Nationwide Study of Breast Cancer Risk Factors in Latinas

Breast cancer is the most common cancer among American women. Any woman can be affected by breast cancer, with risk for the disease increasing with age. Risk for breast cancer is also exacerbated in women who have certain genetic alterations. Mutations in the BRCA1 and BRCA2 genes predispose women to breast and ovarian cancer, and are increasingly recognized in prostate and pancreatic cancers (1-3). In Caucasian and Asian ethnicities BRCA mutations are associated with basal-type/triple-negative disease. However this association between BRCA gene mutations and basal/triple-negative disease has been understudied in other ethnicities (4-6). The incidence and mortality of breast cancer of Hispanics and Native Americans are lower than other ethnicities; however they are underrepresented in epidemiological and clinical studies. Further, it is known that common recurrent mutations in BRCA1 and BRCA2 genes exist in Hispanic/Latino communities which account for 35-45% of mutation carriers (7, 8). The objective of our study is thus to investigate triple negative disease and BRCA gene mutations in Hispanic women

Nationwide Study of Breast Cancer Risk Factors in Latinas

Breast cancer is the most common cancer among American women. Any woman can be affected by breast cancer, with risk for the disease increasing with age. Risk for breast cancer is also exacerbated in women who have certain genetic alterations. Mutations in the BRCA1 and BRCA2 genes predispose women to breast and ovarian cancer, and are increasingly recognized in prostate and pancreatic cancers (1-3). In Caucasian and Asian ethnicities BRCA mutations are associated with basal-type/triple-negative disease. However this association between BRCA gene mutations and basal/triple-negative disease has been understudied in other ethnicities (4-6). The incidence and mortality of breast cancer of Hispanics and Native Americans are lower than other ethnicities; however they are underrepresented in epidemiological and clinical studies. Further, it is known that common recurrent mutations in BRCA1 and BRCA2 genes exist in Hispanic/Latino communities which account for 35-45% of mutation carriers (7, 8). The objective of our study is thus to investigate triple-negative disease and BRCA gene mutations in Hispanic women

The ERCC6 Gene and Age-Related Macular Degeneration

Background: Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the developed countries and is caused by both environmental and genetic factors. A recent study (Tuo et al., PNAS) reported an association between AMD and a single nucleotide polymorphism (SNP) (rs3793784) in the ERCC6 (NM_000124) gene. The risk allele also increased ERCC6 expression. ERCC6 is involved in DNA repair and mutations in ERCC6 cause Cockayne syndrome (CS). Amongst others, photosensitivity and pigmentary retinopathy are hallmarks of CS. Methodology/Principal Findings: Separate and combined data from three large AMD case-control studies and a prospective population-based study (The Rotterdam Study) were used to analyse the genetic association between ERCC6 and AMD (2682 AMD cases and 3152 controls). We also measured ERCC6 mRNA levels in retinal pigment epithelium (RPE) cells of healthy and early AMD affected human donor eyes. Rs3793784 conferred a small increase in risk for late AMD in the Dutch population (The Rotterdam and AMRO-NL study), but this was not replicated in two non-European studies (AREDS, Columbia University). In addition, the AMRO-NL study revealed no significant association for 9 other variants spanning ERCC6. Finally, we determined that ERCC6 expression in the human RPE did not depend on rs3793784 genotype, but, interestingly, on AMD status: Early AMD-affected donor eyes had a 50% lower ERCC6 expression than healthy donor eyes (P = 0.018). Conclusions/Significance: Our meta analysis of four Caucasian cohorts does not replicate the reported association between SNPs in ERCC6 and AMD. Nevertheless, our findings on ERCC6 expression in the RPE suggest that ERCC6 may be functionally involved in AMD. Combining our data with those of the literature, we hypothesize that the AMD-related reduced transcriptional activity of ERCC6 may be caused by diverse, small and heterogeneous genetic and/or environmental determinants

Differential gene and microRNA expression between etoposide resistant and etoposide sensitive MCF7 breast cancer cell lines.

In order to develop targeted strategies for combating drug resistance it is essential to understand it's basic molecular mechanisms. In an exploratory study we have found several possible indicators of etoposide resistance operating in MCF7VP cells, including up-regulation of ABC transporter genes, modulation of miRNA, and alteration in copy numbers of genes

Cellular cytotoxicity assays determined that MCF7VP cells are more resistant to etoposide than the parental MCF7 cells.

<p>Curve fitting of cellular cytotoxicity data with GraphPad prism. (MCF7VP- red squares and MCF7- blue circles). The dotted line represents the actual curve and the solid line depicts the fitted curve. The assay was carried out using 10,000 cells per well of a 96 well plate and 100 µl of various concentrations (0–100 µM) of etoposide (the graph depicts log concentrations of etoposide).</p

GSEA analysis of microarray data showing enrichment of the JAK-STAT and MAP Kinase pathways and upregulation of ECM structural component genes along with qRT-PCR validation of the down-regulation of topoisomerase 2 gene expression in MCF7VP cells.

<p>Fig. 5A. Gene set enrichment analysis of microrray data depicting the enrichment of genes in the JAK-STAT signaling pathway. The GSEA software was used to calculate the enrichment levels. Fig. 5B. Gene set enrichment analysis of microrray data depicting the enrichment of genes in the MAP kinase signaling pathway. The GSEA software was used to calculate the enrichment levels. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045268#pone-0045268-g005" target="_blank">Figure 5C</a>. Gene set enrichment analysis depicting enrichment of ECM (extra-cellular matrix) genes in MCF7VP cells. The GSEA algorithm was used to calculate the enrichment levels. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045268#pone-0045268-g005" target="_blank">Figure 5D</a>. Down-regulation of TOPO2A (the drug target of etoposide) in MCF7VP cells. The microarray data was validated by qRTPCR as depicted in the bar chart which shows differences in fold change.</p

Expression of ABCC1 and ABCC6 in MCF7VP cells, Fig. 3A.

<p>Up-regulation of ABCC1 in MCF7VP cells validated by qRT-PCR. The gene expression level of ABCC1 was found to be up-regulated in the MCF7VP cell line using microfluidic arrays, this was validated using quantitative RT PCR with taqman probes against ABCC1. The fold change was calculated using the delta delta CT method. Fig. 3B. Up-regulation of ABCC6 in MCF7VP cells validated by qRT-PCR. ABCC6 up-regulation was validated with quantitative qRT PCR and taqman probes against ABCC6. The fold change in gene expression between the MCF7 and MCF7VP was calculated using the dd CT method.</p

Gene expression microarray data and GO analysis revealed differential gene expression between MCF7 & MCF7VP cell lines.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045268#pone-0045268-g004" target="_blank">Figure 4A</a>. Heatmap depicting differential gene expression in etoposide resistant and etoposide sensitive MCF7 cells using Affymetrix U133 arrays (>2fold change in expression, p<0.05). Up-regulated genes depicted in red, down-regulated genes in blue (see color bar). Fig. 4B. DAVID analysis of microarray data depicting the number of genes expressed in different cellular mechanisms and pathways (Top 219 genes, p<0.05).</p