Targeting angiogenesis inhibits tumor infiltration and expression of the pro-invasive protein SPARC

Expression of periostin and its clinicopathological relevance in gastric cancer

AIM: To investigate the expression and localization of periostin in gastric cancer and its clinical relevance.

METHODS: Reverse transcriptase polymerase chain reaction was used to measure periostin mRNA expression. Western blotting was carried out to detect periostin protein expression. Immunohistochemistry was performed to localize and quantify the expression of periostin in benign gastric diseases and gastric cancer, and immunostaining results were correlated with gastric cancer pathological stages.

RESULTS: Periostin expression was low at both mRNA and protein levels in normal gastric tissues, but was overexpressed in gastric cancer tissues. Immunohistochemical staining revealed that periostin was overexpressed in primary gastric cancer, as well as in metastatic lymph nodes, but only faint staining was found in benign gastric ulcers. By quantitative analysis of the immunostaining results, periostin expression was increased 2.5-4-fold in gastric cancer, compared to that in benign gastric disease, and there was a trend toward increasing periostin expression with tumor stage.

CONCLUSION: This observation demonstrated that periostin was overexpressed in gastric cancer and lymph node metastasis, which suggests that periostin plays an important role in the progression and metastasis of gastric cancer.

Analysis of gene expression profile of pancreatic carcinoma using cDNA microarray

AIM: To identify new diagnostic markers and drug targets, the gene expression profiles of pancreatic cancer were compared with that of adjacent normal tissues utilizing cDNA microarray analysis.

METHODS: cDNA probes were prepared by labeling mRNA from samples of six pancreatic carcinoma tissues with Cy5-dUTP and mRNA from adjacent normal tissues with Cy3-dUTP respectively through reverse transcription. The mixed probes of each sample were then hybridized with 12800 cDNA arrays (12648 unique human cDNA sequences), and the fluorescent signals were scanned by ScanArray 3000 scanner (General Scanning, Inc.). The values of Cy5-dUTP and Cy3-dUTP on each spot were analyzed and calculated by ImaGene 3.0 software (BioDiscovery, Inc.). Differentially expressed genes were screened according to the criterion that the absolute value of natural logarithm of the ratio of Cy5-dUTP to Cy3-dUTP was greater-than 0.69.

RESULTS: Among 6 samples investigated, 301 genes, which accounted for 2.38% of genes on the microarry slides, exhibited differentially expression at least in 5. There were 166 over-expressed genes including 136 having been registered in Genebank, and 135 under-expressed genes including 79 in Genebank in cancerous tissues.

CONCLUSION: Microarray analysis may provide invaluable information on disease pathology, progression, resistance to treatment, and response to cellular microenvironments of pancreatic carcinoma and ultimately may lead to improving early diagnosis and discovering innovative therapeutic approaches for cancer.