Tumour extracellular vesicles induce neutrophil extracellular traps to promote lymph node metastasis
Lymph nodes (LNs) are frequently the first sites of metastasis. Currently, the only prognostic LN assessment is determining metastatic status. However, there is evidence suggesting that LN metastasis is facilitated by the formation of a pre-metastatic niche induced by tumour derived extracellular vehicles (EVs). Therefore, it is important to detect and modify the LN environmental changes. Earlier work has demonstrated that neutrophil extracellular traps (NETs) can sequester and promote distant metastasis. Here, we first confirmed that LN NETs are associated with reduced patient survival. Next, we demonstrated that NETs deposition precedes LN metastasis and NETs inhibition diminishes LN metastases in animal models. Furthermore, we discovered that EVs are essential to the formation of LN NETs. Finally, we showed that lymphatic endothelial cells secrete CXCL8/2 in response to EVs inducing NETs formation and the promotion of LN metastasis. Our findings reveal the role of EV-induced NETs in LN metastasis and provide potential immunotherapeutic vulnerabilities that may occur early in the metastatic cascade.
Locoregional Recurrence of Esophageal Cancer Treated with Curative Intent Local Salvage Therapy: A Single Center Experience
Locoregional recurrence of esophageal carcinoma after neoadjuvant therapy and en bloc esophagectomy, although uncommon, is challenging to manage. Currently, there are no standard treatment approaches prompting many health care providers to adopt a palliative approach. We describe our experience and outcomes of treating this specific group of patients with a focus on salvage curative intent local therapy. All patients undergoing en bloc esophagectomy following neoadjuvant therapy between 2007 and 2017 at the McGill University Health Centre, a tertiary referral center for esophageal cancer, were identified. Patient follow-up included a structured surveillance protocol with serial endoscopic and cross-sectional imaging studies. Local recurrence was defined as histologically confirmed recurrences at the anastomosis. Regional recurrence was defined as radiological evidence of celiac, mediastinal, or para-esophageal/conduit lymphadenopathy. Demographic, pathologic, therapeutic variables were extracted as well as disease free and overall survival. Of 755 patients identified, locoregional recurrences occurred in 27 patients (3.6%) of whom 18 were included in the analysis. The median disease-free survival post index operation was 15 months (IQR 10-23). The sites of recurrence were local (6/18, 33.3%); regional (8/18, 44.4%); and locoregional (4, 22.2%). Chemoradiation was the most common modality used to treat recurrence (10/18, 55.6%) whilst 4 (22.2%) underwent surgery. Following treatment for locoregional recurrence, 1-year overall survival was 61.1% and at 5 years was 22.2%. Consolidative salvage local therapy for locoregional recurrence after en bloc esophagectomy is feasible and can entail prolonged survival in a subset of patients.
Relation between mismatch repair status, chemoresponse, survival and anatomic location in gastroesophageal adenocarcinoma
It has recently been reported that mismatch repair (MMR) status and microsatellite instability (MSI) status in gastroesophageal carcinomas predict surgical, chemotherapeutic and immunotherapeutic outcomes; however, there is extensive variability in the reported incidence and clinical implications of MMR/MSI status in gastroesophaegal adenocarcinomas. We characterized a Canadian surgical patient cohort with respect to MMR status, clinicopathologic correlates and anatomic tumour location. We investigated MMR and BRAF V600E status of gastroesophaegal adenocarcinomas in patients who underwent gastrectomy or esophagectomy with extended (D2) lymphadenectomy at a single centre between 2011 and 2019. We correlated patterns of MMR expression in the overall cohort and in anatomic location-defined subgroups with treatment response and overall survival using multivariate analysis. In all, 226 cases of gastroesophaegal adenocarcinoma (63 esophageal, 98 gastroesophageal junctional and 65 gastric) were included. The MMR-deficient (dMMR) immunophenotype was found in 28 tumours (12.3%) (15 junctional [15.3%], 13 gastric [20.0%] and none of the esophageal). The majority (25 [89%]) of dMMR cases showed MLH1/PMS2 loss without concurrent BRAF V600E mutation. Two MSH2/ MSH6-deficient gastric tumours and 1 MSH6-deficient junctional tumour were detected. The pathologic response to preoperative chemotherapy was comparable in the dMMR and MMR-proficient (pMMR) cohorts. However, dMMR status was associated with significantly longer median overall survival than pMMR status (5.8 yr v. 2.4 yr, hazard ratio [HR] 1.91, 95% confidence interval [CI] 1.06-3.46), particularly in junctional tumours (4.6 yr v. 1.9 yr, HR 2.97, 95% CI 1.27-6.94). Our study shows that MMR status has at least prognostic value, which supports the need for biomarker testing in gastroesophageal adenocarcinomas, including junctional adenocarcinomas. This highlights the clinical significance of determining the MMR status in all adenocarcinomas of the upper gastrointestinal tract. Response to induction chemotherapy, however, was not influenced by MMR status.
Soluble factors in malignant ascites promote the metastatic adhesion of gastric adenocarcinoma cells
Adenocarcinoma of the proximal stomach is the fastest rising malignancy in North America. It is commonly associated with peritoneal accumulation of malignant ascites (MA), a fluid containing cancer and inflammatory cells and soluble proteins. Peritoneal metastasis (PM) is the most common site of gastric cancer (GC) progression after curative-intent surgery and is the leading cause of death among GC patients. Using a panel of gastric adenocarcinoma cell lines (human: MKN 45, SNU-5; murine: NCC-S1M), we demonstrate that prior incubation of GC cells with MA results in a significant (> 1.7-fold) increase in the number of cells capable of adhering to human peritoneal mesothelial cells (HPMC) (p < 0.05). We then corroborate these findings using an ex vivo PM model and show that MA also significantly enhances the ability of GC cells to adhere to strips of human peritoneum (p < 0.05). Using a multiplex ELISA, we identify MIF and VEGF as consistently elevated across MA samples from GC patients (p < 0.05). We demonstrate that agents that block the effects of MIF or VEGF abrogate the ability of MA to stimulate the adhesion of GC cells to adhere to human peritoneum and promote both ex vivo and in vivo metastases. Agents targeting MIF or VEGF may be relevant to the treatment or prevention of PM in GC patients.
