104 research outputs found
Effects of Cutting Ashe Juniper Woodlands on Small Mammal Populations in the Texas Hill Country
We studied the effects of cutting Ashe juniper (Juniperus ashei Bucholz) woodlands on populations of small mammals at Friedrich Wilderness Park, north of San Antonio, Texas. Three patches of juniper ranging from 1.8 ha to 2.4 ha were cut to provide habitat for endangered black-capped vireos (Vireo atricapillus Woodhouse). We trapped small mammals along transects placed in the treated patches and in untreated areas of the park from October 1995 to May 1996 and again from October 1996 to March 1997. Three species of small mammals were trapped, but Peromyscus pectoralis Osgood (white-ankled mouse) was the most common species captured. Peromyscus pectoralis was more abundant in the treated patches in which the juniper had been removed. Trapping success in the three treated areas was consistently higher (average of 12%) than in the untreated Ashe juniper woodlands (average of 3%). Mice that colonized treated patches survived longer than mice in control areas. Each year the number of P. pectoralis increased during the winter and spring, with juveniles accounting for up to 32% of captures. The management of habitat for an endangered species, such as the black-capped vireo, enhanced the biodiversity of small mammals in this study
Frequent gain of the human telomerase gene TERC at 3q26 in cervical adenocarcinomas
The level of genomic amplification of the human telomerase gene TERC, which maps to chromosome band 3q26, was determined in primary cervical adenocarcinomas. Interphase nuclei prepared from archival material of 12 primary cervical adenocarcinomas, eight of which were human papillomavirus positive, were hybridised with a triple colour probe set specific for centromeres of chromosomes 3 and 7 and the TERC gene. We observed high proportions of nuclei with increased absolute copy numbers for TERC in all tumours (mean 3.3; range 2.3–5.2). Amplification of the human telomerase gene TERC is a consistent aberration in cervical adenocarcinomas. Therefore, application of our probe set may provide an objective genetic test for the assessment of glandular cells in Pap smears and hence for the diagnosis of cervical adenocarcinomas
Gain of chromosome 3q defines the transition from severe dysplasia to invasive carcinoma of the uterine cervix.
Intra-tumour genetic heterogeneity and poor chemoradiotherapy response in cervical cancer
Background:
Intra-tumour genetic heterogeneity has been reported in both leukaemias and solid tumours and is implicated in the development of drug resistance in CML and AML. The role of genetic heterogeneity in drug response in solid tumours is unknown.
Methods:
To investigate intra-tumour genetic heterogeneity and chemoradiation response in advanced cervical cancer, we analysed 10 cases treated on the CTCR-CE01 clinical study. Core biopsies for molecular profiling were taken from four quadrants of the cervix pre-treatment, and weeks 2 and 5 of treatment. Biopsies were scored for cellularity and profiled using Agilent 180k human whole genome CGH arrays. We compared genomic profiles from 69 cores from 10 patients to test for genetic heterogeneity and treatment effects at weeks 0, 2 and 5 of treatment.
Results:
Three patients had two or more distinct genetic subpopulations pre-treatment. Subpopulations within each tumour showed differential responses to chemoradiotherapy. In two cases, there was selection for a single intrinsically resistant subpopulation that persisted at detectable levels after 5 weeks of chemoradiotherapy. Phylogenetic analysis reconstructed the order in which genomic rearrangements occurred in the carcinogenesis of these tumours and confirmed gain of 3q and loss of 11q as early events in cervical cancer progression.
Conclusion:
Selection effects from chemoradiotherapy cause dynamic changes in genetic subpopulations in advanced cervical cancers, which may explain disease persistence and subsequent relapse. Significant genetic heterogeneity in advanced cervical cancers may therefore be predictive of poor outcome
Single-Cell Genetic Analysis Reveals Insights into Clonal Development of Prostate Cancers and Indicates Loss of PTEN as a Marker of Poor Prognosis
Gauging the risk of developing progressive disease is a major challenge in prostate cancer patient management. We used genetic markers to understand genomic alteration dynamics during disease progression. By using a novel, advanced, multicolor fluorescence in situ hybridization approach, we enumerated copy numbers of six genes previously identified by array comparative genomic hybridization to be involved in aggressive prostate cancer [TBL1XR1, CTTNBP2, MYC (alias c-myc), PTEN, MEN1, and PDGFB] in six nonrecurrent and seven recurrent radical prostatectomy cases. An ERG break-apart probe to detect TMPRSS2-ERG fusions was included. Subsequent hybridization of probe panels and cell relocation resulted in signal counts for all probes in each individual cell analyzed. Differences in the degree of chromosomal and genomic instability (ie, tumor heterogeneity) or the percentage of cells with TMPRSS2-ERG fusion between samples with or without progression were not observed. Tumors from patients that progressed had more chromosomal gains and losses, and showed a higher degree of selection for a predominant clonal pattern. PTEN loss was the most frequent aberration in progressers (57%), followed by TBL1XR1 gain (29%). MYC gain was observed in one progresser, which was the only lesion with an ERG gain, but no TMPRSS2-ERG fusion. According to our results, a probe set consisting of PTEN, MYC, and TBL1XR1 would detect progressers with 86% sensitivity and 100% specificity. This will be evaluated further in larger studies
Analysis of genetic copy number changes in cervical disease progression
<p>Abstract</p> <p>Background</p> <p>Cervical dysplasia and tumorigenesis have been linked with numerous chromosomal aberrations. The goal of this study was to evaluate 35 genomic regions associated with cervical disease and to select those which were found to have the highest frequency of aberration for use as probes in fluorescent in-situ hybridization.</p> <p>Methods</p> <p>The frequency of gains and losses using fluorescence in-situ hybridization were assessed in these 35 regions on 30 paraffin-embedded cervical biopsy specimens. Based on this assessment, 6 candidate fluorescently labeled probes (8q24, Xp22, 20q13, 3p14, 3q26, CEP15) were selected for additional testing on a set of 106 cervical biopsy specimens diagnosed as Normal, CIN1, CIN2, CIN3, and SCC. The data were analyzed on the basis of signal mean, % change of signal mean between histological categories, and % positivity.</p> <p>Results</p> <p>The study revealed that the chromosomal regions with the highest frequency of copy number gains and highest combined sensitivity and specificity in high-grade cervical disease were 8q24 and 3q26. The cytological application of these two probes was then evaluated on 118 ThinPrep™ samples diagnosed as Normal, ASCUS, LSIL, HSIL and Cancer to determine utility as a tool for less invasive screening. Using gains of either 8q24 or 3q26 as a positivity criterion yielded specificity (Normal +LSIL+ASCUS) of 81.0% and sensitivity (HSIL+Cancer) of 92.3% based on a threshold of 4 positive cells.</p> <p>Conclusions</p> <p>The application of a FISH assay comprised of chromosomal probes 8q24 and 3q26 to cervical cytology specimens confirms the positive correlation between increasing dysplasia and copy gains and shows promise as a marker in cervical disease progression.</p
Microarray comparative genomic hybridization detection of chromosomal imbalances in uterine cervix carcinoma
BACKGROUND: Chromosomal Comparative Genomic Hybridization (CGH) has been applied to all stages of cervical carcinoma progression, defining a specific pattern of chromosomal imbalances in this tumor. However, given its limited spatial resolution, chromosomal CGH has offered only general information regarding the possible genetic targets of DNA copy number changes. METHODS: In order to further define specific DNA copy number changes in cervical cancer, we analyzed 20 cervical samples (3 pre-malignant lesions, 10 invasive tumors, and 7 cell lines), using the GenoSensor microarray CGH system to define particular genetic targets that suffer copy number changes. RESULTS: The most common DNA gains detected by array CGH in the invasive samples were located at the RBP1-RBP2 (3q21-q22) genes, the sub-telomeric clone C84C11/T3 (5ptel), D5S23 (5p15.2) and the DAB2 gene (5p13) in 58.8% of the samples. The most common losses were found at the FHIT gene (3p14.2) in 47% of the samples, followed by deletions at D8S504 (8p23.3), CTDP1-SHGC- 145820 (18qtel), KIT (4q11-q12), D1S427-FAF1 (1p32.3), D9S325 (9qtel), EIF4E (eukaryotic translation initiation factor 4E, 4q24), RB1 (13q14), and DXS7132 (Xq12) present in 5/17 (29.4%) of the samples. CONCLUSION: Our results confirm the presence of a specific pattern of chromosomal imbalances in cervical carcinoma and define specific targets that are suffering DNA copy number changes in this neoplasm
Identification of novel candidate target genes, including EPHB3, MASP1 and SST at 3q26.2–q29 in squamous cell carcinoma of the lung
<p>Abstract</p> <p>Background</p> <p>The underlying genetic alterations for squamous cell carcinoma (SCC) and adenocarcinoma (AC) carcinogenesis are largely unknown.</p> <p>Methods</p> <p>High-resolution array- CGH was performed to identify the differences in the patterns of genomic imbalances between SCC and AC of non-small cell lung cancer (NSCLC).</p> <p>Results</p> <p>On a genome-wide profile, SCCs showed higher frequency of gains than ACs (<it>p </it>= 0.067). More specifically, statistically significant differences were observed across the histologic subtypes for gains at 2q14.2, 3q26.2–q29, 12p13.2–p13.33, and 19p13.3, as well as losses at 3p26.2–p26.3, 16p13.11, and 17p11.2 in SCC, and gains at 7q22.1 and losses at 15q22.2–q25.2 occurred in AC (<it>P </it>< 0.05). The most striking difference between SCC and AC was gains at the 3q26.2–q29, occurring in 86% (19/22) of SCCs, but in only 21% (3/14) of ACs. Many significant genes at the 3q26.2–q29 regions previously linked to a specific histology, such as EVI1,<it>MDS1, PIK3CA </it>and <it>TP73L</it>, were observed in SCC (<it>P </it>< 0.05). In addition, we identified the following possible target genes (> 30% of patients) at 3q26.2–q29: <it>LOC389174 </it>(3q26.2),<it>KCNMB3 </it>(3q26.32),<it>EPHB3 </it>(3q27.1), <it>MASP1 </it>and <it>SST </it>(3q27.3), <it>LPP </it>and <it>FGF12 </it>(3q28), and <it>OPA1</it>,<it>KIAA022</it>,<it>LOC220729</it>, <it>LOC440996</it>,<it>LOC440997</it>, and <it>LOC440998 </it>(3q29), all of which were significantly targeted in SCC (<it>P </it>< 0.05). Among these same genes, high-level amplifications were detected for the gene, <it>EPHB3</it>, at 3q27.1, and <it>MASP1 </it>and <it>SST</it>, at 3q27.3 (18, 18, and 14%, respectively). Quantitative real time PCR demonstrated array CGH detected potential candidate genes that were over expressed in SCCs.</p> <p>Conclusion</p> <p>Using whole-genome array CGH, we have successfully identified significant differences and unique information of chromosomal signatures prevalent between the SCC and AC subtypes of NSCLC. The newly identified candidate target genes may prove to be highly attractive candidate molecular markers for the classification of NSCLC histologic subtypes, and could potentially contribute to the pathogenesis of the squamous cell carcinoma of the lung.</p
Chromosomal amplifications, 3q gain and deletions of 2q33-q37 are the frequent genetic changes in cervical carcinoma
BACKGROUND: Carcinoma of uterine cervix is the second most common cancers among women worldwide. Combined radiation and chemotherapy is the choice of treatment for advanced stages of the disease. The prognosis is poor, with a five-year survival rate ranging from about 20–65%, depending on stage of the disease. Therefore, genetic characterization is essential for understanding the biology and clinical heterogeneity in cervical cancer (CC). METHODS: We used a genome-wide screening method – comparative genomic hybridization (CGH) to identify DNA copy number changes in 77 patients with cervical cancer. We applied categorical and survival analyses to analyze whether chromosomal changes were related to clinico-pathologic characteristics and patients survival. RESULTS: The CGH analysis revealed a loss of 2q33-q37 (57.1%), gain of 3q (54.5%) and chromosomal amplifications (20.77%) as frequent genetic changes. A total of 15 amplified chromosomal sites were detected in 16 cases that include 1p31, 2q32, 7q22, 8q21.2-q24, 9p22, 10q21, 10q24, 11q13, 11q21, 12q15, 14q12, 17p11.2, 17q22, 18p11.2, and 19q13.1. Recurrent amplified sites were noted at 11q13, 11q21, and 19q13.1. The genomic alterations were further evaluated for prognostic significance in CC patients, and we did not find any correlation with a number of clinical or histological parameters. The tumors harboring HPV18 exhibited higher genomic instability compared to tumors with HPV 16. CONCLUSIONS: This study demonstrated that 2q33-q37 deletions, 3q gains and chromosomal amplifications as characteristic changes in invasive CC. These genetic alterations will aid in the identification of novel tumor suppressor gene(s) at 2q33-q37 and oncogenes at amplified chromosomal sites. Molecular characterization of these chromosomal changes utilizing the current genomic technologies will provide new insights into the biology and clinical behavior of CC
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