Aristolochic acid, a potent human carcinogen produced by Aristolochia plants, is associated with urothelial carcinoma of the upper urinary tract (UUC). Following metabolic activation, aristolochic acid reacts with DNA to form aristolactam (AL)-DNA adducts. These lesions concentrate in the renal cortex, where they serve as a sensitive and specific biomarker of exposure, and are found also in the urothelium, where they give rise to a unique mutational signature in the TP53 tumor-suppressor gene. Using AL-DNA adducts and TP53 mutation spectra as biomarkers, we conducted a molecular epidemiologic study of UUC in Taiwan, where the incidence of UUC is the highest reported anywhere in the world and where Aristolochia herbal remedies have been used extensively for many years. Our study involves 151 UUC patients, with 25 patients with renal cell carcinomas serving as a control group. The TP53 mutational signature in patients with UUC, dominated by otherwise rare A:T to T:A transversions, is identical to that observed in UUC associated with Balkan endemic nephropathy, an environmental disease. Prominent TP53 mutational hotspots include the adenine bases of 5′ AG (acceptor) splice sites located almost exclusively on the nontranscribed strand. A:T to T:A mutations also were detected at activating positions in the FGFR3 and HRAS oncogenes. AL-DNA adducts were present in the renal cortex of 83% of patients with A:T to T:A mutations in TP53, FGFR3, or HRAS. We conclude that exposure to aristolochic acid contributes significantly to the incidence of UUC in Taiwan, a finding with significant implications for global public health.upper urinary tract carcinoma | traditional Chinese medicine | transitional cell carcinoma | DNA damage | herbal medicine

Human platelets are anucleate blood cells that retain cytoplasmic mRNA and maintain functionally intact protein translational capabilities. We have adapted complementary techniques of microarray and serial analysis of gene expression (SAGE) for genetic profiling of highly purified human blood platelets. Microarray analysis using the Affymetrix HGU95Av2 approximately 12 600-probe set maximally identified the expression of 2147 (range, 13%-17%) platelet-expressed transcripts, with approximately 22% collectively involved in metabolism and receptor/signaling, and an overrepresentation of genes with unassigned function (32%). In contrast, a modified SAGE protocol using the Type IIS restriction enzyme

Purpose of review The proteome is the pool of proteins expressed at a given time and circumstance. The word “proteomics” summarizes several technologies for visualization, quantitation and identification of these proteins. Recent advances in these techniques are helping to elucidate platelet processes which are relevant to bleeding and clotting disorders, transfusion medicine and regulation of angiogenesis. Recent findings Over 1100 platelet proteins have been identified using proteomic techniques. Various subproteomes have been characterized, including platelet releasates (the “secretome”), alpha and dense granules, membrane and cytoskeletal proteins, platelet-derived microparticles, and the platelet “phosphoproteome”. Proteomic data about platelets have become increasingly available in integrated databases. Summary Proteomic experiments in resting and activated platelets have identified novel signaling pathways and secreted proteins which may represent therapeutic targets, as well as potential cancer biomarkers.

BackgroundIQGAP1 and IQGAP2 are homologous members of the IQGAP family of scaffold proteins. Accumulating evidence implicates IQGAPs in tumorigenesis. We recently reported that IQGAP2 deficiency leads to the development of hepatocellular carcinoma (HCC) in mice. In the current study we extend these findings, and investigate IQGAP1 and IQGAP2 expression in human HCC.MethodsIQGAP1 and IQGAP2 protein expression was assessed by Western blotting and immunohistochemistry. IQGAP mRNA was measured by quantitative RT-PCR. The methylation status of the Iqgap2 promoter was determined by pyrosequencing of bisulfite-treated genomic DNA.ResultsIQGAP1 and IQGAP2 expression was reciprocally altered in 6/6 liver cancer cell lines. Similarly, immunohistochemical staining of 82 HCC samples showed that IQGAP2 protein expression was reduced in 64/82 (78.0%), while IQGAP1 was present in 69/82 (84.1%). No IQGAP1 staining was detected in 23/28 (82.1%) normal livers, 4/4 (100.0%) hepatic adenomas and 23/23 (100.0%) cirrhosis cases, while IQGAP2 was increased in 22/28 (78.6%), 4/4 (100.0%) and 23/23 (100.0%), respectively. Although the Iqgap2 promoter was not hypermethylated in HCC at any of the 25 CpG sites studied (N = 17), IQGAP2 mRNA levels were significantly lower in HCC specimens (N = 23) than normal livers (N = 6).ConclusionsWe conclude that increased IQGAP1 and/or decreased IQGAP2 contribute to the pathogenesis of human HCC. Furthermore, downregulation of IQGAP2 in HCC occurs independently of hypermethylation of the Iqgap2 promoter. Immunostaining of IQGAP1 and IQGAP2 may aid in the diagnosis of HCC, and their pharmacologic modulation may represent a novel therapeutic strategy for the treatment of liver cancer.