Avaliação de polimorfismos nos genes XPD e XRCC3 em carcinomas orais de células escamosas / Evaluation of polymorphisms in the XPD and XRCC3 genes in oral squamous cell carcinomas

O carcinoma oral de células escamosas (COCE) é importante causa de morbidade e mortalidade em todo o mundo a despeito dos recentes avanços nas formas de tratamento. Diante disto, várias são as pesquisas no intuito de se encontrar marcadores que possam melhorar a avaliação do prognóstico desta doença. Neste sentido têm se destacado os estudos dos polimorfismos genéticos, os quais podem influenciar a suscetibilidade individual para o desenvolvimento do câncer. O objetivo deste estudo foi avaliar a associação entre a frequência dos polimorfismos XPD Lys751Gln e XRCC3 Thr241Met e o perfil clinicopatológico em casos de COCE, incluindo idade, sexo, presença ou não de metástase e gradação histológica de malignidade de Bryne (1998). A amostra foi composta por 54 casos de COCE e 40 casos de hiperplasia fibrosa inflamatória (HFI). Os casos de COCE foram classificados como lesões de baixo ou de alto grau de malignidade. Foram utilizadas amostras de DNA previamente extraído de blocos de parafina. Os genótipos para cada caso foram determinados através da técnica de PCR-RFLP (reação em cadeia da polimerase - polimorfismos de comprimento de fragmentos de restrição). Os resultados foram submetidos aos testes estatísticos Exato de Fisher e Quiquadrado de Pearson e foi calculada a razão de chance (odds ratio) considerando o nível de significância quando p<0,05. Para o XPD, o genótipo Lys/Gln foi mais comum nas HFIs (n=28; 70%) que nos COCEs (n=24; 44,4%) (OR: 0,3; p<0,05). A frequência do alelo Gln foi maior nas lesões de alto grau, em comparação às de baixo grau (0,48 e 0,21, respectivamente) (OR: 3,4; p<0,05). Para o XRCC3, o alelo Met foi mais frequente no COCE que na HFI (0,49 e 0,35, respectivamente) (OR: 2,6; p<0,05). O genótipo Met/Met foi associado à presença de metástases (OR: 8,1; p<0,05). Não houve associação estatística significativa entre os genótipos e a idade ou sexo dos pacientes. Na amostra analisada, a maior frequência do alelo XPD Gln na HIF revela um possível papel protetor dessa variante contra o desenvolvimento do COCE. Todavia, sua associação com lesões de alto grau, indica que esse alelo poderia influenciar no processo de progressão após o tumor instalado. A presença do alelo XRCC3 Met, por sua vez, parece contribuir com o desenvolvimento do COCE e de metástases nessas lesões. (AU)

Oral squamous cell carcinoma (OSCC) is an important cause of morbidity and mortality worldwide despite recent advances in treatment. There are several studies aiming to find markers that may improve the assessment of this disease prognosis. Studies about genetic polymorphisms have gained prominence due to their influence on individual susceptibility to cancer development. The aim of this study was to evaluate the association between the frequency of polymorphisms XPD Lys751Gln and XRCC3 Thr241Met and clinicopathological features of OSCC cases, including age, sex, presence or absence of metastases, and histological grading of malignancy according to Bryne (1998). Sample consisted of 54 cases of OSCC and 40 cases of inflammatory fibrous hyperplasia (IFH). OSCC cases were classified as low or high grade. DNA samples were previously extracted from paraffin blocks. Genotypes for each case were determined through PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism). Results were analyzed by Fisher's exact test and Chi-square test and the odds ratio was calculated considering p < 0.05 to indicate statistical significance. For XPD, Lys/Gln genotype was more common in IFHs (n=28; 70%) than in OSCCs (n=24; 44.4%) (OR: 0.3; p<0.05). Frequency of Gln allele was higher in high-grade lesions when compared to low grade lesions (0.48 and 0.21, respectively) (OR: 3.4; p<0.05). For XRCC3, Met allele was more common in OSCC than in IFH (0.49 and 0.35, respectively) (OR: 2.6; p<0.05). Met/Met genotype was associated with presence of metastases (OR: 8.1; p<0.05). There was no statistically significant association between the genotypes and the age or sex of patients. In the present sample, the higher frequency of XPD Gln allele in IFH reveals a possible protective role of this variant against the development of OSCC. However, its association with high-grade lesions indicates that this allele could influence the tumor progression after the neoplasia development. The presence of XRCC3 Met allele, in turn, seems to contribute to the development of OSCC and metastases. (AU)

Vitamin D receptor (FokI, BsmI and TaqI) gene polymorphisms and type 2 diabetes mellitus : A North Indian study.

Background : The vitamin D receptor (VDR) gene is a candidate gene for susceptibility to several diseases. Studies on association between VDR polymorphisms and risk of type 2 diabetes (T2DM) in different ethnic populations are yet inconclusive. Aims : This study was conducted to evaluate association between VDR polymorphisms and genetic susceptibility to T2DM in the north Indian population. Settings and Design : One hundred clinically diagnosed T2DM patients and 160 healthy controls from the north Indian population were recruited for genetic association study. Materials and Methods : Genomic DNA was extracted from blood and genotyped for the single nucleotide polymorphism SNPs of FokI (T/C) [rs2228570], BsmI (A/G) [rs1544410] and TaqI (C/T) [rs731236] by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. Statistical Analysis Used : Genotype distribution and allelic frequencies were compared between patients and controls. Mean values and odds ratios (ORs) with 95% confidence interval (CI) were calculated using SPSS software (version 15.0). Results : The genotype distribution, allele and haplotype frequencies of VDR polymorphism did not differ significantly between patients and controls. Mean age and waist-hip ratio of patients were found to be associated with VDR polymorphism. Combination studies showed FFBbtt increased the risk of T2DM in north Indians. Conclusions : Our data suggest that VDR gene polymorphism in combination of genotypes is associated with the risk of T2DM and thus requires further studies as a probable genetic risk marker for T2DM.

Study on the association of estrogen receptor genotypes with bone mineral density in Chinese postmenopausal Han women in Beijing / 北京大学学报(医学版)

Objective:To investigate the distribution of polymorphism of estrogen receptor (ER) gene in postmenopausal Han women in Beijing as well as its relationship with bone mineral density (BMD).Methods:Xba Ⅰ,and Pvu Ⅱ polymorphisms of ER gene were studied by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) and BMD were determined by DEXA (dual-energy X-ray absorptiometry).The relationship between BMD and polymorphism of ER gene was studied by variance analysis.Results:Pvu Ⅱ polymorphism of ER gene was not associated with BMD of spongy and compact bone of radius;while Xba Ⅰ polymorphism of ER gene was associated with BMD of spongy and compact bone of radius.The lowest BMD was found with XX genotype while the highest BMD was found with xx genotype.Conclusion:There is high correlation between of Xba Ⅰ polymorphism and BMD of spongy and compact bone of radius.Our study suggested some bases to explore the pathogenesis of osteoporosis and to prevent the development of osteoporosis.

Genetic study of hydatidiform moles by restriction fragment length polymorphisms (RFLPs) analysis

Twenty three hydatidiform moles (HMs) were studied using the techniques of "RFLPs" employing a minisatellite deoxyribonucleic acid probe. Among the 23 HMs, 17 were homozygous types resulting from a duplicated haploid sperm, and two were heterozygous types resulting from fertilization two independent sperms (dispermy). It was revealed that the four histopathologically diagnosed complete HMs (CHMs) were partial HMs (PHMs) with one maternal and 2 paternal chromosome contribution (diandry) or two maternal and 1 paternal alleles (digyny). The locus specific minisatellite probes were useful in classifying CHM into heterozygous and homozygous types as well as in diagnosing PHM. One heterozygous (50%) and 5 homozygous (29.4%) CHMs, and one PHM (25%) progressed to persistent gestational trophoblastic disease (p > 0.5).