Thymosin β4 is a novel potential prognostic marker in gastrointestinal stromal tumors
Thymosin beta‐4 (Tβ4) is a major actin‐sequestering molecule that contributes to cell growth, differentiation, motility, survival, mitosis and angiogenesis. It is overexpressed in certain type of carcinoma and fibrosarcoma cell lines
and is associated with metastatic potential. The aim of this study was to investigate the relationship between Tβ4 expression and clinicopathologic features and VEGF status in gastrointestinal stromal tumors (GISTs).
Retrospectively, 60 GISTs were re‐examined and immunohistochemistry for Tβ4 and VEGF was performed. Increased expression of Tβ4 and VEGF was observed
in 26 (43.3%) and in 19 (31.6%) of the tumors, respectively. Tβ4 expression was positively correlated with VEGF expression (p < 0.01). Tβ4 and VEGF expression were significantly associated with tumor size
(p = 0.00 and p = 0.02, respectively) and high mitosis (p = 0.03 and p = 0.00, respectively). Although Tβ4 expression was positively associated with pleomorphism (p = 0.01), VEGF expression
was positively associated with necrosis (p = 0.03). Tβ4 expression was related with local recurrence and/or metastasis (p = 0.03), but VEGF expression was not (p = 0.12). We firstly demonstrate the presence of Tβ4
protein in GISTs. Our study reveals that increased expression of Tβ4 could be considered as an indicator of aggressive behavior of tumor.