A single nucleotide polymorphism in the 5' untranslated region of RAD51 and ovarian cancer risk in Polish women.

BACKGROUND: DNA repair gene polymorphisms are known to influence cancer risk. The RAD51 gene encodes proteins essential for maintaining genomic stability by playing a central role in holmology-dependent recombinational repair of the DNA double-strand breaks. Aims. We investigated the association of polymorphisms in the DNA repair genes RAD51-135G > C and 172G >T with ovarian cancer risk. METHODS: 120 Polish ovarian cancer patients and 120 healthy controls were genotyped for RAD51 (135G > C and 172G > T) by PCR-RFLP. RESULTS: In the present work no association was detected between ovarian cancer risk and 172G > T polymorphism of the RAD51 gene. The 135G > C polymorphism was associated with ovarian cancer risk. We found evidence of an increased ovarian cancer risk in CC homozygotes (OR 12.97 [95% confidence interval {CI} (5.73-29.36)]) but not in heterozygotes (OR 0.55 [95% CI 0.23-1.29]). We demonstrated a significant positive association between the RAD51 variant 135C allele and ovarian carcinoma, with an adjusted odds ratio (OR) of 6.24 (p < .0001). CONCLUSION: The results indicated that the polymorphism 135G > C of RAD51 may be positively associated with ovarian carcinoma in the Polish population. Further studies on the role of the RAD51 gene on ovarian cancer are warranted.

MTR 2756 A > G polymorphism is associated with the risk of systemic lupus erythematosus in the Polish population.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by overexpression of cytokines and T cell accessory molecules, which is due to a reduction of DNA regulatory region methylation in T cells. It has been shown that polymorphic variants of genes encoding key enzymes of folate and methionine metabolism may have an effect on DNA methylation. Therefore, in patients with SLE (n = 106) and controls (n = 141) we examined the distribution of polymorphisms of genes encoding methionine synthase (MTR); 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase (MTHFD1); and methylenetetrahydrofolate reductase (MTHFR). We found that MTR 2756AG (919DG) or GG (919GG) genotype exhibited 2.005-fold increased risk of SLE (95% CI = 1.177-3.416, P = 0.0146). However, MTHFR 677C > T (A222V) and MTHFD1 1958G > A (R653Q) allele and genotype frequencies did not exhibit statistical differences between SLE patients and controls. Since MTR is located on 1q43, our findings confirm the significance of the role of 1q region and the methyl cycle in etiopathogenesis of SLE.

[Ionizing radiation as a risk factor for thyroid cancer in Krakow and Nowy Sacz regions]. / Promieniowanie jonizujace jako czynnik ryzyka raka tarczycy w obszarze Krakowa i Nowego Sacza.

In a group of 224 patients with thyroid cancer registered from 1990 to 1999 and in 243 controls matched for sex and age doses for the thyroid due to accumulation of 131I after Chernobyl accident and radiological diagnostic procedures involving the neck and dentition was calculated according to Johnson's model and based upon questionnaires. There was a significantly higher dose for the thyroid due to accumulation of 131I in the Krakow area in comparison with the Nowy Sacz area. There was also a significantly higher frequency of radiological procedures involving the thyroid gland preceding the development of thyroid cancer in comparison with the control group. The present findings are concordant with about 40% increase of thyroid cancer in the Krakow area in comparison with the Nowy Sacz region. The present study has indicated that ionising radiation may be a factor involved in the pathogenesis of thyroid cancer and its significant rise within the last 10 years. However, it has not been the main factor, but only one of the risk factors. The study has also indicated that iodine prophylaxis should be continued and that radiological procedures involving the neck and head in patients with nodular goitre should be carried out with caution.