Matrix metalloproteinase 9 -1562C/T polymorphism increased protein levels in patients with colorectal cancer in a sample from southeastern Brazil.

We examined whether the allelic and/or genotypic profile of locus -1562C/T of the matrix metalloproteinase (MMP-9) gene influences the protein expression levels of MMP-9 in patients with colorectal cancer (CRC) compared with controls. A total of 104 patients with CRC and 84 controls were evaluated. Peripheral blood was collected from both groups and DNA extraction was performed for -1562C/T genotyping; the plasma was used for MMP-9 quantification. The CT genotype was associated with increased MMP-9 expression (P = 0.0211). High levels of protein, independently of polymorphisms, were observed in the patient group (P < 0.0001) compared to controls. Mucinous tumors with signet ring cells were more frequent in females (P = 0.0177). Overall, patients older than 50 years showed a significant risk of developing CRC (P = 0.0001). MMP-9 plasma expression was increased in patients with CRC compared to controls, particularly in those with the heterozygous -1562CT genotype.

TNF microsatellite alleles may confer protection against the development of lipodystrophy syndrome in Brazilian HIV patients.

The aim of this study was to evaluate the frequency of TNFa-e microsatellites and the promoter region (TNF-308 and TNF-238) in HIV/AIDS-infected patients presenting or not lipodystrophy syndrome (LS). The design is the genetic case-control association study. Microsatellite and the TNF promoter region polymorphisms were amplified by PCR and submitted to polyacrylamide gel electrophoresis. The genotypes and allele frequencies for 67 HIV-positive patients with lipodystrophy were compared with 50 HIV-positive patients with no evidence of lipodystrophy and with 131 healthy HIV-negative individuals. The presence of the TNFa5 allele could provide HIV/AIDS patients with protection against developing LS. The presence of TNF-308G allele, as well as of its homozygote TNF-308GG, were associated with susceptibility to developing LS. In addition, the presence of the haplotype TNFe3-d3-238G-308A-c1-a5-b7 suggests protection against developing that syndrome. This study highlights that polymorphic sites spanning the region nearby the TNF locus are associated with LS development in HIV/AIDS patients.

The genetic structure of 3'untranslated region of the HLA-G gene: polymorphisms and haplotypes.

The HLA-G gene is predominantly expressed at the maternal-fetal interface. It has been associated with maternal-fetal tolerance and in the inhibition of cytotoxic T lymphocyte and natural killer cytolytic functions. At least two variations in the 3'untranslated region (UTR) of HLA-G locus are associated with HLA-G expression levels, the 14-bp deletion/insertion polymorphism and the +3142 single-nucleotide polymorphism (SNP). However, this region has not been completely characterized yet. The variability of the 3'UTR of HLA-G gene and its haplotype structure were characterized in 155 individuals from Brazil, as well as HLA-G alleles associated with each of the 3'UTR haplotype. The following eight variation sites were detected: the 14-bp polymorphism and SNPs at the positions +3003T/C, +3010C/G, +3027A/C, +3035C/T, +3142G/C, +3187A/G and +3196C/G. Similarly, 11 different 3'UTR haplotypes were identified and several HLA-G alleles presented only one 3'UTR haplotype. In addition, a high linkage disequilibrium among the variation sites was detected, especially among the 14-bp insertion and the alleles +3142G and +3187A, all previously associated with low mRNA availability, demonstrating that their effects are not independent. The detailed analyses of 3'UTR of the HLA-G locus may shed some light into mechanisms underlying the regulation of HLA-G expression.

HLA-G 14-bp polymorphism at exon 8 in Amerindian populations from the Brazilian Amazon.

HLA-G (human leukocyte antigen-G) plays an important role in the modulation of the maternal immune system during pregnancy. HLA-G alleles presenting a 14-bp insertion at exon 8 have been associated with decreased messenger RNA levels, preeclampsia, and miscarriages. This suggests that natural selection may exert a strong influence against the insertion allele in isolated populations. DNA samples from 384 Amazonian Indians spread across seven isolated tribes were evaluated for the 14-bp polymorphism. The insertion frequency (38.54%) was somewhat low. The Ewens-Watterson's neutrality test showed a slight trend toward balancing selection operating at this locus but no correlation between the 14-bp locus and fertility data was found. To sum up, no definitive evidence was obtained indicating that the 14-bp frequencies in Amerindians depart from neutrality.

Identification of a novel 120 bp allele at the TNFd microsatellite locus.

Tumor necrosis factor-alpha (TNF-alpha) is a pro-inflammatory cytokine mainly secreted by macrophages and T-cells that play a key role in the pathogenesis of many infectious and inflammatory diseases. The TNF gene cluster is located within the class-III region of the highly polymorphic major histocompatibility complex on human chromosome 6p21. A cluster of six multiallelic microsatellites has been identified in the TNF region, named TNF a-e. TNFb, TNFc, TNFd, and TNFe are (GA)n repeats, whereas TNFa and TNFf are (GT)n and (CA)n repeats, respectively. The TNFd microsatellite locus maps 8-10 kb centromeric to the TNF-alpha gene, downstream to the TNF-beta gene.

Association of tumor necrosis factor a-2 and a-8 microsatellite alleles with human papillomavirus and squamous intraepithelial lesions among women in Brazil.

Infection with oncogenic human papillomavirus (HPV) is considered to be the major risk factor for cervical cancer. Tumor necrosis factor (TNF) is a pluripotent cytokine that plays an important role in inhibiting the action of microbial agents, and TNF microsatellite polymorphisms have been associated with several diseases, including cancer and viral infections. This study analyzed the associations between TNFa to -e microsatellite polymorphisms and the severity of squamous intraepithelial lesions (SIL), according to the presence of the oncogenic HPV16 and HPV18 types. Samples from 146 HPV-positive women with low-grade SIL (LSIL) and high-grade SIL (HSIL) and samples from 101 healthy women were studied. TNF microsatellite polymorphism typing and HPV detection and typing were performed using PCR-amplified DNA hybridized with sequence-specific primers. Data were analyzed by Fisher's exact test using the GENEPOP software. Significant associations were observed between LSIL and the TNFa-8 allele (4/166; P = 0.04), as well as between TNFa-2 with HPV18 only (16/44; P = 0.002) and TNFa-2 with HPV18 coinfection with HPV16 (16/44; P = 0.001). Patients exhibiting the TNFa-2 allele and harboring HPV18, in the presence or absence of coinfection with HPV16, had an increased risk of HSIL occurrence (13/38; P = 0.04; 5/10; P = 0.04) compared to patients with other HPV types. These results suggest that the TNFa-8 allele is associated with increased susceptibility to the occurrence of LSIL and that despite the presence of a high TNF-alpha production allele, the ability of HPV18 to resist the inhibitory effects of TNF-alpha may contribute to the occurrence of infection and consequently to HSIL in women with cervical HPV18 infection.

Langerhans' cell count and HLA class II profile in cervical intraepithelial neoplasia in the presence or absence of HIV infection.

OBJECTIVES: The progression of immunosuppression in human immunodeficiency virus (HIV)+ women has been correlated with elevated incidence of squamous intraepithelial lesions (SIL), probably indicating the role of local immune milieu. In this study, we analysed S100, and HLA class II molecule expression in cervical biopsies according to HIV status, to the severity of SIL and to human papillomavirus (HPV) type. METHODS: Biopsies from 34 HIV+ and 44 HIV- patients with normal cervix or low- or high-grade SIL were studied. Langerhans' cells (LC) (S100), HLA class II and HLA-DQ molecules were evaluated by immunohistochemistry. HPV detection was performed using polymerase chain reaction (PCR). For statistical analysis Mann-Whitney (P< or =0.05) and Spearman test were used. RESULTS: Epithelial S100 and HLA class II density were significantly increased with the severity of lesion (P=0.032; P=0.005). Epithelial S100+ increased in HPV+ (P=0.038), and HLA class II density decreased in HPV 16+ (P=0.035) or 18+ (P<0.0001) samples. HIV infection was associated with increased stromal S100+ (P=0.0005) and decreased HLA class II densities (P=0.0001). Decreased stromal S100+ was observed in women with CD4<500 cells/microl (P=0.050). Among HIV+ patients with SIL, the lowest S100 and epithelial HLA class II densities were detected in women with CD4<200 cells/microl (P=0.045). CONCLUSIONS: After the establishment of AIDS, increased numbers of immature LCs and a reduction in HLA class II occurred, possibly turning the cervical milieu more favourable to HPV persistence. HPV 16 and 18 infections may interfere with the antigen presenting activity, possibly as an evasion mechanism.