3’UTR Polymorphism of Thymidylate Synthase gene increased the risk of persistence of pre-neoplastic cervical lesions

Background: Cervical cancer is caused by high-risk Human Papillomavirus (hr-HPV) infection associated with cofactors that has been analyzed as predictors of the remission or persistence of cytological abnormalities remission or persistence. These cofactors can be either environmental, epigenetic, or genetic. Polymorphism in genes of enzymes that act on one-carbon metabolism alter their activity and also may be associated with cervical carcinogenesis because they affect DNA synthesis and repair, and gene expression. Therefore, this study aimed to analyze the risk of persistence of pre-neoplastic cervical lesions according to genetic polymorphisms involved in one-carbon metabolism. Methods: Our sample consisted of 106 women, divided into two groups – Remission (n=60), i.e., with the presence of pre-neoplastic lesions at first meeting (T1) and normal cytology after six months of follow-up (T2), and Persistence (n=46), i.e., with the presence of pre-neoplastic lesions at T1 and T2. We obtained cervical samples for cytological analysis (T1 and T2), HPV detection (T1), and evaluation of polymorphism C667T of Methylenetetrahydrofolate Reductase (MTHFR C677T), A2756G of Methionine Synthase (MS A2756G), A66G of Methionine Synthase Reductase (MTRR A66G), double or triple 28 bp tandem repeat in 5’-untranslated enhanced region of Thymidylate Synthase (TSER), and 6 bp deletion at nucleotide1494 in TS 3’-untranslated region (TS3’UTR). To analyze all genetic polymorphisms simultaneously, we calculated the Genetic Risk Score (GRS). Results: We observed no differences between the Remission and Persistence groups regarding the GRS. Also, there were no differences in the genotypic and allelic distribution of MTHFR C677T and MS A2756G polymorphisms. However, the risk of persistence was higher among women with the heterozygote genotype - ins/del [OR (IC95%): 3.22 (1.19 – 8.69), p=0.021], or the polymorphic genotype – del/del [OR (IC95%): 6.50 (1.71 – 24.70), p=0.006] of TS3’UTR. Conclusions: The presence of the TS3’UTR polymorphism increased the risk of persistence of cervical abnormalities. This genetic variant could be a potential marker of cervical carcinogenesis and therefore assist the follow-up of women with persistent pre-neoplastic cervical lesions.

3’UTR Polymorphism of Thymidylate Synthase gene increased the risk of persistence of pre-neoplastic cervical lesions

Background: Cervical cancer is caused by high-risk Human Papillomavirus (hr-HPV) infection associated with cofactors that has been analyzed as predictors of the remission or persistence of cytological abnormalities remission or persistence. These cofactors can be either environmental, epigenetic, or genetic. Polymorphism in genes of enzymes that act on one-carbon metabolism alter their activity and also may be associated with cervical carcinogenesis because they affect DNA synthesis and repair, and gene expression. Therefore, this study aimed to analyze the risk of persistence of pre-neoplastic cervical lesions according to genetic polymorphisms involved in one-carbon metabolism. Our sample consisted of 106 women, divided into two groups – Remission (n=60), i.e., with the presence of pre-neoplastic lesions at first meeting (T1) and normal cytology after six months of follow-up (T2), and Persistence (n=46), i.e., with the presence of pre-neoplastic lesions at T1 and T2. We obtained cervical samples for cytological analysis (T1 and T2), HPV detection (T1), and evaluation of polymorphism C667T of Methylenetetrahydrofolate Reductase (MTHFR C677T), A2756G of Methionine Synthase (MS A2756G), A66G of Methionine Synthase Reductase (MTRR A66G), double or triple 28 bp tandem repeat in 5’-untranslated enhanced region of Thymidylate Synthase (TSER), and 6 bp deletion at nucleotide1494 in TS 3’-untranslated region (TS3’UTR). To analyze all genetic polymorphisms simultaneously, we calculated the Genetic Risk Score (GRS). Results: We observed no differences between the Remission and Persistence groups regarding the GRS. Also, there were no differences in the genotypic and allelic distribution of MTHFR C677T and MS A2756G polymorphisms. However, the risk of persistence was higher among women with the heterozygote genotype - ins/del [OR (IC95%): 3.22 (1.19 – 8.69), p=0.021], or the polymorphic genotype – del/del [OR (IC95%): 6.50 (1.71 – 24.70), p=0.006] of TS3’UTR. Conclusions: The presence of the TS3’UTR polymorphism increased the risk of persistence of cervical abnormalities. This genetic variant could be a potential marker of cervical carcinogenesis and therefore assist the follow-up of women with persistent pre-neoplastic cervical lesions.

Genetic polymorphisms in one-carbon metabolism increased the risk of persistence of pre-neoplastic cervical lesions

Background: Cervical cancer is caused by high-risk Human Papillomavirus (hr-HPV) infection associated with cofactors that has been analyzed as predictors of cytological abnormalities remission or persistence. These cofactors may be classified as environmental, epigenetic or genetic. Polymorphism in genes of enzymes that act on one-carbon metabolism alter their activity and may be associated with cervical carcinogenesis because they affect DNA synthesis and repair, and gene expression. Therefore, the objective of this study was to analyze the risk of persistence of pre-neoplastic cervical lesions according to genetic polymorphisms involved in one-carbon metabolism. Sample group was divided in Remission (n=60) - presence of pre-neoplastic lesion at first meeting (T1), and normal cytology after six months of follow-up (T2), and Persistence (n=46) - presence of pre-neoplastic lesion at T1 and T2. Cervical samples were obtained for cytological analysis (T1 and T2), HPV detection (T1), and evaluation of polymorphism C667T of Methylenetetrahydrofolate Reductase (MTHFR C677T), A2756G of Methionine Synthase (MS A2756G), A66G of Methionine Synthase Reductase (MTRR A66G), double or triple 28 bp tandem repeat in 5'-untranslated enhanced region of Thymidylate Synthase (TSER), and 6 bp deletion at nucleotide1494 in TS 3'-untranslated region (TS3'UTR). Genetic Risk Score (GRS) was calculated for analyze all genetic polymorphism simultaneously. Results: No differences were observed between Remission and Persistence groups of GRS, or genotypic and allelic distribution of MTHFR C677T and MS A2756G polymorphisms. However, higher risk of persistence was observed among women presenting heterozygote genotype - ins/del [OR (IC95%): 3.22 (1.19 – 8.69), p=0.021], or polymorphic genotype – del/del [OR (IC95%): 6.50 (1.71 – 24.70), p=0.006] of TS3’UTR. Conclusions: Presence of TS3’UTR polymorphism increased risk of persistence of cervical abnormalities. This genetic variant could be considered as potential marker of cervical carcinogenesis, assisting follow-up of women with persistent pre-neoplastic cervical lesions.

Genetic polymorphisms in one-carbon metabolism increased the risk of persistence of pre-neoplastic cervical lesions

Background: Cervical cancer is caused by high-risk Human Papillomavirus (hr-HPV) infection associated with cofactors that has been analyzed as predictors of cytological abnormalities remission or persistence. These cofactors may be classified as environmental, epigenetic or genetic. Polymorphism in genes of enzymes that act on one-carbon metabolism alter their activity and may be associated with cervical carcinogenesis because they affect DNA synthesis and repair, and gene expression. Therefore, the objective of this study was to analyze the risk of persistence of pre-neoplastic cervical lesions according to genetic polymorphisms involved in one-carbon metabolism. Sample group was divided in Remission (n=60) - presence of pre-neoplastic lesion at first meeting (T1), and normal cytology after six months of follow-up (T2), and Persistence (n=46) - presence of pre-neoplastic lesion at T1 and T2. Cervical samples were obtained for cytological analysis (T1 and T2), HPV detection (T1), and evaluation of polymorphism C667T of Methylenetetrahydrofolate Reductase (MTHFR C677T), A2756G of Methionine Synthase (MS A2756G), A66G of Methionine Synthase Reductase (MTRR A66G), double or triple 28 bp tandem repeat in 5'-untranslated enhanced region of Thymidylate Synthase (TSER), and 6 bp deletion at nucleotide1494 in TS 3'-untranslated region (TS3'UTR). Genetic Risk Score (GRS) was calculated for analyze all genetic polymorphism simultaneously. Results: No differences were observed between Remission and Persistence groups of GRS, or genotypic and allelic distribution of MTHFR C677T and MS A2756G polymorphisms. However, higher risk of persistence was observed among women presenting heterozygote genotype - ins/del [OR (IC95%): 3.22 (1.19 – 8.69), p=0.021], or polymorphic genotype – del/del [OR (IC95%): 6.50 (1.71 – 24.70), p=0.006] of TS3’UTR. Conclusions: Presence of TS3’UTR polymorphism increased risk of persistence of cervical abnormalities. This genetic variant could be considered as potential marker of cervical carcinogenesis, assisting follow-up of women with persistent pre-neoplastic cervical lesions.

The Allele Frequencies of Three Polymorphisms in Genes Involved in Homocysteine Metabolism in a Group of Unrelated Healthy Singaporeans

The cystathionineβ-synthase (CBS) 844ins68 polymorphism, methionine synthase (MS) A2756G SNP, and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T SNP are associated with homocysteine (Hcy) level in humans. Elevated Hcy level is considered a risk factor for atherosclerotic diseases among Asian populations. Therefore, the three polymorphisms may vary the risk for developing such diseases in Singaporeans. In this study, the three polymorphisms were determined in a group of unrelated healthy Singaporeans (273 Chinese, 127 Indians, and 156 Malays). Regarding allele frequencies, Indians had the highest frequencies of the CBS insertion allele (2.0%) and the MS 2756G allele (26.4%), while Chinese had the highestMTHFR677T allele frequency (27.5%). In addition, theMTHFR677T allele was found significantly lower in Chinese males than in their female counterparts. As the CBS insertion allele was suggested to be associated with lower Hcy level, whereas the MS 2756G allele and theMTHFRT/T genotype were related to higher Hcy level, the MS A/G or G/G genotype and theMTHFRT/T genotype were considered double genetic risk factors for elevated Hcy level. The frequency of such double genetic risk was 0.7% (4 subjects) in the total population consisting of 3 Chinese (1.1%) and 1 Malays (0.6%). NoMTHFRT/T genotype was found in Indians. Such results suggested that Chinese could have higher Hcy levels than Malays while the situation for Indians was complicated. Since human Hcy levels are also affected by environmental factors, further studies are required to better evaluate the association between these three polymorphisms and Hcy levels and/or disease susceptibilities in Singaporeans.

Effects of Methionine Synthase (MS) A2756G and Methionine Synthase Reductase (MSR) A66G Polymorphisms on Methionine Metabolism in Brazilian Pregnant Women and Their Neonates.

Methionine synthase (MS) is a cobalamin dependent enzyme that catalyses the remethylation of homocysteine to methionine. The methionine synthase reductase (MSR) maintains adequate levels of methylcob(III)alamin, the activated cofactor for MS. The aim of this study was to investigate the effect of MS A2756G and MSR A66G polymorphisms on total homocysteine (tHcy), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) levels in 390 pregnant women and their 292 newborns, from Sorocaba city, Brazil. Genotypes of two polymorphisms were determined by PCR-RFLP. Pregnant women with MS 2756AA genotype have higher tHcy and lower Cbl levels than those with 2756G alleles. The MMA values were increased in neonates with MS 2756AA genotypes (Table 1). There are no difference between the maternal values of Cbl, serum folate, tHcy, MMA and SAM according to MSR A66G genotypes.The values of SAM were lower in neonates with MSR 66G alleles than those with AA genotypes (Table 2). We conclude that MS 2756AA genotypes are associated with higher tHcy levels in pregnant women and higher MMA levels in neonates. The MSR 66GG genotypes is associated with lower SAM levels in neonates. Table 1- Distribution of geometric means and confidence intervals 95% (CI 95%) and numbers of subjects for maternal and neonatal values of cobalamin (Cbl), serum folate, total homocysteine (tHcy), methymalonic acid (MMA) and S- adenosylmethionine (SAM) according to genotypes for the polymorphism MS A2756G. Variables Genotypes for MS A2756G Student t Test AA AG + GG Pregnant Women Cbl (pmol/L) 139 (133 – 144) 235 156 (146 – 166) 129 P= 0.001 SF (nmol/L) 14.3 (13.6 – 15.0) 234 14.5 (13.6 – 15.5) 129 P= 0.667 tHcy( μmol/L) 6.8 (6.5 – 7.1) 235 6.2 (5.9 – 6.6) 128 P= 0.036 MMA(nmol/L) 234 (219 – 245) 194 241 (219 – 265) 106 P= 0.610 SAM(nmol/L) 81.8 (77.9 – 86,0) 229 83.1 (79.1 – 87.4) 124 P= 0.663 Neonates Cbl (pmol/L) 227 (212 – 244) 188 234 (213 – 257) 101 P= 0.646 SF (nmol/L) 32.0 (31.0 – 33.0) 186 32.0 (30.8 – 33.2) 99 P= 0.967 tHcy μmol/L) 5.8 (5.5 – 6.1) 185 5.5 (5.1 – 5.9) 100 P= 0.229 MMA(nmol/L) 383 (364 – 402) 183 342 (317 – 369) 100 P= 0.011 SAM(nmol/L) 188 (181 – 196) 178 182 (168 – 197) 98 P= 0.491 Table 2 - Distribution of geometric means and confidence intervals 95% (CI (%%) and number of subjects for neonatal values of cobalamin (Cbl), serum folate, total homocysteine (tHcy), methylmalonic acid (MMA) and S- adenosylmethionine (SAM) according to genotypes for the polymorphism MSR A66G. Variables Genotypes MSR A66G Student t Test AA AG GG Groups not sharing a common superscript letter are significantly different at P<0.05 based on Tukey’s test Neonates Cbl (pmol/L) 225 (202 – 249) 86 229 (214 – 246) 166 247 (205 – 298) 35 P= 0.602 SF (nmol/L) 33.0 (31.6 – 34.4) 84 31.7 (30.7 – 32.7) 166 31.8 (29.7 – 34.2) 33 P= 0.352 tHcy μmol/L) ( 5.7 (5.3 – 6.2) 84 5.6 (5.3 – 5.9) 165 5.9 (5.3 – 6.6) 34 P= 0.618 MMA (nmol/L) 360 (334 – 389) 84 378 (357 – 400) 163 339 (299 – 384) 34 P= 0.230 SAM (nmol/L) 200 (186 – 215)a 82 184 (176 – 192)a 159 170 (149 – 195)b 33 P= 0.032