Upregulation of Atoh1 correlates with favorable survival in gastrointestinal stromal tumor.

Atonal homolog 1 (Atoh1) is crucial to the differentiation of many cell types and participates in tumorigenesis and progression. However, the expression of Atoh1 in gastrointestinal stromal tumors (GIST) and its relationship to clinical characteristics of this disease remain poorly understood. In this study, immunohistochemical analysis using tissue microarray (TMA) was employed to evaluate the expression of Atoh1 in GIST and the correlation between Atoh1 expression and clinicopathological features of GIST as well as patient outcome. High Atoh1 cytoplasmic expression was observed in 77.22% of patients with GIST, which was related to the mitotic index (P = 0.010) and AFIP-Miettinen risk classification (P = 0.045). High Atoh1 nuclear expression was seen in 69.49% of cases, which was associated with mitotic index (P = 0.003) and AFIP-Miettinen risk classification (P = 0.001). The Kaplan-Meier method and log-rank test indicated that high Atoh1 cytoplasmic expression, high Atoh1 nuclear expression, small tumor diameter, low mitotic index and TNM stage significantly correlated with improved survival of GIST patients. Overall, the data suggest that Atoh1 high expression correlates with a good prognosis and it may serve as a favorable prognostic factor for GIST. These results also support a role for Atoh1 as a tumor suppressor gene in GIST.