The diagnostic and prognostic utility of claudin expression in renal cell neoplasms.

This study evaluated the expression patterns of claudins 1, 3, 4, 7, and 8 in human renal cell carcinomas and oncocytomas and correlated expression with patient prognosis. Tissue microarrays were created from paraffin-embedded tissue samples from 141 patients with renal cell carcinomas or oncocytoma (90 clear cell, 22 papillary, 17 chromophobe renal cell carcinomas, and 12 oncocytomas). The staining pattern for claudins 3, 4, 7, and 8 was membranous and/or cytoplasmic, whereas claudin 1 was predominantly membranous in both nonneoplastic renal tissue and tumors. Negative to weak claudin 3 staining was predominantly detected in Fuhrman's grade 1 and 2 clear cell renal cell carcinomas (78%; P=0.016), suggesting that upregulation of claudin 3 potentially occurs concomitantly with increasing grade of clear cell renal cell carcinomas. In addition, Kaplan-Meier univariate analysis showed a significant inverse correlation between moderate to strong claudin 3 and 4 expression with overall survival in clear cell renal cell carcinomas (P=0.038 and P=0.031). Moderate to strong claudin 7 expression was significantly more common in chromophobe renal cell carcinomas (94%) than in oncocytomas (55%; P=0.041). Claudin 8 staining was moderate to strong in 92% of oncocytomas, which differentiated them from papillary and clear cell renal cell carcinomas (14 and 12%; both P<0.0001). Only negative to weak claudin 8 staining was detected in all chromophobe renal cell carcinomas, whereas there were no claudin 8 negative oncocytomas and 8% exhibited a weak staining pattern (P<0.0001). Due to their distinctive expression patterns, claudins 7 and 8 can be used as useful immunohistochemical markers for the separation of chromophobe renal cell carcinomas from oncocytomas, whereas claudins 3 and 4 may serve as indicators of prognosis in clear cell renal cell carcinomas.

Clinical validation of a next-generation sequencing screen for mutational hotspots in 46 cancer-related genes.

Transfer of next-generation sequencing technology to a Clinical Laboratory Improvement Amendments-certified laboratory requires vigorous validation. Herein, we validated a next-generation sequencing screen interrogating 740 mutational hotspots in 46 cancer-related genes using the Ion Torrent AmpliSeq cancer panel and Ion Torrent Personal Genome Machine (IT-PGM). Ten nanograms of FFPE DNA was used as template to amplify mutation hotspot regions of 46 genes in 70 solid tumor samples, including 22 archival specimens with known mutations and 48 specimens sequenced in parallel with alternate sequencing platforms. In the archival specimens, the IT-PGM detected expected nucleotide substitutions (n = 29) and four of six insertions/deletions; in parallel, 66 variants were detected. These variants, except a single nucleotide substitution, were confirmed by alternate platforms. Repeated sequencing of progressively diluted DNA from two cancer cell lines with known mutations demonstrated reliable sensitivity at 10% variant frequency for single nucleotide variants with high intrarun and inter-run reproducibility. Manual library preparation yielded relatively superior sequencing performance compared with the automated Ion Torrent OneTouch system. Overall, the IT-PGM platform with the ability to multiplex and simultaneously sequence multiple patient samples using low amounts of FFPE DNA was specific and sensitive for single nucleotide variant mutation analysis and can be incorporated easily into the clinical laboratory for routine testing.

Frequency and spectrum of BRAF mutations in a retrospective, single-institution study of 1112 cases of melanoma.

The US Food and Drug Administration (FDA) approved vemurafenib to treat patients with metastatic melanoma harboring the BRAF c.1799T>A (p.V600E) mutation. However, a subset of melanomas harbor non-p.V600E BRAF mutations, and these data are of potential importance regarding the efficacy of current targeted therapies. To better understand the BRAF mutation profile in melanomas, we retrospectively analyzed data from 1112 primary and metastatic melanomas at our institution. The cohort included nonacral cutaneous (n = 774), acral (n = 111), mucosal (n = 26), uveal (n = 23), leptomeningeal (n = 1), and metastatic melanomas of unknown primary site (n = 177). BRAF mutation hotspot regions in exons 11 and 15 were analyzed by pyrosequencing or with the primer extension MassARRAY system. A total of 499 (44.9%) specimens exhibited BRAF mutations, involving exon 15 [497 (99.6%)] or exon 11 [2 (0.4%)]. p.V600E was detected in 376 (75.4%) cases; the remaining 123 (24.6%) cases exhibited non-p.V600E mutations, of which p.V600K was most frequent [86 (17.2%)]. BRAF mutations were more frequent in nonacral cutaneous (51.4%) than acral melanomas [18 (16.2%)] (P < 0.001); however, there was no significant difference among cutaneous histological subtypes. All mucosal, uveal, and leptomeningeal melanomas were BRAF wild type (WT). The high frequency of non-p.V600E BRAF mutations in melanoma has important implications because the FDA-approved companion diagnostic test for p.V600E detects some but not all non-p.V600E mutations. However, the therapeutic efficacy of vemurafenib is not well established in these lesions.

Rapid detection and quantitation of BRAF mutations in hairy cell leukemia using a sensitive pyrosequencing assay.

BRAF protooncogene is an important mediator of cell proliferation and survival signals. BRAF p.V600E mutation was recently described as a molecular marker of hairy cell leukemia (HCL). We developed and validated a pyrosequencing-based approach that covers BRAF mutational hotspots in exons 11 (codon 468) and 15 (codons 595 to 600). The assay detects BRAF mutations at an analytical sensitivity of 5%. We screened 16 unenriched archived bone marrow aspirate samples from patients with a diagnosis of HCL (n = 12) and hairy cell leukemia-variant (HCL-v) (n = 4) using pyrosequencing. BRAF p.V600E mutation was present in all HCL cases and absent in all HCL-v. Our data support the recent finding that BRAF p.V600E mutation is universally present in HCL. Moreover, our pyrosequencing-based assay provides a convenient, rapid, sensitive, and quantitative tool for the detection of BRAF p.V600E mutations in HCL for clinical diagnostic testing.

Selected topics on lymphoid lesions in the head and neck regions.

Lymphoid tissue located in the head and neck region include multiple regional lymph node chains as well as mucosa associated lymphoid tissue of the conjunctiva, buccal and nasopharyngeal cavities (Waldeyer's ring), and thyroid and salivary glands. This region is a rich source of antigenic stimuli including infectious agents coming from the outside environment. Many reactive conditions that affect lymphoid tissue in this region may mimic neoplasia. In fact, distinguishing between benign and malignant lymphoid proliferations in the head and neck region is a relatively frequent diagnostic challenge and in many instances, this distinction is not straightforward. It therefore behooves the practicing pathologist to be able to recognize the benign lymphoproliferative disorders that affect this region so as to effectively guide the appropriate clinical management of such patients. Kimura disease, Epstein Barr lymphadenitis, HIV associated salivary gland disease and chronic sialadenitis are benign conditions that not infrequently affect lymphoid tissue in the head and neck region and that share certain overlapping features with malignant lymphoma. In this brief review, we discuss these conditions and highlight clinicopathological features that may help distinguish them from neoplastic lymphoproliferations that may share similar features.

Glioma-associated oncogene homologue 3, a hedgehog transcription factor, is highly expressed in Hodgkin and Reed-Sternberg cells of classical Hodgkin lymphoma.

The hedgehog signaling pathway has been shown to play a pathogenic role in diffuse large B-cell lymphoma and anaplastic large cell lymphoma, but has not been assessed in classical Hodgkin lymphoma. Glioma-associated oncogene homologues 1, 2, and 3 are transcriptional effectors of the hedgehog pathway. In this study, we first used real-time quantitative polymerase chain reaction to investigate the expressions of GLI1, GLI2, and GLI3 in 3 classical Hodgkin lymphoma cell lines. GLI1 and GLI2 were variably expressed, but GLI3 was highly expressed in all cell lines. We then used immunohistochemistry to assess glioma-associated oncogene homologues 1, 2, and 3 in 39 classical Hodgkin lymphoma patient samples. Glioma-associated oncogene homologues 1 and 2 were weakly to variably expressed in a subset of classical Hodgkin lymphoma patient samples. In contrast, glioma-associated oncogene homologue 3 showed strong, uniform nuclear expression in virtually all Hodgkin/Reed-Stenberg cells. We then performed an immunohistochemical survey of glioma-associated oncogene homologue 3 expression in 13 cases of nodular lymphocyte predominant Hodgkin lymphoma and 218 non-Hodgkin lymphomas. Most other lymphoma types showed variable or no expression of glioma-associated oncogene homologue 3, with a minor subset of cases of nodular lymphocyte predominant Hodgkin lymphoma, ALK-positive and ALK-negative anaplastic large cell lymphoma, and B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma showing a glioma-associated oncogene homologue 3 staining pattern indistinguishable from classical Hodgkin lymphoma. Our data provide a rationale to further investigate the biologic significance of glioma-associated oncogene homologue 3 in classical Hodgkin lymphoma biology.

Malakoplakia of the spleen: a case report.

Malakoplakia is an uncommon chronic inflammatory disorder, which is characterized by the presence of histiocytes containing concentric concretions known as Michaelis-Gutmann bodies in a background of mixed inflammation. The urinary tract is the most commonly involved site. However, malakoplakia can be found in a wide range of other organs throughout the body. Its occurrence has been attributed to a defect in the bactericidal capacity of phagocytic cells, and it is usually seen in patients with some degree of immunologic compromise. A case of malakoplakia of the spleen in a patient with Crohn's disease is reported in this article.

Renal sinus myelolipoma coexistent with renal pelvis papillary transitional cell carcinoma: a case report.

A unique case of renal sinus myelolipoma presenting as a mass coexistent with papillary transitional cell carcinoma is reported. The patient was a 64-year-old man with a history of bladder transitional cell carcinoma. He presented with gross hematuria and a filling defect in the renal pelvis on computed tomography scan. Pathological findings revealed an irregular myxoid fatty mass, in addition to high-grade papillary transitional cell carcinoma. The differential diagnosis included myxoid liposarcoma, myxoid variant of malignant fibrous histiocytoma (myxofibrosarcoma), and angiomyolipoma. Immunoperoxidase staining confirmed the presence of hematopoietic cells, whereas diagnostic histological and immunohistochemical features of liposarcoma, myxofibrosarcoma, and angiomyolipoma were absent. Myelolipoma and papillary transitional cell carcinoma appear to be unrelated coexistent entities in this case.

Comparison of thyroid transcription factor-1 expression by 2 monoclonal antibodies in pulmonary and nonpulmonary primary tumors.

Thyroid transcription factor-1 (TTF-1) is a transcription factor that plays a role in the development and physiology of the thyroid and lungs. Expression of TTF-1 is used as a marker of lung and thyroid clinically. Commercially available clones of TTF-1 monoclonal antibodies, 8G7G3/1 and SPT24, have been reported to have different sensitivities for the detection of neoplasms of different origins. Although they are used extensively in daily practice, a comprehensive comparative study of these antibodies in a wide variety of neoplasms is lacking. We examined TTF-1 expression in primary tumors of the lung, prostrate, pancreas, stomach, salivary glands, breast, bladder, colon, and squamous cell carcinoma of the head and neck and compared the results obtained with both TTF-1 clones. The SPT24 clone detected more primary lung tumors of all histologic subtypes. Importantly, the SPT24 clone detected a significantly higher number of squamous cell carcinomas and carcinoid tumors of the lung. Among nonpulmonary primary tumors, a significant number of invasive urothelial carcinoma of the bladder (5.1%) was TTF-1 positive. In addition, a small proportion of prostate (1.2%), stomach (0.9%), salivary gland (1.8%), and colon (2.5%) carcinomas were positive with both clones. Of note, both clones stained the same nonpulmonary tumors with similar intensity and distribution. Carcinomas of the pancreas, breast, and squamous cell carcinomas of the head and neck were negative with both clones. In summary, the SPT24 clone detected a higher number of pulmonary non-small cell tumors of all histologic subtypes whereas both clones stained a similar proportion of nonpulmonary tumors.

Hepatic adenomatosis.

Hepatic adenomatosis was first described in 1985 by Flejou et al as multiple adenomas, arbitrarily more than 10, in an otherwise normal liver parenchyma. Several authors have suggested that it is a distinct entity from hepatic adenoma, which is predominantly seen in young women taking oral contraceptives. Although considered a benign disease, it can be associated with potentially fatal complications such as malignant transformation and intraperitoneal hemorrhage due to rupture. Although its etiology and natural history have not been fully elucidated, germline mutation of hepatocyte nuclear factor 1alpha, which is associated with maturity-onset diabetes of the young type 3, has recently been implicated in a subset of cases. Currently, there is no consensus on patient management. However, surgical removal of large lesions may significantly improve symptoms and reduce the risk of complications. Genetic counseling may now play an important role in case management.