Satoshi Nara

Minimally invasive intraductal papillary-mucinous carcinoma of the pancreas: Clinicopathologic study of 104 intraductal papillary-mucinous neoplasms

Invasive intraductal papillary-mucinous carcinoma (I-IPMC) is a heterogeneous entity with various postoperative outcomes. The aim of this study is to characterize early-stage I-IPMC with nonaggressive characteristics. One hundred and four patients with intraductal papillary-mucinous neoplasm (IPMN) were clinicopathologically investigated. The lesions were classified into 53 noninvasive IPMNs (adenoma, borderline, and noninvasive IPMC) and 51 I-IPMCs on the basis of the WHO classification. I-IPMCs were divided further into 26 minimally invasive IPMCs (MI-IPMCs) and 25 invasive carcinomas originating in IPMC (IC-IPMCs) by new diagnostic criteria proposed in this study. We examined invasiveness of I-IPMC on 4 patterns, and defined simple and practical diagnostic criteria of minimal invasion for each invasive pattern. The disease-specific survival rates after 3, 5, and 10 years were 100%, 100%, and 100% for both noninvasive IPMN and MI-IPMC, and 51%, 38%, and 0% for IC-IPMC. The overall and disease-specific survival rates for MI-IPMC were both significantly better than those for IC-IPMC (P<0.001), but there was no significant difference between noninvasive IPMN and MI-IPMC. Multivariate analysis showed that the factors indicative of poor prognosis were a diagnosis of I-IPMC classified as IC-IPMC and a high level of serum carbohydrate antigen 19-9. The prognosis of IC-IPMC was not significantly different from that of pancreatic ductal carcinoma in each of the corresponding tumor-node-metastasis stages. These findings suggest that a category of MI-IPMC provides more accurate and useful information of the stage and the aggressiveness of I-IPMC.

Clinical utility of circulating tumor DNA for molecular assessment in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies. The genomic landscape of the PDAC genome features four frequently mutated genes (KRAS, CDKN2A, TP53, and SMAD4) and dozens of candidate driver genes altered at low frequency, including potential clinical targets. Circulating cell-free DNA (cfDNA) is a promising resource to detect and monitor molecular characteristics of tumors. In the present study, we determined the mutational status of KRAS in plasma cfDNA using multiplex picoliter-droplet digital PCR in 259 patients with PDAC. We constructed a novel modified SureSelect-KAPA-Illumina platform and an original panel of 60 genes. We then performed targeted deep sequencing of cfDNA and matched germline DNA samples in 48 patients who had ≥1% mutant allele frequencies of KRAS in plasma cfDNA. Importantly, potentially targetable somatic mutations were identified in 14 of 48 patients (29.2%) examined by targeted deep sequencing of cfDNA. We also analyzed somatic copy number alterations based on the targeted sequencing data using our in-house algorithm, and potentially targetable amplifications were detected. Assessment of mutations and copy number alterations in plasma cfDNA may provide a prognostic and diagnostic tool to assist decisions regarding optimal therapeutic strategies for PDAC patients.

Multicenter comparative study of laparoscopic and open distal pancreatectomy using propensity score-matching

Laparoscopic distal pancreatectomy has been shown to be associated with favorable postoperative outcomes using meta‐analysis. However, there have been no randomized controlled studies yet. This study aimed to compare laparoscopic and open distal pancreatectomy using propensity score‐matching.

Marginal survival benefit in the treatment of early hepatocellular carcinoma.

BACKGROUND & AIMS Early treatment has been recommended for hepatocellular carcinoma (HCC) due to its high cure rate. However, the reported survival benefits of treating early HCC may be affected by lead time. METHODS Early HCC was defined as a well-differentiated cancer containing Glissons triad (carcinoma in situ). We applied the concept of lead time to chronic liver disease, which is originally the length of time between screen-detected and symptom-detected disease. To evaluate prolongation of survival with treatment of early HCC, survivals of patients with early and overt HCCs smaller than 2.0 cm treated with liver resection were compared. To calculate lead time and survival benefit of liver resection, survivals of untreated early and overt HCC patients were compared. RESULTS After liver resection, median overall survival of 46 patients with early HCC (8.8 years; 95% CI, 7.2-11.2) was significantly longer than that of the 202 with overt HCC (6.8 years; 95% CI, 6.2-8.3, p = 0.0257). The prolongation in survival time with liver resection for early HCC was 34.7 (95% CI, 22.1-46.5) months. On the other hand, comparing liver resection and natural history, the survival benefits of surgery for 12 patients with early and 16 with overt HCC were 74.7 (95% CI, 51.9-97.4) and 73.4 (95% CI, 57.9-88.9) months, respectively. Consequently, the lead time and survival benefit with resection for early HCC were estimated as 33.4 (95% CI, 18.9-47.8) and 1.3 (95% CI, -22.1-24.7) months, respectively. CONCLUSIONS Survival benefit of resection for early HCC is marginal because of a long lead time, and early HCC is therefore not a target lesion for surgery.

Genomic Sequencing Identifies ELF3 as a Driver of Ampullary Carcinoma

Ampullary carcinomas are highly malignant neoplasms that can have either intestinal or pancreatobiliary differentiation. To characterize somatic alterations in ampullary carcinomas, we performed whole-exome sequencing and DNA copy-number analysis on 60 ampullary carcinomas resected from clinically well-characterized Japanese and American patients. We next selected 92 genes and performed targeted sequencing to validate significantly mutated genes in an additional 112 cancers. The prevalence of driver gene mutations in carcinomas with the intestinal phenotype is different from those with the pancreatobiliary phenotype. We identified a characteristic significantly mutated driver gene (ELF3) as well as previously known driver genes (TP53, KRAS, APC, and others). Functional studies demonstrated that ELF3 silencing in normal human epithelial cells enhances their motility and invasion.

Arterial reconstruction during pancreatoduodenectomy in patients with celiac axis stenosis- : Utility of doppler ultrasonography

Celiac axis stenosis is found at an incidence of 2%–24% in the general population. During pancreatoduodenectomy in patients with celiac axis stenosis, division of the gastroduodenal artery from the common hepatic artery may cause acute ischemia of the upper abdominal organs, such as the liver, stomach, or spleen. Under these circumstances, the clinical indications of arterial reconstruction remain controversial. Between 1994 and 2003, seven patients with celiac axis stenosis (n = 4) or occlusion (n = 3) underwent pancreatoduodenectomy at our hospital. Arterial reconstruction, including division of the median arcuate ligament, was conducted in two patients; the replaced right hepatic artery was preserved in one patient, and no vascular refinement was undertaken in the remaining four of the seven patients. In two of the four patients without arterial reconstruction or preservation, the serum levels of liver enzymes were markedly elevated (> 800 IU/l) on postoperative day 1, and these patients subsequently developed liver abscesses. Two patients who underwent arterial reconstruction and three patients who showed no decrease in intrahepatic arterial flow under Doppler ultrasonography after clamping of the gastroduodenal artery developed no ischemic complications. Although our experience is limited, when intraoperative Doppler ultrasonography indicates a decrease in the hepatic arterial signals, we believe that reconstruction of the hepatic artery will be necessary to minimize ischemic complications in the liver in patients with celiac axis stenosis.

Prognostic impact of marginal resection for patients with solitary hepatocellular carcinoma: Evidence from 570 hepatectomies

BACKGROUND During resection of a hepatocellular carcinoma, surgeons encounter occasionally a situation where marginal resection is inevitable because of a close association between the hepatocellular carcinoma and major vasculature and/or underlying impaired liver function. We investigated the impact of marginal resection on recurrence-free survival after a resection of a solitary hepatocellular carcinoma. METHODS The data of 570 patients who underwent macroscopically curative hepatectomy for a solitary hepatocellular carcinoma in our institution between 1990 and 2007 were analyzed. Marginal resection and non-marginal resection were defined as a cancer-negative surgical margin of ≤ 1 mm and a surgical margin of >1 mm, respectively. The macroscopic appearance of the hepatocellular carcinoma was classified as the simple nodular type or non-simple nodular type based on the classification of the Liver Cancer Study Group of Japan, and patients were categorized into 4 groups: group A, simple nodular type with cirrhosis; group B, simple nodular type without cirrhosis; group C, non-simple nodular type with cirrhosis; and group D, non-simple nodular type without cirrhosis. RESULTS The surgical margins were diagnosed as cancer-positive in 31 patients, as marginal resection in 165 patients, and as non-marginal resection in 374 patients. The marginal resection group showed a better recurrence-free survival than the positive surgical margin group (P = .001), and also a worse recurrence-free survival than the non-marginal resection group (P = .003). In groups A, B, and C, the recurrence-free survival rates were similar between marginal resection and non-marginal resection patients (P = .458), while in group D, marginal resection was a significant poor prognostic factor of recurrence-free survival in both univariate and multivariate analyses. CONCLUSION Marginal resection is acceptable in group A, B, and C patients, because it did not negatively affect postoperative recurrence-free survival.

Establishment of six new human biliary tract carcinoma cell lines and identification of MAGEH1 as a candidate biomarker for predicting the efficacy of gemcitabine treatment

The aim of this study was to establish new biliary tract carcinoma (BTC) cell lines and identify predictive biomarkers for the potential effectiveness of gemcitabine therapy. Surgical specimens of BTC were transplanted directly into immunodeficient mice to establish xenografts, then subjected to in vitro cell culture. The gemcitabine sensitivity of each cell line was determined and compared with the genome‐wide gene expression profile. A new predictive biomarker candidate was validated using an additional cohort of gemcitabine‐treated BTC cases. From 55 BTC cases, we established 19 xenografts and six new cell lines. Based on their gemcitabine sensitivity, 10 BTC cell lines (including six new and four publicly available ones) were clearly categorized into two groups, and MAGEH1 mRNA expression in the tumor cells showed a significant negative correlation with their sensitivity to gemcitabine. Immunohistochemically, MAGEH1 protein was detected in three (50%) out of six sensitive cell lines, and four (100%) out of four resistant cell lines. In the validation cohort of gemcitabine‐treated recurrence cases, patients were categorized into “effective” and “non‐effective” groups according to the RECIST guidelines for assessment of chemotherapeutic effects. MAGEH1 protein expression was detected in two (40%) out of five “effective” cases and all four (100%) “non‐effective” cases. We have established a new BTC bioresource that covers a wide range of biological features, including drug sensitivity, and is linked with clinical information. Negative expression of MAGEH1 protein serves as a potential predictive marker for the effectiveness of gemcitabine therapy in BTC.

Macrophage-capping protein as a tissue biomarker for prediction of response to gemcitabine treatment and prognosis in cholangiocarcinoma

Cholangiocarcinoma is one of the deadliest malignancies worldwide. Recent studies reported that treatment with gemcitabine was effective in prolonging survival. However, as the treatment only benefited a limited subset of patients, selection of patients before treatment is required. To discover biomarkers predictive of the response to gemcitabine treatment in cholangiocarcinoma, we examined the proteome of three types of material resource; ten cell lines, nine xenografts and nine surgically resected primary tumors from patients who exhibited different response to gemcitabine treatment. Two-dimensional difference gel electrophoresis generated quantitative protein expression profiles including 3571 protein spots. We detected 172 protein spots with significant correlation with response to gemcitabine treatment. All proteins corresponding to these 172 protein spots were identified by mass spectrometry. We found that the macrophage-capping protein (CapG) was associated with response to gemcitabin treatment in all three types of material source. Immunohistochemical validation in an additional set of 196 cholangiocarcinoma cases revealed that CapG expression was associated with lymphatic invasion status and overall survival. Multivariate analysis showed that CapG protein expression was an independent prognostic factor for overall survival. In conclusion, CapG was identified as a novel candidate biomarker to predict response to gemcitabine treatment and survival in cholangiocarcinoma.

Clinical significance of tumor-infiltrating immune cells focusing on BTLA and Cbl-b in patients with gallbladder cancer.

The host immune system plays a significant role in tumor control, although most cancers escape immune surveillance through a variety of mechanisms. The aim of the present study was to evaluate the clinicopathological significance of a novel co‐inhibitory receptor, B and T lymphocyte attenuator (BTLA), the anergy cell marker Casitas–B‐lineage lymphoma protein‐b (Cbl‐b), and clinical implications of tumor‐infiltrating immune cells in gallbladder cancer (GBC) tissues. We investigated 211 cases of GBC, 21 cases of chronic cholecystitis (CC), and 11 cases of xanthogranulomatous cholecystitis (XGC) using immunohistochemistry to detect tissue‐infiltrating immune cells and their expression of BTLA and Cbl‐b, and carried out correlation and survival analyses. The density of infiltrating T cells was significantly higher in CC and XGC than in GBC. The density ratio of BTLA+ cells to CD8+ T cells (BTLA/CD8) and that of Cbl‐b+ cells to CD8+T cells (Cbl‐b/CD8) were significantly higher in GBC than in CC and XGC. The FOXP3/CD4, BTLA/CD8, and Cbl‐b/CD8 ratios were significantly correlated with each other, and also with malignant phenotypes. Survival analyses revealed that a lower density of tumor‐infiltrating CD8+ cells, and higher Foxp3/CD4, BTLA/CD8, and Cbl‐b/CD8 ratios were significantly associated with shorter overall survival and disease‐free survival in GBC patients. Multivariate analyses showed that M factor, perineural invasion, BTLA/CD8, and Cbl‐b/CD8 were closely associated with shorter overall survival. These findings suggest that higher ratios of BTLA/CD8 and Cbl‐b/CD8 are independent indicators of unfavorable outcome in GBC patients, and that upregulation of BTLA in cancer tissues is involved in inhibition of antitumor immunity.