7078

TIMP3

HSMRK222|K222|K222TA2|SFD;TIMP metallopeptidase inhibitor 3;TIMP3;TIMP metallopeptidase inhibitor 3

MIG-5 protein|TIMP-3|metalloproteinase inhibitor 3|protein MIG-5|tissue inhibitor of metalloproteinases 3

22q12.1-q13.2|22q12.3

protein-coding

BACKGROUND: Osteosarcoma is the most common solid malignant diseases of childhood, occurring in approximately 6 children per million annually; however, to the authors' knowledge to date, the cause of osteosarcoma has remained mostlyunknown. Genetic alterations of genes that are specific for osteosarcoma have not been identified. Genetic alternations in the status of DNA methylation, known asepigenetic alterations, are the most common molecular alterations in human neoplasia. Aberrant methylation in the promoter region of tumor-related genes isassociated closely with epigenetically mediated gene silencing, which is a common feature in human tumors. METHODS: The authors analyzed CpG islands of 5 different gene loci for aberrant methylation profiles in 30 pairs of osteosarcoma and corresponding normal tissues by using the quantitative methylation-specific polymerase chain reaction method. The objectives of this study were to characterize the methylation changes in osteosarcoma more extensively and to identify epigenetic biomarkers that may be useful in the diagnosis and prevention of osteosarcoma. RESULTS: For the Ras effector homologue (RASSF1A), tissue inhibitor of metalloproteinase 3 (TIMP3), O-6-methylguanine DNA methyltransferase (MGMT), and death-associated protein kinase 1 (DAPK1) genes, significant differences were observed in the degree of hypermethylation between tumors and normal tissues (P < 0.01 and P < 0.001, respectively). Measurement of the cumulative multiple promoter hypermethylation revealed striking differences between tumor specimens and normal tissues (t = 7.31; P < .001). There also was a significant difference in the levels of DNA methylation between the metastatic and nonmetastatic high-grade osteosarcomas (t = 4.57; P < .01). In addition, themethylation levels were associated closely with gender (t = 6.44; P < .001). CONCLUSIONS: The results indicated that tumor tissues from patients with osteosarcoma had a significantly higher incidence of hypermethylation for several genes compared with corresponding normal tissues. The epigenetic changes observed in this study may have prognostic importance for patients with osteosarcoma.#CI- Copyright 2006 American cancer Society.

PURPOSE: The aim of present study was to investigate the methylation and expression status of spleen tyrosine kinase (SYK) in human hepatocellular carcinoma (HCC) and to evaluate this information for its ability to predict disease prognosis. E-cadherin and TIMP-3 methylation was also analyzed here as control because both were associated with poor prognosis in some types of tumors. EXPERIMENTAL DESIGN: We analyzed the methylation status of SYK, E-cadherin, and TIMP-3 in 124 cases of HCC and assessed the correlation of such methylations with clinicopathologic variables and prognosis after tumor resection. RESULTS: We found that SYK, E-cadherin, and TIMP-3 genes were methylated in 27%, 27%, and 42% of HCC neoplastic tissues, respectively. The loss of SYK mRNA or Syk protein expression was highly correlated with SYK gene methylation. The patients with methylated SYK in neoplastic tissues had a significantly lower overall survival rate after hepatectomy than those with unmethylated SYK. No significant difference in overall survival rates, however, was found between groups of patients with methylated and unmethylated E-cadherin or TIMP-3. Patients with negative Syk protein expression had a significantly lower overall survival rate than those with positive Syk protein expression. Multivariate analyses indicatedthat factors affecting overall survival were tumor-node-metastasis stage, child-Pugh classification, SYK methylation, or Syk protein status. CONCLUSIONS: Our results indicate that SYK methylation and loss of Syk expression in HCC neoplastic tissues are independent biomarkers of poor patient outcome and that determination of SYK methylation or Syk expression status may offer guidance forselecting appropriate treatments.