The deubiquitination enzyme USP46 functions as a tumor suppressor by controlling PHLPP-dependent attenuation of Akt signaling in colon cancer.

PH domain leucine-rich-repeats protein phosphatase (PHLPP) is a family of Ser/Thr protein phosphatases that serve as tumor suppressors by negatively regulating Akt. Our recent studies have demonstrated that the ubiquitin proteasome pathway has an important role in the downregulation of PHLPP in colorectal cancer. In this study, we show that the deubiquitinase USP46 stabilizes the expression of both PHLPP isoforms by reducing the rate of PHLPP degradation. USP46 binds to PHLPP and directly removes the polyubiquitin chains from PHLPP in vitro and in cells. Increased USP46 expression correlates with decreased ubiquitination and upregulation of PHLPP proteins in colon cancer cells, whereas knockdown of USP46 has the opposite effect. Functionally, USP46-mediated stabilization of PHLPP and the subsequent inhibition of Akt result in a decrease in cell proliferation and tumorigenesis of colon cancer cells in vivo. Moreover, reduced USP46 protein level is found associated with poor PHLPP expression in colorectal cancer patient specimens. Taken together, these results indentify a tumor suppressor role of USP46 in promoting PHLPP expression and inhibiting Akt signaling in colon cancer.

Classification of probe-based confocal laser endomicroscopy findings in pancreaticobiliary strictures.

BACKGROUND AND STUDY AIMS: The accurate diagnosis of indeterminate pancreaticobiliary strictures presents a clinical dilemma. Probe-based confocal laser endomicroscopy (pCLE) offers real-time in vivo microscopic tissue examination that may increase sensitivity for the detection of malignancy. the objective of this study was to develop and validate a standard descriptive classification of pcle in the pancreaticobiliary system. PATIENTS AND METHODS: A total of 102 patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) with pCLE to assess indeterminate pancreaticobiliary strictures were enrolled in a multicenter registry; 89 of these patients were evaluable. Information and data on the following were collected prospectively: clinical, ERCP, tissue sampling, pCLE, and follow-up. A uniform classification of pCLE findings ("Miami Classification") was developed, consisting of a set of image interpretation criteria. Thereafter, these criteria were tested through blinded consensus review of 112 randomized pCLE videos from 47 patients, and inter-observer variability was assessed in 42 patients . RESULTS: A consensus definition of the specific criteria of biliary and pancreatic pCLE findings for indeterminate strictures was developed. Single-image interpretation criteria did not have a high enough sensitivity for predicting malignancy. However, combining two or more criteria significantly increased the sensitivity and predictive values. The characteristics most suggestive of malignancy included the following: thick white bands (>20 µm), or thick dark bands (>40 µm), or dark clumps or epithelial structures. These provided sensitivity, specificity, positive predictive value, and negative predictive value of 97%, 33%, 80%, and 80% compared with 48%, 100%, 100%, and 41% for standard tissue sampling methods. Inter-observer variability was moderate for most criteria. CONCLUSION: The Miami Classification enables a structured, uniform, and reproducible description of pancreaticobiliary pCLE. Combining individual characteristics improves the sensitivity for the detection of malignancy.

A multicenter U.S. experience with EUS-guided fine-needle aspiration using the Olympus GF-UM30P echoendoscope: safety and effectiveness.

BACKGROUND: The aim of this study was to determine the safety, efficacy, and accuracy of endoscopic ultrasound (EUS)-guided fine-needle aspiration using the GF-UM30P echoendoscope. METHODS: GF-UM30P-guided EUS-guided fine-needle aspiration results from 3 EUS referral centers were prospectively recorded. Successful sampling required that the needle tip be seen within the lesion on at least 1 pass. Aspirates were considered adequate if they were diagnostic for cancer, contained suspicious or atypical cells, or were adequately cellular for interpretation but nondiagnostic. RESULTS: EUS-guided fine-needle aspiration was attempted on 162 lesions in 152 patients with no complications. Sampling was successful in 150 of 162 (93%) attempts (mean lesion size 2.5 +/- 1.2 cm (range 0.7 to 6.0 cm). Aspirates were adequately cellular in 138 of 162 (85%) attempts (43% diagnostic, 15% suspicious and/or atypical cells, 27% adequate cellularity but nondiagnostic). Sampling failed in 12 of 162 (7%) attempts. Ten of 12 (83%) failures and 11 of 12 (92%) inadequate aspirates occurred when lesions measured less than 2 cm. The sensitivity for malignancy was 93% if only successfully sampled lesions with surgically confirmed negative results were included. However, it was 68% if all attempts were included and when unconfirmed high/moderate suspicion negative results were counted as false negatives and low suspicion negative results as true negatives. CONCLUSIONS: The GF-UM30P may be clinically useful for EUS-guided fine-needle aspiration if a curved linear array instrument is unavailable.

The role of endosonography in the diagnosis and management of pancreatic cancer.

Among the various diagnostic tests that may be used to detect and stage pancreatic cancer, endoscopic ultrasound (EUS) is among the most promising. It is a highly sensitive test for detecting pancreatic tumors and for detecting the invasion of these tumors into the portal venous system or loco-regional lymph nodes. With the development of EUS-guided fine-needle puncture, tissue diagnosis of imaged lesions is now possible. This latest advance has improved the specificity and overall accuracy of EUS and also allows for the development of therapeutic applications, such as celiac plexus neurolysis. In this article we review the materials, methods, and clinical applications of EUS for the evaluation of pancreatic cancer.

Combined magnification endoscopy with chromoendoscopy in the evaluation of patients with suspected malabsorption.

BACKGROUND: Magnification endoscopy and chromoendoscopy together have been used to evaluate mucosal detail in a number of conditions, including Barrett's esophagus and flat colonic polyps, but they have not been used to evaluate villous atrophy in the proximal small intestine. METHODS: Thirty-four patients suspected of having a malabsorption syndrome (either celiac disease or tropical sprue) were evaluated using an Olympus magnification gastroscope in both normal and high magnification settings. Indigo carmine dye spraying techniques were used to assist in evaluating duodenal mucosa for evidence of villous atrophy. The accuracy of endoscopically predicted villous atrophy was assessed by histologic evaluation of biopsy specimens taken in the descending duodenum. RESULTS: Magnification endoscopy with dye spraying was both highly sensitive (94%) and specific (88%) in identifying patients with villous atrophy. This technique was more accurate (91%) in identifying patients with partial atrophy than standard endoscopy (9%, p < 0.01) and was also useful in identifying patients with patchy villous atrophy (5 of 5) to allow directed biopsies of abnormal tissue. CONCLUSION: Magnification endoscopy with chromoendoscopy is a promising technique for the evaluation of patients with suspected malabsorption. This technique is especially valuable in patients with partial atrophy, where villous abnormalities can be patchy and the duodenum usually appears normal during standard endoscopy.

Biliary stent replacement cytology.

Using fluoroscopic guidance, polyethylene biliary stents are replaced endoscopically or percutaneously when bile duct stenosis recurs. To improve the sensitivity of conventional biliary cytology, we examined cells recovered from removed stents. Biliary stents removed endoscopically from each of 11 patients were rinsed with saline; next, the rinse was centrifuged and the sediment smeared and Papanicolaou stained. Three patients with choledocholithiasis had biliary stent replacement cytology (BSRC) to exclude a neoplastic etiology. Eight patients with clinicoradiologic evidence of hepatobiliary or pancreatic carcinoma had BSRCs performed for pathologic documentation of carcinoma. BSRC from six of eight patients with clinicoradiologically malignant biliary strictures contained malignant cells, predominantly in loose clusters, but also singly (sensitivity 75%, specificity 100%; positive predictive value 75%, negative predicative value 60%). Reparative epithelial atypia was also present in all cases. BSRC from two patients with clinicoradiological evidence of carcinoma of the biliary region and from three with choledocholithiasis contained only bile pigment, leukocytes, and benign epithelial cells. The sampling of cells which have accumulated on, or in biliary stents, improves the sensitivity of biliary cytology. This is most applicable when 1) a patient is inoperable, 2) tissue biopsy is neither feasible nor diagnostic, 3) prior brush, suction, percutaneous, or endoscopic needle aspiration cytology is inconclusive, and 4) permanent metal stent is needed.

Prospective multicenter trial of esophageal Z-stent placement for malignant dysphagia and tracheoesophageal fistula.

BACKGROUND: Conventional esophageal prosthesis placement has been associated with a 6% to 8% perforation rate and numerous postplacement complications. Expandable esophageal stents have been developed to preclude the above but there are few studies that have prospectively defined clinical results and subsequent stent-related complications. METHODS: All patients who underwent esophageal Z-stent placement at nine university or referral hospitals were prospectively assessed. Data collected included patient demographics, acute and subacute placement problems, the ability to occlude airway fistulas, prestent and poststent dysphagia scores, and patient survival. RESULTS: Fifty-four of 56 patients (96%) with refractory dysphagia or malignant esophagoairway fistulae had 73 Z-stents successfully inserted. Initial distal deployment occurred in 13% of the patients and an additional 17% required balloon dilation to achieve maximal diameter. Acute placement complications occurred in 11% of patients and included severe pain (3), bleeding from necrotic tumor (2), and hiatal hernia intussusception (1). No perforations occurred. Eight of 11 patients (73%) had complete tracheoesophageal fistula occlusion and mean dysphagia score (+/- SD) improved from 2.6 (0.7) to 1.1 (1.2) (p < 0.01). Fifteen stents (27%) had delayed migration at a mean of 1 month and 3 required surgery for retrieval. Three patients had ultimate stent erosion resulting in bleeding in 2 (exsanguination 1) or fistula (treated with a conventional stent). CONCLUSIONS: The authors conclude that esophageal Z-stents can be placed safely and successfully in the majority of patients. The tendency of distal deployment during placement and subsequent migration problems at a time distant from placement in a patient subset deserve attention and are currently being addressed.

Increased expression of the cyclin D1 gene in Barrett's esophagus.

Previous studies have found a 3-10-fold amplification and overexpression of the cyclin D1 gene in about 32% of human esophageal squamous cell carcinoma. The purpose of this study was to evaluate the prevalence of increased expression of the cyclin D1 protein in Barrett's esophagus. Using 69 formalin-fixed and paraffin-embedded human esophageal specimens, which had been removed endoscopically or obtained at surgery during 1993 and 1994, all immunohistochemical analyses were performed using an avidin-biotin complex immunoperoxidase technique. Increased nuclear expression of the cyclin D1 protein was noted in 32 of 69 samples (46%; 44% of the samples from males and 50% of the samples from females). Positive nuclear staining for the cyclin D1 protein in Barrett's disease with intestinal metaplasia was found in 38% of the male cases and 25% of the female cases, whereas in gastric metaplasia it was positive in 33% of men and 48% of women. Nuclear accumulation of the cyclin D1 protein was also found in both dysplastic and nondysplastic lesions, and it was not associated with sex, age, or cigarette or alcohol consumption. Samples from patients taking proton pump inhibitors tended to be less frequently positive (32%) for cyclin D1 nuclear staining when compared to patients taking H2 antagonists (45%) or antacids (55%). These studies suggest that increased expression of cyclin D1 is an early event in the tumorigenic process of esophageal adenocarcinomas and that the increased expression of this gene might predispose the epithelium to malignant transformation.

Rothmund-Thomson syndrome associated with annular pancreas and duodenal stenosis: a case report.

The Rothmund-Thomson syndrome is a rare autosomal recessive condition. It is primarily a clinical diagnosis with manifestations that include poikiloderma, short stature, sparse hair, juvenile cataracts, small hands and feet, bone defects, photosensitivity, hypogonadism, defective dentition, onychodystrophy, and hyperkeratosis. There is only one published case of associated gastrointestinal abnormalities. We report a patient with Rothmund-Thomson syndrome with annular pancreas and duodenal stenosis.

Hb Leslie, an unstable hemoglobin due to deletion of glutaminyl residue beta 131 (H9) occurring in association with beta0-thalassemia, HbC, and HbS.

A new unstable hemoglobin, Hb Leslie, has been observed in three generations of a Georgia family. The propositus, a 42-yr-old black veteran with hemolytic anemia and splenomegaly, has a hemoglobin variant with an electrophoretic mobility similar to that of hemoglobin F. The variant comprises about 85% of the total hemoglobin and was isolated by chromatography. Chemical analysis has identified the abnormality as a deletion of the glutaminyl residue in position 131 (H9) of the beta-chain. Deletion of this critical residue which participates in the alpha1beta1 contact causes decreased stability of the hemoglobin without significant changes in functional properties or morphologic abnormalities in the erythrocyte. Family studies revealed hemoglobin Leslie occurring in combination with beta0-thalassemia, HbS, and HbC. All persons with the various Hb Leslie combinations, including the propositus, have no clinical manifestations other than anemia. In some the anemia is fully compensated. There is no history of drug-associated hemolysis.

Hemoglobin Fort Gordon or alpha2beta2145 Tyr replaced by Asp, a new high-oxygen-affinity hemoglobin variant.

Hemoglobin Fort Gordon, alpha2beta2145 Tyr replaced by Asp (HC2), has been observed in a 20-year-old black male with compensatory erythrocytosis. The variant was readily identified by electrophoresis and chromatography, and comprised about 30% of the red cell hemoglobin. The substitution was identified through analyses of tryptic peptides of various digests of the isolated beta chain. The oxygen affinity of whole blood was increased; two components were observed one of which had a greatly increased affinity for oxygen and a markedly reduced subunit cooperativity. It appears that the Tyr replaced by Asp substitution resembles the Tyr replaced by His substitution in hemoglobin Bethesda (Bunn, H. F. et al. (1972) J. Clin. Invest. 51, 2299-2309; Olson, J. S. and Gibson, G. H. (1972) J Biol. Chem. 247, 3662-3670; Adamson et al. (1972) J. Clin. Invest. 51, 2883-2888) in that both inhibit the quarternary change of the oxy to the deoxy conformation, resulting in greatly altered functional properties. Studies of a few members of the family were negative.