Cancer of the papilla of Vater (CPV) has a significantly better outcome compared to
pancreatic cancer (PC) after curative resection. Increasing evidence suggests that prognostic differences are influenced by a different
tumor biology. Secreted
protein acidic and rich in cystein (SPARC)/
osteonectin is a multifunctional matricellular
protein involved in cell-matrix interactions and might be involved in
tumor pathogenesis and progression. We examined quantitative SPARC
mRNA expression in CPV and PC to evaluate if varying expression might contribute to the different
biologic behaviour of these entities. Quantitative real-time reverse transcription-PCR was performed to analyze expression of SPARC
mRNA in a series of 31 PC and 8 CPV specimens and corresponding uninvolved pancreatic tissues. Relative
mRNA levels (ratio
tumor/normal) were calculated as (SPARC/
beta-actin in
tumor)/(SPARC/
beta-actin in paired normal tissue). SPARC expression levels were associated with clinical and histopathological parameters. SPARC
mRNA expression was detected in all
tumor and normal tissues of the pancreas and papilla of Vater. In
pancreatic cancer, 15/31 (48.4%) patients showed overexpression of SPARC (ratio
tumor/normal >1) whereas in CPV only 1/8 (12.5%) exhibited SPARC overexpression and this difference was statistically significant (p<0.05, Mann-Whitney test). No associations were detected with T- and N-categories, grading or prognosis. In conclusion, SPARC
mRNA overexpression is significantly more frequent in CP than CPV and adds further evidence that CP and CPV are biologically different
tumor entities.