Circulating tumor cell and cell-free RNA capture and expression analysis identify platelet-associated genes in metastatic lung cancer.

BACKGROUND: Circulating tumor cells (CTC) and plasma cell-free RNA (cfRNA) can serve as biomarkers for prognosis and treatment response in lung cancer. One barrier to the selected or routine use of CTCs and plasma cfRNA in precision oncology is the limited quantity of both, and CTCs are only seen in metastatic disease. As capture of CTCs and plasma cfRNA presents an opportunity to monitor and assess malignancies without invasive procedures, we compared two methods for CTC capture and identification, and profiled mRNA from CTCs and plasma cfRNA to identify potential tumor-associated biomarkers. METHODS: Peripheral blood was collected from ten patients with small cell lung cancer (SCLC), ten patients with non-small cell lung cancer (NSCLC) and four healthy volunteers. Two methods were used for CTC capture: the standard epithelial cell adhesion molecule (EpCam) CellSearch kit (unicapture) and EpCAM plus HER2, EGFR and MUC-1 specific combined ferrofluid capture (quadcapture). For the quadcapture, anti-cytokeratin 7 (CK7) was additionally used to assist in CTC identification. NanoString analysis was performed on plasma cfRNA and on mRNA from combined ferrofluid isolated CTCs. Expression data was analyzed using STRING and Reactome. RESULTS: Unicapture detected CTCs in 40% of NSCLC and 60% of SCLC; whereas, quadcapture/CK7 identified CTCs in 20% of NSCLC and 80% of SCLC. Bioinformatic analysis of NanoString data identified high expression of a platelet factor 4 (PF4)-related group of transcripts. CONCLUSIONS: Quadcapture ferrofluid reagent did not significantly improve CTC capture efficacy. NanoString analysis based on CTC and plasma cfRNA data highlighted an intriguing PF-4-centric network in patients with metastatic lung cancer.

Prognostic Significance of MUC-1 in Circulating Tumor Cells in Patients With Metastatic Pancreatic Adenocarcinoma.

OBJECTIVES: Development of targeted therapies for pancreatic cancer could be enhanced by a reliable method for noninvasive tumor cell assessment. In this pilot study, we isolated and phenotypically characterized circulating tumor cells (CTCs) from patients with metastatic pancreatic cancer and explored their relationship to clinical outcome. METHODS: Peripheral blood from 50 patients was collected at treatment initiation and first disease evaluation for CTC enumeration and phenotyping by CellSearch® system. Expression of human mucin 1 (MUC-1) was performed. RESULTS: Forty-eight and 37 patients had evaluable samples at baseline and first disease evaluation, respectively. The cohort was 62% male, with a median age of 63 years. At least 1 CTC per 7.5 mL was detected in 23 patients (48%) pretreatment and 11 patients (30%) at first disease evaluation. No difference was seen in overall survival between patients with 1 or more CTCs versus no CTC at baseline (P = 0.14). Patients with MUC-1 expressing CTC (n = 10) had shorter median overall survival compared with those with MUC-1 negative CTC (n = 13; 2.7 vs 9.6 m; P = 0.044). CONCLUSIONS: Circulating tumor cell enumeration and phenotypic characterization from metastatic pancreatic cancer patients are feasible. No correlation was found between CTC isolation and survival. However, the presence of MUC-1 expressing CTC demonstrated a trend toward inferior survival.