Gene expression profiles induced by E6 from non-European HPV18 variants reveals a differential activation on cellular processes driving to carcinogenesis

AbstractCervical cancer in developed countries remains as a major concern on public health policies due to incidence and mortality rates. Persistent infection with high risk human papillomavirus is a necessary etiological agent in the progression to invasive cervical carcinoma. A proposed hypothesis is the association between more aggressive HPV variants and the risk to develop cervical cancer. In order to have a global perspective in terms of cellular transcripts and molecular pathways affected by HPV18 E6 intratype variants; we conducted a genome wide analysis of gene expression. Our results show that E6 derived from non-European variants are able to up-regulate cellular transcripts associated to the hallmarks of cancer; such as cell cycle, migration, Wnt pathway and mTor signaling. Moreover, we were able to show that HPV18 E6 from African variant had a major effect on cellular processes such as cell cycle and migration as confirmed by functional studies

A Molecular Characterization of the Allelic Expression of the BRCA1 Founder Δ9–12 Pathogenic Variant and Its Potential Clinical Relevance in Hereditary Cancer:International Journal of Molecular Sciences

Hereditary breast and ovarian cancer (HBOC) syndrome is a genetic condition that increases the risk of breast cancer by 80% and that of ovarian cancer by 40%. The most common pathogenic variants (PVs) causing HBOC occur in the BRCA1 gene, with more than 3850 reported mutations in the gene sequence. The prevalence of specific PVs in BRCA1 has increased across populations due to the effect of founder mutations. Therefore, when a founder mutation is identified, it becomes key to improving cancer risk characterization and effective screening protocols. The only founder mutation described in the Mexican population is the deletion of exons 9 to 12 of BRCA1 (BRCA1Δ9–12), and its description focuses on the gene sequence, but no transcription profiles have been generated for individuals who carry this gene. In this study, we describe the transcription profiles of cancer patients and healthy individuals who were heterozygous for PV BRCA1Δ9–12 by analyzing the differential expression of both alleles compared with the homozygous BRCA1 control group using RT–qPCR, and we describe the isoforms produced by the BRCA1 wild-type and BRCA1Δ9–12 alleles using nanopore long-sequencing. Using the Kruskal–Wallis test, our results showed a similar transcript expression of the wild-type allele between the healthy heterozygous group and the homozygous BRCA1 control group. An association between the recurrence and increased expression of both alleles in HBOC patients was also observed. An analysis of the sequences indicated four wild-type isoforms with diagnostic potential for discerning individuals who carry the PV BRCA1Δ9–12 and identifying which of them has developed cancer

Full-Exon Pyrosequencing Screening of BRCA Germline Mutations in Mexican Women with Inherited Breast and Ovarian Cancer

Hereditary breast cancer comprises 10% of all breast cancers. The most prevalent genes causing this pathology are BRCA1 and BRCA2 (breast cancer early onset 1 and 2), which also predispose to other cancers. Despite the outstanding relevance of genetic screening of BRCA deleterious variants in patients with a history of familial cancer, this practice is not common in Latin American public institutions. In this work we assessed mutations in the entire exonic and splice-site regions of BRCA in 39 patients with breast and ovarian cancer and with familial history of breast cancer or with clinical features suggestive for BRCA mutations by massive parallel pyrosequencing. First we evaluated the method with controls and found 41–485 reads per sequence in BRCA pathogenic mutations. Negative controls did not show deleterious variants, confirming the suitability of the approach. In patients diagnosed with cancer we found 4 novel deleterious mutations (c.2805_2808delAGAT and c.3124_3133delAGCAATATTA in BRCA1; c.2639_2640delTG and c.5114_5117delTAAA in BRCA2). The prevalence of BRCA mutations in these patients was 10.2%. Moreover, we discovered 16 variants with unknown clinical significance (11 in exons and 5 in introns); 4 were predicted as possibly pathogenic by in silico analyses, and 3 have not been described previously. This study illustrates how massive pyrosequencing technology can be applied to screen for BRCA mutations in the whole exonic and splice regions in patients with suspected BRCA-related cancers. This is the first effort to analyse the mutational status of BRCA genes on a Mexican-mestizo population by means of pyrosequencing

Variants of uncertain significance (VUS) detected in patients.

1<p>D: deletion; M: missense mutation; S: synonimous mutation; Ts: transition; Tv: transvertion.</p>2<p>B: benign; PD: probably damaging.</p

Evaluation of the methodological strategy for the detection of BRCA mutations.

1<p>Number of reads per nucleotide.</p>a<p>Types of mutations: F: frameshift; S: stop.</p

Detection of BRCA deleterious mutations in patients.

1<p>Number of reads per nucleotide.</p>2<p>Types of mutations: F: frameshift; S: stop.</p

Distribution of homopolymeric tracts across the reads.

<p>The base number signals are plotted against the sequence reads of the control run.</p

Clinical features of the patients with <i>BRCA</i> mutations.

a<p>ER  =  estrogen receptor; PR  =  progesterone receptor; HER2/neu  =  human epidermal growth factor receptor 2; Ki-67 =  antigen KI 67.</p

Genealogy of the family 15 carrier of the deleterious mutation c.2639_2640delTG in <i>BRCA2</i>.

<p>Individuals with cancer are represented with dark circles or with dark squares; the type of cancer is indicated as follows: Br: unilateral breast cancer; Cr: colorectal cancer; NE: Not especified neoplasia; L: lung cancer; La: laryngeal cancer; Ga: gastric cancer. Index patient is denoted with an arrow. Current age or known ages of cancer diagnosis and decease are showed. Numbers inside the rhombi indicate quantity of first-degree relatives. Asymptomatic carriers are represented with a midline.</p