Application of fluorescence in situ hybridization (FISH) as a tool to aid cytogenetics in 1,409 fetal samples.

AIM: To evaluate the technical application of fluorescence in situ hybridization (FISH) as a support to classical cytogenetic in numerical chromosomal aneuploidies studies in samples of amniotic fluid, chorionic villus, and fetal loss. MATERIALS AND METHODS: The authois performed cytogenetic analyses in 1,409 patients (678 amniocentesis, 512 chorionic villus samples, and 219 spontaneous abortions) during one year. FISH molecular study aided traditional cytogenetic in 90 cases. These cases were indicated based on the diagnostic hypothesis of each patient or when no cellular growth was obtained. The authors standardized the FISH in discoloured slides. RESULTS: They had 85% positive FISH in amniotic fluid, 70% in chorionic villus, and 90% in abortion material using 13, 18, 21 X and Y centromeric probes. It showed 12% of altered FISH in amniotic fluid (100% trisomies), 10% in chorionic'villus (50% trisomy and 50% X - monosomy), and 22% in abortion material (50% trisomy, 25% X-monosomy, and 25% triploidy). FISH and cytogenetic analysis confirmed the results. CONCLUSION: This technique revolutionized clinical and research applications of cytogenetics. In this particular paper, FISH was a valuable and reliable technique to promptly identify rapid detection of aneuploidies in interphase cells, metaphase spread and paraffin-embedded samples. It is hoped that, in the future, the economic viability of array CGH and FISH, with the decreasing cost of testing and their genomics advantages can be incorporated as routine and customized in the approach of prenatal diagnosis.

Fas/CD95 promoter polymorphism gene and its relationship with cervical carcinoma.

OBJECTIVE: Apoptosis is an important fail-safe control in human papillomavirus (HPV)-associated carcinogenesis. We tested the hypothesis that the A/G polymorphism at -670 of Fas promoter is associated with an increased risk for cervical cancer, using a matched case-control setting. METHODS: The material in this case-control study consisted of 91 patients with cervical carcinoma and 176 population-based control subjects, recruited between 2002 and 2004; all the ethnic Brazilian women had histologically confirmed cervical carcinoma. Control subjects were age-matched; healthy women who were selected following a negative cervical cytology and normal colposcopy. Fas genotyping was performed using a PCR-RFLP technique. RESULTS: No significant difference existed in the distribution of the Fas polymorphisms (wild, heterozygous, mutant) between the cases and controls. The heterozygous (OR: 4.85, 95% CI: 1.1-22.6) genotypes among the younger (< 48 yrs) cancer patients were almost 5-fold increased, as compared with the wild type. No such increase was observed among the patients older than 48 years. CONCLUSIONS: Our data suggest that 670A/G polymorphism in the promoter region of the death receptor Fas is associated with an increased risk of cervical cancer among Brazilian women under 48 years. The mechanisms would be the inhibition of apoptosis by Fas -670G allele-mediated down-regulation of Fas transcription.

Study of p53 codon 72 polymorphism in patients with breast cancer.

Breast cancer is a common disease in Western societies, with an incidence of 46.31/100,000 women/year in Brazil. The tumor suppressor gene TP53 is one of the most studied genes regarding the presence of mutations. Indeed, 50% of all tumors are known to exhibit changes in the TP53 nucleotide sequence due to carcinogenic processes. As to the presence of polymorphism, the TP53 gene is polymorphic at the nucleotide residue 347 (codon 72). In the current study, we examine if this polymorphism is associated with the clinicopathological parameters of breast cancer patients in a Brazilian population. One hundred and thirteen patients with breast cancer were included. The polymorphic region of the TP53 gene was PCR-amplified from genomic DNA obtained from buccal cells. Specific primers for the Pro and Arg allele were used. Correlations of polymorphism with age, staging, nuclear grade, lymph node status, estrogen receptor status and lymphatic and/or blood vessel invasion were evaluated. Statistical analysis was performed using the Fisher's exact test. The frequency of p53 Arg/Arg was 57% and of the heterozygous allele Arg/Pro it was 39%. There was no correlation between polymorphism and clinicopathological parameters. According to our results, the TP53 polymorphism, at the 347 residue, is not associated with any clinicopathological findings of patients with breast cancer.

Differential gene expression assessed by cDNA microarray analysis in breast cancer tissue under tamoxifen treatment.

Our purpose was to identify tamoxifen (TAM) responsive genes after 30 days of TAM treatment in tumor tissues obtained from women with breast cancer using microarray expression analysis. In our study, we identified 12 candidates to be considered as tamoxifen-modulated genes. Among them, we selected two candidates the TEGT BI-1 (testis enhanced gene transcript Bax Inhibitor-1) and the CD63 gene in order to further confirm their differential expression under tamoxifen effects. We observed that both were down-regulated in tumor tissues of patients during TAM treatment. TEGT is able to inhibit the expression of Bax, which is known to promote apoptosis. On the other hand, CD63 encodes a cell membrane protein and it seems to be involved in mechanisms of platelet activation, cell adhesion and cell motility. We therefore hypothesize that TAM would be able to modulate tumor growth by down-regulating genes involved in mechanisms such as cell cycle control, tumor invasion and metastasis.

Progesterone receptor (PROGINS) polymorphism and the risk of endometrial cancer development.

The progesterone receptor gene (PROGINS) has been identified as a risk modifier for benign and malignant gynecological diseases. The present case-control study is to evaluate the role of the PROGINS polymorphisms, as risk factor, for endometrial cancer development and to investigate the association between these genetics variants and clinical/pathologic variables of endometrial cancer. PROGINS polymorphism was examined in a total of 121 patients with endometrial cancer and 282 population-based control subjects, all located at the same area in São Paulo, SP, Brazil. The genotyping of PROGINS polymorphism was determined by polymerase chain reaction. The frequencies of PROGINS polymorphism T1/T1, T1/T2, and T2/T2 were 82.6%, 14.9%, and 2.5% in the endometrial cancer patients and 78.4%, 21.6%, and 0% in the controls, respectively. The chi(2) test showed a higher incidence of the T2/T2 genotype in the endometrial cancer group subjects, these results were statistically different (P= 0.012). However, due to the fact that there were no women in the control group showing homozygosis for the allele T2, the correct evaluation of odds ratio could not be properly calculated. Regarding the clinical and pathologic findings observed within the group of patients with endometrial cancer, there was significant correlation between T1/T2 genotype and the presence of myoma (P= 0.048). No correlations were observed among the other variables. These data suggest that the PROGINS polymorphism T2/T2 genotype might be associated with an increased risk of endometrial cancer.