Prevalence of the NKG2D Thr72Ala Polymorphism in Patients with Cervical Carcinoma

Background: The natural killer group 2, member D (NKG2D) receptor is mainly situated on the surface of NK and CD8(+) alpha beta T cells that are involved in the defense against viral agents and in cancer immunosurveillance. The G > A transition (Thr72Ala) (rs2255336) located in the NKG2D region encoding the transmembrane part of this receptor has been associated with decreased functionality of NK and T cells. Methods: Using polymerase chain reaction-restriction fragment length polymorphisms, we examined the NKG2D Thr72Ala polymorphism in patients with cervical cancer (n = 353) and controls (n = 366) in a Polish population. Results: We observed an increased frequency of Thr/Thr or/and Thr/Ala genotypes in controls compared with all patients with cervical cancer; however, these differences were not significant. We found a significantly increased frequency of the NKG2D 72Thr allele in controls than in all patients (odds ratio [OR] = 0.7410 [95% confidence intervals (CI) = 0.5683-0.9662, p = 0.0265]). Moreover, stratification of patients based on cancer stage showed a significant increase in the Thr/Thr genotype frequency (OR = 0.3086 [95% CI = 0.09097-1.047, p = 0.0461]), as well as in the Thr/Thr and Thr/Ala genotype frequency (OR = 0.4504 [95% CI = 0.2891-0.7018, p = 0.0003]), in controls compared with patients with cervical cancer in stages III and IV. The frequency of the NKG2D 72Thr allele was also significantly increased in controls as compared with patients in stage III and IV cancer (OR = 0.4699 [95% CI = 0.3170-0.6967, p = 0.0001]). Conclusion: Our studies may suggest that the women with cervical cancer bearing the NKG2D 72Thr gene variant might be protected against progression to advanced stages of this cancer.