Sanghee Kang

Expression of Liver–Intestine Cadherin and Its Correlation with Lymph Node Metastasis in Gastric Cancer: Can It Predict N Stage Preoperatively?

BackgroundReliable method to predict lymph node metastasis is not yet available. In the present study, therefore, we examined LI-cadherin expression in human gastric cancer and attempted to find its relationship with clinicopathologic data, especially with lymph node metastasis. We also analyzed the expression in preoperative biopsy specimen to uncover its possibility of prognostication for lymph node metastasis.MethodsThe paired preoperative endoscopic biopsy and postoperative resected specimens from 208 patients who had surgically been treated for gastric cancer were retrospectively analyzed immunohistochemically for expression of LI-cadherin.ResultsThere were 47 (22.6%) and 161 (77.4%) tumors which had positive and negative LI-cadherin expression, respectively. LI-cadherin expression was significantly correlated with tumor histology and lymph node metastasis: Furthermore, reduced expression of LI-cadherin was closely associated with tumor progression and lymph node metastasis in human gastric carcinoma. LI-cadherin expressions in both resected tumor and preoperative endoscopic tissues were found to be independent factors associated with lymph node metastasis.ConclusionsThere is a close association between reduced expression of LI-cadherin and lymph node metastasis in human gastric cancer. Immunohistochemical study of LI-cadherin is relatively simple compared to sentinel node navigation surgery, and it could be a practical prediction method for lymph node metastasis in patients with this malignancy.

BMP-2 induces motility and invasiveness by promoting colon cancer stemness through STAT3 activation

Bone morphogenetic proteins (BMPs) have been involved in metastatic progression and tumorigenesis of many cancer types. However, it remains unclear how BMP-2 contributes to the initiation and development of these cancers. Here, we investigated the role of BMP-2 in colon cancer stem cell (CSC) development from colon cancer cells. We also determined the effects of BMP-2 on CSC development and epithelial-mesenchymal transition (EMT) in human colon cancer cell lines HCT-116 and SW620. We found that BMP-2 enhanced sphere formation of colon cancer cells without serum. Also, BMP-2-induced spheres displayed up-regulation of stemness markers (CD133+ and EpCAM+) and increased drug resistance, hallmarks of CSCs. Importantly, expression of EMT activators p-Smad1/5 and Snail and N-cadherin was increased in the spheres’ cells, indicating that BMP-2 signaling might result in CSC self-renewal and EMT. Furthermore, siRNA-mediated knockdown of signal transducer and activator of transcription 3 (STAT3) in HCT-116 cells reversed BMP-2-induced EMT and stem cell formation. Taken together, our results suggest that the BMP-2 induced STAT3-mediated induction of colon cancer cell metastasis requires an EMT and/or changes in CSC markers.

High Occupational Stress and Low Career Satisfaction of Korean Surgeons

Surgery is a demanding and stressful field in Korea. Occupational stress can adversely affect the quality of care, decrease job satisfaction, and potentially increase medical errors. The aim of this study was to investigate the occupational stress and career satisfaction of Korean surgeons. We have conducted an electronic survey of 621 Korean surgeons for the occupational stress. Sixty-five questions were used to assess practical and personal characteristics and occupational stress using the Korean occupational stress scale (KOSS). The mean KOSS score was 49.31, which was higher than the average of Korean occupational stress (45.86) or that of other specialized professions (46.03). Young age, female gender, long working hours, and frequent night duties were significantly related to the higher KOSS score. Having spouse, having hobby and regular exercise decreased the KOSS score. Multiple linear regression analysis showed that long working hours and regular exercise were the independent factors associated with the KOSS score. Less than 50% of surgeons answered that they would become a surgeon again. Most surgeons (82.5%) did not want to recommend their child follow their career. Korean Surgeons have high occupational stress and low level of career satisfaction. Graphical Abstract

Analysis of the occupational stress of Korean surgeons: a pilot study

Purpose Surgeons serve one of the most challenging and stressful professions. Ineffective control of occupational stress leads to burnout of the surgeon. The aim of this study was to obtain preliminary data on the sources and the degree of stress of surgeons and to determine the feasibility of the survey. Methods A total of 63 surgeons in our three affiliated hospitals were enrolled in this study. Fifty-five questions were used to assess the demographics, characteristics and Korean occupational stress scale (KOSS), which were prepared and validated by the National Study for Development and Standardization of Occupational Stress. Results Forty-seven of the 63 surgeons participated in this study (74.6%). The mean KOSS score of the survey was 50.9 ± 8.55, which was significantly higher than that of other professions (P < 0.01). Drinking and smoking habits were not related to the KOSS score. Doing exercise was related to a low KOSS score in terms of low KOSS total score (P < 0.01). Average duty hours (P < 0.01) and night duty days per week (P = 0.01) were strongly related to higher KOSS in the linear regression analysis. Conclusion This is the first study to evaluate job stress of surgeons in Korea. This study showed that Korean Surgeons had higher occupational stress than other Korean professions. A larger study based on this pilot study will help generate objective data for occupational stress of Korean Surgeons by performing a survey of the members of the Korean Surgical Society.

Occupational stress and related factors among surgical residents in Korea

Purpose The application rate for surgical residents in Korea has continuously decreased over the past few years. The demanding workload and the occupational stress of surgical training are likely causes of this problem. The aim of this study was to investigate occupational stress and its related factors in Korean surgical residents. Methods With the support of the Korean Surgical Society, we conducted an electronic survey of Korean surgical residents related to occupational stress. We used the Korean Occupational Stress Scale (KOSS) to measure occupational stress. We analyzed the data focused on the stress level and the factors associated with occupational stress. Results The mean KOSS score of the surgical residents was 55.39, which was significantly higher than that of practicing surgeons (48.16, P < 0.001) and the average score of specialized professionals (46.03, P < 0.001). Exercise was the only factor found to be significantly associated with KOSS score (P = 0.001) in univariate analysis. However, in multiple linear regression analysis, the mean number of assigned patients, resident occupation rate and exercise were all significantly associated with KOSS score. Conclusion Surgical residents have high occupational stress compared to practicing surgeons and other professionals. Their mean number of assigned patients, resident recruitment rate and exercise were all significantly associated with occupational stress for surgical residents.

Iron chelator-induced apoptosis via the ER stress pathway in gastric cancer cells.

Many reports have shown the anticancer effects of iron deficient on cancer cells, but the effects of iron-chelators on gastric cancer have not been clearly elucidated. Recently, we reported that iron chelators induced an antiproliferative effect in human malignant lymphoma and myeloid leukemia cells. In the present study, we investigated the antitumor activity of these two iron-chelating agents, deferoxamine (DFO) and deferasirox (DFX), with gastric cancer cell lines, and their apoptosis-inducing effects as the potential mechanism. We found that iron chelators displayed significant antiproliferative activity in human gastric cancer cell lines, which may be attributed to their induction of G1 phase arrest and apoptosis. We also found that iron chelators induced reactive oxygen species (ROS) production, resulting in the activation of both c-Jun N-terminal kinase (JNK) and endoplasmic reticulum (ER) stress apoptotic pathways in gastric cancer cells. Taken together, our data suggest that iron chelators induced apoptosis in gastric cancer, involving ROS formation ER stress and JNK activation.

The significance of microsatellite instability in colorectal cancer after controlling for clinicopathological factors

Abstract The colorectal cancer (CRC) patients with microsatellite instability (MSI) have distinct clinicopathological characteristics consisting of factors predicting positive and negative outcomes, such as a high lymph node harvest and poor differentiation. In this study, we measured the value of MSI as a prognostic factor after controlling for these discrepant factors. A total of 603 patients who underwent curative surgery for stages I to III colorectal cancer were enrolled. The patients were divided into microsatellite instability high (MSI-H) and microsatellite stable/microsatellite instability low (MSS/MSI-L) groups. Propensity score matching was used to match clinicopathological factors between the 2 groups. MSI-H patients had a high lymph node harvest (median: 31.0 vs 23.0, P < .001), earlier-stage tumors (P < .001), advanced T stage (89.3% vs 74.0%, P = .018), and poor differentiation (19.6% vs 2.0%, P < .001). Survival analysis showed better survival in the MSI-H group, but the difference was not statistically significant (P = .126). Propensity score matching was performed for significant prognostic factors identified by Cox hazard regression. After the matching, the survival difference by MSI status was estimated to be larger than before, and reached statistical significance (P = .045). In conclusion, after controlling for pathological characteristics, MSI-H could be a potent prognostic factor regarding patient survival.

Anti-metastatic effect of metformin via repression of interleukin 6-induced epithelial–mesenchymal transition in human colon cancer cells

Metformin, a first-line drug used to treat type 2 diabetes, has also been shown to have anticancer effects against a variety of malignancies, including colorectal cancer. Although inhibition of the mTOR pathway is known to be the most important mechanism for the antitumor effects of metformin, other mechanisms remain unclear. The purpose of this study was to identify the antitumor mechanism of metformin in colorectal cancer using high-throughput data, and then test the mechanism experimentally. We identified the gene signature of metformin-treated colon cancer cells. This signature was processed for prediction using colon adenocarcinoma patient data from the Cancer Genome Atlas to classify the patients showing a gene expression pattern similar to that in metformin-treated cells. This patient group showed better overall and disease-free survival. Furthermore, pathway analysis revealed that the metformin-predicted group was characterized by decreased interleukin (IL)-6 pathway signaling, epithelial–mesenchymal transition, and colon cancer metastatic signaling. We induced epithelial–mesenchymal transition in colon cancer cell lines via IL-6 treatment, which increased cell motility and promoted invasion. However, these effects were blocked by metformin. These findings suggest that blockade of IL-6-induced epithelial–mesenchymal transition is an antitumor mechanism of metformin.

Efficacy and safety of a novel partially absorbable mesh in totally extraperitoneal hernia repair

Purpose Partially absorbable mesh has been introduced and used for inguinal hernia repair for the purpose of minimizing pain and improving abdominal wall compliance. In this study, we evaluate the efficacy and safety of ProFlex mesh, a partially absorbed mesh with new structural architecture. Methods We retrospectively reviewed 64 cases of totally extraperitoneal herniorrhapy (TEP) from January 2013 to December 2014 for their clinical features, including operation time, pain, postoperative complications, and recurrence. Results There were no significant differences in operation time, hospital stay, postoperative pain, or complications between the 28 patients who received the ProFlex mesh and the 36 who received nonabsorbable lightweight mesh, although one patient who received the nonabsorbable had a recurrence during follow-up. There were differences in operation time, complications, and hospital stay according to the surgeons previous operation volume. Conclusion This study showed that there were significant differences in the fixation strength of different polypropylene meshes in combination with various fibrin glues. ProFlex, a partially absorbable mesh with new architecture, was feasible and safe in TEP.

Usefulness of 18F-FDG PET/CT to Detect Metastatic Mucinous Adenocarcinoma Within an Inguinal Hernia

Metastatic mucinous adenocarcinoma in an inguinal hernia is a rare disease and the image findings of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) are little known. Here, we introduce a 57-year-old man with metastatic mucinous adenocarcinoma in an inguinal hernia. On initial 18F-FDG PET/CT, hypermetabolism was observed in mucinous adenocarcinoma of the cecum, and adenocarcinomas of the transverse and ascending colon, respectively. Follow-up 18F-FDG PET/CT revealed newly developed multiple hypermetabolism in peritoneal seeding masses and nodules in the pelvic cavity and scrotum. Peritoneal carcinomatosis in the right pelvic side wall was extended to the incarcerated peritoneum and mesentery in the right inguinoscrotal hernia.18F-FDG PET/CT was useful to reveal unexpected peritoneal seeding within the inguinal hernia. Also, this case demonstrated that metastatic mucinous adenocarcinomas had variably intense FDG uptake.