Increased expression of integrin-linked kinase is correlated with melanoma progression and poor patient survival.

Abstract

PURPOSE: Integrin-linked kinase (ILK), a key component of the extracellular matrix adhesion, has been studied extensively in recent years. Overexpression of ILK in epithelial cells results in anchorage-independent cell growth with increased cell cycle progression. Furthermore, increased ILK expression is correlated with progression of several human tumor types, including breast, prostate, and colon carcinomas. However, the role of ILK overexpression in human melanoma pathogenesis is not known. To investigate whether ILK plays a role in melanoma progression, we measured ILK expression in primary melanoma biopsies at various stages of invasion and evaluated the prognostic value of ILK expression in human melanoma. EXPERIMENTAL DESIGN: We used tissue microarray and immunohistochemistry to determine ILK expression in 67 primary melanomas and analyzed the correlation between ILK expression and melanoma progression and 5-year patient survival. RESULTS: We show that strong ILK expression is significantly associated with melanoma thickness. Strong ILK expression was observed in 0, 22, 33, and 63% in melanoma biopsies </=0.75, 0.76-1.50, 1.51-3.0, and >3.0 mm in thickness, respectively. Furthermore, strong ILK expression was detected in 83% of the tumors with lymph node invasion compared with only 18% for tumors without lymph node invasion (P < 0.01). Strikingly, our data revealed that strong ILK expression is inversely correlated with 5-year patient survival (P < 0.05). CONCLUSION: ILK expression increases dramatically with melanoma invasion and progression and is inversely correlated with patient survival.