The data were analyzed using GEArray Expression Nilotinib msds Analysis software (Superarray). If spot intensity increased by more than two fold, this gene was deemed upregulated. In contrast, if spot intensity decreased by more than two fold, the gene was deemed downregulated. Statistical analysis All quantitative data were expressed as mean �� SD and analyzed using Student t-tests. The differential expression of GKN1 among different groups was determined by Kruskal-Wallis test. All statistical analyses were performed using the SPSS statistical software package (version 11.0, SPSS Inc. Chicago, USA). A P value of<0.05 was consi-dered statistically significant. Results Expression of GKN1 in cancer cell lines and gastric tissue specimens We first performed RT-PCR and immunoblot analysis to detect expression of GKN1 mRNA and protein levels in cancer cell lines and tissue specimens.

We found that GKN1 mRNA was weakly expressed in gastric cancer MKN 28 cells, and was absence in AGS, N87, MKN45, SNU16, SNU1, and KATO cells (Figure (Figure1A).1A). The GKN1 protein was also not detectable in any of the seven cell lines (Figure (Figure1A).1A). In contrast, GKN1 mRNA and protein were abundance in normal gastric epithelial cells that were obtained from healthy volunteers (Figure (Figure1B).1B). In 39 gastric cancer tissues, GKN1 mRNA was only weakly expressed in 3 tissues, and absence in the remaining 36 tissues. GKN1 protein was weakly expressed in 2 gastric cancer tissues, and absence in the remaining 37 tissues. However, GKN1 mRNA and protein were abundantly expressed in all of the 39 corresponding distant non-cancerous tissues (Figure (Figure11B).

Figure 1 Down regulation of GKN1 in gastric cancer cell lines and gastric tissue specimens. GKN1 RNA and protein were extracted from tumor cell lines and gastric tissue samples and then subjected to RT-PCR and Western blotting analysis. A: GKN1 expression in gastric … Next, we immunohistochemically stained GKN1 in the tissue sections of normal gastric mucosae (from healthy volunteers), atrophic gastritis, intestinal metaplasia, dysplasia, and gastric cancer and their corresponding distant non-cancerous mucosae. We found that the GKN1 protein was abundantly expressed in the upper glandular layer of the top one third superficial epithelium, while expression of GKN1 protein was progressively down regulated from normal gastric mucosa, atrophic gastritis, intestinal metaplasia and dysplasia, to gastric cancer (Table (Table2)2) (Figure (Figure2).

2). This reduction in expression was statistically significant (p<0.05). Table 2 GKN1 expression detected by immunohistochemistry in gastric tissues Figure 2 Immunohistochemical detection of GKN1 protein in gastric tissue specimens. Paraffin sections were immunostained with anti-GKN1 Dacomitinib antibody and reviewed for GKN1 levels.