Clinicopathologic and prognostic significance of SATB1 in cutaneous malignant melanoma

Background: Special AT-rich sequence-binding protein-1 (SATB1), a new type of gene regulator, has been reported to be expressed in several human cancers and may have malignant potential. However, no data on SATB1 expression and its relationship to tumor progression in cutaneous malignant melanoma (CMM) has yet been reported. Objective: We examined the immunohistochemical expression of SATB1 in CMM to determine whether it could serve as a prognostic marker. Methods: A total of 97 samples of primary CMM and controls were immunostained for SATB1. The following clinicopathologic variables were evaluated: age, gender, subtype, SATB1 expression, Breslow thickness, Clark level, presence of ulceration, lymph node metastasis, distant metastasis, and survival. Statistical analyses were performed to assess for associations. Several parameters were analyzed for survival using the Kaplan-Meier method and Cox proportional-hazards model. Results: Forty cases (85.1%) of CMM showed positive staining for SATB1 by immunohistochemistry. The intensity of SATB1 staining was significantly higher in CMM than in nevus NV and normal skin (NS) (P<0.01). High SATB1 expression was significantly correlated with Breslow thickness, Clark level, mortality, presence of ulceration, and lymph node metastasis (P<0.01). Moreover, Kaplan-Meier analysis revealed that SATB1 overexpression was significantly associated with worse survival (P<0.01). Further univariate analysis and multivariate regression analysis indicated that SATB1 expression was an independent prognostic marker for CMM (P=0.03). Conclusions: The overexpression of SATB1 correlated with metastatic potential of CMM and is a novel independent prognostic marker for predicting outcome.