RABL6A Promotes Oxaliplatin Resistance in Tumor Cells and Is a New Marker of Survival for Resected Pancreatic Ductal Adenocarcinoma Patients.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by early recurrence following pancreatectomy, rapid progression, and chemoresistance. Novel prognostic and predictive biomarkers are urgently needed to both stratify patients for clinical trials and select patients for adjuvant therapy regimens. This study sought to determine the biological significance of RABL6A (RAB, member RAS oncogene family-like protein 6 isoform A), a novel pancreatic protein, in PDAC. Analyses of RABL6A protein expression in PDAC specimens from 73 patients who underwent pancreatic resection showed that RABL6A levels are altered in 74% of tumors relative to adjacent benign ductal epithelium. Undetectable RABL6A expression, found in 7% (5/73) of patients, correlated with improved overall survival (range 41 to 118 months with 3/5 patients still living), while patients with RABL6A expression had a worse outcome (range 3.3 to 100 months, median survival 20.3 months) (P = 0.0134). In agreement with those findings, RABL6A expression was increased in pancreatic cancer cell lines compared to normal pancreatic epithelial cells, and its knockdown inhibited pancreatic cancer cell proliferation and induced apoptosis. Moreover, RABL6A depletion selectively sensitized cells to oxaliplatin-induced arrest and death. This work reveals that RABL6A promotes the proliferation, survival, and oxaliplatin resistance of PDAC cells, whereas its loss is associated with extended survival in patients with resected PDAC. Such data suggest RABL6A is a novel biomarker of PDAC and potential target for anticancer therapy.

Recommendations for the reporting of surgically resected thymic epithelial tumors.

Thymic epithelial tumors include thymoma and thymic carcinoma. Histologic findings and extent of disease are key determinants of prognosis and help guide postoperative management in patients with thymic epithelial tumors. Given the relative rarity of these tumors, the use of tumor guidelines and checklists can facilitate accurate and comprehensive pathologic reporting in this setting. Diagnostic nomenclature (World Health Organization, Suster-Moran classifications) and staging criteria (modified Masaoka system) are emphasized.

Mandatory second opinion in cytopathology.

BACKGROUND: Mandatory review of outside pathologic material is intended to detect interpretive errors that may have a clinically significant impact on patient care. Prior to definitive treatment of referred patients, the University of Iowa Carver College of Medicine requires a review of pertinent pathologic material previously obtained at outside institutions. The aims of this study were to determine if this local standard of practice has a measurable impact on patient care. METHODS: The pathologic diagnoses of 499 second opinion cytology cases seen at the University of Iowa Carver College of Medicine were studied. Each second opinion was classified as "no diagnostic disagreement", "minor disagreement", or "major disagreement" with respect to the originating institution's interpretation. The clinical impact of major disagreement cases was determined by pathologic and clinical follow-up via chart review. RESULTS: Second opinion cytology resulted in 37 cases (7.4% of total cases) with major diagnostic disagreements. Clinical and pathologic follow-up was available in 30 of the major disagreement cases; second opinion diagnosis was better supported in 22 of these cases compared to the outside diagnosis. The second opinion in 6 major disagreement cases prompted changes in clinical management. CONCLUSIONS: Major disagreements in second opinion cytology are common, likely reflective of the challenges inherent in the interpretation of cytologic specimens. Although mandatory second opinion of outside cytologic material prompted changes in clinical management in only a small fraction of cases (1.2%), this rate was similar to those previously published for surgical pathology second opinion. These findings support the notion that mandatory second opinion policy as an important part of patient care.

Altered expression of iron regulatory genes in cirrhotic human livers: clues to the cause of hemosiderosis?

Hepatic iron deposition unrelated to hereditary hemochromatosis occurs commonly in cirrhosis but the pathogenesis of this condition is unknown. The aim of this study was to compare the expression of genes involved in the regulation of iron metabolism in cirrhotic (n=22) and control human livers (n=5). Transcripts were quantitated by real-time RT-PCR and protein levels were assessed by western blot. Hepatic iron concentrations (HICs) were measured by a spectrophotometric method. Levels of hepcidin mRNA did not differ between controls and cirrhotic livers; there was a highly significant correlation between hepcidin transcript levels and HIC in the latter group. Ferroportin, divalent metal transporter-1 (DMT1), and ferritin heavy chain mRNA levels were significantly higher in cirrhotic human livers than in controls (P=0.007, 0.039, and 0.025, respectively). By western blot, ferroportin and DMT1 levels were generally diminished in the cirrhotic livers compared to controls; neither correlated with HIC. In contrast, the abundance of ferritin increased with increasing HIC in the cirrhotic livers, whereas transferrin receptor decreased, indicating physiologically appropriate regulation. In conclusion, hepcidin expression appears to be appropriately responsive to iron status in cirrhosis. However, there are complex alterations in DMT1 and ferroportin expression in cirrhotic liver, including decreases in ferroportin and DMT1 at the protein level that may play a role in aberrant regulation of iron metabolism in cirrhosis.

Generation and characterization of monoclonal antibodies to NIAM: a nuclear interactor of ARF and Mdm2.

Nuclear interactor of ARF and Mdm2 (NIAM) is a newly discovered growth inhibitor that helps maintain chromosomal stability. It is functionally linked to the ARF-Mdm2-p53 tumor suppressor pathway and is predicted to be a tumor suppressor, but the lack of antibodies capable of detecting the endogenous human protein has delayed efforts to define its role in human tumorigenesis. This study reports the development, screening, and characterization of several monoclonal antibodies (MAbs) that specifically recognize endogenous human NIAM protein by Western blotting, immunoprecipitation, immunofluorescence, and immunohistochemistry. These MAbs are predicted to be important tools for evaluating the expression and physiological function of NIAM in normal versus neoplastic human cells and tissues.

Small peripheral pulmonary adenocarcinoma: morphologic and molecular update.

The dichotomous histopathologic separation of lung carcinoma into "small cell" and "nonsmall cell" categories is validated by marked clinical and biologic differences between these groups of tumors. However, nonsmall cell carcinoma represents a heterogenous group of tumors, and the subclassification of nonsmall cell lung carcinoma at the molecular, morphologic, and epidemiologic levels has led to the promise of precise treatment and better prognostication. Histomorphologic aspects of small peripheral adenocarcinomas that represent good prognosis include pure bronchioloalveolar carcinoma, minimal invasion within a mixed invasive and lepidic growth pattern tumor, and minimal scar within a lepidic growth pattern tumor. Activating mutations and increased gene copy number of the epidermal growth factor receptor protein and locus, respectively, have been shown to help predict responsiveness to small molecule receptor tyrosine kinase inhibitors in lung adenocarcinoma. These important concepts of morphology and molecular pathology are reviewed, and recommendations for application of these concepts to the practice of surgical pathology are provided.

Comparison of fungal culture versus surgical pathology examination in the detection of Histoplasma in surgically excised pulmonary granulomas.

CONTEXT: Granulomatous pulmonary nodules are common in areas endemic for Histoplasma infection, and may require surgical excision to exclude neoplasia. Surgeons may elect to routinely send material directly to the clinical microbiology laboratory for fungal and mycobacterial cultures. OBJECTIVE: To determine if tissue from surgically excised pulmonary granulomatous nodules removed from patients in a geographic area endemic for Histoplasma infection should be routinely submitted for fungal culture. DESIGN: Retrospective review and comparison of surgical pathology histochemical findings and clinical microbiology results of 30 surgical (wedge) lung excisions that demonstrated granulomatous nodule at the time of frozen section. RESULTS: Twenty cases demonstrated fungal organisms consistent with Histoplasma species via histochemical fungal stains. Of these 20 cases, 17 were tested in the microbiology laboratory using direct smear examination and fungal culture; Histoplasma was detected in 1 case (1/17). Eight cases revealed no organisms by surgical pathology. Of these, 6 were tested in the microbiology laboratory, and all 6 were negative by culture and direct smear (0/6). The remaining 2 cases demonstrated organisms other than Histoplasma by surgical pathology examination. CONCLUSIONS: Surgical pathology examination of granulomatous pulmonary nodules detected Histoplasma organisms with greater sensitivity than culture and direct smear. There were no false-negative surgical pathology diagnoses when compared with microbiological results. These findings suggest that it is not necessary to routinely send material from solitary pulmonary granulomas for fungal culture when the material is removed from immunocompetent patients in a geographic area endemic for histoplasmosis.

Immunohistochemical expression of osteopontin in epithelioid mesotheliomas and reactive mesothelial proliferations.

The morphologic distinction of epithelioid mesothelioma from a reactive mesothelial proliferation can be difficult. Recent studies have demonstrated that serum osteopontin levels are increased in patients with mesotheliomas. We sought to determine if osteopontin expression is diagnostically helpful in distinguishing epithelioid mesothelioma from reactive mesothelial proliferations. We studied 7 cases of epithelioid mesothelioma and 20 cases of reactive mesothelial proliferations by immunohistochemical analysis using standard technique. All 7 mesotheliomas and 19 of 20 reactive mesothelial proliferations showed osteopontin expression. Osteopontin expression is not restricted to malignant mesothelial proliferations, and immunohistochemical analysis for osteopontin is not helpful in determining reactive vs malignant mesothelial proliferations. The reported usefulness of osteopontin as a serum tumor marker for mesothelioma may be due to differences in the amount or character of secreted protein in malignant mesothelioma compared with reactive mesothelial proliferations.

Subinvolution of the placental site as an anatomic cause of postpartum uterine bleeding: a review.

CONTEXT: Subinvolution of the placental site is an anatomic cause of delayed postpartum uterine bleeding that may be underrecognized by general surgical pathologists. OBJECTIVE: To review the physiology of uteroplacental arterial development and normal postpartum involution, and to present the characteristic clinical and histopathologic features of subinvolution. DATA SOURCES: Literature review (MEDLINE via PubMed and Ovid) regarding the pathology and pathophysiology of placental site subinvolution. Review of the clinical and pathologic characteristics of our own institution's previously diagnosed cases of subinvolution from hysterectomy and endomyometrial curettage specimens. CONCLUSIONS: Surgical pathologists must be aware of the cardinal histopathologic findings of subinvolution, and this diagnosis must be considered in every postpartum curettage or hysterectomy specimen presented to the surgical pathologist. Subinvolution of the placental site is an important diagnosis, as this process implies an idiopathic cause, rather than an iatrogenic cause, of postpartum uterine bleeding. The etiology of placental site subinvolution remains poorly characterized.

A simple, focused, computerized query to detect overutilization of laboratory tests.

CONTEXT: Although there is nearly universal agreement that laboratory tests are overutilized, the degree of overutilization in a given institution is difficult to quantify and monitor across time. OBJECTIVE: To detect and clearly document repetitive daily ordering of a commonly ordered laboratory test (serum sodium) by employing a simple, focused, computerized query of a test result database followed by chart review and validation. DESIGN: A retrospective computerized query of our clinical data repository was performed to find inpatients who displayed normal serum sodium test results on 4 or more consecutive days, without any abnormal values during the same admission. The search was limited to a 1-month period. A subset of these patients was selected for chart review. RESULTS: One hundred sixteen patients met our criteria, and the tests ordered for those patients comprised 5.1% of the monthly volume of serum sodium tests ordered in our institution. Chart review revealed a consistent lack of documentation of medical necessity for repeat testing as well as persistence of repeat serum sodium orders until the end of the patients' hospital course. CONCLUSIONS: We conclude that a focused query of data derived from a clinical data repository can detect and document overutilization of a common laboratory test in a convincing fashion within a given institution.

A preliminary diagnosis service provides prospective blinded dual-review of all general surgical pathology cases in an academic practice.

Quality assurance of diagnostic accuracy in surgical pathology is an important part of a pathologist's total quality management program. At our academic institution, the quality of diagnostic accuracy is monitored via dual-review of every general surgical pathology case, which accounts for nearly 20,000 cases per year. This comprehensive dual-review is achieved by operating a preliminary diagnosis service, staffed by a senior or board eligible resident. Analysis of a portion of our dual-review data (6300 cases) demonstrates an overall diagnostic concordance rate of 95.4% and a clinical major discrepancy rate of 0.29% between the preliminary diagnosis and staff pathologist diagnosis, comparable to other published rates. The incorporation of a preliminary diagnosis service into our academic surgical pathology practice has proven to be beneficial with regard to quality assurance and resident education. Other academic institutions may similarly benefit from the addition of such a service.

Telomerase reverse transcriptase subunit expression is associated with chondrosarcoma malignancy.

Expression of the telomerase reverse transcriptase subunit telomerase reverse transcriptase gene is associated with most human malignancies. Because telomerase reverse transcriptase is rarely expressed in normal tissue, its presence in pathologic specimens is considered a marker of transformed cells. Moreover, high levels of expression have been correlated with poor prognosis in many cancers. Although telomerase activity has been found in chondrosarcomas, its prognostic significance in these malignant cartilage tumors is unknown. Malignancy in cartilage-derived tumors is assessed routinely by histomorphologic grading, but even well differentiated, low-grade lesions can metastasize. This unpredictable behavior greatly complicates the clinical treatment of cartilage tumors, making better prognostic indicators desirable. To address this issue we used immunohistochemistry to compare telomerase reverse transcriptase expression in a collection of 61 tumors consisting of malignant chondrosarcomas of varying grade and benign enchondromas. Associated case histories were reviewed to test the hypothesis that telomerase reverse transcriptase expression levels correlated with subsequent tumor recurrence. We found that the relative abundance of telomerase reverse transcriptase-expressing cells correlated significantly with grade and recurrence. These findings indicate that telomerase reverse transcriptase immunostaining may be a useful adjunct to the conventional three-level grading system.