To identify the molecular mechanisms of bladder cancer invasion pathophysiology. To assess EMMPRIN, p65NFkappaB and p38MAPK expressions which play a role in signal transmission system of muscle and non muscle invasive bladder tumors. Fifty-seven patients with non muscle invasive tumors (mean age 65.2 +/- 16.1) and 34 patients with muscle invasive tumors (mean age 62.2 +/- 20.7) were included in this study. Normal tissue from the same patients' bladders were used as control group. Patients had either TUR or radical cystectomy and paraffin sections were prepared for immunohistochemistry. Expression density was evaluated semiquantitively according to tumor grade and invasion depth. Results were compared with Mann Whitney U, Wilcoxon W, Chi Square and variation analysis tests. MAPK and EMMPRIN expression was increased according to tumor grade (p < 0.05). These expressions were also significantly higher in muscle invasive tumors than in non muscle invasive ones (p < 0.05). In normal tissue samples of both TUR and radical cystectomy materials, EMMPRIN, NFkappaB and MAPK expressions were lower than in tumor samples (p < 0.05). NFkappaB wasn't related to tumor grade/stage (p > 0.05). It can be stated that MAPK and EMMPRIN expression is related to the grade of bladder tumor and that NFkappaB positivity is not related to the grade/stage of the disease. In future positivity of lymph nodes and visceral metastasis and survival must be assessed to define the relationship with the expressions in long term follow up studies involving a larger number of patients.