples had higher CTC counts than pre- and intra-operative samples, which reflected previous data that surgical manipulation might temporarily boost tumor cell spread. CTC size differed between patients and treatment histories, with chemotherapy-treated PDAC patients having smaller CTCs than untreated patients. This indicated that there was a possible biological effect of medication and disease stage.
The iMF device outperformed superior recovery, higher enrichment, lower operational complexity, and improved clinical sensitivity as compared to the immunomagnetic method. This study demonstrated inertial microfluidics as a powerful, label-free rare-cell isolation method that is capable of capturing heterogeneous CTC and CEC cells in pancreatic disease. The integrations in the liquid biopsy workflow hold significant promise to increase early detection and guide in clinical decision making and improve time monitoring of pancreatic cancer progression.
Reference: Macaraniag C, Khan I, Barabanova A, et al. Benchmarking microfluidic and immunomagnetic platforms for isolating circulating tumor cells in pancreatic cancer. Lab Chip. 2025;25(20):5292-5301. doi:10.1039/D5LC00512D
