Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteínas de Fusão bcr-abl/genética , Proteínas de Homeodomínio/genética , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , RNA Mensageiro/genética , Adolescente , Adulto , Sequência de Bases , Criança , Pré-Escolar , Humanos , Índia , Lactente , Leucemia Prolinfocítica Tipo Células B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Transcrição Gênica , Adulto JovemRESUMO
Breast cancer is initiated by exposure to endogenous and exogenous estrogens. A case-control (n= 250-500) study was undertaken to investigate the role of Single Nucleotide Polymorphisms (SNP's) in CYP17 (T34C), CYP19 (Trp39Arg) and FGFR2(C906T). Genotyping was done using the Taqman allelic discrimination assay for CYP17 (T34C) and FGFR2 (T906C) and PCR-CTPP for CYP19 (Trp39Arg). There was a significant protective association of the (TT/CC) genotype of the CYP17 gene against the risk of developing breast cancer (OR= 0.68, 95% CI: 0.49-0.96), which was more significant in postmenopausal women (OR= 0.56, 95% CI: 0.35-0.89) (p= 0.015). CYP19 (Trp39Arg) is a rare polymorphism and all the cases were homozygous for the wild type Trp allele (100%); this was also the case for 99.2% of the controls. We were unable to detect any variant form of the CYP19 gene in south Indian women. There was no significant association between the risk of breast cancer and FGFR2 (C906T). These results suggest that the CYP17 TT/CC genotype is associated with decreased risk for breast cancer, especially in post menopausal women.
Assuntos
Aromatase/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Esteroide 17-alfa-Hidroxilase/genética , Feminino , Frequência do Gene , Humanos , ÍndiaRESUMO
The present study was undertaken to examine the frequencies of GSTM1 (Null/Present), GSTP1 (Ile105Val) and p53 (Arg72Pro) genotypes and their relations to breast cancer susceptibility in South Indian women. This case - control study involved 250 consecutive breast cancer cases and 500 healthy controls matched in five-year age categories in the ratio of 1:2. Genotyping was performed by PCR for GSTM1, Real-Time Allelic discrimination assay for GSTP1 and PCR-CTPP for p53. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression after adjusting for the known risk factors for breast cancer. The frequencies for the GSTM1 Null genotype were 26% in the cases and 22% in the controls; for GSTP1 Ile/Ile, Ile/Val, Val/Val the frequencies were 46.6%, 41.9% and 11.5%, respectively, in cases and 46.0%, 43.8% and 10.2% in controls; for p53 Arg/Arg, Arg/Pro & Pro/Pro the frequencies were 26.4%, 50.0% and 23.6% in cases and 27.0%, 44.8% and 28.2% in controls. A nonsignificant elevation in breast cancer risk was observed among women who had the GSTM1 Null genotype (OR=1.24; 95% CI=0.83-1.84), the p53 Arg/Arg genotype (OR=1.28; 95% CI=0.81-2.03) and the Pro/Arg genotype (OR=1.49; 95% CI=0.99-2.25), and the GSTP1 Val/Val genotype (OR=1.1; 95% CI=0.64-1.91).
Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Glutationa S-Transferase pi/genética , Glutationa Transferase/deficiência , Glutationa Transferase/genética , Proteína Supressora de Tumor p53/genética , Substituição de Aminoácidos , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Feminino , Genótipo , Humanos , Índia , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo Genético , Polimorfismo de Nucleotídeo Único , Religião , Fatores de RiscoRESUMO
The aim of this work was to study the mutation profile in hMSH2 and hMLH1 genes in hereditary nonpolyposis colorectal cancer (HNPCC) patients in India. On the basis of the Bethesda criteria, 31 colorectal cancer patients were studied first for microsatellite instability, using the five markers recommended by the Bethesda guidelines. Twelve of 31 tumor samples were found to be MSI-H, 9 of 31 were MSI-L, and the rest were MSS. The 12 patients with MSI-H were analyzed for mutations in hMSH2 and hMLH1 genes using PCR-denaturing high-performance liquid chromatography (dHPLC), followed by sequencing of samples showing abnormal peaks. Of the five mutations detected, three were found to be deleterious mutations (hMSH2-R680X, hMLH1-E671X, and a splice junction mutation IVS16-2A --> G); one had a mutation of probable significance (hMLH1-C680G) and one was of unknown significance (hMSH2-R171K). This study has also shown that most of the early-onset colon (4/7) and early-onset rectal (15/21) cancers are MSS or MSI-L. This is the first study to describe the mutation in hMSH2 and hMLH1 in Indian patients, a low incidence region for colorectal cancer. A two-stage procedure using MSI testing followed by PCR-dHPLC was found to be an efficient method in studying the mutation profile in high-risk patients.
