Pancreatic cancer is an aggressive malignancy with a poor prognosis. The disease and its treatment can cause significant nutritional impairments that often adversely impact patient quality of life (QOL). The pancreas has both exocrine and endocrine functions and, in the setting of cancer, both systems may be affected. Pancreatic exocrine insufficiency (PEI) manifests as weight loss and steatorrhea, while endocrine insufficiency may result in diabetes mellitus. Surgical resection, a central component of pancreatic cancer treatment, may induce or exacerbate these dysfunctions. Nutritional and metabolic dysfunctions in patients with pancreatic cancer lack characterization, and few guidelines exist for nutritional support in patients after surgical resection. We reviewed publications from the past two decades (1995–2016) addressing the nutritional and metabolic status of patients with pancreatic cancer, grouping them into status at the time of diagnosis, status at the time of resection, and status of nutritional support throughout the diagnosis and treatment of pancreatic cancer. Here, we summarize the results of these investigations and evaluate the effectiveness of various types of nutritional support in patients after pancreatectomy for pancreatic adenocarcinoma (PDAC). We outline the following conservative perioperative strategies to optimize patient outcomes and guide the care of these patients: (1) patients with albumin < 2.5 mg/dL or weight loss > 10% should postpone surgery and begin aggressive nutrition supplementation; (2) patients with albumin < 3 mg/dL or weight loss between 5% and 10% should have nutrition supplementation prior to surgery; (3) enteral nutrition (EN) should be preferred as a nutritional intervention over total parenteral nutrition (TPN) postoperatively; and, (4) a multidisciplinary approach should be used to allow for early detection of symptoms of endocrine and exocrine pancreatic insufficiency alongside implementation of appropriate treatment to improve the patient’s quality of life.

The microenvironment that surrounds pancreatic ductal adenocarcinoma (PDAC) is profoundly desmoplastic and immunosuppressive. Understanding triggers of immunosuppression during the process of pancreatic tumorigenesis would aid in establishing targets for effective prevention and therapy. Here, we interrogated differential molecular mechanisms dependent on cell of origin and subtype that promote immunosuppression during PDAC initiation and in established tumors. Transcriptomic analysis of cell-of-origin–dependent epithelial gene signatures revealed that Nt5e/CD73, a cell-surface enzyme required for extracellular adenosine generation, is one of the top 10% of genes overexpressed in murine tumors arising from the ductal pancreatic epithelium as opposed to those rising from acinar cells. These findings were confirmed by IHC and high-performance liquid chromatography. Analysis in human PDAC subtypes indicated that high Nt5e in murine ductal PDAC models overlaps with high NT5E in human PDAC squamous and basal subtypes, considered to have the highest immunosuppression and worst prognosis. Multiplex immunofluorescent analysis showed that activated CD8+ T cells in the PDAC tumor microenvironment express high levels of CD73, indicating an opportunity for immunotherapeutic targeting. Delivery of CD73 small-molecule inhibitors through various delivery routes reduced tumor development and growth in genetically engineered and syngeneic mouse models. In addition, the adenosine receptor Adora2b was a determinant of adenosine-mediated immunosuppression in PDAC. These findings highlight a molecular trigger of the immunosuppressive PDAC microenvironment elevated in the ductal cell of origin, linking biology with subtype classification, critical components for PDAC immunoprevention and personalized approaches for immunotherapeutic intervention. Significance: Ductal-derived pancreatic tumors have elevated epithelial and CD8+GZM+ T-cell CD73 expression that confers sensitivity to small-molecule inhibition of CD73 or Adora2b to promote CD8+ T-cell–mediated tumor regression. See related commentary by DelGiorno, p. 977

Overexpression of Semaphorin-3E enhances pancreatic cancer cell growth and associates with poor patient survival

This study aims to evaluate the prognostic value of MUC expression in US GC patients. A total of 70 tumor specimens were collected from GC patients who underwent surgery or endoscopic resection between 2013 and 2019 at a tertiary referral center in the US. MUC expression status including MUC1, MUC2, MUC5AC, and MUC6 was evaluated by immunohistochemical staining. The positive rates of MUC1, MUC2, MUC5AC, and MUC6 were 71.4%, 78.6%, 74.3%, and 33.3%, respectively. Patients with positive MUC1 expression had a significantly higher rate of aggressive pathologic features including diffuse-type cancer (42.0% vs. 0%; p < 0.001), advanced GC (80.0% vs. 30.0%, p < 0.001), lymph node metastasis (62.0% vs. 20.0%; p = 0.001), and distant metastasis (32.0% vs. 5.0%; p = 0.017) compared with those with negative MUC1 expression. However, the differences in the pathologic features were not observed according to MUC2, MUC5AC, and MUC6 expression status. In early gastric cancer (EGC), patients with a high level of MUC1 expression showed a higher rate of lymphovascular invasion (71.4% vs. 21.4%; p = 0.026) and EGC meeting non-curative resection (85.7% vs. 42.9%; p = 0.061) than those with negative MUC1. In US GC patients, MUC1 expression is associated with aggressive pathological features, and might be a useful prognostic marker.

Existing patient-derived xenograft (PDX) mouse models of solid tumors lack a fully tumor donor–matched, syngeneic, and functional immune system. We developed a model that overcomes these limitations by engrafting lymphopenic recipient mice with a fresh, undisrupted piece of solid tumor, whereby tumor-infiltrating lymphocytes (TILs) persisted in the recipient mice for several weeks. Successful tumor engraftment was achieved in 83% to 89% of TIL-PDX mice, and these were seen to harbor exhausted immuno-effector as well as functional immunoregulatory cells persisting for at least 6 months postengraftment. Combined treatment with interleukin-15 stimulation and immune checkpoint inhibition resulted in complete or partial tumor response in this model. Further, depletion of cytotoxic T lymphocytes and/or natural killer cells before combined immunotherapy revealed that both cell types were required for maximal tumor regression. Our TIL-PDX model provides a valuable resource for powerful mechanistic and therapeutic studies in solid tumors.