Objective: To investigate the expression effect and biological significance of NADPH oxidase l (NOX1) on the growth of human Gastrointestinal stromal tumor (GIST) at a protein level and the correlation between its expression level and patient prognosis.
Methods: We enrolled a total of 146 patients confirmed by histopathology to be GIST tumors. Immunohistochemistry(IHC) analysis with GIST tissue microarray was used to assess NOXl level. The relativity study between NOXl expression level and GIST patient prognosis was evaluated. NOX1 mRNA expression was subsequently demonstrated using online database Oncomine.
Results: Significance association with mitotic index (χ2 = 9.476, p = 0.009) and grade (χ2 = 11.392, p =0.010) was observed for low NOX1 cytoplasm staining of GIST cells and poor performance status in 78 of 146 (53.42%) GIST tissues, while for GIST patients with high expression of NOX1, there was no significant survival difference in disease progression. By univariate analysis, prognosis of GIST patients for overall survival (OS) rates were significantly positively correlated with NOX1 expression level (c2=2.429, p=0.014), tumor diameter (c2=2.048, p=0.004), mitotic index (c2=2.665, p<0.001), and grade (c2=3.162, p=0.001). Moreover, multivariate analyses demonstrated that low cytoplasm expression of NOX1 (c2=2.144, p=0.046) and mitotic index (c2=2.513, p=0.001) were striking related with OS rates, the difference was statistically significant. Kaplan-Meier survival curves further exhibited that low NOX1 cytoplasm expression and advanced mitotic index had a more unfavorable prognosis in GIST patients.
Conclusion: These conclusions indicate that the degree of malignancy of GIST patients is closely related to NOX1 cytoplasm expression and mitotic index, both of which may be taken as an important role in the occurrence and development of GIST. It may act as an unfavorable predictive marker, indicating a new approach of gene therapy for GIST.