Endocrine Abstracts (2011) 26 OC4.4

HLA-G polymorphism and papillary thyroid cancer histological aggressiveness

A Dardano1, R Rizzo2, A Polini1, M Stignani2, S Tognini1, M Ferdeghini3, O Baricordi2 & F Monzani1

1University of Pisa, Pisa, Italy; 2University of Ferrara, Ferrara, Italy; 3University of Verona, Verona, Italy.

Introduction: Human leukocyte antigen-G (HLA-G) is a non-classical HLA-class Ib molecule with multiple immunoregulatory properties. Its main role is the maintenance of tolerance between maternal immune system and semiallogenic fetus. The expression of HLA-G antigen has been reported in several cancers and seems to play an important role in the escape of tumour cells from immune surveillance. A 14 bp insertion/deletion polymorphism in exon 8 of the 3′ untranslated region of the HLA-G gene has been reported to be associated with HLA-G mRNA stability.

Aim: To evaluate the prevalence of the 14 bp insertion (+14 bp) and deletion (−14 bp) polymorphism in the HLA-G gene in patients affected by papillary thyroid carcinoma (PTC) as well as autoimmune thyroiditis. The possible association between HLA-G 14 bp polymorphism and thyroid cancer aggressiveness was also assessed.

Patients and methods: We studied 182 patients (147 F) with PTC; 120 patients (104 F) with autoimmune thyroiditis and 245 healthy subjects (191 F), matched for sex and age, served as control groups. HLA-G polymorphism was studied by PCR techniques.

Results: The frequency of the 14 bp insertion polymorphism was significantly higher in patients with PTC and autoimmune thyroiditis as compared to healthy controls (0.48 and 0.46 vs 0.38, P=0.0003 and P=0.01, respectively). Among PTC patients, a significant correlation was found between +14 bp allele and advanced TNM stage (ρ: 0.37, P<0.0001), as well as higher tumour aggressiveness, expressed as lymph node and/or multifocality and/or thyroid capsule invasion (ρ: 0.39, P<0.0001). A positive correlation between the +14 bp allele and cancer dimension was also observed (ρ: 0.15, P<0.05).

Conclusions: Our preliminary data show, for the first time, an increased frequency of the 14 bp insertion polymorphism in PTC patients, suggesting a potential role of the HLA-G polymorphism in PTC immune escape and aggressiveness. The polymorphism may be also involved in the reported increased prevalence of PTC in patients with autoimmune thyroiditis.

Article tools

My recent searches

No recent searches.