The prognostic role of Filamin A protein expression in patients with non-small-cell lung cancer M. Gachechiladze * , J. Skarda * Palacky University, Pathology, Olomouc, Czech Republic Objective: An actin-binding protein Filamin A (FLNA) serves as a scaffold in various signaling pathways. Recently, it has been reported that FLNA interacts with BRCA1 protein and is required for efficient regulation of early stages of DNA repair processes. As DNA repair proteins are important prognostic markers for non-small-cell lung cancer (NSCLC) patients, we aimed to investigate the role of FLNA protein expression in NSCLC, as well as its correlation with BRCA1 protein expression. Method: We performed a preliminary study of FNLA and BRCA1 protein expression in 50 NSCLC patients. Formalin-fixed paraffin-embedded tissue sections were stained by immunohistochemistry using antibodies against FLNA C-terminus (EP2405Y, LSBio), BRCA1 N-termunus (MS110) and against phosphorilated forms of BRCA1 at ser1524 and ser1423 (Abcam). Staining intensity was estimated semi-quantitatively and correlated with all available clinico-pathological factors. Results: FLNA expression was significantly higher in cancer, compared to normal lung tissue. Positive correlation has been revealed between FLNA and BRCA1 phospho-ser1423 expression. Also, 5 year overall survival rate was higher in patients with strong FLNA expression. Conclusion: According to our preliminary study results the prognostic role of FLNA protein expression deserves to be a subject for further studies in patients with NSCLC.