Evaluation of myosin VI, E-cadherin and beta-catenin immunostaining in renal cell carcinoma

Our study population consisted of 152 patients who underwent surgery for RCCs between 1990 and 1999. The tumours were examined with three immunohistochemical markers: myosin VI, E-cadherin and beta-catenin.The immunostaining for cytoplasmic myosin VI was common (72%). One-third of the tumours were immunopositive for nuclear myosin VI. Cytoplasmic myosin VI immunopositivity and nuclear beta-catenin immunostaining were associated with lower Fuhrman grades (p = 0.04 and p = 0.005, respectively), but not stages. There was no significant association between myosin VI immunostaining and the histological subtype of RCC. Nuclear myosin VI was associated with the nuclear expression of beta-catenin. A direct association could also be proven between membranous E-cadherin and cytoplasmic beta-catenin. Cytoplasmic myosin VI immunostaining was a marker of poorer prognosis in multivariate Cox regression model adjusted with stage and Fuhrman grade with hazard ratio 2.4 (95% confidence interval 1.1 to 5.0 with p = 0.024).Cytoplasmic myosin VI immunopositivity and nuclear beta-catenin immunostaining were associated with lower Fuhrman grades, and there was a strong positive relationship between E-cadherin immunostaining and beta-catenin immunostaining in RCCs. Cytoplasmic myosin VI immunostaining was associated with poorer prognosis in RCCs.Renal cell carcinoma (RCC) is a cancer of increasing incidence and mortality [1]. By diagnosis, up to one-third of patients already have a metastasised disease and half of the remaining patients will suffer a recurrence after curative treatment [2]. The behaviour of RCC can be difficult to predict even though there are many well-known prognostic factors for the disease. Myosins are a large family of molecular motor proteins and their immunoexpression has previously been demonstrated in variety of epithelial cancers including RCCs [3-5]. Myosin VI is one of the so-called unconventional myosins that moves in a reverse direction when compared to the o