London L. P. J. Ooi

Profiling microRNA expression in hepatocellular carcinoma reveals microRNA-224 up-regulation and apoptosis inhibitor-5 as a microRNA-224-specific target

Like other cancers, aberrant gene regulation features significantly in hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) were recently found to regulate gene expression at the post-transcriptional/translational levels. The expression profiles of 157 miRNAs were examined in 19 HCC patients, and 19 up-regulated and 3 down-regulated miRNAs were found to be associated with HCC. Putative gene targets of these 22 miRNAs were predicted in silico and were significantly enriched in 34 biological pathways, most of which are frequently dysregulated during carcinogenesis. Further characterization of microRNA-224 (miR-224), the most significantly up-regulated miRNA in HCC patients, revealed that miR-224 increases apoptotic cell death as well as proliferation and targets apoptosis inhibitor-5 (API-5) to inhibit API-5 transcript expression. Significantly, miR-224 expression was found to be inversely correlated with API-5 expression in HCC patients (p < 0.05). Hence, our findings define a true in vivo target of miR-224 and reaffirm the important role of miRNAs in the dysregulation of cellular processes that may ultimately lead to tumorigenesis.

MicroRNA-216a/217-induced epithelial-mesenchymal transition targets PTEN and SMAD7 to promote drug resistance and recurrence of liver cancer

Tumor recurrence and metastases are the major obstacles to improving the prognosis of patients with hepatocellular carcinoma (HCC). To identify novel risk factors associated with HCC recurrence and metastases, we have established a panel of recurrence‐associated microRNAs (miRNAs) by comparing miRNA expression in recurrent and nonrecurrent human HCC tissue samples using microarrays (recurrence is defined as recurrent disease occurring within a 2‐year time point of the original treatment). Among the panel, expression of the miR‐216a/217 cluster was consistently and significantly up‐regulated in HCC tissue samples and cell lines associated with early tumor recurrence, poor disease‐free survival, and an epithelial‐mesenchymal transition (EMT) phenotype. Stable overexpression of miR‐216a/217‐induced EMT increased the stem‐like cell population, migration, and metastatic ability of epithelial HCC cells. Phosphatase and tensin homolog (PTEN) and mothers against decapentaplegic homolog 7 (SMAD7) were subsequently identified as two functional targets of miR‐216a/217, and both PTEN and SMAD7 were down‐regulated in HCC. Ectopic expression of PTEN or SMAD7 partially rescued miR‐216a/217‐mediated EMT, cell migration, and stem‐like properties of HCC cells. Previously, SMAD7 was shown to be a transforming growth factor beta (TGF‐β) type 1 receptor antagonist. Here, we further demonstrated that overexpression of miR‐216a/217 acted as a positive feedback regulator for the TGF‐β pathway and the canonical pathway involved in the activation of phosphoinositide 3‐kinase/protein kinase K (PI3K/Akt) signaling in HCC cells. Additionally, activation of the TGF‐β‐ and PI3K/Akt‐signaling pathways in HCC cells resulted in an acquired resistance to sorafenib, whereas blocking activation of the TGF‐β pathway overcame miR‐216a/217‐induced sorafenib resistance and prevented tumor metastases in HCC. Conclusion: Overexpression of miR‐216a/217 activates the PI3K/Akt and TGF‐β pathways by targeting PTEN and SMAD7, contributing to hepatocarcinogenesis and tumor recurrence in HCC. (Hepatology 2013;58:629–641)

Perforation of the Gastrointestinal Tract Secondary to Ingestion of Foreign Bodies

Ingesting a foreign body (FB) is not an uncommon occurrence. Most pass through the gastrointestinal (GI) tract uneventfully, and perforation is rare. The aim of this study was to report our experience with ingested FB perforations of the GI tract treated surgically at our institution. A total of 62 consecutive patients who underwent surgery for an ingested FB perforation of the GI tract between 1990 and 2005 were retrospectively reviewed. Three patients with no definite FB demonstrated intraoperatively were included. The patients had a median age of 58 years, and 37 (60%) were male. Of the 59 FBs recovered, 55 (93%) were toothpicks and dietary FBs such as fish bones or bone fragments. A definitive preoperative history of FB ingestion was obtained for only two patients, and 36 of 52 patients (69%) wore dentures. Altogether, 18 (29%) perforations occurred in the anus or distal rectum, and 44 perforations were intraabdominal, with the most common abdominal site being the distal ileum (39%). Patients with FB perforations in the stomach, duodenum, and large intestine were significantly more likely to be afebrile (P = 0.043), to have chronic symptoms (> 3 days) (P < 0.001), to have a normal total white blood cell count (P < 0.001), and to be asymptomatic or present with an abdominal mass or abscess (P < 0.001) compared to those with FB perforations in the jejunum and ileum. Ingested FB perforation in the adult population is most commonly secondary to unconscious accidental ingestion and is frequently caused by dietary FBs especially fish bones. A preoperative history of FB ingestion is thus rarely obtained, although wearing dentures is a common risk factor. FB perforations of the stomach, duodenum, and large intestine tend to present with a longer, more innocuous clinical picture than perforations in the jejunum or ileum.

Exome sequencing identifies distinct mutational patterns in liver fluke–related and non-infection-related bile duct cancers

The impact of different carcinogenic exposures on the specific patterns of somatic mutation in human tumors remains unclear. To address this issue, we profiled 209 cholangiocarcinomas (CCAs) from Asia and Europe, including 108 cases caused by infection with the liver fluke Opisthorchis viverrini and 101 cases caused by non–O. viverrini–related etiologies. Whole-exome sequencing (n = 15) and prevalence screening (n = 194) identified recurrent somatic mutations in BAP1 and ARID1A, neither of which, to our knowledge, has previously been reported to be mutated in CCA. Comparisons between intrahepatic O. viverrini–related and non–O. viverrini–related CCAs demonstrated statistically significant differences in mutation patterns: BAP1, IDH1 and IDH2 were more frequently mutated in non–O. viverrini CCAs, whereas TP53 mutations showed the reciprocal pattern. Functional studies demonstrated tumor suppressive functions for BAP1 and ARID1A, establishing the role of chromatin modulators in CCA pathogenesis. These findings indicate that different causative etiologies may induce distinct somatic alterations, even within the same tumor type.

Critical Appraisal of 232 Consecutive Distal Pancreatectomies With Emphasis on Risk Factors, Outcome, and Management of the Postoperative Pancreatic Fistula : A 21-Year Experience at a Single Institution

OBJECTIVE To critically analyze a large single-institution experience with distal pancreatectomy (DP), with particular attention to the risk factors, outcome, and management of the postoperative pancreatic fistula (PF). DESIGN Retrospective study. SETTING Tertiary referral center. PATIENTS A total of 232 consecutive patients with pancreatic or extrapancreatic disease necessitating DP over 21 years. INTERVENTIONS Twenty-one patients underwent spleen-preserving DP, 117 underwent DP with splenectomy, and 94 underwent DP with multiorgan resection. MAIN OUTCOME MEASURES The perioperative and postoperative data of patients who underwent DP were analyzed. This included factors associated with postoperative morbidity with particular attention to the PF (defined by the International Study Group of Pancreatic Fistula) and changing trends in operative and perioperative data during the study period. RESULTS The overall operative morbidity and mortality were 47% (107 patients) and 3% (7 patients), respectively. During the study period, the rates of resection increased from 3 cases to 23 per year, and increasingly these were performed for smaller and incidental lesions. The morbidity rate remained unchanged, but there was a decline in postoperative stay and the need for care in the intensive care unit. Pancreatic fistulas occurred in 72 patients (31%); 41 (18%) were grade A, 13 (6%) grade B, and 18 (8%) grade C. Increased weight, higher American Society of Anesthesiologists score, blood loss greater than 1 L, increased operation time, decreased albumin level, and sutured closure of the stump without main duct ligation were associated with a postoperative PF on univariate analysis. A DP with splenectomy was associated with a higher incidence of grade B or C PF and non-PF-related complications. Ninety-two percent of PFs were successfully managed nonoperatively. Clinical outcomes correlated well with PF grading, as evidenced by the progressive increase in outcome measures such as postoperative stay, readmissions, reoperations, radiologic interventions, and non-PF-related complications from grade A to C PFs. CONCLUSIONS Pancreatic fistula is the most common complication after DP and its incidence varies depending on the definition applied. Several risk factors for developing a PF were identified. Splenic preservation after DP is safe. The grade of a PF correlates well with clinical outcomes, and most PFs may be managed nonoperatively.

A review of mucinous cystic neoplasms of the pancreas defined by ovarian-type stroma: clinicopathological features of 344 patients.

Despite formal definitions of mucinous cystic neoplasms (MCNs) and intraductal papillary neoplasms (IPMNs) by the World Health Organization (WHO) and Armed Forces Institute of Pathology (AFIP), several controversies with regard to MCNs remain. The aim of this review was to determine the clinicopathological features of MCNs defined by ovarian-type stroma (OS) as proposed by the WHO and AFIP and to compare them with MCNs defined by less stringent criteria. A MEDLINE search was conducted to identify English-language articles on pancreatic MCNs from 1996 to 2005. Twenty-five studies were identified. The studies were divided into 2 groups: group A included 10 studies with 344 patients whereby the presence of OS was a criteria for the diagnosis of MCNs, and group B, included 15 studies comprising 761 patients whereby the presence of OS was not mandatory for the diagnosis of MCNs. Patients in group A (MCNs as defined by OS) were almost always female (99.7%), with a mean age of 47 (range, 18–95) years. MCNs were located predominantly in the body or tail of the pancreas (94.6%) and had a mean size of 8.7 cm (range, 0.6–35 cm); 76% were symptomatic, 6.8% demonstrated ductal communication, and 27% were malignant. At a mean follow-up of 57.5 (range, 1–264) months and 43 (range, 2–257) months after surgery, 97.9% of benign and 61.9% of malignant neoplasms were disease free, respectively. Patients in group B were older and had a higher proportion of males. Neoplasms were more evenly distributed in the pancreas, were smaller, communicated more frequently with the pancreatic duct, and were composed of a higher proportion of malignant tumors compared with group A. Their clinicopathological features were intermediate between those of group A and patients with IPMN. Pancreatic MCNs with OS have unique and distinct clinicopathological features. MCNs should be defined by the presence of OS, as it is the most reliable way of distinguishing MCNs from IPMN. Adoption of “looser” criteria will result in misclassification of some IPMNs as MCNs.

Splenic abscesses from 1987 to 1995.

BACKGROUND Isolated splenic abscesses is an uncommon clinical entity that is being increasingly recognized as a cause of intraabdominal sepsis in a wide variety of clinical situations, and involving a wide range of organisms. The increasing incidence of immunosuppressed states in this decade due to the use of chemotherapy for oncology, immunosuppression therapy for transplantation, and acquired immune deficiency syndrome, has changed the disease pattern of splenic abscesses. METHOD Data from 287 cases reported in the English literature between 1987 and 1995 were collected, analyzed, and compared with two previous reviews of cases reported before 1987. RESULTS Staphylococcus, Salmonella, and Escherichia coli are the most common organisms cultured. Immunosuppressed states were present in 33.5% of cases, with intravenous drug abuse and acquired immune deficiency syndrome accounting for half these cases. Computerized tomography and ultrasonography are diagnostic, with a sensitivity of 92.2% and 87.2%, respectively. Nonoperative management has a success rate of less than 65%, but salvage splenectomy does not increase mortality compared with splenectomy as initial therapy. CONCLUSIONS Splenic abscesses are increasingly recognized with immunosuppressed states. Percutaneous radiologically guided drainage may be suitable in some cases, but splenectomy with appropriate antibiotics is the definitive treatment.

Expression of the FAT10 gene is highly upregulated in hepatocellular carcinoma and other gastrointestinal and gynecological cancers

The ubiquitin-like modifier (UBL) family has recently generated much interest in the scientific community, as it is implicated to play important regulatory roles via novel protein–protein modification. FAT10 (diubiquitin) belongs to this family of proteins, comprising two ubiquitin-like moieties fused in tandem, and has been implicated to be involved in the maintenance of spindle integrity during mitosis. As FAT10 may play a role in the regulation of genomic stability, we examined if there is an association between FAT10 expression and hepatocellular carcinoma (HCC) or other cancers. Northern blot analyses revealed upregulation of FAT10 expression in the tumors of 90% of HCC patients. In situ hybridization as well as immunohistochemistry utilizing anti-FAT10 antibodies localized highest FAT10 expression in the nucleus of HCC hepatocytes rather than the surrounding immune and non-HCC cells. FAT10 expression was also found to be highly upregulated in other cancers of the gastrointestinal tract and female reproductive system. In conclusion, we demonstrated upregulation of FAT10 expression in various gastrointestinal and gynecological cancers. Its overexpression is unrelated to the general increase in protein synthesis or a general immune/inflammatory response to cancer. Rather, FAT10 may modulate tumorigenesis through its reported interaction with the MAD2 spindle-assembly checkpoint protein.

CT in the Preoperative Diagnosis of Fish Bone Perforation of the Gastrointestinal Tract

OBJECTIVE Foreign body perforation of the gastrointestinal (GI) tract has diverse clinical manifestations, and the correct preoperative diagnosis is seldom made. We report our experience with the use of CT in the preoperative diagnosis of fish bone perforation of the GI tract in seven patients. To our knowledge, this series is the largest to date addressing the role of CT in the diagnosis of fish bone perforation. CONCLUSION Clinical presentation and radiography are unreliable in the preoperative diagnosis of fish bone perforation of the GI tract. This limitation can be overcome with the use of CT, which is accurate in showing the offending fish bone. The accuracy of CT is limited by observer dependence. A high index of suspicion should always be maintained for the correct diagnosis to be made.

MiR-214 Targets β-Catenin Pathway to Suppress Invasion, Stem-Like Traits and Recurrence of Human Hepatocellular Carcinoma

The down-regulation of miR-214 has previously been observed in human hepatocellular carcinoma (HCC). Here, we demonstrated the down-regulation of miR-214 is associated with cell invasion, stem-like traits and early recurrence of HCC. Firstly, we validated the suppression of miR-214 in human HCC by real-time quantitative RT-PCR (qRT-PCR) in 20 paired tumor and non-tumor liver tissues of HCC patients and 10 histologically normal liver tissues from colorectal cancer patients with liver metastases. Further qRT-PCR analysis of 50 HCC tissues from an independent cohort of HCC patients of whom 29 with early recurrent disease (<2 years) and 21 with late recurrent disease demonstrated that the suppression of miR-214 was significantly more suppressed in samples from HCC patients with early recurrent disease compared those from patients with no recurrence. Re-expression of miR-214 significantly suppressed the growth of HCC cells in vitro and reduced their tumorigenicity in vivo. The enhancer of zeste homologue 2 (EZH2) and β-catenin (CTNNB1) was identified as two potential direct downstream targets of miR-214 through bioinformatics analysis and experimentally validated the miRNA-target interactions with a dual-firefly luciferase reporter assay. In corroborate with this, both EZH2 and CTNNB1 are found to be significantly overexpressed in human HCC biopsies. Since EZH2 can regulate CTNNB1, CTNNB1 can also be an indirect target of miR-214 through EZH2. Silencing EZH2 or CTNNB1 expression suppressed the growth and invasion of HCC cells and induced E-cadherin (CDH1), known to inhibit cell invasion and metastasis. Furthermore, the silencing of miR-214 or overexpression of EZH2 increased EpCAM+ stem-like cells through the activation of CTNNB1. Interestingly, the up-regulation of EZH2, CTNNB1 and the down-regulation of CDH1 in HCC patients correlated with early recurrent disease and can be an independent predictor of poor survival. Therefore, miR-214 can directly or indirectly target CTNNB1 to modulate the β-catenin signaling pathway in HCC.