ECE2014 Poster Presentations Thyroid Cancer (70 abstracts)
Introduction: Thyroid carcinomas are the most often endocrine malignancy and their incidence is still growing. Thus, the finding of genetic predispositions to the thyroid cancer is desired. One of the genetic causes can be risk variants of tumor suppressor genes in patients. Our goal was to determine the influence of polymorphisms Val109Gly (T/G) in gene CDKN1B encoding protein p27/Kip1 and Arg72Pro (C/G) in gene TP53 encoding protein p53 on the development of thyroid cancer. Both these genes are crucial in regulation of cell cycle.
Methods: Three cohorts were studied 345 patients with sporadic medullary thyroid carcinoma (MTC), 269 patients with papillary thyroid carcinoma (PTC), and 374 healthy controls. DNA was isolated from peripheral leukocytes or from thyroid cancer tissues using QIAamp DNA Blood Kit or Trizol. Variants of polymorphisms were analyzed using TaqMan specific sonds on LightCycler 480. Statistical evaluation was performed by NCSS 2004 programme.
Results: Although total distributions of alleles of each gene were not different in patients compared to controls, the remarkable risk is in combination of specific alleles of these genes. G allele in TP53 in combination with T allele in CDKN1B is more often in patients with PTC than in controls (84.4 vs 74.7%, OR=1.82; 95%CI (1.232.70); P=0.003) and specifically the TT genotype in CDKN1B is the most risk in comparison with controls (70.8 vs 56.6%, OR=1.86; 95%CI (1.182.94); P=0.01). In MTC patients, C allele in TP53 with GG genotype in CDKN1B is more frequent compared to controls (6.2 vs 2.9%, OR=2.2; 95%CI (1.194.08); P=0.016).
Conclusion: It seems that genetic variants of tumor suppressor genes and mainly their cumulative risk effect play the role in the development of PTC and MTC. This work was supported by IGA MH CZ NT/13901-4 and MH CZ 00023761.