Differential Expression of SPARC in Intestinal-type Gastric Cancer Correlates with Tumor Progression and Nodal Spread

Abstract

AIMS: Nodal spread is the single most important prognostic factor of survival in gastric cancer patients. In this study, genes that were upregulated in the lymph node metastases of gastric cancer were identified and may serve as putative novel therapeutic target. METHODS: Complementary DNA (cDNA) microarray analysis and quantitative real-time polymerase chain reaction of primary gastric carcinomas and matched lymph node metastasis were carried out. Immunohistochemistry with anti-SPARC antibodies was performed on large tissue sections of 40 cases with primary gastric carcinoma (20 diffuse, 20 intestinal) and the corresponding lymph node metastases, as well as on tissue microarrays of 152 gastric cancer cases. RESULTS: A cDNA microarray identified SPARC as being upregulated in primary gastric carcinoma tissue and the corresponding lymph node metastasis compared with the nonneoplastic mucosa. SPARC was expressed in fibroblasts and, occasionally, in tumor cells. However, the level of immunoreactivity was particularly strong in stromal cells surrounding the tumor. The level of expression of SPARC, determined by immunohistochemistry, correlated in intestinal-type gastric cancer with the local tumor growth, nodal spread, and tumor stage according to the International Union Against Cancer. CONCLUSIONS: Our study provides transcriptional and translational evidence for the differential expression of SPARC in gastric cancer tissue. On the basis of our observations and those made by others, we hypothesize that SPARC is a promising novel target for the treatment of gastric cancer.