Overexpression of CD55 correlates with tumor progression and poor prognosis in gastric stromal tumors

Backgrounds: Accumulating evidences have demonstrated that CD55 can protect cells from complement-mediated attack, and is involved in tumor dedifferentiation, migration, invasiveness, and metastasis. However, the role of CD55 in gastrointestinal stromal tumors (GISTs) has not been investigated. Aims: Our study aimed to analyze the expression of CD55 in gastric GISTs and its correlations with clinicopathologic characteristics and prognosis. Materials and methods: A total of 118 gastric GIST patients were included in our study. CD55 expression in GIST tissue samples was evaluated using immunohistochemistry. Cumulative survival was conducted using the Kaplan–Meier method. Cox regression analyses were performed to identify factors associated with progression-free survival (PFS) for patients with gastric GISTs. Results: Of 118 gastric GISTs patients included in our study, 44 (37.3%) were positive for CD55 expression. Positive CD55 expression in gastric GISTs was closely associated with tumor size (13.52±7.35 vs 5.07±1.90 cm, respectively; P<0.001), Ki 67 labeling index (P=0.001), mitotic counts (P=0.005), NIH risk classification (P<0.001), PLR (P<0.001), and metastasis at initial diagnosis (P=0.002). Kaplan–Meier analyses revealed that tumor size (P<0.001), mitotic counts (P<0.001), Ki 67 labeling index (P<0.001), PLR (P<0.001), metastasis at initial diagnosis (P=0.031), and CD55 expression (P<0.001) were statistically significant risk factors affecting PFS of patients with gastric GISTs. Cox multivariate survival analysis showed that mitotic counts, Ki 67 labeling index, and CD55 expression were independent predictors of PFS for gastric GISTs. Conclusion: CD55 may be a potential prognostic marker in gastric GISTs patients.