Circulating Tumor Cells and Transforming Growth Factor Beta in Resected Pancreatic Adenocarcinoma

Background: Portal vein (PV) circulating tumor cells (CTCs) and elevated peripheral blood (PB) levels of biomarkers have been associated with poor outcomes in pancreatic ductal adenocarcinoma (PDAC). Although transforming growth factor-beta (TGFβ) is associated with CTCs in breast cancer, there are limited data evaluating a comprehensive biomarker panel and CTCs in PDAC patients. The authors hypothesized that tumor progression biomarkers would be associated with PV CTCs. Methods: PDAC patients at one institution were enrolled January to August 2018 and underwent preincision PB draws (T0) and on postoperative day 1 (T3), plus intraoperative PV draws before tumor manipulation (T1) and after resection (T2). CTCs were detected using CellSearch. Plasma biomarker levels (pg/mL) were measured with a multiplex bead assay. Patients were divided into two groups: high (≥3 CTCs/7.5 mL blood) versus low (<3). Clinicopathologic variables and biomarkers were compared in the two groups. Results: Fourteen had complete blood draws with PDAC resection, with five demonstrating high CTCs. Fewer patients in the high-CTC group received preoperative radiation (78 versus 20%), whereas more of the high-CTC had pT3 tumors (80 versus 11%) (all P < 0.037). High-CTC patients demonstrated higher TGFβ-2 levels (T0 [906 versus 586], T1 [1337 versus 627], T2 [1149 versus 445]), as well as higher TGFβ-3 (T0 [320 versus 173], T2 [605 versus 120]) (all P < 0.021). Conclusions: PDAC patients with high CTCs demonstrated a distinct biomarker profile with elevated PB and PV levels of immunosuppressive cytokines (TGFβ-2 and TGFβ-3). These exploratory results prompt further study into interrupting TGFβ signaling.