Renal cell carcinoma (RCC) is a common urologic tumor and accounts for about 3% of all human malignancies . The annual mortality-to-incidence ratio of RCC is significantly higher compared to other urological malignancies, and its incidence has been increasing steadily in recent decades . Interestingly, even organ-confined RCC of comparable stage and grade can demonstrate a significantly-varying tendency towards tumor progression and systemic spread. Correspondingly, the development of metastases can be observed in a substantial number of patients with tumors initially classified as stage T1b or T2 even more than five years after the initial treatment, hereby demonstrating the limited value of classical patients' and tumor characteristics such as tumor stage and grade to predict the clinical outcome of an individual patient.
An essential step in local disease progression and in the formation of metastases is the invasion of tumour cells into the extracellular matrix. Cell adhesion molecules and extra-cellular matrix proteins support either an increase or a decrease in the ability of tumours cells to adhere to surrounding tissue. Among the extracellular matrix proteins identified, Fibronectin (FN) seems to play an important role in both inhibition and promotion of cellular attachment by interacting with different receptors.
FN is a glycoprotein that is involved in cellular adhesion and migration processes including embryogenesis, wound healing, blood coagulation, host defense, and metastasis. The molecule is widely distributed in healthy membrane, in the lamina propria, in vessel structures, nerves and smooth-muscle cell layers . However, up to now the function of FN is not clearly known [4, 5]. Few studies described the potential role of FN in different malignancies [5–8]. For example in hepatocellular carcinoma an overexpression of FN protein was found . Elevated plasma levels were detected in patients suffering from gastrointestinal and head/neck cancer . In non-malignant diseases particularly in thrombosis, hemostasis, vascular disease and platelet function the definitive role of FN is still unclear [9–11].
The aim of this study is to elucidate a possible role of FN1 in the development of RCC using mRNA expression analyses. 212 renal tissue samples from patients undergoing surgery for renal tumors were analysed using quantitative real time PCR. FN1 mRNA expression was significantly increased in RCC compared to corresponding normal renal tissue. Furthermore, our data suggest FN1 as marker for progressive disease especially in papillary RCC.