Biomedical subjects

Tae Ho Hwang

Publications and source records attributed to Tae Ho Hwang.

5 recordsLinked to original sources

PubMed2005

Expression of double-stranded RNA-activated protein kinase in small-size peripheral adenocarcinoma of the lung.

The authors investigated the protein expression of double-stranded RNA-activated protein kinase (PKR), which was identified by using a previous cDNA microarray study, to discover PKR's correlations with several pathological parameters and to elucidate its role in neoplastic transformation and progression of lung adenocarcinomas. Immunohistochemistry for PKR was performed and a semiquantitative scoring method was calculated based on staining intensity and percentage of immunoreactive tumor cells (high vs low) for one bronchioloalveolar carcinoma (BAC), 16 adenocarcinomas consisting of BAC and invasive carcinoma (mixed) and 21 invasive adenocarcinomas without BAC (invasive). The BAC had high-grade expression and the mixed type tended to more frequently show high-grade expression than the invasive type (P = 0.028). There were no significant associations with age, tumor size, lymph node metastasis, lymphovascular invasion or the pathological stage. The Kaplan-Meier survival curves demonstrated that the patients with high-grade PKR expression had significantly shorter survival periods than those patients with low-grade PKR expression (P = 0.018). These results do not support the concept of PKR as a tumor suppressor in small-size peripheral adenocarcinomas of the lung.

Adenocarcinoma↗

PubMed2005

Vaccinia virus and oncolytic virotherapy of cancer.

Vaccinia viruses possess many of the key attributes necessary for an ideal viral backbone for use in oncolytic virotherapy. These include a short lifecycle, with rapid cell-to-cell spread. strong lytic ability, a large cloning capacity and well-defined molecular biology. In addition, although capable of replicating in human cells, they are not considered a natural health problem and are especially well characterized. having been delivered to millions of individuals during the campaign to eradicate smallpox. A variety of tumor-targeting mutations have been described in several different vaccinia strains and the expression of a variety of different transgenes has been studied. Early clinical results using either vaccine strains or genetically modified vaccinia strains have demonstrated antitumor effects. Future prospects for the development of these viruses will be discussed.

Antineoplastic Agents↗

PubMed2004

Gene expression profiling of breast cancers with emphasis of beta-catenin regulation.

To gain molecular understanding of carcinogenesis of breast cancer, gene expression profiles were analyzed using cDNA microarray representing 4,600 cDNAs in 10 breast cancer samples and the adjacent noncancerous breast tissues from the same patients. The alterations in gene expression levels were confirmed by reversetranscription PCR in four randomly selected genes. Genes that were differently expressed in cancer and noncancerous tissues were identified. 106 (of which 55 were known) and 49 (of which 28 were known) genes were up- or down-regulated, respectively, in greater than 60% of the breast cancer samples. In cancer tissues, genes related to cell cycle, transcription, metabolism, cell structure/motility and signal transduction were mostly up-regulated. Furthermore, three cancer tissues showing immunohistochemically aberrant accumulation of beta-catenin in the nucleus and/or cytoplasm revealed down-regulation of Siah and Axin genes and up-regulation of Wnt and c-myc genes. These findings were highly consistent with Wnt signaling pathway associated with beta-catenin regulation previously suggested by others. Our studies, therefore, provide not only a molecular basis to understand biological processes of breast cancer but also useful resources to define the mechanism of beta-catenin expression in tumorigenesis of breast cancer.

Adult↗

PubMed2003

A gene expression in study human gastric adenocarcinoma using a cDNA microarray.

BACKGROUND/AIMS: cDNA microarray provides a powerful alternative with an unprecedented view scope in monitoring gene expression levels and leads to discoveries of regulatory pathways involved in complicated biological processes. Our aim was to explore the different gene expression patterns in early and advanced gastric cancer. METHODS: By using a cDNA microarray representing 4,608 cDNA clusters, we studied the expression profiling in 10 paired gastric adenocarcinoma samples and the adjacent noncancerous gastric tissues. The alterations in gene expression levels were confirmed by Northern blot and reverse-transcription (RT) PCR. RESULTS: Genes that were differently expressed in cancer and noncancerous tissues were identified. Forty-four and 92 (26 and 43 of them were known, respectively) genes or cDNA were up- and down-regulated, respectively, in more than 80% of gastric adenocarcinoma samples. The semi-quantitative RT-PCR results were consistent with the microarray findings. To distinguish between early and advanced gastric cancers, we used a supervised learning classification approach. When we used 16 and 20 genes as predictors, the prediction was all yielded statistically significant. Moreover, when we used 9 genes, we could predict with the highest accuracy. CONCLUSIONS: These results may provide not only a new molecular basis for understanding biological properties of gastric adenocarcinoma, but also useful resources for future development of therapeutic targets and diagnostic markers for gastric adenocarcinoma.

Adenocarcinoma↗

PubMed2002

Potential role of Homer-2a on cutaneous vascular anomaly.

Homer protein was identified based on its rapid induction in rat hippocampal granule cell neurons following excitatory synaptic activity. Although the presence of the Homer gene in the peripheral tissues has been observed in previous reports, the physiological function of the Homer protein in these tissues has not been noted. In this experiment, a Homer-2a cDNA fragment was successfully amplified by RTPCR in the involuting phase of human hemangioma but not in the human vascular malformation and normal vessel. After isolation of full Homer cDNA in a mouse liver cDNA library, E1-deleted recombinant adenovirus expressing the Homer protein (Adv.CMV.mHomer-2a) was constructed to determine its physiological function in peripheral tissues. Adv.CMV.mHomer2a, but not Adv.CMV.LacZ (recombinant adenovirus expressing Beta-galactosidase), strongly inhibited the growth rate of HUVECs (human umbilical vein endothelial cells) probably via inducing apoptosis determined by acridine orange/ethidium bromide (AO/EB) staining methods. This study suggests that the Homer gene is present in human specimens in the involuting phase of hemangioma, and it might be involved in the growth control.

Adolescent↗