Expression of secreted protein acidic and rich in cysteine is an independent prognostic indicator of a poor clinical outcome in oropharyngeal carcinoma patients

Abstract

Conclusion: SPARC-expression is an indicator of the prognosis in terms of OS, independent of HPV-infection. HPV-negative patients with SPARC-Low show survival as favorable as HPV-positive patients, probably because of their higher salvage rate after relapse than SPARC-High patients. Objective: The objectives of the study were to clarify the correlation between the expression of secreted protein acidic and rich in cysteine (SPARC) and HPV-status, and to determine the prognostic value of SPARC-expression in oropharyngeal squamous cell carcinoma (OPSCC) patients. Methods: Fifty-three formalin-fixed and paraffin-embedded tissues were obtained from patients with OPSCC who underwent curative treatment. The SPARC protein was detected by immunohistochemistry. SPARC-expression level was divided into two categories, SPARC-High and SPARC-Low, according to the staining index. Results: Twenty-two out of the 53 OPSCC patients were HPV-positive. There was no significant correlation between the HPV-status and SPARC-expression level. Multivariate Cox proportional hazards regression analysis revealed that the HPV-status and SPARC-expression are independent prognostic indicators of favorable and unfavorable overall survival (OS) (p = 0.021 and p = 0.012), respectively. For disease-free survival, the HPV-status was the only predictive factor (p = 0.022). After stratification by the HPV-status, high SPARC-expression was a significant predictor of poor OS in HPV-negative OPSCC patients using Kaplan–Meier analysis and the log-rank test (p = 0.014). Ten out of 28 SPARC-Low patients relapsed, among which six patients (60%) were salvaged. However, 14 out of 25 SPARC-High patients relapsed, and only three patients (21.4%) were salvaged.

Keywords:

• Oropharyngeal carcinoma
• human papillomavirus
• secreted protein acidic and rich in cysteine
• prognostic indicator

Acknowledgments

This work was supported by a scientific research grant from the Ministry of Education, Science, Sports, Culture and Technology of Japan (C21592189). We thank Dr Seiko Sawada-Kitamura from the Department of Human Pathology, Kanazawa University, Graduate School of Medicine for critical comments and suggestions.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.