Emergence and whole-genome sequence of Senecavirus A in Colombia

In 2015 and 2016, Senecavirus A (SVA) emerged as an infectious disease in Brazil, China and the United States (US). In a Colombian commercial swine farm, vesicles on the snout and coronary bands were reported and tested negative for foot-and-mouth disease virus (FMDv), but positive for SVA. The whole-genome phylogenetic analysis indicates the Colombian strain clusters with the strains from the United States, not with the recent SVA strains from Brazil.

Are ER+PR+ and ER+PR- breast tumors genetically different? A CGH array study

The estrogen receptor (ER) is a well-known predictor of breast cancer response to endocrine therapy. ER+ progesterone receptor (PR)- breast tumors have a poorer response to endocrine therapy and a more aggressive phenotype than ER+PR+ tumors. A comparative genomic hybridization array technique was used to examine 25 ER+PR+ and 23 ER+PR- tumors. Tissue microarrays composed of 50 ER+PR+ and 50 ER+PR- tumors were developed to validate the comparative genomic hybridization array results. The genes of interest were analyzed by fluorescence in situ hybridization. The ER+PR- group had a slightly different genomic profile when compared with ER+PR+ tumors. Chromosomes 17 and 20 contained the most overlapping gains, and chromosomes 3, 8, 9, 14, 17, 21, and 22 contained the most overlapping losses when compared with the ER+PR+ group. The gained regions, 17q23.2-q23.3 and 20q13.12, and the lost regions, 3p21.32-p12.3, 9pter-p13.2, 17pter-p12, and 21pter-q21.1, occurred at different alteration frequencies and were statistically significant in the ER+PR- tumors compared with the ER+PR+ tumors. ER+PR- breast tumors have a different genomic profile compared with ER+PR+ tumors. Differentially lost regions in the ER+PR- group included genes with tumor suppressor functions and genes involved in apoptosis, mitosis, angiogenesis, and cell spreading. Differentially gained regions included genes such as MAP3K3, RPS6KB1, and ZNF217. Amplification of these genes could contribute to resistance to apoptosis, increased activation of the PI3K/Akt/mTOR pathway, and the loss of PR in at least some ER+PR- tumors.

Transmission of influenza A virus in pigs

Influenza A virus infections cause respiratory disease in pigs and are a risk to public health. The pig plays an important role in influenza ecology because of its ability to support replication of influenza viruses from avian, swine and human species. Influenza A virus is widespread in pigs worldwide, and influenza A virus interspecies transmission has been documented in many events. Influenza A virus is mostly transmitted through direct pig-to-pig contact and aerosols although other indirect routes of transmission may also exist. Several factors contribute to differences in the transmission dynamics within populations including among others vaccination, pig flow, animal movement and animal introduction which highlights the complexity of influenza A transmission in pigs. In addition, pigs can serve as a reservoir of influenza A viruses for other pigs and other species and understanding mechanisms of transmission within pigs and from pigs to other species and vice versa is crucial. In this paper, we review the current understanding of influenza virus transmission in pigs. We highlight the ubiquity of influenza A virus in the pig population and the widespread distribution of pandemic H1N1 virus worldwide while emphasizing an understanding of the routes of transmission and factors that contribute to virus spread and dissemination within and between pig populations. In addition, we describe transmission events between pigs and other species including people. Understanding transmission is crucial for designing effective control strategies and for making well-informed recommendations for surveillance.

3q26 (hTERC) gain studied by fluorescence in situ hybridization as a persistence-progression indicator in low-grade squamous intraepithelial lesion cases

Gains of 3q26 chromosome region, where the human telomerase RNA gene (hTERC) is located, have been previously documented in cervical carcinomas and preneoplastic lesions. The aim of our study was to define the value of 3q26 gains related to persistence-progression in cervical specimens with cytologic diagnosis for low-grade squamous intraepithelial lesions, using liquid-based cytology (ThinPrep; Hologic, Marlborough, MA) and fluorescence in situ hybridization. For these purposes, 55 patients were included in the study: 25 cases with a negative cytologic diagnosis for squamous intraepithelial lesion or malignancy (20 premenopausal and 5 postmenopausal women, used as control negative cases) and 30 low-grade squamous intraepithelial lesion cases. The follow-up was performed using cytology at 6, 12, and 24 months after the low-grade squamous intraepithelial lesion diagnosis. When the cytology result showed a high-grade lesion, colposcopy and biopsy were performed. Fluorescence in situ hybridization technique with a 3q26 2-color commercial probe was performed to determine the number of hTERC copies. There were no differences between premenopausal and postmenopausal normal cases. Low-grade squamous intraepithelial lesion cases with regression in the follow-up at 6, 12, and 24 months showed a percentage of cells with 3q26 gains similar to the control cases and lower than low-grade squamous intraepithelial lesion cases with persistence or progression (P < .05). Fluorescence in situ hybridization results were similar in preserved and frozen samples. However, in frozen samples, the number of cells suitable to be evaluated by fluorescence in situ hybridization was lower than in preserved (nonfrozen) cases. In conclusion, the determination by fluorescence in situ hybridization of 3q26 gains in low-grade squamous intraepithelial lesion cases could be useful to predict the persistence-progression of such cervical lesions using both preserved and frozen cervical material.

Does polysomy of chromosome 17 have a role in ERBB2 and topoisomerase IIalpha expression? Gene, mRNA and protein expression: a comprehensive analysis

OBJECTIVES

ERBB2 is an oncogene with prognostic and predictive value. Topoisomerase IIalpha is an enzyme encoding close to the ERBB2 oncogene, that represents a molecular target for anthracyclines. An indirect mechanism of increasing ERBB2 and topoisomerase IIalpha gene copy number is chromosome 17 polysomy. The aim of the present study was to clarify the implication of polysomy 17 in ERBB2 and topoisomerase IIalpha expression. In addition, we assessed the relation of ERBB2 and topoisomerase IIalpha gene dosage to mRNA and protein levels.

METHODS

We selected 83 cases diagnosed as invasive breast cancer. We analysed ERBB2 and topoisomerase IIalpha genes, mRNA and protein by fluorescence in situ hybridisation, real-time reverse-transcription polymerase chain reaction and immunohistochemistry.

RESULTS

We observed a progressive increase in mRNA expression from 0+ to 3+ and also a significant difference in the ERBB2 RNA levels between normal and amplified cases. We found that polysomy of chromosome 17 does not affect the ERBB2 expression and that topoisomerase IIalpha mRNA expression is not related to gene status.

CONCLUSIONS

Our results demonstrate that polysomy of chromosome 17 is not related to ERBB2 expression. Thereby, it is important to use centromeric probes to clearly discriminate between true ERBB2 gene amplification and polysomy of chromosome 17.

Methotrexate resistance in vitro is achieved by a dynamic selectionprocess of tumor cell variants emerging during treatment

Genetic instability leads to tumor heterogeneity, which in turn provides a source of cell variants responsible for drug resistance. However, the source of resistant cells during the process of acquired resistance is poorly understood. Our aim has been to characterize the mechanism by which acquired resistance to methotrexate emerges during the course of cancer cell treatment in vitro. We recently demonstrated that, in vitro, HT-29 colon cancer cells become transiently sensitive to methotrexate by depleting the extracellular milieu of survival factors; on the other hand, the cell population under treatment can reversibly adapt to grow below a critical cell density in the presence of the drug. Here, we show that this adapted cell population gives rise to permanent resistant populations through repeated cycles of cell death and growth. This increased cell turnover, but not merely cell proliferation, is required for the appearance of increasing degrees of stable resistance that are progressively selected by drug pressure. Such a process, taking place in multiple steps, is here designated "dynamic selection." The analysis of sensitive and resistant HT-29 cell populations revealed that methotrexate induces genomic instability--characterized by centrosome amplification and aberrant chromosome recombination--leading to a low-level amplification of the 5q chromosome arm as one of the earliest genetic events selected during treatment. Therefore, this model provides a mechanism by which a tumor cell population lacking resistant subpopulations before treatment is able to acquire the genetic changes required for stable drug resistance.

The MYC oncogene in breast cancer progression: from benign epithelium to invasive carcinoma

One hypothesis for breast cancer development suggests that breast carcinogenesis involves a progression of events leading from benign epithelium to hyperplasia (with or without atypia) to carcinoma in situ and then invasive carcinoma. The MYC gene (alias c-Myc) is a transcriptional regulator whose expression is strongly associated with cell proliferation and cell differentiation. The present study is a descriptive analysis of MYC status throughout the hypothesized stages of invasive ductal carcinoma progression. A tissue microarray (TMA) was constructed including representative selected areas (normal cells, hyperplasia, in situ carcinoma, and invasive carcinoma) from each of 15 patients. Fluorescence in situ hybridization (FISH) with the LSI c-MYC/CEN8/IgH probe was performed. Two cases displayed MYC amplification (13%), showing this amplification only in the invasive carcinoma zones selected. Five cases displayed polysomy of chromosome 8 (33%), detected only in ductal in situ and invasive zones selected. Benign lesions and normal adjacent cells were classified as normal. None of the hyperplasia specimens and normal specimens analyzed showed any alterations in MYC status or any aneusomies of chromosome 8. The presence of MYC amplification only in invasive cells suggests that the finding of MYC amplification could reflect an advanced tumor progression.

Polysomy of chromosome 17 in breast cancer tumors showing an overexpression of ERBB2: a study of 175 cases using fluorescence in situ hybridization and immunohistochemistry

Introduction

One of the most common genetic aberrations associated with breast cancer is the amplification and overexpression of the ERBB2 proto-oncogene located at chromosome 17, bands q12-21. The amplification/overexpression occurs in 25 to 30% of all breast cancers. In breast cancer, aneusomy of chromosome 17, either monosomy or polysomy, is frequently observed by conventional cytogenetics and fluorescence in situ hybridization (FISH). The aim of this study was to discover whether or not numerical aberrations on chromosome 17 have a correlation to the amplification or overexpression of the ERBB2 gene and to analyze their clinical implications in subgroups showing 2+ or 3+ positive scores by immunohistochemistry (IHC).

Methods

We used FISH on a series of 175 formalin-fixed paraffin-embedded breast carcinomas to detect ERBB2 amplification, using a dual-probe system for the simultaneous enumeration of the ERBB2 gene and the centromeric region of chromosome 17, as well as using IHC to detect overexpression. We analyzed clinical and pathological variables in a subgroup of patients with 2+ and 3+ IHC scores (147 patients), to describe any differences in clinicopathological characteristics between polysomic and non-polysomic cases with the use of the χ² test.

Results

We found 13% of cases presenting polysomy, and three cases presented monosomy 17 (2%). According to the status of the ERBB2 gene, instances of polysomy 17 were more frequently observed in non-amplified cases than in FISH-amplified cases, suggesting that the mechanism for ERBB2 amplification is independent of polysomy 17. Polysomy 17 was detected in patients with 2+ and 3+ IHC scores. We found that nodal involvement was more frequent in polysomic than in non-polysomic cases (P = 0.046).

Conclusions

The determination of the copy number of chromosome 17 should be incorporated into the assesment of ERBB2 status. It might also be helpful to differentiate a subgroup of breast cancer patients with polysomy of chromosome 17 and overexpression of ERBB2 protein that probably have genetic and clinical differences.

Characterization of HER1 (c-erbB1) Status in Locally Advanced Breast Cancer Using Fluorescence in situ Hybridization and Immunohistochemistry

Epidermal growth factor receptor (EGFR) is a 170-kDa transmembrane glycoprotein encoded by the HER1 protooncogene, located at 7p12. This receptor is related to the pathogenesis of breast cancer. The aim of this study was to analyze the status of HER1 using fluorescence in situ hybridization (FISH) and immunohistochemistry in a series of 48 patients with locally advanced breast cancer (LABC). Before neoadjuvant chemotherapy, core biopsies were taken from patients with LABC and were processed into paraffin blocks. Biopsies were then studied using FISH with a HER1 probe (Vysis, Downers Grove, Ill., USA). They were also analyzed immunohistochemically using two different EGFR antibodies from DakoCytomation (Denmark, A/S) and from Zymed (San Francisco, Calif., USA). HER1 amplifications were not found, although 31% of the cases presented aneusomy of chromosome 7. Only 2 cases presented EGFR expression. LABC presented a low level of EGFR expression. HER1 amplification was not present in LABC, although the polysomy of chromosome 7 was a common finding.