Expression levels of STAT5 isoforms (STAT5A and STAT5B) were statistically significant different (P = 0.0008; Spearman's rank correlation coefficient), with higher expression level displayed by STAT5B. The expression level of COX-2 was nearly uniformly increased in all NSCLC subtypes, at the level of 70%. This evidence concerns the gene STAT5B and non-small cell lung carcinoma.