Heritable genomic diversity in breast cancer driver genes and associations with risk in a Chilean population

BACKGROUND: Driver mutations are the genetic components responsible for tumor initiation and progression. These variants, which may be inherited, influence cancer risk and therefore underlie many familial cancers. The present study examines the potential association between SNPs in driver genes SF3B1 (rs4685), TBX3 (rs12366395, rs8853, and rs1061651) and MAP3K1 (rs72758040) and BC in BRCA1/2-negative Chilean families. METHODS: The SNPs were genotyped in 486 BC cases and 1258 controls by TaqMan Assay. RESULTS: Our data do not support an association between rs4685:C > T, rs8853:T > C, or rs1061651:T > C and BC risk. However, the rs12366395-G allele (A/G + G/G) was associated with risk in families with a strong history of BC (OR = 1.2 [95% CI 1.0-1.6] p = 0.02 and OR = 1.5 [95% CI 1.0-2.2] p = 0.02, respectively). Moreover, rs72758040-C was associated with increased risk in cases with a moderate-to-strong family history of BC (OR = 1.3 [95% CI 1.0-1.7] p = 0.02 and OR = 1.3 [95% CI 1.0-1.8] p = 0.03 respectively). Finally, risk was significantly higher in homozygous C/C cases from families with a moderate-to-strong BC history (OR = 1.8 [95% CI 1.0-3.1] p = 0.03 and OR = 1.9 [95% CI 1.1-3.4] p = 0.01, respectively). We also evaluated the combined impact of rs12366395-G and rs72758040-C. Familial BC risk increased in a dose-dependent manner with risk allele count, reflecting an additive effect (p-trend = 0.0002). CONCLUSIONS: Our study suggests that germline variants in driver genes TBX3 (rs12366395) and MAP3K1 (rs72758040) may influence BC risk in BRCA1/2-negative Chilean families. Moreover, the presence of rs12366395-G and rs72758040-C could increase BC risk in a Chilean population.

Rendimiento de dos índices predictores de mortalidad (PSI y CURB-65) en pacientes adultos inmunocompetentes hospitalizados por neumonía adquirida en la comunidad / Yield of two mortality predictors in immunocompetent patients with community acquired pneumonia

Background: The severity of community acquired pneumonia (CAP) can be evaluated by the PSI and CURB-65 scales. However, it is unknown whether their predictive capacity varies according to the etiology of the disease. Aim: To compare the performance of these scales in adults with viral, bacterial, mixed, and no agent detected CAP. Material and Methods: We studied 725 patients hospitalized for CAP aged 18 to 95 years (47% females) Urinary S. pneumoniae and Legionella antigens were detected by immuno-chromatography (Binax®). Respiratory viruses and bacteria were detected by PCR in nasopharyngeal smears. The proportions of deaths, admission to the intensive care unit (ICU), and oxygen therapy were compared between mild and non-severe patients defined by PSI (I/II and I-III) and CURB-65 (1 and 1-2), according to the causative agent. Results: Ten percent of patients died. A causative agent was detected in 65%. The proportion of mild and non-severe patients according to PSI and CURB-65, and of deceased patients, admitted to the ICU and with oxygen therapy was similar in the four categories per agent. There were no deaths among non-severe patients with bacterial CAP. However, 6% of patients with CAP caused by virus or without causative agents, died. No deaths occurred among mild patients with bacterial CAP. In viral CAP, no deaths occurred among patients classified as mild only by PSI. The yields of PSI were greater than those of CURB-65 in non-severe patients who died and were admitted to the ICU with bacterial and viral CAP (5 and 14%; 7 and 12% respectively, p = 0.04). Conclusions: The prognostic performance of PSI in CAP varies according to the causative agent in adults. It is higher in non-severe bacterial cases, and superior to CURB-65.

Molecular analysis of the eighteen most frequent mutations in the BRCA1 gene in 63 Chilean breast cancer families

BRCA1 gene mutations account for nearly all families with multiple cases of both early onset breast and/or ovarian cancer and about 30% of hereditary breast cancer. Although to date more than 1,237 distinct mutations, polymorphisms, and variants have been described, several mutations have been found to be recurrent in this gene. We have analyzed 63 Chilean breast/ovarian cancer families for eighteen frequent BRCA1 mutations. The analysis of the five exons and two introns in which these mutations are located was made using mismatch PCR assay, ASO hybridization assay, restriction fragment analysis, allele specific PCR assay and direct sequentiation techniques. Two BRCA1 mutations (185delAG and C61G) and one variant of unknown significance (E1250K) were found in four of these families. Also, a new mutation (4185delCAAG) and one previously described polymorphism (E1038G) were found in two other families. The 185delAG was found in a 3.17 % of the families and the others were present only in one of the families of this cohort. Therefore these mutations are not prominent in the Chilean population. The variant of unknown significance and the polymorphism detected could represent a founder effect of Spanish origin.

P53 Codon 72 polymorphism and risk of cervical cancer

Storey et al. (1998) implicated the proline/argine polymorphism of the codon 72 of the tumor-suppressor gene p53 in the development of cervical cancer (CC) with the observation that the p53 protein is more efficiently inactivated by the E6 oncoprotein of human papillomavirus in p53 arginine as compared with its proline isoform. These authors further noted that in the United Kingdom, individuals homozygous for the arginine allele were several times more susceptible to HPV-associated tumorigenesis that proline/arginine heterozygotes. Subsequent studies in different countries failed to unanimously confirm this association. Motivated by the high incidence of CC in Chile, we undertook a case control study obtaining the following frequencies for genotypes PP, AP and AA in 60 ICC cases and 53 carefully selected controls: 0.067, 0.250, 0.683 and 0.075, 0.453, 0.472 respectively. A significant difference (X2 = 3.19 p < 0.02) and an odds ratio of 2.62 supported Storey et al (1998)'s results. In addition, rejecting previous hypotheses about the world distribution of the p53 codon 72 polymorphism, we conclude that this distribution most likely represents ancient human dispersal routes. Several methodological and biological explanations for the results obtained in previous negative association studies are briefly discussed

Analysis of 5382insC (BRCA1) and 6174delT (BRCA2) mutations in 382 healthy Chilean women with a family history of breast cancer

Breast cancer is the most common malignancy among women. Chilean studies reveal that this cancer presents the third highest mortality rate. A family history of breast cancer is one of the major risk factors for the development of this disease. BRCA1 and BRCA2 are the two main hereditary breast cancer susceptibility genes, and mutations in these genes are related to inherited breast cancer. In specific populations only some mutations have been found to be associated with susceptibility. The purpose of this study was to establish the frequency of 5382insC (BRCA1) and 6174delT (BRCA2) germline mutations in 382 healthy Chilean women with at least two relatives affected with breast cancer and in probands and their relatives from 8 high risk families for breast cancer, using mismatch PCR assay. The results obtained showed that 5382insC and 6174delT mutations were not found in either of the groups studied. The ethnic origin of the contemporary Chilean population and the data reported in the literature suggest that these mutations may be absent or have a very low frequency in this population.. This genetic study is part of a breast cancer screening program that also includes annual mammography and clinical breast examination over a five-year period. Strategies to reduce morbidity and mortality associated with breast cancer lie in early detection in women with genetic risk.