Purpose: To investigate the effect of alterations in mRNAs of ABO and FUT2 genes on the expression of ABH histo-blood group antigens in lung cancer patients. Methods: Totals of 18 patients with blood group A, 14 with group B, 8 with group AB and 9 with group O, were assessed for blood group A/B/H antigens by immunohistochemical staining. Expression of A/B enzyme and FUT2 mRNA was detected in tumor tissues and corresponding lung tissues adjacent to tumors from lung cancer patients using RT-PCR. Results: Expression of FUT2 and A/B enzyme mRNA in lung tissue adjacent to tumors was statistically greater than that in tumor tissues (χ2=14.118, P<0.001). Expression of FUT2 mRNA was statistically lower than that of A/B enzyme in tumor tissues from lung cancer patients whose blood group was A/B/AB (χ2=7.813, P=0.005). Only tumor tissues from 9 patients with mRNA expression of A/B enzyme and FUT2 gene lacked blood group antigens. In particular, expression of A/B antigens was not detected in five cases with A/B mRNA expression, a significant association being observed between the expression of enzyme and antigens (Pearson’s R=0.867;kappa’s coefficient =0.858, P<0.001). Conclusion:Expression of A/B/H blood group antigens was not detected in lung cancer tissues, which may have resulted from down-regulation of ABO/FUT2 gene transcription. Furthermore, the FUT2 gene may indirectly regulate expression of A/B blood group antigens by influencing H antigen expression.