The results of our study indicate the potential role of the studied genes in the differentiation of NSCLC histopathological subtypes: RASSF1A and FUS1 could be regarded as markers differentiating SCC and NSCC, as their expression levels were significantly lower in squamous cell carcinoma subtype; similar role could be assign to NPRL2/G21 in differentiating SCC and AC subtypes. This evidence concerns the gene RASSF1 and squamous cell carcinoma.