Increased expression of SHP-1 is associated with local recurrence after radiotherapy in patients with nasopharyngeal carcinoma

Abstract

Background and Purpose: Nasopharyngeal carcinoma (NPC) is a major cancer in southern China. Src homology phosphatase-1 (SHP-1) is a tyrosine phosphatase that regulates growth, differentiation, cell cycle progression, and oncogenesis. We determined the clinical significance of SHP-1 expression in the tumors of NPC patients from southern China who were treated with radiotherapy.

Material and Methods: SHP-1 expression was determined by real-time PCR and western blotting of nasopharyngeal carcinoma tissues of 50 NPC patients and nasopharyngeal tissues of 50 non-NPC patients who had chronic nasopharyngeal inflammation. SHP-1 expression was measured in nasopharyngeal carcinoma samples of 206 NPC patients by immunohistochemistry and survival analysis was performed.

Results: The tumors of NPC patients had significantly increased expression of SHP-1 at mRNA and protein levels relative to patients with chronic nasopharyngeal inflammation. Survival analysis of NPC patients indicated that SHP-1 expression was significantly associated with poor local recurrence-free survival (p = 0.008), but not with nodal recurrence-free survival, distant metastasis-free survival, or overall survival.

Conclusion: SHP-1 appears to be associated with radiation resistance of NPC cells and can be considered as a candidate marker for prognosis and/or therapeutic target in patients with this type of cancer.