Activating mutations in the BRAF kinase gene have recently been reported in human cancers. The aim of the present study was to determine the frequency of BRAF mutations in thyroid cancer and their correlation with clinicopathological parameters. We analyzed exons 11 and 15 of BRAF gene in six human thyroid cancer cell lines and 207 paraffin-embedded thyroid tumor tissues. A missense mutation was found at T1796A (V599E) in exon 15 in four of the six cell lines and 51 of 207 thyroid tumors (24.6%; 0 of 20 follicular adenoma, 0 of 11 follicular carcinoma, 49 of 170 papillary carcinomas, and 2 of 6 undifferentiated carcinomas). Activation of MAPK kinase-MAPK pathway was observed in cell lines harboring BRAF mutation. BRAF mutation-associated enhanced cell growth was suppressed by MAPK kinase inhibitor, U0126. Examination of 126 patients with papillary thyroid cancer showed that BRAF mutation correlated significantly with distant metastasis (P = 0.033) and clinical stage (P = 0.049). Our results indicate that activating mutation of BRAF gene could be a potentially useful marker of prognosis of patients with advanced thyroid cancers.

Despite advances in characterizing the pathophysiology and genetics of pituitary tumors, molecular mechanisms of their pathogenesis are poorly understood. Recently, we isolated a transforming gene [pituitary tumor-transforming gene (PTTG)] from rat pituitary tumor cells. Here we describe the cloning of human PTTG, which is located on chromosome 5q33 and shares striking sequence homology with its rat counterpart. Northern analysis revealed PTTG expression in normal adult testis, thymus, colon, small intestine, brain, lung, and fetal liver, but most abundant levels of PTTG mRNA were observed in several carcinoma cell lines. Stable transfection of NIH 3T3 cells with human PTTG cDNA caused anchorage-independent transformation in vitro and induced in vivo tumor formation when transfectants were injected into athymic mice. Overexpression of PTTG in transfected NIH 3T3 cells also stimulated expression and secretion of basic fibroblast growth factor, a human pituitary tumor growth-regulating factor. A proline-rich region, which contains two PXXP motifs for the SH3 domain-binding site, was detected in the PTTG protein sequence. When these proline residues were changed by site-directed mutagenesis, PTTG in vitro transforming and in vivo tumor-inducing activity, as well as stimulation of basic fibroblast growth factor, was abrogated. These results indicate that human PTTG, a novel oncogene, may function through SH3-mediated signal transduction pathways and activation of growth factor(s).

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(1) Mature miRNAs, ranging from 18 to 25 nucleotides in length, processed by two-step cleavage involving Drosha and Dicer are thought to negatively regulate messenger RNA (mRNA). The mature miRNA binds to target mRNA and induces its cleavage or translational repression depending on the degree of complementarity.(2) Although hundreds of miRNAs have been already cloned, only a small number of them have been characterized.Recently, several miRNAs have been reported to be involved in cell proliferation or apoptosis in various types of cancers. (3,4) MiR-15a and miR-16 induce apoptosis by targeting BCL2, and these miRNAs are frequently deleted or underexpressed in chronic lymphocytic leukemia.(5) Let-7 expression is reduced in lung cancer with poor prognosis, (6) and inversely correlates with expression of RAS protein, suggesting a possible mechanism for cancer cell proliferation.(7) Compared to these underexpressed miRNAs, miR-21 has an antiapoptotic function and is overexpressed in glioblastoma. Knockdown of miR-21 in glioblastoma cells induced caspase activation, resulting in apoptotic cell death.(8) Thus, miRNAs can act as both tumor suppressor and oncogene.The miR-17-92 cluster, composed of seven miRNAs (miR-17-5p, miR-17-3p, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92-1) and located in intron 3 of the C13orf25 gene, is overexpressed in lung cancer and B-cell lymphoma.(9,10) Enforced expression of truncated clusters comprising miR-17-5p~19b (miR-17-19b), the vertebrate-specific portion of the miR-17-92 cluster, accelerated tumor development in a mouse B-cell lymphoma model, suggesting oncogenic function of miR-17-19b. On the other hand, O'Donnell et al. have reported that expression of oncogenic E2F1 is negatively regulated by miR-17-5p and miR-20a, members of the cluster, implying that they act as a tumor suppressors.(11) Thus, the function of the cluster is still controversial.In thyroid cancer, overexpression of several miRNAs has been reported. He et al. have reported that three miRNAs (miR-221, miR-222, and miR-146) are overexpressed in papillary thyroid carcinomas (PTC) and regulate KIT expression.(12) Another group has also shown that miR-221, miR-222 and miR-181b are overexpressed in PTC, and inhibition of miR-221 by antisense oligonucleotides led to attenuation of cell growth.(13) In follicular thyroid cancers (FTC), miR-197 and miR-346 are significantly overexpressed. (14) In vitro overexpression of either miRNA induced cell proliferation, whereas inhibition led to growth arrest. Very recently, Visone et al. have reported that significant decrease in miR-30d, miR-125b, miR-26a, and miR-30a-5p was detected in human anaplastic thyroid cancers (ACT). (15) ATC are highly aggressive and fatal tumors with less than 8 months of mean survival after diagnosis.(16) Various treatment patterns including radiation and chemotherapy have been tried in ATC, but they are mostly unsuccessful.(17) Therefore, the identification of miRNAs involved in proliferation or apoptosis in ATC cells has important therapeutic imp...

To test the hypothesis that bacterial contamination of menstrual blood could be a local biologic event in the development of endometriosis, menstrual blood was cultured and bacterial endotoxin was measured in menstrual blood and peritoneal fluid. Our results suggest that compared with control women, higher colony formation of Escherichia coli in menstrual blood and endotoxin levels in menstrual fluid and peritoneal fluid in women with endometriosis may promote Toll-like receptor 4-mediated growth of endometriosis.