Tumor-infiltrating monocytic myeloid-derived suppressor cells contribute to the development of an immunosuppressive tumor microenvironment in gastric cancer

BACKGROUND

Gastric cancer (GC) is characterized by an immunosuppressive and treatment-resistant tumor immune microenvironment (TIME). Here, we investigated the roles of different immunosuppressive cell types in the development of the GC TIME.

METHODS

Single-cell RNA sequencing (scRNA-seq) and multiplex immunostaining of samples from untreated or immune checkpoint inhibitor (ICI)-resistant GC patients were used to examine the correlation between certain immunosuppressive cells and the prognosis of GC patients.

RESULTS

The results of the scRNA-seq analysis revealed that tumor-infiltrating monocytic myeloid-derived suppressor cells (TI-M-MDSCs) expressed higher levels of genes with immunosuppressive functions than other immunosuppressive cell types. Additionally, M-MDSCs in GC tissues expressed significantly higher levels of these markers than adjacent normal tissues. The M-MDSCs were most enriched in GC tissues relative to adjacent normal tissues. Among the immunosuppressive cell types assessed, the M-MDSCs were most enriched in GC tissues relative to adjacent normal tissues; moreover, their presence was most strongly associated with a poor prognosis. Immediate early response 3 (IER3), which we identified as a differentially expressed gene between M-MDSCs of GC and adjacent normal tissues, was an independent poor prognostic factor in GC patients (P = 0.0003). IER3+ M-MDSCs expressed higher levels of genes with immunosuppressive functions than IER3- M-MDSCs and were abundant in treatment-resistant GC patients.

CONCLUSIONS

The present study suggests that TI-M-MDSCs, especially IER3+ ones, may play a predominant role in the development of the immunosuppressive and ICI-resistant GC TIME.

The degree of satisfaction and level of learning in male and female surgical residents: a nationwide questionnaire survey of graduating residents in Japan

PURPOSE

Since 2002, the Japan Surgical Society has established a board certification system for surgeons to be certified for a specialty. Surgery remains a male-dominated field in Japan. This study aimed to clarify if the Japanese surgical residency training system is equally suitable for female and male residents.

METHODS

The Japan Surgical Society conducted the first questionnaire survey regarding the system of surgical training for the residents in 2016. The questionnaire included the degree of satisfaction with 7 aspects of the training system, including the number and variety of cases experienced and duration and quality of instruction, and the learning level for 31 procedures. The degree of satisfaction and level of learning were compared between female and male residents.

RESULTS

The degree of satisfaction was similar for all items between female and male residents. Female residents chose breast surgery as their subspecialty more frequently than male residents and were more confident in breast surgery procedures than male residents. Conversely, fewer female residents chose gastrointestinal surgery and were less confident in gastrointestinal surgery procedures than male residents.

CONCLUSION

Female residents were as satisfied with the current surgical training system as male residents. However, there may be room for improvement in the surgical system, considering that fewer applications for gastrointestinal surgery come from female residents than from males.

Single-cell transcriptome analysis reveals functional changes in tumour-infiltrating B lymphocytes after chemotherapy in oesophageal squamous cell carcinoma

BACKGROUND

Tumour immune microenvironment is related with carcinogenesis and efficacy of immunotherapy. B cells play major roles in humoral immunity, but detailed functions of tumour-infiltrating B lymphocytes (TIL-Bs) are unknown. Therefore, our aim was to investigate the functional heterogeneity of TIL-Bs in oesophageal squamous cell carcinoma (ESCC) and lymph nodes (LNs) during chemotherapy.

METHODS

Single-cell transcriptome analysis was performed on 23 specimens. We also performed immunohistochemical analysis of immunoglobulin κ C (IGKC), an antibody-secreting cell (ASC) marker, in 166 ESCC samples and evaluated the implication of IGKC in 2-year recurrence free survival (RFS) and 3-year overall survival (OS).

RESULTS

A total of 81,246 cells were grouped into 24 clusters. We extracted B cell clusters based on canonical markers and identified 12 TIL-B subtypes in ESCC. We found that several functions, such as co-stimulation and CD40 signalling, were enhanced in TIL-Bs after chemotherapy. The proportion of naive B cells (NBCs) decreased and B cell activation genes were up-regulated in NBCs after chemotherapy. The proportion of ASCs in tumours increased with the loss of migratory abilities and antibody production in ASCs was promoted after chemotherapy. Differentially expressed genes up-regulated with chemotherapy in ASCs correlated with prolonged survival with oesophageal cancer (p = .028). In a metastatic LN, the ASC proportion increased and B cell differentiation was enhanced. In immunohistochemical analysis, RFS and OS of high IGKC expression cases were significantly better than those of low IGKC expression cases (RFS: p < .0001, OS: p < .0001). And in multivariable analysis, the expression of IGKC was an independent favourable prognostic factor for RFS (hazard ratio (HR): 0.23, 95% confidence interval (CI): 0.12-0.45, p < .0001) and OS (HR: 0.20, 95% CI: 0.086-0.47, p = .0002) in ESCC.

CONCLUSIONS

Our findings provide novel insights for the heterogeneity of TIL-Bs during chemotherapy and will be useful to understand the clinical importance of TIL-Bs.

Validation study of a skill assessment tool for education and outcome prediction of laparoscopic distal gastrectomy

BACKGROUND

The Japanese operative-rating scale for laparoscopic distal gastrectomy (JORS-LDG) was developed through cognitive task analysis together with the Delphi method to measure intraoperative performance during laparoscopic distal gastrectomy. This study aimed to investigate the value of this rating scale as an educational tool and a surgical outcome predictor in laparoscopic distal gastrectomy.

METHODS

The surgical performance of laparoscopic distal gastrectomy was assessed by the first assistant, through self-evaluation in the operating room and by video raters blind to the case. We evaluated inter-rater reliability, internal consistency, and correlations between the JORS-LDG scores and the evaluation methods, patient characteristics, and surgical outcomes.

RESULTS

Fifty-four laparoscopic distal gastrectomy procedures performed by 40 surgeons at 16 institutions were evaluated in the operating room and with video recordings using the proposed rating scale. The video inter-rater reliability was > 0.8. Participating surgeons were divided into the low, intermediate, and high groups based on their total scores. The number of laparoscopic surgeries and laparoscopic gastrectomy procedures performed differed significantly among the groups according to laparoscopic distal gastrectomy skill levels. The low, intermediate, and high groups also differed in terms of median operating times (311, 266, and 229 min, respectively, P < 0.001), intraoperative complication rates (27.8, 11.8, and 0%, respectively, P = 0.01), and postoperative complication rates (22.2, 0, and 0%, respectively, P = 0.002).

CONCLUSIONS

The JORS-LDG is a reliable and valid measure for laparoscopic distal gastrectomy training and could be useful in predicting surgical outcomes.

Is there disparity between regions and facilities in surgical resident training in Japan? Insights from a national survey

PURPOSE

This study sought to assess the disparity between regions and facilities in surgical resident training in Japan via a national level needs-assessment.

METHODS

A survey was sent to all 909 graduating residents of 2016. Residents trained in the six prefectures with a population of 7 million or more were included in the large prefecture (LP) group. Residents trained in the other 41 prefectures were included in the small prefecture (SP) group. Each group was further divided into a university hospital (UH) group and a non-university hospital (NUH) group.

RESULTS

The response rate was 56.3% (n = 512). Excluding nine residents who did not report their prefectures and facilities, surveys from 503 residents were analyzed. The UH group received significantly more years of training. In the SP and UH groups, there were significantly fewer residents who had performed 150 procedures or more under general anesthesia in comparison to the LP and NUH groups, respectively. Self-assessed competencies for several procedures were significantly lower in the SP and UH groups.

CONCLUSION

Disparity in surgical resident training was found between regions and facilities in Japan. The surgical residency curriculum in Japan could be improved to address this problem.

Are graduating residents sufficiently competent? Results of a national gap analysis survey of program directors and graduating residents in Japan

PURPOSE

To evaluate the self-assessed competency of graduating residents (GRs) in Japan upon completion of their residency and to identify the gap between their competency and the competency expected by their program directors (PDs).

METHOD

A list of 31 essential surgical procedures was compiled according to the consensus of surgical educators from around the country. A survey with this list was sent to all 909 GRs and their 611 PDs in 2016. The GRs rated their competency to perform these procedures and the PDs were asked to evaluate the expected competency of their GRs using the Zwisch Scale.

RESULT

The response rate was 56.3% for the GRs and 76.8% for the PDs. Fewer than half of the GRs who responded felt confident performing ten (32%) of the surgical procedures evaluated. For most procedures, the GRs' self-reported competency was lower than the expectation reported by their PDs. This gap was more than 10% for 13 of the procedures.

CONCLUSION

More than half of the GRs in Japan lacked the confidence in their skill to perform one-third of the surgical procedures selected for evaluation in this study. These findings should be used to update the surgical education curriculum in Japan.

A snapshot of surgical resident training in Japan: results of a national-level needs assessment survey

PURPOSE

To evaluate the status of surgical training in Japan through a national-level needs assessment.

METHODS

A survey was sent to all 909 graduating residents (GRs) and their 611 program directors (PDs) for the year 2016. A working group of surgical educators from around the country was formed under the education committee of the Japan Surgical Society. The survey items were developed by consensus of this working group. The survey investigated the knowledge and problems of the current curriculum, and the status of the current residency training.

RESULTS

The response rates were 56.3% of the GRs and 76.8% of the PDs. Among the participants, 47.6% of the GRs and 29.4% of the PDs believed that the residency curriculum did not match the clinical experience. Over 80% of the GRs and PDs agreed on the importance of training outside of the OR, whereas only 13% of the GRs had received such training regularly. Trainees also reported a lower satisfaction rate about the opportunity to train outside of the OR.

CONCLUSION

This national-level needs assessment of surgical training in Japan identified several gaps in the curriculum. These results provide valuable data to assist the ongoing efforts for surgical residency curriculum improvement.

Metastatic esophageal carcinosarcoma comprising neuroendocrine carcinoma, squamous cell carcinoma, and sarcoma: A case report

RATIONALE

Esophageal carcinosarcoma generally comprises 2 histological components: squamous cell carcinoma (SqCC) and sarcoma. Esophageal carcinosarcoma comprising 3 components is extremely rare and no reports have described therapeutic effects for this disease with metastasis.

PATIENT CONCERNS

A 76-year-old man with dysphagia presented to a local clinic. Gastrointestinal endoscopy revealed a polypoid tumor in the middle esophagus and he was referred to our hospital.

DIAGNOSIS AND INTERVENTIONS

Thoracoscopic esophagectomy with super-extended (D3) nodal dissection and gastric tube reconstitution was performed, which resulted in carcinosarcoma comprising neuroendocrine carcinoma (NEC), SqCC, and sarcoma. Pathological stage was T1bN1M0 stage IIB according to the TNM Classification of Malignant Tumors-7th edition. The NEC component was observed in lymph node. At 47 days after surgery, lymph nodes, liver, and bone metastasis appeared, and tumor markers such as ProGRP and NSE were elevated. Combination chemotherapy with cisplatin and etoposide (EP) adapted to NEC was performed.

OUTCOMES

The patient showed complete response within 4 cycles of chemotherapy. However, the disease recurred 5.5 months after the final course of EP chemotherapy.

LESSONS

A therapeutic strategy based on assessment of which component caused metastasis might be important for metastatic carcinosarcoma comprising 3 components, although more accumulation of data about the efficacy of chemotherapy is necessary. Moreover, elucidation of the mechanisms underlying generation of carcinosarcoma is expected in the future.

Feasibility of Prophylactic Pancreatojejunostomy in Possible High-Risk Patients for Prevention of Pancreatic Fistula during Enucleation or Limited Pancreatic Resection

The aim of this study was to assess the feasibility of prophylactic pancreatojejunostomy after enucleation or limited pancreatic resection regarding the risk of postoperative pancreatic fistula (PF). We retrospectively reviewed the medical records of 32 patients who underwent enucleation or limited pancreatic resection and compared the clinical parameters between patients with ( n = 10) and without ( n = 22) prophylactic pancreatojejunostomy. Prophylactic pancreatojejunostomy was performed in patients with a possible high risk ofPF. No operation-related mortality occurred. Operation time was significantly longer ( P < 0.01) and blood loss significantly greater ( P < 0.01) in patients with pancreatojejunostomy. Overall complications were more frequent ( P = 0.02) and postoperative hospital stay was significantly longer ( P = 0.02) in patients with pancreatojejunostomy. However, other assessed factors including the prevalence of postoperative PF did not differ between groups. In conclusion, prophylactic pancreatojejunostomy is feasible, and its efficacy in preventing PF after enucleation or limited pancreatic resection in high-risk patients will require further study.

Feasibility of Prophylactic Pancreatojejunostomy in Possible High-Risk Patients for Prevention of Pancreatic Fistula during Enucleation or Limited Pancreatic Resection

The aim of this study was to assess the feasibility of prophylactic pancreatojejunostomy after enucleation or limited pancreatic resection regarding the risk of postoperative pancreatic fistula (PF). We retrospectively reviewed the medical records of 32 patients who underwent enucleation or limited pancreatic resection and compared the clinical parameters between patients with (n = 10) and without (n = 22) prophylactic pancreatojejunostomy. Prophylactic pancreatojejunostomy was performed in patients with a possible high risk ofPF. No operation-related mortality occurred. Operation time was significantly longer (P < 0.01) and blood loss significantly greater (P < 0.01) in patients with pancreatojejunostomy. Overall complications were more frequent (P = 0.02) and postoperative hospital stay was significantly longer (P = 0.02) in patients with pancreatojejunostomy. However, other assessed factors including the prevalence of postoperative PF did not differ between groups. In conclusion, prophylactic pancreatojejunostomy is feasible, and its efficacy in preventing PF after enucleation or limited pancreatic resection in high-risk patients will require further study.

Pancreatic stellate cells reorganize matrix components and lead pancreatic cancer invasion via the function of Endo180

Specific cell populations leading the local invasion of cancer are called "leading cells". However, the underlying mechanisms are unclear. Here, we identified leading cells in pancreatic cancer and determined how these cells lead and promote cancer cell invasion in the extracellular matrix (ECM). Using three-dimensional matrix remodeling assay, we found that pancreatic stellate cells (PSCs) frequently invaded the collagen matrix with pancreatic cancer cells (PCCs), which invaded behind the invading PSCs. In addition, invading PSCs changed the alignment of collagen fibers, resulting in ECM remodeling and an increase in the parallel fibers along the direction of invading PSCs. Endo180 expression was higher in PSCs than in PCCs, Endo180 knockdown in PSCs attenuated the invasive abilities of PSCs and co-cultured PCCs, and decreased the expression level of phosphorylated myosin light chain 2 (MLC2). In mouse models, Endo180-knockdown PSCs suppressed tumor growth and changes in collagen fiber orientation in co-transplantation with PCCs. Our findings suggest that PSCs lead the local invasion of PCCs by physically remodeling the ECM, possibly via the function of Endo180, which reconstructs the actin cell skeleton by phosphorylation of MLC2.

Degree of desmoplasia in metastatic lymph node lesions is associated with lesion size and poor prognosis in pancreatic cancer patients

Pancreatic cancer is characterized by increased hyperplasia of fibrotic tissue, termed desmoplasia, and lymph node metastasis is an independent prognostic factor in this disease. However, there are no reports focused on desmoplasia in pancreatic cancer lymph node metastases. The present study evaluated a range of factors and investigated their association with poor prognosis in pancreatic cancer cases with lymph node metastasis, including the degree of desmoplasia in lesions. To identify the poor prognostic factors associated with lymph node metastasis, the present study retrospectively reviewed the clinical data of 65 patients with lymph node metastases that underwent surgical pancreatic cancer resection between 2007 and 2012 at a single institution. The investigation focused on the degree of fibrosis in metastatic lesions in 216 lymph nodes, and investigated associations with prognosis or clinicopathological findings. The ratios of the fibrotic area in metastatic lymph node lesions were evaluated and classified into three categories, high (≥70%), moderate (10-70%) and low (<10%). Desmoplasia was not observed in cancer-free lymph nodes. The size of metastatic lymph node lesions was additionally measured, and a significant association between metastatic lesion size and the degree of desmoplasia was observed (P<0.001). The degree of desmoplasia was additionally associated with local extranodal invasion. In the analysis of 65 pancreatic cancer patients with metastatic lymph nodes, the presence of multiple metastatic lymph nodes with moderate or high desmoplasia was significantly associated with poor survival (high, P=0.0048; moderate/high, P=0.0075). Of several clinicopathological factors, the presence of multiple metastatic lymph nodes with high or moderate desmoplasia was associated with overall survival in univariate (P=0.0098) and multivariate (P=0.0466) analyses. The degree of desmoplasia in metastatic lymph nodes is associated with lesion size, and the presence of multiple metastatic lymph nodes with desmoplasia is an independent poor prognostic factor, suggesting that the desmoplasia may have an important role in the malignant progression of lymph node metastases.

Feasibility and safety of modified inverted T-shaped method using linear stapler with movable cartridge fork for esophagojejunostomy following laparoscopic total gastrectomy

BACKGROUND

We previously reported the use of an inverted T-shaped method to obtain a suitable view for hand sewing to close the common entry hole when the linear stapler was fired for esophagojejunostomy after laparoscopic total gastrectomy (LTG). This conventional method involved insertion of the fixed cartridge fork to the Roux limb and the fine movable anvil fork to the esophagus to avoid perforation of the jejunum. However, insertion of the movable anvil fork to the esophagus during this procedure often requires us to strongly push down the main body of the stapler with the fixed cartridge fork to bring the direction of the anvil fork in line with the direction of the long axis of the esophagus while controlling the opening of the movable anvil fork. We therefore modified this complicated inverted T-shaped method using a linear stapler with a movable cartridge fork. This modified method involved insertion of the movable cartridge fork into the Roux limb followed by natural, easy insertion of the fixed anvil fork into the esophagus without controlling the opening of the movable cartridge fork.

METHODS

We performed LTG in a total of 155 consecutive patients with gastric cancer from November 2007 to December 2015 in Kyushu University Hospital. After LTG, we performed the conventional inverted T-shaped method using a linear stapler with a fixed cartridge fork in 61 patients from November 2007 to July 2011 (fixed cartridge group). From August 2011, we used a linear stapler with a movable cartridge fork and performed the modified inverted T-shaped method in 94 patients (movable cartridge group). We herein compare the short-term outcomes in 94 cases of LTG using the modified method (movable cartridge fork) with those in 61 cases using the conventional method (fixed cartridge fork).

RESULTS

We found no significant differences in the perioperative or postoperative events between the movable and fixed cartridge groups. One case of anastomotic leakage occurred in the fixed cartridge group, but no anastomotic leakage occurred in the movable cartridge group.

CONCLUSIONS

Although there were no remarkable differences in the short-term outcomes between the movable and fixed cartridge groups, we believe that the modified inverted T-shaped method is technically more feasible and reliable than the conventional method and will contribute to the improved safety of LTG.

Systemic chemotherapy with pronounced efficacy and neutropenia in a granulocyte-colony stimulating factor-producing advanced gastric neuroendocrine carcinoma

An advanced granulocyte-colony stimulating factor (G-CSF)-producing tumor is rare, and it exhibits leukocytosis in association with high serum G-CSF levels. A 67-year-old male with a 1-month history of bloody emesis and black stools was revealed to exhibit leukocytosis, anemia and a high serum concentration of G-CSF. During a gastrointestinal endoscopy, an ulcerating tumor was identified in the stomach. Computed tomography and a fluorodeoxyglucose-positron emission tomography scan demonstrated direct invasion of the gastric tumor into the transverse colon, regional lymphadenopathy, lung nodules and diffuse high uptake of FDG in bone marrow. The histological diagnosis was a G-CSF-producing neuroendocrine carcinoma (NEC) (tumor 4b, node 2, metastasis 1, pulmonary, clinical stage IV). Systemic chemotherapy consisting of cisplatin and irinotecan was started. Common terminology criteria of adverse events grade 3 tumor lysis syndrome and gastric penetration appeared. Grade 4 neutropenia lasted for 10 days despite intensive G-CSF administration. Prominent shrinkage of the primary and the metastatic tumors was observed subsequent to 3 cycles of chemotherapy. Total gastrectomy and resection of the transverse colon were subsequently performed. Systemic chemotherapy was effective for a G-CSF-producing advanced gastric NEC with careful monitoring and appropriate supportive care for severe adverse events.

Laparoscopic excision of neurogenic retrorectal tumors

Retrorectal tumors (RT) are uncommon and usually managed by open surgical excision. Laparoscopic excision for RT has been reported in only a small number of papers. We aimed to assess the laparoscopic approach for RT and to discuss the factors that made this procedure difficult. We performed laparoscopic excision using a five-trocar technique for neurogenic RT in three patients. Tumors were successfully excised laparoscopically in two patients. However, the third patient required open conversion because the tumor was strongly adhered to the sacrum and could not be mobilized by dissection, resulting in poor visualization of the dissected site. Laparoscopic excision for RT provides excellent intraoperative visualization and good cosmesis in selected patients, but firm adherence to the sacrum may cause difficulty with this procedure.

Quality of life after total vs distal gastrectomy with Roux-en-Y reconstruction: Use of the Postgastrectomy Syndrome Assessment Scale-45

AIM

To investigate the detrimental impact of loss of reservoir capacity by comparing total gastrectomy (TGRY) and distal gastrectomy with the same Roux-en-Y (DGRY) reconstruction. The study was conducted using an integrated questionnaire, the Postgastrectomy Syndrome Assessment Scale (PGSAS)-45, recently developed by the Japan Postgastrectomy Syndrome Working Party.

METHODS

The PGSAS-45 comprises 8 items from the Short Form-8, 15 from the Gastrointestinal Symptom Rating Scale, and 22 newly selected items. Uni- and multivariate analysis was performed on 868 questionnaires completed by patients who underwent either TGRY (n = 393) or DGRY (n = 475) for stage I gastric cancer (52 institutions). Multivariate analysis weighed of six explanatory variables, including the type of gastrectomy (TGRY/DGRY), interval after surgery, age, gender, surgical approach (laparoscopic/open), and whether the celiac branch of the vagus nerve was preserved/divided on the quality of life (QOL).

RESULTS

The patients who underwent TGRY experienced the poorer QOL compared to DGRY in the 15 of 19 main outcome measures of PGSAS-45. Moreover, multiple regression analysis indicated that the type of gastrectomy, TGRY, most strongly and broadly impaired the postoperative QOL among six explanatory variables.

CONCLUSION

The results of the present study suggested that TGRY had a certain detrimental impact on the postoperative QOL, and the loss of reservoir capacity could be a major cause.

Molecular Characteristics of Pancreatic Ductal Adenocarcinomas with High-Grade Pancreatic Intraepithelial Neoplasia (PanIN) Are Different from Those without High-Grade PanIN

AIMS

We reported that pancreatic ductal adenocarcinomas (PDACs) without high-grade pancreatic intraepithelial neoplasia (PanIN) in the vicinity had worse prognoses than PDACs with high-grade PanIN. However, the molecular characteristics of PDACs with and without high-grade PanIN have not been compared. The aim of this study is to clarify the molecular characteristics of PDACs with and without high-grade PanIN.

METHOD AND RESULTS

We reviewed all of a consecutive series of 100 patients with PDACs and divided them into 2 groups: the PDACs with PanIN-2 or PanIN-3 in the background (the PanIN-high group, n = 60) and the PDACs without PanIN-2 or PanIN-3 in the background (the PanIN-low group, n = 40). We evaluated the p53, p16, and SMAD4 expressions in the invasive ductal carcinoma (IDC) components by immunohistochemical staining. KRAS mutation was also analyzed in 80 tumors. The PanIN-low group showed significantly more frequent "high p53 expression" and "loss of SMAD4 expression" than the PanIN-high group (p = 0.048 and p = 0.019, respectively). Loss of p16 expression was not significantly different between the groups. The rate of KRAS wild type was significantly higher in the PanIN-low group than the PanIN-high group (p = 0.024).

CONCLUSIONS

Our results demonstrated that the molecular characteristics in the PDACs with high-grade PanIN were different from those in the PDACs without high-grade PanIN. PDACs without high-grade PanIN may develop via a pathway other than the PanIN-carcinoma sequence.

Survival outcomes of 220 consecutive patients with three-staged thoracoscopic esophagectomy

Patients with thoracic esophageal cancer are often treated by minimally invasive esophagectomy. However, the long-term survival benefits of minimally invasive esophagectomy remain unclear. Two approaches are available for thoracoscopic surgery: one with the patient in the left lateral decubitus position (LLDP), and the other with the patient in the prone position (PP). We investigated the survival benefit of thoracoscopic esophagectomy according to the tumor stage and patient position during the thoracoscopic procedure. We reviewed the records of 220 consecutive patients with esophageal cancer treated from 1998 to 2012. In total, 146 and 74 patients were treated with thoracoscopic esophagectomy in the LLDP and PP, respectively. No patients were initially proposed to be candidates for esophagectomy by thoracotomy during the study period. Data collection was performed with a focus on survival and recurrent disease. Among all the 220 patients, the overall 5-year survival rates were 83.7%, 74.1%, 45.5%, 78.6%, 44.2%, 29.4% and 24.3% in the patients with pStage IA, IB, IIA, IIB, IIIA, IIIB and IIIC disease, respectively. Despite the greater number of dissected mediastinal lymph nodes in the PP procedure, there were no significant differences in the survival curves between the LLDP and PP procedures. The long-term results of thoracoscopic esophagectomy are comparable and acceptable. The PP procedure was not confirmed to offer a superior survival benefit to the LLDP procedure in this retrospective study.

Duodenal Epithelial Neoplasms Complicating von Recklinghausen's Disease: An Immunohistochemical Analysis in Two Patients

The authors report two patients with von Recklinghausen's disease and carcinoid tumors of the duodenum; one patient, in addition, also showed complications of an adenocarcinoma of the ampulla of Vater and multiple schwannomas, while the other patient was associated with an leiomyoblastoma of the duodenum. Histologically, both carcinoid tumors demonstrated glandular structures and psammoma bodies. Immunohistochemically, both carcinoid tumors stained diffusely positive against somatostatin. Duodenal carcinoid tumors associated with von Recklinghausen disease are characterized by originating in an ampullary lesion, by the presence of glandular structures, psammoma bodies, or both, and by being rich in somatostatin. A high prevalence of duodenal carcinoids has previously been recognized in patients with von Recklinghausen's disease, however, the association of adenocarcinoma of the small intestine and von Recklinghausen's disease is extremely rare.

Remote transmission of live endoscopy over the Internet: Report from the 87th Congress of the Japan Gastroenterological Endoscopy Society

Live demonstration of endoscopy is one of the most attractive and useful methods for education and is often organized locally in hospitals. However, problems have been apparent in terms of cost, preparation, and potential risks to patients. Our aim was to evaluate a new approach to live endoscopy whereby remote hospitals are connected by the Internet for live endoscopic demonstrations. Live endoscopy was transmitted to the Congress of the Japan Gastroenterological Endoscopic Society by 13 domestic and international hospitals. Patients with upper and lower gastrointestinal diseases and with pancreatobiliary disorders were the subjects of a live demonstration. Questionnaires were distributed to the audience and were sent to the demonstrators. Questions concerned the quality of transmitted images and sound, cost, preparations, programs, preference of style, and adverse events. Of the audience, 91.2% (249/273) answered favorably regarding the transmitted image quality and 93.8% (259/276) regarding the sound quality. All demonstrators answered favorably regarding image quality and 93% (13/14) regarding sound quality. Preparations were completed without any outsourcing at 11 sites (79%) and were evaluated as 'very easy' or 'easy' at all but one site (92.3%). Preparation cost was judged as 'very cheap' or 'cheap' at 12 sites (86%). Live endoscopy connecting multiple international centers was satisfactory in image and sound quality for both audience and demonstrators, with easy and inexpensive preparation. The remote transmission of live endoscopy from demonstrators' own hospitals was preferred to the conventional style of locally organized live endoscopy.

Outcomes of cervical end-to-side triangulating esophagogastric anastomosis with minimally invasive esophagectomy

BACKGROUND

Esophagogastric anastomosis after esophagectomy has been performed with a variety of techniques during the past decade. However, anastomotic leakage and stricture are still important clinical problems after esophagogastric anastomosis, causing burdensome symptoms and poor quality of life. Herein, we describe a novel cervical end-to-side triangulating esophagogastric anastomoasis using linear stapler.

METHODS

A total of 90 patients (85 % male; mean age 63 years) with thoracic esophageal cancer who underwent cervical end-to-side esophagogastric triangular anastomosis using a linear stapler after minimally invasive esophagectomy between November 2006 and April 2013 were retrospectively reviewed.

RESULTS

The median operation time was 602 min (range 424-936 min). The volume of blood loss during the entire operative procedure was 127 ml (range 0-700 ml). There were no cases of anastomotic leakage in this study, although four patients (4.4 %) developed dysphagia associated with benign anastomotic stricture formation. All patients with a benign anastomotic stricture underwent balloon dilation, which resulted in improvement in their symptoms.

CONCLUSIONS

Considering the absence of anastomotic leakage and low rate of anastomotic stricture formation in this study, our modified triangular esophagogastric anastomosis technique appears promising and may contribute to reduced morbidity and mortality rates following esophagectomy.

Laparoscopic surgery for gastric gastrointestinal stromal tumor is feasible irrespective of tumor size

PURPOSE

To compare the outcomes of laparoscopic surgery and open surgery for gastric gastrointestinal stromal tumors (GISTs) by size-matched analysis and evaluate whether laparoscopic surgery for lesions of >5 cm is feasible.

PATIENTS AND METHODS

Data of 44 consecutive patients with gastric GIST who underwent surgery from 1988 to 2011 were reviewed. Twenty-three patients who underwent successful laparoscopic surgery were compared with 10 patients with similar tumor sizes who underwent open surgery. Among the 23 patients in the laparoscopic group, we compared postoperative results between GISTs of ≤5 cm and >5 cm.

RESULTS

There were no differences in clinicopathological characteristics between the laparoscopic surgery group (LG) and the open surgery group (OG). The operation time was not different, but the blood loss (5.5 mL [range, 0-425 mL] in LG and 125 mL [range, 0-676 mL] in OG) (P=.008) and postoperative hospital stay (21 days in OG and 8 days in LG) (P<.001) were significantly less in the LG. Postoperative complications and recurrence were not different. Comparison between patients with lesions of >5 cm and patients with smaller lesions in the LG found that smaller lesions were associated with a shorter postoperative hospital stay (7.5 days versus 11 days) (P=.037).

CONCLUSIONS

Laparoscopic resection of primary gastric GISTs is feasible even for tumors of >5 cm.

3-T MRI safety assessments of magnetic dental attachments and castable magnetic alloys

OBJECTIVES

To assess the safety of different magnetic dental attachments during 3-T MRI according to the American Society for Testing and Materials F2182-09 and F2052-06e1 standard testing methods and to develop a method to determine MRI compatibility by measuring magnetically induced torque.

METHODS

The temperature elevations, magnetically induced forces and torques of a ferromagnetic stainless steel keeper, a coping comprising a keeper and a cast magnetic alloy coping were measured on MRI systems.

RESULTS

The coping comprising a keeper demonstrated the maximum temperature increase (1.42 °C) for the whole-body-averaged specific absorption rate and was calculated as 2.1 W kg⁻¹ with the saline phantom. All deflection angles exceeded 45°. The cast magnetic alloy coping had the greatest deflection force (0.33 N) during 3-T MRI and torque (1.015 mN m) during 0.3-T MRI.

CONCLUSIONS

The tested devices showed minimal radiofrequency (RF)-induced heating in a 3-T MR environment, but the cast magnetic alloy coping showed a magnetically induced deflection force and torque approximately eight times that of the keepers. For safety, magnetic dental attachments should be inspected before and after MRI and large prostheses containing cast magnetic alloy should be removed. Although magnetic dental attachments may pose no great risk of RF-induced heating or magnetically induced torque during 3-T MRI, their magnetically induced deflection forces tended to exceed acceptable limits. Therefore, the inspection of such devices before and after MRI is important for patient safety.

Surgery of upper GI gastrointestinal stromal tumors: our experience, prognostic analysis

BACKGROUND/AIMS

To review our treatment experience of gastrointestinal stromal tumors (GISTs) of the upper gastrointestinal tract and identify the prognostic factors that influence tumor recurrence.

METHODOLOGY

Data of 46 consecutive patients with upper GI GISTs who underwent surgery from 1988 to 2011 were reviewed. The overall and disease-free survival rates and influence of clinicopathologic variables on disease-free survival rate were evaluated.

RESULTS

The median age was 64 years (range, 20-86 years). R0 resections were performed in 43 (93.5%) patients. With a median follow-up time of 33 months (1-275 months), there were 5 (10.9%) recurrences and 2 mortalities in the high-risk group. The overall survival and recurrence-free survival rates at 5 years were 92.1% and 84.6%, respectively. Male gender, tumor size of >10 cm, high numbers of mitotic figures, R1 resection, high risk according to the Joensuu criteria, and a Ki-67 index of >10% were associated with a poor prognosis.

CONCLUSIONS

Surgical resection of low- and intermediate-risk GISTs has excellent results. High counts of mitotic figures, male gender, incomplete resection, large tumor size, and a high Ki-67 index are associated with a poor prognosis.

Laparoscopic total gastrectomy for remnant gastric cancer: feasibility study

BACKGROUND

The benefits and feasibility of laparoscopic surgery for remnant gastric cancer are still unclear. The purpose of this study was to describe the detailed procedure and to evaluate the clinical short-term outcomes of laparoscopic total gastrectomy (LTG) compared with open total gastrectomy (OTG) for remnant gastric cancer (RGC).

METHODS

Of 1,247 consecutive patients who underwent gastrectomy for gastric cancer in our department at Kyushu University Hospital from January 1996 to May 2012, 22 patients who underwent successful curative resection of RGC with precise nodal dissection were enrolled in this study. Twelve patients underwent LTG and the remaining ten patients underwent OTG. We analyzed the clinical short-term outcomes of LTG and compared the results between LTG and OTG groups to evaluate the safety and feasibility of LTG.

RESULTS

Twelve patients with RGC successfully underwent LTG without open conversion and morbidity. The mean operation time of LTG, 362.3 ± 68.4 min, was significantly longer than that of OTG (p = 0.0176), but the mean blood loss of LTG, 65.8 ± 62 g, was smaller than that of OTG (p < 0.01). The mean postoperative times to resumption of water and food intake were significantly shorter in the LTG group than in the OTG group (p < 0.01). The overall 3-year survival rate was comparable between the LTG and OTG groups (77.8 vs. 100 %; p = 0.9406).

CONCLUSIONS

This study shows that LTG is a feasible and reliable procedure for the treatment of RGC in terms of short-term outcomes.

Triangulating stapling technique for esophagogastrostomy after minimally invasive esophagectomy

BACKGROUND

The triangulating stapling technique is one of the reconstruction methods used that provides favorable surgical outcomes in several areas of the digestive tract. However, the results in the cervical esophagogastric anastomosis are not well documented.

METHODS

Using a prospectively maintained comprehensive database, we reviewed the surgical results of 160 consecutive patients who underwent minimally invasive esophagectomy followed by cervical triangulating stapling esophagogastrostomy during 2 periods from May 2002 to May 2012 so as to determine the efficacy of the triangulating stapling technique using 2 different types of stapling devices.

RESULTS

The rates of anastomotic leakage and stricture in this series were low (1% and 15%, respectively). The rate of anastomotic stricture was significantly reduced when a linear stapler with a cutting knife was used (9%). A logistic regression analysis showed a reduction of anastomotic stricture to be significantly associated with the use of only a linear stapler with a cutting knife.

CONCLUSION

Cervical esophagogastric anastomosis by the triangulating stapling technique is safe and feasible. We consider a linear stapling device equipped with a cutting knife to be more suitable for performing the triangulating stapling technique.

[Surgical treatment of gastroentero-pancreatic neuroendocrine tumor]

The treatment of choice for gastroentero-pancreatic neuroendocrine tumor(NET)is resection. Because it is difficult to determine the histological grade of NET before operation, the treatment strategy is usually made based on an imaging study including the tumor's size. Some selected gastrointestinal NETs are indicated for endoscopic resection, while others are resected surgically with lymph node dissection. The types of resections for pancreatic NETs vary from enucleation to pancreatectomy with or without regional lymph node dissection, based on the type of excessive hormone, tumor size, distance from the main pancreatic duct, and the presence of type 1 multiple endocrine neoplasia. Hepatic metastases are also resected, if indicated, and even in patients having unresectable metastatic lesions, multidisciplinary therapy including reduction surgery of over 90% of tumor volume might lead to a favorable prognosis. Postoperative adjuvant therapy is recommended for neuroendocrine carcinoma, while there is no evidence to support adjuvant therapy for curatively resected well-differentiated NET.

The risk of lymph node metastasis in mucosal gastric carcinoma: especially for a mixture of differentiated and undifferentiated adenocarcinoma

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) is gaining wider acceptance for the treatment of early gastric carcinoma (EGC) and its indication has been extended to mucosal gastric carcinoma with undifferentiated component in some institutes. Our aims were to confirm the frequency of lymph node metastasis in such cases and clarify the demarcation in indications for ESD.

METHODOLOGY

We evaluated medical data of 287 patients with mucosal gastric carcinoma who underwent surgical resection between 1996 and 2008. The tumours were histologically classified into purely differentiated (PD), differentiated-predominant mixed (DPM), undifferentiated-predominant mixed (UPM) and purely undifferentiated (PU) types.

RESULTS

Lymph node metastasis was identified in seven (2.4%) of the 287 patients and was detected more frequently in UPM (10%, two of 20) and PU (4%, four of 98), compared with PD (none of 148) (p=0.01 and 0.02, respectively). In mixed-type carcinoma, size was a significant risk factor for lymph node metastasis (p=0.04).

CONCLUSIONS

It might be better to select gastrectomy rather than ESD for the treatment of mucosal gastric carcinoma with an undifferentiated component.

Improvement of quality of life and survival using self-expandable metal stent placement for severe malignant stenosis of the gastric body: a case report

Introduction

Advanced gastric carcinoma often decreases quality of life because of upper gastrointestinal tract stenosis. Self-expandable metal stents have been thought to be an effective, minimally invasive treatment for stenosis. However, the effectiveness of self-expandable metal stent placement for carcinomatous stenosis of the gastric body and antrum has not been clarified, and there have been few reports of such cases.

Case presentation

A 74-year-old Japanese woman developed stenosis of the gastric body and antrum caused by advanced gastric cancer during first-line chemotherapy. She developed weight loss and poor nutrition due to inadequate intake. Self-expandable metal stent placement for stenosis of the gastric body and antrum ameliorated her symptoms rapidly and improved her general condition and quality of life. Eight days after self-expandable metal stent placement, second-line chemotherapy could be administered safely. Oral intake and nutritional status were maintained for 117 days after self-expandable metal stent placement, and she died of gastric cancer 176 days after self-expandable metal stent placement and initiation of second-line chemotherapy.

Conclusions

Self-expandable metal stent placement for carcinomatous stenosis in the gastric body and antrum could be an effective therapeutic strategy for patients with inadequate oral uptake. It may provide rapid improvement of the patient’s general condition and oral intake with minimal complications, comparatively long-term symptom relief, and a survival benefit by allowing second-line chemotherapy.

MicroRNA-10a is overexpressed in human pancreatic cancer and involved in its invasiveness partially via suppression of the HOXA1 gene

BACKGROUND

There is increasing evidence that microRNAs are differentially expressed in many types of cancers. Despite progress in analyses of microRNAs in several types of cancers, the functional contributions of microRNAs to pancreatic cancer remain unclear.

METHODS

In the present study, the expression levels of specific microRNAs identified by microarray analyses were examined in a panel of 15 pancreatic cancer cell lines. We then investigated the functional roles of these microRNAs in the proliferation and invasion of pancreatic cancer cells.

RESULTS

Based on the microarray data, we found frequent and marked overexpression of miR-10a, miR-92, and miR-17-5p in pancreatic cancer cell lines. Microdissection analyses revealed that miR-10a was overexpressed in pancreatic cancer cells isolated from a subset of primary tumors (12 of 20, 60%) compared with precursor lesions and normal ducts (P<.01). In vitro experiments revealed that miR-10a inhibitors decreased the invasiveness of pancreatic cancer cells (P<.01), but had no effect on their proliferation. Inhibition of HOXA1, a target of miR-10a, promoted the invasiveness of pancreatic cancer cells (P<.01).

CONCLUSIONS

The present data suggest that miR-10a is overexpressed in a subset of pancreatic cancers and is involved in the invasive potential of pancreatic cancer cells partially via suppression of HOXA1.

MicroRNA-10b is overexpressed in pancreatic cancer, promotes its invasiveness, and correlates with a poor prognosis

BACKGROUND

MicroRNAs (miRNAs) have been gaining attention as new, key molecules that contribute to carcinogenesis. In pancreatic cancer, previous profiling analyses of miRNA expression have shown that several miRNAs are differently expressed in normal and cancerous tissues. Several pancreatic cancer-specific miRNAs differed, however, in each analysis.

METHODS

We investigated the miRNA expression profiles of the pancreatic cancer cell lines CAPAN-1 and CFPAC1 and an immortalized human normal pancreatic ductal epithelial cell line (HPDE) using a high-throughput, TaqMan, qRT-PCR array analysis. We also analyzed the expression levels of this miRNA in microdissected (n = 15) and formalin-fixed, paraffin-embedded (FFPE) (n = 115) samples from pancreatic cancers by quantitative RT-PCR. Finally, we investigated the effects of this miRNA on the invasiveness of pancreatic cancer cells.

RESULTS

Based on the microarray analysis, miR-372, miR-146a, miR-204, miR-10a, and miR-10b showed particularly large differences (>10-fold changes) between both pancreatic cell lines and HPDE cells. Thirteen of the 15 pancreatic cancer cell lines showed 2.1- to 36.4-fold (median, 15.3-fold) greater levels of miR-10b than HPDE cells. Microdissection analysis revealed that miR-10b exhibited greater expression levels in pancreatic cancer cells (n = 5) than in normal pancreatic ductal cells (n = 10) (P < .020). Analysis of FFPE samples showed that high miR-10b expression was associated with a lesser overall survival (P = .014). Furthermore, miR-10b correlated with the invasiveness of pancreatic cancer cells (P < .01).

CONCLUSION

miR-10b is overexpressed in pancreatic cancer and may be involved in the invasiveness in pancreatic cancer cells, thereby leading to a poor prognosis.

Inhibition of p600 expression suppresses both invasiveness and anoikis resistance of gastric cancer

BACKGROUND

Advanced gastric cancers often metastasize to distant organs and the peritoneum, leading to a poor prognosis. Both invasiveness and resistance to anchorage-independent cell death (anoikis) are important factors in the process of metastasis. p600 (600-kDa protein), recently identified from a cervical cancer cell line, plays a role in both anoikis resistance and cell migration. In this study, we examined whether p600 is involved in the progression of gastric cancer.

METHODS

We used both normal gastric mucosal cells and cancer cells laser-microdissected from 42 gastric cancers and their normal counterparts, and compared their p600 mRNA expression levels with quantitative reverse transcriptase-polymerase chain reaction. We inhibited p600 expression in two gastric cancer cell lines with siRNA and examined its effect on the invasiveness and anoikis resistance both in vitro and in vivo.

RESULTS

Expression of p600 mRNA was significantly higher in gastric cancer cells than in normal mucosal cells (P = 0.027). The invasion assay revealed that invasiveness was significantly reduced by inhibition of p600 (P < 0.01). In vitro experiments revealed that cell viability and colony-formation capacity under anchorage-independent conditions were significantly reduced by inhibition of p600 (P < 0.05). In vivo experiments also showed that the establishment of intraperitoneal disseminated tumors was significantly suppressed by transient inhibition of p600 (P < 0.001).

CONCLUSIONS

Our results strongly suggest that p600 is involved in gastric cancer progression, and has a potential to be a new molecular target for gastric cancer therapy.

MicroRNA expression as a predictive marker for gemcitabine response after surgical resection of pancreatic cancer

Background

To improve the prognosis of patients after resection of pancreatic cancer, the most appropriate and efficient treatment should be provided to specific subsets of patients. Our aim was to identify promising microRNAs as markers to predict responses to gemcitabine in patients with resected pancreatic cancer.

Methods

Two gemcitabine-resistant pancreatic cancer cell lines were established, and global microRNA expression analyses was performed by quantitative reverse transcription–polymerase chain reaction (qRT-PCR). Eleven miRNAs were selected as putative predictive markers and analyzed by means of macrodissected formalin-fixed, paraffin-embedded samples obtained from 90 patients with or without gemcitabine treatment after resection of pancreatic cancer.

Results

We identified 24 microRNAs whose expression was altered in gemcitabine-resistant cells. qRT-PCR analyses showed that patients with high miR-142-5p and miR-204 expression had significantly longer survival times than those with low miR-142-5p (P = 0.0077) and miR-204 (P = 0.0054) expression in the gemcitabine-treated group. This was not seen in the nontreated group. Multivariate analyses showed that miR-142-5p expression was an independent prognostic marker only in patients treated with gemcitabine (P = 0.034).

Conclusions

miR-142-5p is a promising predictive marker for gemcitabine response in patients with resected pancreatic cancer.

Pleiotropic effects of mitiglinide in type 2 diabetes mellitus

This study investigated the effects of mitiglinide in 16 patients with type 2 diabetes mellitus treated with 30 mg/day mitiglinide, divided into three doses given just before each meal, for approximately 12 months. A 450 kcal meal tolerance test was performed at baseline and after 3, 6 and 12 months, and levels of plasma glucose and immunoreactive insulin were measured. Various parameters of glucose metabolism and lipid metabolism, urinary albumin and markers of atherosclerosis, coagulation and fibrinolysis were also determined. Mitiglinide showed a rapid stimulatory effect on insulin secretion and reduced the levels of plasma glucose. The free fatty acid level significantly decreased at 60 min after the meal tolerance test. Mitiglinide also significantly lowered glycosylated haemoglobin and raised 1,5-anhydroglucitol after 6 months, and significantly decreased urinary albumin after 12 months. These data indicate that mitiglinide may have beneficial effects not only on glycaemic control but also on lipid metabolism and urinary albumin excretion, and may have a role in the prevention of the vascular complications of diabetes.

Combination with low-dose gemcitabine and hTERT-promoter-dependent conditionally replicative adenovirus enhances cytotoxicity through their crosstalk mechanisms in pancreatic cancer

To overcome the limited clinical efficacy of conditionally replicative adenoviruses (CRAds), we investigated the effects of combination therapy with gemcitabine (GEM) and the hTERT-promoter-dependent CRAd (hTERT-CRAd), Ad5/3hTERTE1. This combination therapy exhibited enhanced cytotoxic effects on pancreatic cancer both in vitro and in vivo. Furthermore, we revealed that this enhancement effect was due to the multiple bidirectional interactions between hTERT-CRAd and GEM. The GEM-sensitizing effect of E1 expression derived from hTERT-CRAd, and the enhancement effect by GEM on hTERT promoter activity which led to the increase of adenovirus E1 and viral infectivity. This combination therapy may be a promising therapeutic approach for pancreatic cancer.

hTERT-promoter-dependent oncolytic adenovirus enhances the transduction and therapeutic efficacy of replication-defective adenovirus vectors in pancreatic cancer cells

Adenovirus-mediated gene therapy shows promise for cancer therapy, but transgene expression of replication-defective adenovirus may be low and transient in clinical settings. Recent reports have shown that the use of a conditionally replication-competent adenovirus (CRAd) enhanced the gene transduction of a replication-defective adenovirus vector. The control of tumor-stromal interactions has also been determined to be important in cancer therapy. In this study, we investigated the effect of the human telomerase reverse transcriptase (hTERT)-CRAd, Ad5/3hTERTE1, which possesses the tumor-specific hTERT promoter with the chimeric fiber 5/3, on the transgene expression and therapeutic efficacy of a replication-defective adenovirus vector expressing NK4 under the control of the CMV promoter, Ad-NK4. In addition, we established a new strategy to target both cancer cells and cancer-stromal interactions. Human pancreatic cancer cells were infected with Ad-NK4 and either Ad5/3hTERTE1 (CRAd-combination group) or Ad5/3hTERTLuc (control-combination group). In the CRAd-combination group, Ad-NK4-delivered transgene expression was increased, leading to an enhanced inhibitory effect on the invasion of cancer cells. In in vivo experiments, NK4 expression within tumors and its inhibitory effect on tumor growth, angiogenesis, and metastasis were enhanced in the CRAd-combination group. These results suggest that hTERT-CRAd enhances the transgene expression and therapeutic efficacies of Ad-NK4, possibly through the in-trans replication of Ad-NK4 induced by adenovirus E1 derived from co-infected hTERT-CRAd. This approach may be a promising combination therapy against advanced pancreatic cancer.

S100A4 mRNA is a diagnostic and prognostic marker in pancreatic carcinoma

OBJECTIVE

The aim of this study is to evaluate the clinical significance of S100A4 mRNA expression in pancreatic cancer.

MATERIALS AND METHODS

We obtained invasive ductal carcinoma (IDC) cells from ten lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 20 lesions, and normal ductal cells from 20 normal pancreatic tissues by laser microdissection of frozen tissues. S100A4 expression was examined in the microdissected cells and in formalin-fixed paraffin-embedded (FFPE) samples of 87 pancreatic cancers by quantitative reverse transcription-polymerase chain reaction.

RESULTS

IDC cells expressed higher levels of S100A4 than IPMN cells (P = 0.002) and normal ductal cells (P < 0.001), although the difference between IPMN cells and normal ductal cells was not statistically significant (P = 0.070). Analysis of FFPE samples revealed that high S100A4 expression was significantly associated with a shorter overall survival (P = 0.023). In immunohistochemical analysis, the extent of S100A4 mRNA expression was significantly correlated with the expression of S100A4 protein (P = 0.028).

CONCLUSION

S100A4 could be a marker for malignancy in pancreatic tumors and for poor prognosis in patients with pancreatic cancer.

MicroRNA-21 modulates biological functions of pancreatic cancer cells including their proliferation, invasion, and chemoresistance

Due to the poor prognosis of pancreatic cancer, novel diagnostic modalities for early diagnosis and new therapeutic strategy are urgently needed. Recently, microRNA-21 (miR-21) was reported to be strongly overexpressed in pancreatic cancer as well as in other solid cancers. We investigated the functional roles of miR-21, which have not been fully elucidated in pancreatic cancer. miR-21 expression was assessed in pancreatic cancer cell lines (14 cancer cell lines, primary cultures of normal pancreatic epithelial cells and fibroblasts, and a human normal pancreatic ductal epithelial cell line) and pancreatic tissue samples (25 cancer tissues and 25 normal tissues) by quantitative real-time reverse transcription-PCR amplification. Moreover, we investigated the proliferation, invasion, and chemoresistance of pancreatic cancer cells transfected with miR-21 precursor or inhibitor. miR-21 was markedly overexpressed in pancreatic cancer cells compared with nonmalignant cells, and miR-21 in cancer tissues was much higher than in nonmalignant tissues. The cancer cells transfected with the miR-21 precursor showed significantly increased proliferation, Matrigel invasion, and chemoresistance for gemcitabine compared with the control cells. In contrast, inhibition of miR-21 decreased proliferation, Matrigel invasion, and chemoresistance for gemcitabine. Moreover, miR-21 positively correlated with the mRNA expression of invasion-related genes, matrix metalloproteinase-2 and -9, and vascular endothelial growth factor. These data suggest that miR-21 expression is increased in pancreatic cancer cells and that miR-21 contributes to the cell proliferation, invasion, and chemoresistance of pancreatic cancer.

[A case of early recurrence with multiple liver metastases after curative operation of gastric cancer successfully treated by S-1/CDDP combination chemotherapy]

A 68-year-old man underwent esophagogastroduodenoscopy (EGD) in February 2005. A type 2 advanced gastric cancer was observed on the gastric antrum. Abdominal US and CT revealed no distant metastasis. Curative distal gastrectomy with D2 lymph node dissection was therefore performed the next month. Postoperative staging was stage I B. In June 2005, he had symptoms of right hypochondralgia, general fatigue and appetite loss. An abdominal CT the next month revealed multiple liver metastases and so S-1/CDDP combination chemotherapy was initiated. After two courses of chemotherapy, marked decreases in size of the liver metastasis were recognized. However, we had to change the chemotherapy regimen because of adverse effect from the chemotherapy regime after the initial 2 courses. The patient died from tumor progression in May 2006.

Down-regulation of deoxycytidine kinase enhances acquired resistance to gemcitabine in pancreatic cancer

BACKGROUND

The functional roles of deoxycytidine kinase (dCK) in acquired resistance to gemcitabine remain unknown in pancreatic cancer. Here, the functional involvement of dCK in gemcitabine-resistance of pancreatic cancer was investigated.

MATERIALS AND METHODS

The levels of the dCK gene as well as other gemcitabine-related genes (hENT1, RRM1 and RRM2) were analyzed in gemcitabine-resistant pancreatic cancer cells (GR cells) using quantitative real-time reverse transcription polymerase chain reaction. The effects of inhibition of these genes on sensitivity to gemcitabine were evaluated.

RESULTS

In GR cells, expression of dCK was significantly reduced compared with that of parental cells (p < 0.05). The dCK-targeting siRNA significantly reduced gemcitabine sensitivity (p < 0.01) without affecting cell proliferation. The RRM1- and RRM2-targeting siRNAs increased gemcitabine sensitivity (p < 0.05) and reduced cell proliferation even without gemcitabine treatment. The hENT-targeting siRNA did not affect gemcitabine sensitivity or cell proliferation.

CONCLUSION

Down-regulation of dCK specifically enhanced acquired resistance to gemcitabine in pancreatic cancer cells without affecting their proliferation.