The relationship between SPARC expression in primary tumor and metastatic lymph node of resected pancreatic cancer patients and patients' survival.

Background: Previous researches in pancreatic cancer demonstrated a negative correlation between secreted protein acidic and rich in cysteine (SPARC) expression in primary tumor and survival, but not for SPARC expression in lymph node. In the present study, we aimed to evaluate the SPARC expression in various types of tissues and its impact on patients' prognosis.

Methods: The expression of SPARC was examined by immunohistochemistry in resected pancreatic cancer specimens. Kaplan-Meier analyses and Cox proportional hazards regression were applied to assess the mortality risk.

Results: A total of 222 tissue samples from 73 patients were collected to evaluate the SPARC expression, which included 73 paired primary tumor and adjacent normal tissues, 38 paired metastatic and normal lymph nodes. The proportion of positive SPARC expression in metastatic lymph node was high (32/38), whereas in normal lymph node it was negative (0/38). Positive SPARC expression in primary tumor cells was associated with a significantly decreased overall survival (P=0.007) and disease-free survival (P=0.003), whereas in other types of tissues it did not show a predictive role for prognosis. Univariate and multivariate analyses both confirmed this significance.

Conclusion: SPARC can serve a dual function role as both predictor for prognosis and potentially biomarker for lymph node metastasis in resected pancreatic cancer patients.