Immunoexpression of cyclooxygenase-2 in primary gastric carcinomas and lymph node metastases

AIM: To evaluate immunoexpression of cyclooxygenase-2 (COX-2) in primary gastric carcinomas and respective lymph node metastases. METHODS: Immunohistochemistry to analyze COX-2 expression was performed on tissue microarray slices obtained from 36 specimens of gastrectomy and satellite lymph nodes from patients with gastric carcinoma. RESULTS: Immunostaining was seen in most cases, and COX-2 expression was higher in lymph node me-tastases than in corresponding primary gastric tumors of intestinal, diffuse and mixed carcinomas, with a statistically signif icant difference in the diffuse histotype (P = 0.0108). CONCLUSION: COX-2 immunoexpression occurs frequently in primary gastric carcinomas, but higher expression of this enzyme is observed in lymph node metastases of the diffuse histotype.

Identification of differential gene expressions in colorectal cancer and polyp by cDNA microarray

AIM： TO screen the differential expressed genes in colorectal cancer and polyp tissue samples. METHODS： Tissue specimens containing 16 cases of colorectal adenocarcinoma and colorectal polyp vs nor- mal mucosae were collected and subjected to cDNA microarray and bioinformatical analyses. Quantitative reverse transcription-polymerase chain reaction （qRT- PCR） was used to confirm some of the cDNA microarray data.RESULTS： The experimental data showed that eight genes were differentially expressed, most of which were upregulated in adenomatous polyp lesions. Forty-six genes expressions were altered in colorectal cancers, of which 29 were upregulated and 17 downregulated, as compared to the normal mucosae. In addition, 18 genes were similarly altered in both adenomatous polyps and colorectal cancer, qRT-PCR analyses confirmed the cDNA microarray data for four of those 18 genes： MTA1, PDCD4, TSC1 and PDGFRA. CONCLUSION： These differentially expressed genes likely represent biomarkers for early detection of co- Iorectal cancer and may be potential therapeutic targets after confirmed by further studies.

Correlation of chromosomal polysomy with overexpression of c-myc and c-erbB-2 in primary nasopharyngeal carcinoma: Tissue microarray study

Many genes may be involved in nasopharyn-geal carcinoma (NPC) development and progression. Several known oncogenes, including c-myc and c-erb-B2, have been shown to have structural alteration and aberrant expression in NPC. Here, we constructed a tissue microarray to deter-mine the status of c-myc and c-erbB-2 oncogenes at the DNA and protein levels using interphase fluorescence in situ hy-bridization (FISH) and immunohistochemistry (IHC) and to define the diagnostic, prognostic importance of the genetic changes. Results showed that amplification of c-myc and c-erbB-2 was not found in NPC. Polysemy 8 and 17 were observed in 43%-50% and 20%-27% of NPC tumors, respectively. Overexpressions of c-myc and c-erbB-2 onco-proteins were detected in 53.6% and 54.5% cases of NPC with polysomy 8 and 17, respectively. There was no signifi-cant correlation between c-myc and c-erbB-2 staining and the clinical stage. But overexpression of c-erbB-2 was associ-ated with polysemy 17 in NPC. These findings suggest that