Background: Haptoglobin (Hp), an acute-phase protein, is known as a potential diagnostic
biomarker in human diseases. Two alleles of Hp (Hp1
) exist in humans allowing three
phenotypes (Hp1-1, Hp2-1, and Hp2-2), which influence the biophysical and biological properties
Objective: This work aimed to investigate the variation of serum level and fucosylation change
among Hp phenotypes in patients with lung cancer compared to healthy donors.
Methods: 44 patients with lung cancer and 26 healthy blood donors who lived in the Northern-Thailand
region were investigated by the glycoproteomic procedure.
Results: The phenotypic distribution of the Hp (Hp1-1:Hp2-1:Hp2-2) in healthy donors was
0.04:0.38:0.58, while the patient group was 0.09:0.52:0.39. The Hp1
allele frequency of patients
with lung cancer (0.34) was higher than the healthy donor (0.23). Glycoprotein blotting technique
represented that the level of serum Hp and its fucosylation were significantly higher among lung
cancer patients compared to those of the healthy donors. However, a downward trend in the fucosylation
level from Hp1-1 to Hp2-1, Hp2-2, was seen in the patient group, but varying in the serum
Hp level. An N-linked glycan was enzymatically released from discrete Hp multimers of Hp2-1
and Hp2-2 samples. Analysis of glycan profiling by MALDI-TOF-MS showed that reduction of
the fucosylated glycan was associated with the size of Hp multimers, resulting in the lower level of
fucosylation in Hp2-1 and Hp2-2, respectively.
Conclusion: Our finding demonstrates that the Hp phenotype is a dependent risk factor for lung
cancer and should be incorporated into further clinical and biochemical investigations of diseases,
including lung cancer.