Coagulation-related Factors, Thrombomodulin and Protein Z, are not Associated with Risk for Oral Cancer

Background: The link between thrombosis and cancer has been well established. Levels of protein Z and thrombomodulin indirectly regulate thrombin productionl and therefore may affect cancer susceptibility. Patients and Methods: The functional polymorphisms -13A/G and -33G/A in protein Z and thrombomodulin genes (respectively) influence transcription. The two polymorphisms were investigated in 160 oral cancer patients and 168 controls of equivalent age, gender and ethnicity using restriction fragment length polymorphism typing. Results: The frequency of the -13G allele, which results in lower expression of protein Z gene, was not significantly elevated in patients compared to controls (8.1% and 6.3%, respectively; odds ratio 1.35, 95% confidence interval 0.72-2.56). No carriers of the thrombomodulin low expression -33A allele were identified, underscoring the rarity of this allele in Caucasians. Conclusion: Inherited predisposition affecting protein Z or thrombomodulin levels does not modulate susceptibility to oral cancer. Any possible contribution of thrombin to oral oncogenesis may involve other factors.