GDP-L-Fuc:N-acetyl-␤-D-glucosaminide ␣136fucosyl-transferase (␣1-6FucT; EC 2.4.1.68), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a Triton X-100 extract of porcine brain microsomes. The purification procedures included sequential affinity chromatographies on GlcNAc␤1-2Man␣1-6(GlcNAc␤1-2Man␣1-2)-Man␤1-4GlcNAc␤1-4GlcNAc-Asn-Sepharose 4B and synthetic GDP-hexanolamine-Sepharose 4B columns. The enzyme was recovered in a 12% final yield with a 440,000-fold increase in specific activity. SDS-polyacrylamide gel electrophoresis of the purified enzyme gave a major band corresponding to an apparent molecular mass of 58 kDa. The ␣1-6FucT has 575 amino acids and no putative N-glycosylation sites. The cDNA was cloned in to pSVK3 and was then transiently transfected into COS-1 cells. ␣1-6FucT activity was found to be high in the transfected cells, as compared with non-or mocktransfected cells. Northern blotting analyses of rat adult tissues showed that ␣1-6FucT was highly expressed in brain. No sequence homology was found with other previously cloned fucosyltransferases, but the enzyme appears to be a type II transmembrane protein like the other glycosyltransferases.It has been reported that the structures of glycopeptides change during the development and differentiation of embryos (1-4). Detailed analysis of specific antigens on the surface of various carcinoma cells revealed that carcinoma-specific sugar chains are expressed on the cell surface. A well documented phenotypic alteration of these specific sugar chains is the increase in the molecular weight of cell surface complex type N-linked glycan in transformed cells. This change has been observed regardless of the nature of the transforming agent: oncogenic viruses (5-9), chemical mutagens (10 -11), or DNA from unrelated tumor cells (12)(13)(14). This phenomenon was thought to reflect the deviation of carcinoma cells from the ordinary differentiation processes. ␣-Fucose residue attached to asparagine-linked GlcNAc also have some relationship with carcinogenesis. A difference in the binding pattern of serum ␣-fetoprotein with lentil lectin between hepatocellular carcinomas and benign liver diseases has been reported (15-17). Analyses of the carbohydrate structure of ␣-fetoprotein from hepatocellular carcinoma cell lines have indicated that almost all of the carbohydrates of ␣-fetoprotein are ␣1-6-fucosylated (18). ␣-Fetoprotein produced by germ cell tumors, such as yolk sac tumors, is also highly fucosylated (19). The activity of ␣1-6FucT 1 was higher in hepatocellular carcinoma tissue than in non-tumor tissue (20) and was induced by the transfection of the ras protooncogene into 3T3 fibroblast cells (21). Schachter et al. (22,23) first characterized ␣1-6FucT in porcine liver using a partially purified enzyme extract. The special release of ␣1-6FucT from platelets during blood clotting has been reported (24, 25), alteration of fucosylation has been reported in cystic fibrosis glycoproteins from different s...

Microcystic stromal tumor (MCST) is a recently described subtype of ovarian tumor characterized by prominent microcystic histologic pattern and diffuse immunoreactivity for CD10 and vimentin. However, its pathobiology, particularly its histogenesis, remains largely unclear. Here, we report 2 cases of ovarian MCST, in which we have performed extensive histologic, immunohistochemical, and genetic investigations to determine its distinct nature among ovarian neoplasms. The patients were 32 and 41 years of age. Both tumors were solid and cystic masses involving the right ovary. Microscopically, tumor cells with generally bland, round-to-ovoid nuclei grew in microcystic, macrocystic, and solid patterns. Intervening thick fibrous stroma was observed. Immunohistochemically, tumor cells were diffusely and strongly positive for CD10, vimentin, and Wilms tumor 1. Furthermore, we detected aberrant nuclear expression of β-catenin protein in both cases. Of interest, mutation analyses revealed the presence of an identical point mutation, c.98C>G, in exon 3 of β-catenin (CTNNB1) in both tumors. This is an oncogenic mutation that causes replacement of serine with cysteine at codon 33, leading to the loss of a phosphorylation site in the β-catenin protein. The results of this study strongly suggest that dysregulation of the Wnt/β-catenin pathway plays a fundamental role in the pathogenesis of ovarian MCST. Finally, by comparing the immunophenotype of MCST with its histologic mimics and other ovarian sex cord-stromal tumors, we were able to identify unique features of MCST and a panel of markers useful in differential diagnosis.

Transcription factor ATF-2 is a nuclear target of stress-activated protein kinases, such as p38, which are activated by various extracellular stresses, including UV light. Here, we show that ATF-2 plays a critical role in hypoxia-and high-cell-density-induced apoptosis and the development of mammary tumors. Compared to wild-type cells, Atf-2 ؊/؊ mouse embryonic fibroblasts (MEFs) were more resistant to hypoxia-and anisomycininduced apoptosis but remained equally susceptible to other stresses, including UV. Atf-2 ؊/؊ and Atf-2MEFs could not express a group of genes, such as Gadd45␣, whose overexpression can induce apoptosis, in response to hypoxia. Atf-2 ؊/؊ MEFs also had a higher saturation density than wild-type cells and expressed lower levels of Maspin, the breast cancer tumor suppressor, which is also known to enhance cellular sensitivity to apoptotic stimuli. Atf-2 ؊/؊ MEFs underwent a lower degree of apoptosis at high cell density than wild-type cells. Atf-2 ؉/؊ mice were highly prone to mammary tumors that expressed reduced levels of Gadd45␣ and Maspin. The ATF-2 mRNA levels in human breast cancers were lower than those in normal breast tissue. Thus, ATF-2 acts as a tumor susceptibility gene of mammary tumors, at least partly, by activating a group of target genes, including Maspin and Gadd45␣.

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A total of 443 patients with lung cancer underwent brush and forceps biopsy through a fibreoptic bronchoscope. The biopsy was taken from the area of suspected malignancy which had been brushed.Of 443