Background. Class III beta-tubulin (TUBB3) is one of the eight beta tubulin isotypes identified in human. It is constitutively expressed in brain and testis but not in lung tissue. TUBB3 is also known to appear in solid tumors, in particular in non-small cell lung cancer (NSCLC), and it is often associated with poor prognosis and resistance to taxanes and Vinka alkaloids. Objective: We have suggested that TUBB3 expression may cover not only the primary tumor but also a wide adjacent area of morphologically normal lung tissue. To check the hypothesis we have measured TUBB3 expression both in the non-small cell lung carcinoma (NSCLC) and remote lung tissue derived from the same lung. 60surgical biopsy specimens of NSCLC and morphologically normal lung tissue of 30patients were investigated. Materials and methods. Biopsy specimens were converted to suspension, fixed in 4 % formaldehyde and analyzed by flow cytometry using monoclonal antibodies to TUBB3. The method was developed in the laboratory of medicinal chemistry research Institute of experimental diagnostics and therapy of tumors (N.N. Blokhin Russian Cancer Research Center) and patented. Results. Fraction of TUBB3-positive cells in the group of adjacent lung tissue specimens was lower compared to NSCLC group but still positive in the majority of adjacent lung tissue specimens (25 of 30) and achieved up to 39 % of cells. Conclusion. We suggest that TUBB3 expression in adjacent morphologically normal lung tissue indicates presence of transformed and potentially malignant cells far from the primary site.