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HHLA2 is a newly identified member of the B7 immune checkpoint family, but its function and crosstalk with immune cells is not fully understood. To gain insights into the HHLA2 expression profile and to determine the clinical significance and function of HHLA2 in pancreatic cancer, we performed immunohistochemistry (IHC) analyses on tissue microarrays (TMAs) of pancreatic ductal adenocarcinoma (PDAC, n = 92) with matched peritumoral tissues as well as in cohorts of precancerous lesions: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). We found that HHLA2 was rarely detected in normal acinar, islet, and ductal cells but widely expressed from early pancreatic precancerous lesions to invasive PDAC. The overall HHLA2 positivity was 95% (19/20) in low grade PanIN and 70.73% (29/41) in IPMN. HHLA2 expression was detected in 77.17% (71/92) of the PDAC cases and was significantly associated with better prognosis in this cohort. Our findings suggest that HHLA2 may behave as a costimulatory ligand in pancreatic cancer, which differs from other B7 family members that are largely characterized as checkpoint inhibitors. Further investigation of the HHLA2 signaling pathway and its receptors is warranted by our data and may lead to novel therapeutic interventions., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The progression of pancreatic cancer (PC) is significantly associated with tumor immune escape, which may be associated with nature killer (NK) cell dysfunction. CD226, CD96, and TIGIT, which share the ligand CD155, play important roles in the regulation of NK cell function. The present study was conducted to investigate the roles of these molecules in NK cells from PC patients. Expression of these molecules on NK cells was detected from samples of 92 pancreatic cancer patients and 40 healthy controls. The expression of CD155 was also evaluated by immunohistochemistry in 88 pancreatic cancer tissues. The percentage of CD226+ and CD96+ NK cells was significantly lower in PC patients than in the healthy controls; however, the mean fluorescence intensity of CD226 and CD96 was not significantly different between the two groups. TIGIT expression on NK cells from PC patients was similar to that in the healthy controls. Additionally, the expression of CD226 was positively correlated with CD96. Further analysis demonstrated that the decrease in the percentage of CD226+ and CD96+ NK cells was associated with tumor histological grade and lymph node metastasis. Moreover, the CD155 levels in PC tissues were significantly higher than those in adjacent tissues. Our results suggest that a lower percentage of CD226+ and CD96+ NK cells may contribute to tumor immune escape in PC patients; moreover, the use of NK cells with high CD226 and CD96 expression to treat PC cells with high CD155 expression may have potential and should be explored in the future.

Objective: To evaluate the methods of diagnosis and surgical treatment for nonfunctional islet cell tumor (NICT)., Methods: Forty-four patients with non-functional islet cell tumor treated at the First Affiliated Hospital of Nanjing Medical University during January 1968 to June 2008 were analyzed retrospectively. There were 9 males and 35 females, aged from 7- to 70-years-old. Clinical manifestation: 15 cases (34.1%) of abdominal masses, 17 patients (38.6%) with epigastric or back pain, 5 cases of jaundice, 5 cases (11.4%) for upper abdominal fullness or vomiting, 10 cases (22.7%) of pancreatic tumor noticed by routine health checkups or imaging examinations. Imaging examination: CT scan, sonography, ERCP, MRI, upper GI series were performed in 33 (75.0%), 16 (36.4%), 6 (13.6%), 2 (4.5%), and 10 cases (22.7%) respectively. Operation methods: 39 patients (88.6%) underwent surgical resection and the other 5 patients did not., Complications: pancreatic fistula in 7 patients (15.9%), intra-abdominal bleeding in 4 (9.1%), gastrojejunal anastomosis outlet obstruction in 1 (2.3%), biliary fistula in 2 (4.5%) and incisional infection in 3 (6.8%). Surgery related mortality happened in 2 patients (4.5%), both treated before 1999. Twenty-five patients underwent operation between January 1999 and June 2008 were followed up for 6 to 108 months. All survive except one died 75 months after the surgery for unknown reason., Conclusions: No specific clinical manifestation is recognized for non-functional islet cell tumor. Spiral CT is an optimal diagnostic method, while surgery is the first choice for treatment. Middle segmental pancreatectomy has become an alternative surgical protocol for NICT.