Lymph node involvement is rare in mucinous cystic neoplasms of the pancreas: Role of minimally invasive surgery.

Mucinous cystic neoplasm (MCN) is a premalignant cystic tumor of the pancreas. Resection of MCN in the distal pancreas is a standard treatment; however, at present, there is no consensus on the necessity or extent of lymph node dissection, and minimally invasive pancreatectomy is commonly the preferred surgical technique. Thus, the present study aimed to assess the efficacy of minimally invasive surgery and the extent of lymph node metastasis as factors in determining an appropriate surgical treatment for MCN. The present study retrospectively analyzed 21 consecutive patients who underwent distal pancreatectomy (DP) for MCN under general anesthesia at Chiba University Hospital (Chiba, Japan) between April 2011 and July 2019. All 21 patients were female. DP with a splenectomy was performed in all the patients. A total of 14 patients underwent laparoscopic DP (LDP). No lymph node metastasis was found in any of the patients. The minimally invasive surgery group had lower operative blood loss and a shorter hospital stay than the open surgery group. There was no significant difference in the number of dissected lymph nodes between the open surgery group and the minimally invasive surgery group. Preoperative findings of malignancy in MCN included solid components on enhanced CT and endoscopic ultrasonography, high carbohydrate antigen 19-9 values and large tumor size. In conclusion, DP with spleen preservation, which is minimally invasive, may be preferentially considered as a surgical technique for MCN without malignant findings because lymph node metastases are rare in MCN and were not observed in the present study.

TRIM27-USP7 complex promotes tumour progression via STAT3 activation in human hepatocellular carcinoma.

BACKGROUND & AIMS: TRIM27 is stabilized by binding to USP7 and mediates tumour progression in several cancers; however, the roles of TRIM27-USP7 complex on STAT3 activation in HCC are unknown. METHODS: Regulations and functions of TRIM27 for activating STAT3 in HCC were assessed using 207 HCC samples or HCC cells. RESULTS: TRIM27 expression was increased in some cases of HCC. High TRIM27 expression was an independent predictor for poor prognosis in HCC after surgery. It was correlated with the expression of EpCAM, vimentin, MMP-9, and activation of STAT3 in HCC. TRIM27 expression was correlated with USP7 expression, and HCC with high TRIM27 expression together with high USP7 expression showed enhanced STAT3 activation, resulting in poorer prognosis. p-JAK1 expression was correlated with STAT3 activation in HCC with high TRIM27 expression. In vitro, USP7 knockdown decreased TRIM27 expression, suggesting that USP7 was essential for TRIM27 stabilization. Knocking down of TRIM27 or USP7 suppressed STAT3 activation and overexpression of TRIM27 accelerated STAT3 activation; therefore, the formation of TRIM27-USP7 complex was needed for STAT3 activation, which led to aggressive tumour proliferation and invasion by enhancing EMT and CSC-like property. Binding of JAK1 to TRIM27-USP7 complex was confirmed in vitro. Deletion of TRIM27-USP7 complex by USP7 inhibitor significantly inhibited tumour cell invasion by suppressing STAT3 activation. CONCLUSIONS: TRIM27 is stabilized by binding to USP7 and is related to aggressive tumour progression in HCC via STAT3 activation, resulting in poor prognosis after operation. Therefore, TRIM27-USP7 complex is a useful prognostic predictor and a promising therapeutic target for HCC.

Impact of resection margin status on survival after operation for pancreatic head cancer with extrapancreatic nerve plexus invasion.

BACKGROUND: Extrapancreatic nerve plexus (PL) invasion of pancreatic ductal adenocarcinoma (PDAC) is an important factor for determining resectability and surgical method. We sought to clarify the characteristics of PDAC with PL invasion and clinical impact of the resection margin status on prognosis for PDAC with PL invasion. METHODS: A total of 242 patients with pancreatic head cancer who underwent pancreatectomy were evaluated. Clinicopathological data and patient survival were analyzed. RESULTS: Pathological PL invasion was observed in 68 patients (28.1%). Patients with PL invasion had significantly shorter disease-free survival (DFS) and showed trends toward worse overall survival (OS) than those without PL invasion. While multivariate analysis revealed that PL invasion was not an independent prognostic factor, PL invasion was associated with extensive venous invasion and a high percentage of lymph node metastases, both of which were independent factors affecting DFS and OS. Among patients with PL invasion, there was no significant difference in DFS and OS between the R0 and R1 resection groups. CONCLUSIONS: PL invasion is a common pathological feature of aggressive PDAC with high propensity for invasiveness and metastatic potential. The microscopic resection margin status may not affect the survival of pancreatic head cancer patients with PL invasion.

Prosaposin, tumor-secreted protein, promotes pancreatic cancer progression by decreasing tumor-infiltrating lymphocytes.

Glycoproteins produced by tumor cells are involved in cancer progression, metastasis, and the immune response, and serve as possible therapeutic targets. Considering the dismal outcomes of pancreatic ductal adenocarcinoma (PDAC) due to its unique tumor microenvironment, which is characterized by low antitumor T-cell infiltration, we hypothesized that tumor-derived glycoproteins may serve as regulating the tumor microenvironment. We used glycoproteomics with tandem mass tag labeling to investigate the culture media of three human PDAC cell lines, and attempted to identify the key secreted proteins from PDAC cells. Among the identified glycoproteins, prosaposin (PSAP) was investigated for its functional contribution to PDAC progression. PSAP is highly expressed in various PDAC cell lines; however, knockdown of intrinsic PSAP expression did not affect the proliferation and migration capacities. Based on the immunohistochemistry of resected human PDAC tissues, high PSAP expression was associated with poor prognosis in patients with PDAC. Notably, tumors with high PSAP expression showed significantly lower CD8+ T-cell infiltration than those with low PSAP expression. Furthermore, PSAP stimulation decreased the proportion of CD8+ T cells in peripheral blood monocytes. Finally, in an orthotopic transplantation model, the number of CD8+ T cells in the PSAP shRNA groups was significantly increased, resulting in a decreased tumor volume compared with that in the control shRNA group. PSAP suppresses CD8+ T-cell infiltration, leading to the promotion of PDAC progression. However, further studies are warranted to determine whether this study contributes to the development of a novel immunomodulating therapy for PDAC.

Preoperative Diagnosis of Lymph Node Metastasis of Perihilar Cholangiocarcinoma Using Diffusion-Weighted Magnetic Resonance Imaging.

INTRODUCTION: Although the prognosis of patients with resected perihilar cholangiocarcinoma (PHC) with histological lymph node metastasis (LNM) is poor, preoperative prediction of LNM is difficult. This study aimed to evaluate the diagnostic performance of diffusion-weighted magnetic resonance imaging (DWI) for LNM of PHC. METHOD: Consecutive patients who underwent surgical resection of PHC between January 2012 and May 2020 were retrospectively reviewed. The lymph node (LN) area (mm2) and apparent diffusion coefficient (ADC) value ( × 10-3 mm2/s) of pericholedochal LNs were measured by DWI. The characteristics of the patients and the LNs were evaluated according to the histological presence or absence of regional LNM. Univariate and multivariate analyses were performed to identify the predictors of LNM of PHC. RESULTS: Of the 93 eligible patients, 49 (53%) were LNM positive and 44 (47%) were LNM negative. Although the characteristics of the patients were similar between the two groups, the mean ADC value was significantly lower in the LNM positive group than in the LNM negative group. On multivariate analysis, mean ADC value ≤1.80 × 10-3 mm2/s was independently associated with LNM of PHC (risk ratio: 12.5, 95% confidence interval: 3.05-51.4; p = 0.0004). The sensitivity, specificity and accuracy of mean ADC values ≤ 1.80 × 10-3 mm2/s for predicting LNM of PHC were 94%, 55% and 75%, respectively. CONCLUSIONS: DWI might be useful for the preoperative diagnosis of LNM of PHC.

Influence of sarcopenia as defined by EWGSOP2 on complications after pancreaticoduodenectomy and on the prognosis of pancreatic head cancer: A prospective cohort study.

OBJECTIVES: It has been reported that sarcopenia is associated with higher postoperative complication rates in various surgeries and with a poorer prognosis in various carcinomas. However, many of these reports did not strictly follow the definition of sarcopenia. Therefore, we prospectively evaluated the influence of sarcopenia, as defined by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2), on complications after pancreaticoduodenectomy (PD) and on the prognosis of pancreatic head carcinoma. METHODS: We prospectively investigated 180 patients who underwent PD at Chiba University Hospital from January 2016 to March 2020. The skeletal muscle mass, grip strength, and gait speed of the patients were measured preoperatively. Sarcopenia was defined in accordance with the EWGSOP2 definition. We evaluated the frequency and severity of postoperative complications in infectious, non-infectious, and overall complications. We analyzed the prognosis of 83 patients with pancreatic head carcinoma who underwent PD. RESULTS: There were no differences in the severity and frequency of infectious, non-infectious, and overall complications between patients with and without sarcopenia. In patients with pancreatic head carcinoma, the recurrence-free and overall survival rates were significantly lower in patients with sarcopenia than in those without sarcopenia (P = 0.017 and P = 0.011, respectively). In multivariate analysis, sarcopenia was an independent risk factor for poor recurrence-free survival and overall survival (HR, 4.48; 95% CI, 1.68-11.98; P = 0.003 and HR, 3.25; 95% CI, 1.19-8.86; P = 0.021, respectively). CONCLUSIONS: Sarcopenia, as defined by EWGSOP2, did not affect complications after PD. Sarcopenia is an important prognostic factor for surgically resected pancreatic head carcinoma.

Tumor-suppressive role of Smad ubiquitination regulatory factor 2 in patients with colorectal cancer.

Smad ubiquitination regulatory factor 2 (Smurf2) plays various roles in cancer progression. However, the correlation between Smurf2 and clinical outcomes has not been determined in patients diagnosed with colorectal cancer and colorectal liver metastases. We analyzed 66 patients with colorectal cancer who developed liver metastases. Smurf2 expression was assessed using immunohistochemical analysis of primary and metastatic liver tumors. High Smurf2 expression in both primary and metastatic tumors was significantly associated with longer overall survival time and time to surgical failure. Multivariate analyses revealed that low Smurf2 expression in primary tumors was an independent predictor of poor prognosis. In vitro experiments using colon cancer cell lines demonstrated that short interfering RNA knockdown of Smurf2 increased cell migration and tumor sphere formation. Western blot analyses revealed that Smurf2 knockdown increased the protein expression of epithelial cell adhesion molecule (EpCAM). Thus, in summary, high Smurf2 expression in cancer cells was found to be an independent predictor of better prognosis in patients with primary colorectal cancer and consequent liver metastases. The tumor-suppressive role of Smurf2 was found to be associated with cell migration and EpCAM expression; hence, Smurf2 can be considered a positive biomarker of cancer stem cell-like properties.

Fat signal fraction assessed with MRI predicts hepatic recurrence following hepatic resection for colorectal liver metastases.

PURPOSE: The effect of hepatic steatosis on the development of colorectal liver metastases (CRLM) remains unknown. This study evaluated the usefulness of fat signal fraction assessed with magnetic resonance imaging (MRI) and the effect of hepatic steatosis on hepatic recurrences following initial hepatectomy for CRLM. METHODS: Between January 2013 and December 2019, 64 patients underwent initial hepatectomy for CRLM. The medical records of these patients were reviewed to evaluate the recurrence and survival outcomes. RESULTS: The fat signal fraction was positively correlated with the nonalcoholic fatty liver disease activity score and liver-spleen ratio. Recurrence following the initial hepatectomy was observed in 48/64 patients, and hepatic recurrence was observed in 30/64 patients. The fat signal fraction was significantly higher in patients with hepatic recurrence after initial hepatectomy. The hepatic recurrence rate was 69.2% in patients with fat signal fraction ≥ 0.0258, which was significantly higher than that in patients with fat signal fraction < 0.0258. Hepatic recurrence-free survival rate was significantly higher in patients with fat signal fraction < 0.0258 than in those with fat signal fraction ≥ 0.0258. Multivariate analyses revealed that fat signal fraction ≥ 0.0258 was an independent risk factor for hepatic recurrence. CONCLUSION: The fat signal fraction assessed with MRI was significantly associated with hepatic recurrence following initial hepatectomy for CRLM.

Yin Yang 1 regulates ITGAV and ITGB1, contributing to improved prognosis of colorectal cancer.

Yin Yang 1 (YY1) is a multifunctional transcription factor with critical roles in carcinogenesis and metastasis. However, its biological role and clinical impact in colorectal cancer (CRC) remain unclear. In the present study, the function and underlying molecular mechanisms of YY1 in CRC progression were investigated. The immunohistochemistry (IHC) of 143 CRC tissues revealed a significant correlation of low YY1 expression with aggressive clinicopathological features, increased metastasis and recurrence and poor patient survival. Multivariate analysis identified low YY1 expression as an independent poor prognostic factor. Subsequently, the IHC of 66 paired CRC primary tumor and liver metastasis tissues revealed that low YY1 expression in the primary CRC was significantly associated with multiple liver metastases, major hepatectomy, extrahepatic metastasis and poor prognosis. In vitro experiments revealed that YY1 knockdown promoted the migration and invasion of CRC cells. To examine the downstream genes of YY1, a cDNA microarray assay was conducted and the differentially expressed genes between the YY1­knockdown and control cells were compared. Integrin alpha V (ITGAV) and integrin beta 1 (ITGB1) were identified as upregulated hub genes using gene enrichment analysis and protein­protein interaction analyses. Western blotting and IHC confirmed YY1 expression to be negatively correlated with ITGAV and ITGB1 expression. In summary, it was revealed that YY1, as a tumor­suppressor in CRC, contributes to the survival of patients with CRC. Low YY1 expression was associated with the poor prognosis of the patients with primary CRC and liver metastases. YY1 suppressed the expression of ITGAV and ITGB1, and this transcriptional regulation may lead to the suppression of CRC cell migration and invasion.

The effect of the low stromal ratio induced by neoadjuvant chemotherapy on recurrence patterns in borderline resectable pancreatic ductal adenocarcinoma.

The optimal regimens of neoadjuvant chemotherapy (NAC) and its biological and physiological modification of the tumor microenvironment (TME) in patients with borderline resectable pancreatic ductal adenocarcinoma (BR PDAC) remain unknown. A deeper understanding of the complex stromal biology of the TME will identify new avenues to establish treatment strategies for PDAC patients. Herein, we sought to clarify whether stromal remodeling by NAC affects recurrence patterns and prognosis in BR PDAC patients. We retrospectively analyzed data from 104 BR PDAC patients who underwent pancreatectomy with or without NAC (upfront surgery [UpS], n = 44; gemcitabine + nab-paclitaxel [GnP], n = 28; and gemcitabine + S-1 [GS], n = 32) to assess the correlations of treatment with early recurrence, the stromal ratio, and Ki-67 levels. Eighty-six patients experienced recurrence, and those with liver metastasis had significantly shorter recurrence-free survival than those with other recurrence patterns. The frequency of liver metastasis was significantly higher in patients with a low stromal ratio than in those with a high stromal ratio in the NAC group but not in the UpS group. Patients in the GnP group had significantly higher Ki-67 than those in the GS and UpS groups. A low stromal ratio was positively correlated with high Ki-67 in the NAC group but not in the UpS group. The low stromal ratio induced by NAC promoted early liver metastasis in patients with BR PDAC. Our findings provide new insights into the complexity of stromal biology, leading to consideration of the optimal NAC regimen.

Surgical implications of the confluence patterns of the left intrahepatic bile ducts in right hepatectomy for perihilar cholangiocarcinoma.

BACKGROUND: Although the most important goal in surgery for perihilar cholangiocarcinoma (PHC) is to achieve tumor-free proximal ductal margins, little is known about the implications of confluence patterns of the left intrahepatic bile ducts for the proximal ductal margin status in right hepatectomy (RH) for PHC. METHODS: Of 203 patients who underwent surgical resection for PHC with curative intent, confluence patterns of the left intrahepatic bile duct were evaluated in 94 consecutive patients who underwent RH, and they were classified into the following two types: normal type: the bile duct of segment 4 (B4) drained into the common trunk of the bile ducts of segment 2 (B2) and segment 3 (B3) at the right side of the umbilical portion of the left portal vein to form the left hepatic duct; and hepatic confluence type: B2 entered the common trunk of B3 and B4 at the hepatic confluence or B4 entered the common trunk of B2 and B3 at the hepatic confluence. The proximal ductal margin status following RH was compared between the two types of confluence patterns. RESULTS: Of 94 consecutive patients, 69 (73%) were the normal type, and 25 (27%) were the hepatic confluence type. There were no significant differences in patients' characteristics, surgical characteristics, surgical outcomes, and histopathological features between the two groups. However, in patients with Bismuth-Corlette type II and IIIa PHC, the achievement rates of negative proximal ductal margins at the first dividing line were significantly higher in the hepatic confluence type group than in the normal type group (16/16 [100%] vs 34/52 [65%], respectively; P = .007). CONCLUSIONS: Confluence patterns of the left intrahepatic bile ducts might affect proximal ductal margin status in RH for PHC.

[A Case of Hepatocellular Carcinoma with Erythrocytosis].

Hepatocellular carcinoma is associated with a relatively high rate of paraneoplastic syndrome, but the frequency of erythrocytosis is low. We report a case of hepatocellular carcinoma with preoperative erythrocytosis and hypererythropoietinemia. The case is a 50-year-old man who has been cured by interferon treatment for hepatitis C 20 years ago(SVR). He visited our hospital with the complaint of right hypochondrial pain, and was diagnosed with hepatocellular carcinoma, which occupied S8/5/7 of the liver, and showed erythrocytosis and high erythropoietin(Epo)as tumor-related symptoms. A right hepatic lobectomy was performed, and the patient was discharged 13 days after the operation. The red blood cell count and Epo were normalized immediately after the operation. One year and 2 months after the operation, multiple lung metastases recurred, and chemotherapy is currently underway. Hepatocellular carcinoma with erythrocytosis and hypererythropoietinemia has been reported to have a poor prognosis, and multimodal treatment and strict surveillance are considered necessary.

C4b-binding protein α-chain enhances antitumor immunity by facilitating the accumulation of tumor-infiltrating lymphocytes in the tumor microenvironment in pancreatic cancer.

BACKGROUND: Recent studies indicate that complement plays pivotal roles in promoting or suppressing cancer progression. We have previously identified C4b-binding protein α-chain (C4BPA) as a serum biomarker for the early detection of pancreatic ductal adenocarcinoma (PDAC). However, its mechanism of action remains unclear. Here, we elucidated the functional roles of C4BPA in PDAC cells and the tumor microenvironment. METHODS: We assessed stromal C4BPA, the C4BPA binding partner CD40, and the number of CD8+ tumor-infiltrating lymphocytes in resected human PDAC tissues via immunohistochemical staining. The biological functions of C4BPA were investigated in peripheral blood mononuclear cells (PBMCs) and human PDAC cell lines. Mouse C4BPA (mC4BPA) peptide, which is composed of 30 amino acids from the C-terminus and binds to CD40, was designed for further in vitro and in vivo experiments. In a preclinical experiment, we assessed the efficacy of gemcitabine plus nab-paclitaxel (GnP), dual immune checkpoint blockades (ICBs), and mC4BPA peptide in a mouse orthotopic transplantation model. RESULTS: Immunohistochemical analysis revealed that high stromal C4BPA and CD40 was associated with favorable PDAC prognosis (P=0.0005). Stromal C4BPA strongly correlated with the number of CD8+ tumor-infiltrating lymphocytes (P=0.001). In in vitro experiments, flow cytometry revealed that recombinant human C4BPA (rhC4BPA) stimulation increased CD4+ and CD8+ T cell numbers in PBMCs. rhC4BPA also promoted the proliferation of CD40-expressing PDAC cells. By contrast, combined treatment with gemcitabine and rhC4BPA increased PDAC cell apoptosis rate. mC4BPA peptide increased the number of murine T lymphocytes in vitro and the number of CD8+ tumor-infiltrating lymphocytes surrounding PDAC tumors in vivo. In a preclinical study, GnP/ICBs/mC4BPA peptide treatment, but not GnP treatment, led to the accumulation of a greater number of CD8+ T cells in the periphery of PDAC tumors and to greater tumor regression than did control treatment. CONCLUSIONS: These findings demonstrate that the combination of GnP therapy with C4BPA inhibits PDAC progression by promoting antitumor T cell accumulation in the tumor microenvironment.

Phosphorylated mTOR expression as a predictor of survival after liver resection for colorectal liver metastases.

BACKGROUND: Phosphorylated mammalian target of rapamycin (p-mTOR) plays a crucial role in the process of cancer progression. Common gene mutations of colorectal cancer lead to the activation of the PI3k/Akt/mTOR pathway. In this study, we determined whether p-mTOR expression in colorectal liver metastases is a predictive marker of prognosis following liver resection. METHODS: Eighty-one patients with colorectal liver metastases who had undergone curative resection were evaluated using immunohistochemistry of p-mTOR. Data regarding clinicopathological features and patient survival were analyzed. RESULTS: The p-mTOR expression in colorectal liver metastases was detected in 55 (67.9%) patients. Patients whose metastases had high p-mTOR expression showed a significantly lower overall survival rate after resection as compared to patients with low p-mTOR expression (p = 0.016), while there was no significant difference in the disease-free survival between the two groups. Repeat resection for recurrence was performed more frequently in patients with p-mTOR positive than others (p = 0.024). Multivariate analysis showed that p-mTOR expression was an independent prognostic factor of overall survival after liver resection (p = 0.019). CONCLUSIONS: mTOR was frequently activated in colorectal liver metastases, and the p-mTOR expression was a biological marker for predicting the overall survival of patients with colorectal liver metastases following liver resection.

Complement factor B regulates cellular senescence and is associated with poor prognosis in pancreatic cancer.

BACKGROUND: The interplay between cancer cells and stromal components, including soluble mediators released from cancer cells, contributes to the progression of pancreatic ductal adenocarcinoma (PDAC). Here, we set out to identify key secreted proteins involved in PDAC progression. METHODS: We performed secretome analyses of culture media of mouse pancreatic intraepithelial neoplasia (PanIN) and PDAC cells using Stable Isotope Labeling by Amino acid in Cell culture (SILAC) with click chemistry and liquid chromatography-mass spectrometry (LC-MS/MS). The results obtained were verified in primary PDAC tissue samples and cell line models. RESULTS: Complement factor B (CFB) was identified as one of the robustly upregulated proteins, and found to exhibit elevated expression in PDAC cells compared to PanIN cells. Endogenous CFB knockdown by a specific siRNA dramatically decreased the proliferation of PDAC cells, PANC-1 and MIA PaCa-II. CFB knockdown induced increases in the number of senescence-associated-ß-galactosidase (SA-ß-gal) positive cells exhibiting p21 expression upregulation, which promotes cellular senescence with cyclinD1 accumulation. Furthermore, CFB knockdown facilitated downregulation of proliferating cell nuclear antigen and led to cell cycle arrest in the G1 phase in PDAC cells. Using immunohistochemistry, we found that high stromal CFB expression was associated with unfavorable clinical outcomes with hematogenous dissemination after surgery in human PDAC patients. Despite the presence of enriched CD8+ tumor infiltrating lymphocytes in the PDAC tumor microenvironments, patients with a high stromal CFB expression exhibited a significantly poorer prognosis compared to those with a low stromal CFB expression. Immunofluorescence staining revealed a correlation between stromal CFB expression in the tumor microenvironment and an enrichment of immunosuppressive regulatory T-cells (Tregs), myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs). We also found that high stromal CFB expression showed a positive correlation with high CD8+/Foxp3+ Tregs populations in PDAC tissues. CONCLUSIONS: Our data indicate that CFB, a key secreted protein, promotes proliferation by preventing cellular senescence and is associated with immunological tumor promotion in PDAC. These findings suggest that CFB may be a potential target for the treatment of PDAC.

Recurrence patterns and their effects on clinical outcomes after R1 resection of colorectal liver metastases: a propensity score-matched analysis.

PURPOSE: The prognostic significance of the surgical margin status remains controversial for patients who undergo hepatectomy for colorectal liver metastases. This study evaluated the influence of R1 resection on recurrence patterns and prognosis in these patients. METHODS: Between January 2001 and December 2016, 232 consecutive Japanese patients underwent initial hepatic resection for colorectal liver metastases. Their medical records were reviewed to evaluate recurrence and survival outcomes. RESULTS: Relative to patients with R0 resection, patients with R1 resection had significantly poorer recurrence-free survival (RFS) and overall survival (OS). However, after propensity score matching, there were no significant differences in RFS and OS associated with the margin status. Nevertheless, R1 resection was associated with a significantly higher incidence of intrahepatic recurrence and early recurrence, while R0 resection was associated with a significantly higher re-resection rate for hepatic recurrence. Only eight of 55 patients with R1 resection developed recurrence at the R1 resection margin, whereas 36 patients developed recurrence at other sites/organs. CONCLUSION: Among patients with similar characteristics, R1 resection does not affect long-term outcomes. This suggests that R1 resection itself is not a cause of a poor prognosis, but rather a potent indicator of aggressive tumor biology.

Prediction of mismatch repair deficient biliary tract cancer: Role of morphological features and host immune response detected by routine hematoxylin-eosin staining.

BACKGROUND/PURPOSE: The objective of this study was to determine the frequency and predictors of biliary tract cancer (BTC) with deficient DNA mismatch repair (dMMR) in Japan. METHODS: Immunostaining and microsatellite instability analysis were performed for mismatch repair-related proteins in tissue specimens from 662 patients who underwent surgery for BTC between 2001 and 2017 to identify dMMR-BTC. We compared dMMR-BTC and proficient MMR (pMMR)-BTC based on patient demographics, pathological features, and host immune responses characterized by the percentage of stromal tumor infiltrating lymphocytes (sTIL percentage) and tertiary lymphoid structures (TLS). RESULTS: The incidence of dMMR-BTC was 2.3%. Significant predictors of dMMR-BTC were its primary lesion being intrahepatic cholangiocarcinoma (odds ratio [OR] 6.34, P = .004), presence of signet ring cell component (OR 35.62, P < .001), sTIL percentage ≥40% (OR 3.43, P = .038), and presence of TLS (OR 22.22, P < .001). The sensitivity, specificity, and negative likelihood ratio for any one or more of these four variables to be positive were 93.3%, 57.8%, and 0.12, respectively. CONCLUSION: Evaluation of histopathological findings and host immune response based on conventional histochemical staining is useful for efficient and inexpensive diagnostic screening of dMMR-BTC patients.

Differential effects of KRAS mutational status on long-term survival according to the timing of colorectal liver metastases.

BACKGROUND: The relationship between KRAS mutational status and timing of colorectal liver metastasis (CRLM) remains unclear. This study evaluated the relationship between KRAS mutational status and long-term survival in patients with synchronous CRLM. METHODS: Of the 255 patients who underwent initial hepatic resection for CRLM between January 2001 and December 2018, the KRAS mutational status was examined in 101 patients. Medical records of these patients were reviewed to evaluate recurrence and survival outcomes. RESULTS: KRAS mutant status was identified in 38 patients (37.6%). The overall survival (OS) was significantly better in patients with wild-type KRAS than in those with mutant KRAS status. In patients with synchronous metastases, the OS of patients with wild-type KRAS was significantly better than those with mutant KRAS. Multivariate analyses indicated shorter OS to be independently associated with positive primary lymph node, and large tumor size and R1 resection in patients with metachronous metastasis, whereas to be independently associated with mutant KRAS status in patients with synchronous metastasis. Furthermore, in the subgroup of patients with synchronous metastases, the repeat resection rate for hepatic recurrence was significantly high in those with wild type KRAS than in those with mutant KRAS. CONCLUSION: KRAS mutation is an independent prognostic factor in patients with synchronous CRLM, but not in patients with metachronous CRLM.

Clinical implication of ICG test in major hepatectomy for biliary tract cancer.

BACKGROUND: Major hepatectomy with bile duct resection (BDR) is associated with severe postoperative complications; therefore, evaluation of preoperative liver function is important. However, little is known about mechanisms of increased severe complications in patients with poor liver function. The aim of this study was to evaluate whether indocyanine green retention rate after 15 minutes of injection (ICG-R15) is useful for predicting the risk of severe postoperative complications in this operation, and to reveal the mechanisms of increasing severe complications by focusing on immune function and liver regeneration after hepatectomy. METHODS: Patients receiving major hepatectomy with BDR between 2000 and 2017 were retrospectively reviewed. Severe postoperative complications were defined as Clavien-Dindo grade ≥IV. RESULTS: In 284 patients undergoing major hepatectomy with BDR, ICG-R15 was correlated with severe postoperative complications, with cut-off value of 11.8%. In brief, the incidences of hyperbilirubinemia, coagulopathy, liver failure, respiratory failure, severe complications, and mortality were higher in the high ICG-R15 group. Moreover, high ICG-R15 (≥11.8%) was an independent factor for predicting severe complications after major hepatectomy with BDR. Immune dysfunction in the early phase after operation, prolonged postoperative immunosuppression, and delayed liver regeneration were reasons for increasing severe postoperative complications in patients with high ICG-R15. CONCLUSIONS: High ICG-R15 is an independent risk factor for severe complications after major hepatectomy with BDR, and its cut-off value is 11.8%. Compromised condition and delayed liver regeneration induced by immune dysfunction are reasons of increased severe postoperative complications in patients with high ICG-R15.

Usefulness of the MALDI-TOF MS technology with membrane filter protocol for the rapid identification of microorganisms in perioperative drainage fluids of hepatobiliary pancreatic surgery.

Surgical site infections (SSIs) are significant and frequent perioperative complications, occurring due to the contamination of the surgical site. The late detection of SSIs, especially organ/space SSIs which are the more difficult to treat, often leads to severe complications. An effective method that can identify bacteria with a high accuracy, leading to the early detection of organ/space SSIs, is needed. Ninety-eight drainage fluid samples obtained from 22 patients with hepatobiliary pancreatic disease were analyzed to identify microorganisms using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) with a new membrane filtration protocol and rapid BACpro® pretreatment compared to sole rapid BACpro® pretreatment. The levels of detail of rapid BACpro® pretreatment with or without filtration were also evaluated for the accuracy of bacterial identification. We found that reliable scores for E. coli and E. faecalis were obtained by inoculation with 1.0 × 104 CFU/ml after preparation of the membrane filter with rapid BACpro®, indicating approximately 10-folds more sensitive compared to sole rapid BACpro® pretreatment in drainage fluid specimens. Among 60 bacterial positive colonies in drainage fluid specimens, the MALDI-TOF MS and the membrane filtration with rapid BACpro® identified 53 isolates (88.3%) with a significantly higher accuracy, compared to 25 isolates in the rapid BACpro® pretreatment group (41.7%) (p < 0.001). Among the 78 strains, 14 enteric Gram-negative bacteria (93.0%) and 55 Gram-positive cocci (87.3%) were correctly identified by the membrane filtration with rapid BACpro® with a high reliability. This novel protocol could identify bacterial species within 30 min, at $2-$3 per sample, thus leading to cost and time savings. MALDI-TOF MS with membrane filter and rapid BACpro® is a quick and reliable method for bacterial identification in drainage fluids. The shortened analysis time will enable earlier selection of suitable antibiotics for treatment of organ/space SSIs to improve patients' outcomes.