Search results for "12E7 Antigen"
showing 7 items of 7 documents
Ectodomain shedding of CD99 within highly conserved regions is mediated by the metalloprotease meprin β and promotes transendothelial cell migration.
2016
The adhesion molecule CD99 is essential for the transendothelial migration of leukocytes. In this study, we used biochemical and cellular assays to show that CD99 undergoes ectodomain shedding by the metalloprotease meprin β and subsequent intramembrane proteolysis by γ-secretase. The cleavage site in CD99 was identified by mass spectrometry within an acidic region highly conserved through different vertebrate species. This finding fits perfectly to the unique cleavage specificity of meprin β with a strong preference for aspartate residues and suggests coevolution of protease and substrate. We hypothesized that limited CD99 cleavage by meprin β would alter cellular transendothelial migratio…
CD99 Immunoreactivity in Atypical Fibroxanthoma
2002
Atypical fibroxanthoma (AFX), a pleomorphic superficial cutaneous tumor of low-grade malignancy, shares many morphologic features with malignant melanoma (MM) and squamous cell carcinoma (SCC). Absence of S-100, keratin, and desmin immunoreactivity is the clue for this diagnosis. In a search for positive markers, we tested 26 cases of AFX with 2 antibodies: O13 (CD99) and protein gene product 9.5 (PGP9.5). We also included 10 cases of poorly differentiated SCC and 10 cases of MM in the study. In AFX, CD99 immunoreactivity was present in 19 cases (73%), whereas focal PGP9.5 immunoreactivity was found in only 9 cases (35%). None of the SCC cases showed CD99 immunostaining. No CD99 immunoreact…
Immunohistochemical Study as a Tool in Differential Diagnosis of Pediatric Malignant Rhabdoid Tumor
2010
Malignant rhabdoid tumors (MRTs) are aggressive childhood neoplasms, occurring mainly in the kidney and brain. We describe 2 unusual cases of extrarenal and noncranial location (liver and soft tissue with dissemination) mimicking hepatoblastoma, neuroblastoma or Ewing sarcoma. Both cases revealed a polyphenotypic profile, combined with cytokeratin, vimentin, and CD99 expression. INI1/BAF-47 showed negative protein nuclear expression in both cases, suggesting a diagnosis of MRT. An extensive immunohistochemical panel was performed to exclude pediatric tumors reminiscent of MRT. The genetic studies failed to detected MYCN amplification, 11q23 deletion, and EWS break-apart positivity. No alter…
Immunohistochemical detection of EWS and FLI-1 proteinss in Ewing sarcoma and primitive neuroectodermal tumors: comparative analysis with CD99 (MIC-2…
2001
The molecular analysis of the t(11;22) rearrangement involving EWS/FLI-1 genes is likely to be of diagnostic value in Ewing sarcoma (ES) and primitive neuroectodermal tumors (PNET). The objective of the current study was to analyze the immunohistochemical expression of the EWS and FLI-1 proteins in a group of small round-cell tumors (SRCT) to determine their specificity and relevance in their differential diagnosis. Forty-eight cases-10 conventional ES, 4 large-cell ES, 5 PNET, 9 neuroblastomas (NB), 6 undifferentiated synovial sarcomas (SS), 5 rhabdomyosarcomas (RB), 5 non-Hodgkin lymphomas (NHL), 1 round-cell liposarcoma, and 3 mesenchymal chondrosarcomas-were analyzed. Immunocytochemistr…
Clinicopathological and immunohistochemical analysis of 20 cases of Merkel cell carcinoma in search of prognostic markers.
2005
Aims: To evaluate the clinicopathological and immunohistochemical characteristics of Merkel cell carcinoma (MCC) in an attempt to find new, potentially significant, prognostic markers. Methods and results: Clinical data and follow-up, histopathological features (pattern, cell size, thickness, mitoses, vascular invasion, lymphocytic infiltration) and immunohistochemical detection [CK20, thyroid transcription factor (TTF-1), chromogranin A, synaptophysin, p53, Ki67, Fli-1, CD99, c-Kit] were evaluated in 20 cases of MCC. Fli-1 and CD99 were detected in 90% and 55% of cases, respectively. Tumour size > 30 mm, stage II, ‘absent’ lymphocytic infiltration, and the presence of > 50% of Ki67+ tumo…
Inhibin-α, CD99, HEA125, PLAP, and chromogranin immunoreactivity in testicular neoplasms and the androgen insensitivity syndrome
2000
We investigated 115 testicular and 3 epididymal tumors and 6 cases of the complete androgen insensitivity syndrome (AIS) for the expression of inhibin-alpha, CD99, HEA125, PLAP, and chromogranin, using monoclonal antibodies and standard immunhistochemical techniques. Ihibin-alpha was detected in the neoplastic cells in 27 of 27 primary Leydig cell tumors (LCTs), 1 of 1 metastatic LCT, 6 of 20 Sertoli cell tumors (SCTs), 4 of 5 juvenile granulosa cell tumors (GCTs), and 2 of 5 unclassified sex cord-stromal tumors (USCSTs). Except for 2 choriocarcinomas, the choriocarcinomatous component of 1 mixed germ cell tumor, and a small focus of inhibin-positive syncytiotrophoblast in 1 embryonal carci…
Quantification of the heterogeneity of prognostic cellular biomarkers in ewing sarcoma using automated image and random survival forest analysis
2014
Driven by genomic somatic variation, tumour tissues are typically heterogeneous, yet unbiased quantitative methods are rarely used to analyse heterogeneity at the protein level. Motivated by this problem, we developed automated image segmentation of images of multiple biomarkers in Ewing sarcoma to generate distributions of biomarkers between and within tumour cells. We further integrate high dimensional data with patient clinical outcomes utilising random survival forest (RSF) machine learning. Using material from cohorts of genetically diagnosed Ewing sarcoma with EWSR1 chromosomal translocations, confocal images of tissue microarrays were segmented with level sets and watershed algorithm…