Mucin-type O-glycosylation is initiated by a large family of UDP-GalNAc: polypeptide N-acetyl-galactosaminyltransferases (GalNAc-transferases). Individual GalNAc-transferases appear to have different functions and Northern analysis indicates that they are differently expressed in different organs. This suggests that O-glycosylation may vary with the repertoire of GalNAc-transferases expressed in a given cell. In order to study the repertoire of GalNAc-transferases in situ in tissues and changes in tumors, we have generated a panel of monoclonal antibodies (MAbs) with well defined specificity for human GalNAc-T1, -T2, and -T3. Application of this panel of novel antibodies revealed that GalNAc-transferases are differentially expressed in different cell lines, in spermatozoa, and in oral mucosa and carcinomas. For example, GalNAc-T1 and -T2 but not -T3 were highly expressed in WI38 cells, and GalNAc-T3 but not GalNAc-T1 or -T2 was expressed in spermatozoa. The expression patterns in normal oral mucosa were found to vary with cell differentiation, and for GalNAc-T2 and -T3 this was reflected in oral squamous cell carcinomas. The expression pattern of GalNAc-T1 was on the other hand changed in tumors to either total loss or expression in cytological poorly differentiated tumor cells, where the normal undifferentiated cells lacked expression. These results demonstrate that the repertoire of GalNActransferases is different in different cell types and vary with cellular differentiation, and malignant transformation. The implication of this is not yet fully understood, but it suggests that specific changes in sites of O-glycosylation of proteins may occur as a result of changes in the repertoire of GalNActransferases.
Aim: To define the clinical and histopathological characteristics of primary lacrimal sac lymphoma in a predominantly white population. Methods: Specimens of lacrimal sac lymphoma and follow up data were solicited from members of the Ophthalmic Oncology Task Force of the European Organization for Research and Treatment of Cancer (EORTC) and the European Ophthalmic Pathology Society (EOPS). Specimens were stained with haematoxylin and eosin and an immunohistochemical panel against leucocyte antigens was applied. Diagnosis was reached by consensus of five experienced pathologists according to the World Health Organization classification system. The histopathological findings were correlated with the clinical data. Results: Of 15 primary lacrimal sac lymphomas, five (33%) were diffuse large B cell lymphoma (DLBCL), five (33%) were extranodal marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT lymphoma), three were classified as ''transitional MALT lymphoma,'' being in transition from MALT lymphoma to DLBCL, and two were unclassified B cell lymphomas. Nine of the patients were female, and the median age at the time of diagnosis was 71 years (range 45-95 years). The most frequent presenting symptoms were epiphora (85%), swelling in the region of the lacrimal sac (79%), and dacryocystitis (21%). All but one patient presented in stage I. Systemic spread occurred in three of nine patients (33%). The 5 year overall survival was 65%. Conclusions: DLBCL and MALT lymphoma are equally common in the lacrimal sac in contrast with the remaining periorbital and/or orbital region where MALT lymphoma predominates.
The aim of this study was to evaluate the sentinel node biopsy (SNB) technique for melanoma using both radiocolloid and blue dye in 241 clinically N0 patients with melanomas >1.0 mm, or thinner lesions exhibiting regression/ulceration. We showed that an increase in injected radioactivity increased both the number of visualized nodes at lymphoscintigraphy and the number of SNs removed surgically. At least one SN was removed in 98% (236) of patients, and all nodes were identified with the probe. Seventy-four per cent of the 194 patients injected with blue dye had stained SNs. In 46% (144) of the lymph node basins, there was a discrepancy between the nodes visualized at lymphoscintigraphy and the nodes removed at surgery. There were 38 unusually located nodes. Only eight of these were removed surgically; none contained metastases. SN metastases were detected in 22% (53) of patients. There were nine haematoxylin and eosin (HE)-negatives, all of which were found by immunohistochemistry. The false negative rate for the SNB procedure was 4% (2/55). The complication rate was 6% after SNB and 29% after complete node dissection. In conclusion, SN status is a strong prognostic factor in melanoma patients, and SNB has made the approach to radical lymphadenectomy more rational.
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