Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

FRA3B at human chromosomal band 3p14.2 is the most active common fragile site in the human genome. The molecular mechanism of fragility at this region remains unknown but does not involve expansion of a trinucleotide or minisatellite repeat as has been observed for several of the cloned rare fragile sites. Deletions and rearrangements at FRA3B have been observed in a number of distinct tumors. The recently identified putative tumor suppressor gene FHIT spans FRA3B, and various groups have reported identifying deletions in this gene in different tumors. Using a high density of PCR amplifiable markers within FRA3B searching for deletions in the FRA3B region, we have analysed 21 tumor cell lines derived from renal cell, pancreatic, and ovarian carcinomas. We found a commonly deleted region in the renal cell and ovarian carcinoma cell lines located in the middle of an HPV16 viral integration site. Despite the presence of deletions in the FRA3B region in most of the cell lines, we did not detect alterations in FHIT exons in any of the cell lines examined. Thus, deletions of 3p14.2 in these carcinoma cell lines may simply reflect instability of the FRA3B region during tumor progression.
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PMID:Frequent homozygous deletions in the FRA3B region in tumor cell lines still leave the FHIT exons intact. 948 9

The second joint conference of the AACR and the EACR held in Oxford from 9-12 September 1997 was successful from many vantage points. While providing an optimal setting in which European and American cancer researchers could meet and exchange information, the conference had an excellent scientific programme which encompassed both methodological updates on important models used in cancer research and presentations of recent key advances in the molecular genetics of cancer. Lower eukaryotes are established model organisms used to elucidate fundamental but complex eukaryotic processes, such as those involved in tumorigenesis and cancer progression, and the progressive availability of their genome sequence makes them even more attractive. Transgenic mouse models are increasingly used not only for the study of one gene of interest but for investigation of the interactions among genes involved in the same pathway. The family of tumour suppressor genes is growing fast and several presentations were devoted to recently identified members such as the Von Hippel-Lindau gene, the FHIT gene and the PTEN gene. The systematic analysis of loss of heterozygosity on multiple loci in tumour specimens can provide the basis for preliminary models of molecular multistep progression in some tumour types, even though this is limited by the high degree of complexity found. Mechanisms of cell cycle regulation and apoptosis continue to be dissected and to constitute a fruitful area of investigation, with important recent insights on the p53-MDM2 autoregulatory loop and on the involvement of E2F-1 in apoptosis.
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PMID:Recent advances in the molecular genetics of cancer. Second joint conference of the American Association of Cancer Research and the European Association of Cancer Research, Oxford, 9-12 September 1997. 954 79

Allelic losses involving chromosome 3p are frequently observed in cervical cancers. Deletion mapping studies of primary cervical carcinomas have localized common regions of deletion to 3p14.2 and 3p21. The candidate tumor suppressor gene FHIT has been mapped to 3p14.2, and previous studies have demonstrated reduced or aberrant FHIT transcripts and reduced or absent Fhit protein expression in a large percentage of cervical cancer-derived cell lines and primary cervical carcinomas. To expand these observations to preinvasive cervical epithelial lesions and to determine whether loss of Fhit protein expression might be associated with tumor progression, immunohistochemical methods were used to examine Fhit expression in 95 invasive cervical carcinomas, 33 high-grade squamous intraepithelial lesions (HSILs) associated with concurrent invasive cancer, 38 HSILs unassociated with invasive cancer, 24 low-grade squamous intraepithelial lesions, and 22 normal cervix samples. All normal cervical epithelia and low-grade squamous intraepithelial lesions exhibited diffuse cytoplasmic immunostaining of moderate to strong intensity. Fhit protein expression was markedly reduced or absent in 67 of 95 (71%) invasive cancers, 17 of 33 (52%) HSILs associated with invasive cancer, and 8 of 38 (21%) HSILs without associated invasive cancer. The results confirm that Fhit protein expression is reduced or absent in the majority of cervical carcinomas and suggest that loss of Fhit expression often accompanies cervical tumor progression. Moreover, absent or reduced Fhit protein is observed at a significantly higher frequency in HSILs associated with progression to invasive cancer than in HSILs with unknown risk for progression (P = 0.012). These findings suggest that loss of Fhit expression in HSILs could serve as a useful marker of high-grade preinvasive lesions that have an increased likelihood of progression to invasive carcinoma.
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PMID:Loss of fhit expression in invasive cervical carcinomas and intraepithelial lesions associated with invasive disease. 1099 36

Our previous results on breast tumors show that LOH (loss of heterozygosity) at the FHIT locus is associated with reduced Fhit protein expression. We have also shown that LOH at this locus is significantly higher in tumors from patients carrying the BRCA2 999de15 mutation than in tumors without this mutation, presumably because of lack of DNA repair. Here, our aim was to determine the relationship of FHIT LOH with breast tumor progression. Five microsatellite markers located within the FHIT gene were typed in 239 breast tumors and corresponding normal tissue, and the LOH results were compared with clinicopathologic factors and LOH at other chromosome regions. LOH at FHIT is associated with estrogen- and progesterone-negative breast tumors, high S-phase fraction, reduced patient survival, and LOH at chromosome regions 6q, 7q, 8p, 9p, 11p, 11q, 13q, 16q, 17p, 17q, 18q, and 20q. A multivariate analysis shows that LOH at FHIT results in a 60% increased relative risk of dying. We conclude that the loss of FHIT results in growth advantage of breast tumor cells, is associated with unstable genome, and may be of prognostic value.
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PMID:Alterations of the FHIT gene in breast cancer: association with tumor progression and patient survival. 1142 71

Recent genomewide analyses of alternative splicing (AS) indicate that up to 70% of human genes may have alternative splice forms, suggesting that AS together with various posttranslational modifications plays a major role in the production of proteome complexity. Splice-site selection under normal physiological conditions is regulated in the developmental stage in a tissue type-specific manner by changing the concentrations and the activity of splicing regulatory proteins. Whereas spliceosomal errors resulting in the production of aberrant transcripts rarely occur in normal cells, they seem to be an intrinsic property of cancer cells. Changes in splice-site selection have been observed in various types of cancer and may affect genes implicated in tumor progression (for example, CD44, MDM2, and FHIT) and in susceptibility to cancer (for example, BRCA1 and APC). Splicing defects can arise from inherited or somatic mutations in cis-acting regulatory elements (splice donor, acceptor and branch sites, and exonic and intronic splicing enhancers and silencers) or variations in the composition, concentration, localization, and activity of regulatory proteins. This may lead to altered efficiency of splice-site recognition, resulting in overexpression or down-regulation of certain splice variants, a switch in splice-site usage, or failure to recognize splice sites correctly, resulting in cancer-specific splice forms. At least in some cases, changes in splicing have been shown to play a functionally significant role in tumorigenesis, either by inactivating tumor suppressors or by gain of function of proteins promoting tumor development. Moreover, cancer-specific splicing events may generate novel epitopes that can be recognized by the host's immune system as cancer specific and may serve as targets for immunotherapy. Thus, the identification of cancer-specific splice forms provides a novel source for the discovery of diagnostic or prognostic biomarkers and tumor antigens suitable as targets for therapeutic intervention.
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PMID:Alterations of pre-mRNA splicing in cancer. 1564 50

Early in tumorigenesis, a DNA damage-response network is activated in preneoplastic cells that delays or prevents cancer. Activation of the Chk2 G(2)/M checkpoint kinase and loss of fragile histidine triad (Fhit) tumor suppressor expression increase cellular susceptibility to DNA-damaging 'oncogenic' stressors, particularly in precursor or precancerous lesions. To understand the mechanism of oral carcinogenesis, we assessed the association between phosphorylated Chk2 (pChk2) and Fhit expression in oral squamous cell carcinoma. Loss of Fhit expression was an early event during oral carcinogenesis, whereas a decrease in the number of pChk2-positive cells was associated with tumor progression. Although tyrosine 114 is known to be essential to Fhit's tumor-suppressing activity, both wild-type and tyrosine 114 mutant Fhit increased the population of subG(1) DNA-containing HSC-3 OSCC cells with elevated pChk2 levels. In particular, when cells were exposed to ionizing radiation, pChk2 levels were upregulated dramatically, as were those of its downstream target Cdc25C. Knockdown of Fhit with FHIT small interfering RNA diminished the ionizing radiation-induced Chk2 phosphorylation in HEK293 cells. Furthermore, Fhit-deficient mice demonstrated a decrease in the number of pChk2-positive cells not only in dysplastic lesions but also in N-nitrosobenzylamine-induced papilloma of the forestomach, suggesting that lack of Fhit expression and the resultant defects of the ataxia telangiectasia mutated-Chk2 pathway can cause a difference in the incidence of N-nitrosobenzylamine-induced forestomach lesions. These findings suggest that Fhit plays a key role in the regulation of the ataxia telangiectasia mutated-Chk2 DNA damage response during oral carcinogenesis.
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PMID:Restoration of fragile histidine triad expression restores Chk2 activity in response to ionizing radiation in oral squamous cell carcinoma cells. 1816 29

Genetic aberrations are crucial in renal tumor progression. In this study, we describe loss of heterozygosity (LOH) and DNA-copy number abnormalities in clear cell renal cell carcinoma (cc-RCC) discovered by genome-wide single nucleotide polymorphism (SNP) arrays. Genomic DNA from tumor and normal tissue of 22 human cc-RCCs was analyzed on the Affymetrix GeneChip Human Mapping 10K Array. The array data were validated by quantitative polymerase chain reaction and immunohistochemistry. Reduced DNA copy numbers were detected on chromosomal arm 3p in 91%, on chromosome 9 in 32%, and on chromosomal arm 14q in 36% of the tumors. Gains were detected on chromosomal arm 5q in 45% and on chromosome 7 in 32% of the tumors. Copy number abnormalities were found not only in FHIT and VHL loci, known to be involved in renal carcinogenesis, but also in regions containing putative new tumor suppressor genes or oncogenes. In addition, microdeletions were detected on chromosomes 1 and 6 in genes with unknown impact on renal carcinogenesis. In validation experiments, abnormal protein expression of FOXP1 (on 3p) was found in 90% of tumors (concordance with SNP array data in 85%). As assessed by quantitative polymerase chain reaction, PARK2 and PACRG were down-regulated in 57% and 100%, respectively, and CSF1R was up-regulated in 69% of the cc-RCC cases (concordance with SNP array data in 57%, 33%, and 38%). Genome-wide SNP array analysis not only confirmed previously described large chromosomal aberrations but also detected novel microdeletions in genes potentially involved in tumor genesis of cc-RCC.
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PMID:Loss of heterozygosity and copy number abnormality in clear cell renal cell carcinoma discovered by high-density affymetrix 10K single nucleotide polymorphism mapping array. 1859 4

To gain insight into the role of genomic alterations in breast cancer progression, we conducted a comprehensive genetic characterization of a series of four cell lines derived from MCF10A. MCF10A is an immortalized mammary epithelial cell line (MEC); MCF10AT is a premalignant cell line generated from MCF10A by transformation with an activated HRAS gene; MCF10CA1h and MCF10CA1a, both derived from MCF10AT xenografts, form well-differentiated and poorly-differentiated malignant tumors in the xenograft models, respectively. We analyzed DNA copy number variation using the Affymetrix 500 K SNP arrays with the goal of identifying gene-specific amplification and deletion events. In addition to a previously noted deletion in the CDKN2A locus, our studies identified MYC amplification in all four cell lines. Additionally, we found intragenic deletions in several genes, including LRP1B in MCF10CA1h and MCF10CA1a, FHIT and CDH13 in MCF10CA1h, and RUNX1 in MCF10CA1a. We confirmed the deletion of RUNX1 in MCF10CA1a by DNA and RNA analyses, as well as the absence of the RUNX1 protein in that cell line. Furthermore, we found that RUNX1 expression was reduced in high-grade primary breast tumors compared to low/mid-grade tumors. Mutational analysis identified an activating PIK3CA mutation, H1047R, in MCF10CA1h and MCF10CA1a, which correlates with an increase of AKT1 phosphorylation at Ser473 and Thr308. Furthermore, we showed increased expression levels for genes located in the genomic regions with copy number gain. Thus, our genetic analyses have uncovered sequential molecular events that delineate breast tumor progression. These events include CDKN2A deletion and MYC amplification in immortalization, HRAS activation in transformation, PIK3CA activation in the formation of malignant tumors, and RUNX1 deletion associated with poorly-differentiated malignant tumors.
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PMID:Delineating genetic alterations for tumor progression in the MCF10A series of breast cancer cell lines. 2016 62

FHIT (fragile histidine triad) is a tumor-suppressor gene located at chromosome band 3p14.2. The genomic locus, which is greater than 1 Mb, contains 10 small exons that make up the 1.1-kb FHIT cDNA. The coding region starts in exon 5 and stops in exon 9, producing a 16.8-kDa cytoplasmic protein. The FHIT locus contains the hereditary renal cell carcinoma (RCC) t(3;8) translocation, and also encompasses the FRA3B common fragile region (for review, 1). Numerous studies have proven that the FHIT gene is inactivated by deletions in both primary tumors and cell lines derived from head and neck, stomach, lung, and kidney cancers (2-6). Since FHIT is inactivated in so many cancers, it is essential to learn its normal function and analyze how the loss of its function contributes to the progression and development of cancer. For example, an early event in the lungs of a smoker is breakage at the FHIT locus, causing a reduced or absent FHIT protein expression in the preneoplastic lesions. Compensation for the functional loss of FHIT via a recombinant, nonfragile FHITgene may prove therapeutically useful (7,8). Our studies have also shown that the FHIT gene is altered or absent in the majority of transitional-cell carcinoma (TCC) cases of the bladder examined (9). Through the utilization of molecular techniques such as those described here, FHIT alterations may be detected in an early stage of cancer, and thus prove to be a useful diagnostic tool to prevent cancer progression.
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PMID:Analyzing the FHIT Gene by RT-PCR, Western Blotting, and Immunohistochemistry. 2131 89

The dual role of the microRNA-29 (miR-29) family in tumor progression and metastasis in solid tumors has been reported. Evidence for the role of miR-29 in tumor malignancy and its prognostic value in overall survival (OS) and relapse-free survival (RFS) in non-small cell lung cancer (NSCLC) remains conflicting. Mechanistic studies presented herein demonstrated that c-Myc suppressed the expression of miR-29b, promoting soft agar growth and invasion capability in lung cancer cells. Interestingly, the decrease in the expression of miR-29b by c-Myc is responsible for soft agar growth and invasiveness mediated by FHIT loss due to promoter methylation. Among patients, low expression of miR-29b and FHIT was more common in tumors with high c-Myc expression than in tumors with low c-Myc expression. Kaplan-Meier and Cox regression analysis showed that tumors with high c-Myc, low miR-29b and low FHIT expression had shorter OS and RFS periods than their counterparts. In conclusion, the decrease in the expression of miR-29b by c-Myc may be responsible for FHIT loss-mediated tumor aggressiveness and for poor outcome in NSCLC. Therefore, we suggest that restoration of the miR-29b expression using the c-Myc inhibitor might be helpful in suppressing tumor aggressiveness mediated by FHIT loss and consequently improving outcomes in NSCLC patients with tumors with low expression of FHIT.
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PMID:c-Myc suppresses microRNA-29b to promote tumor aggressiveness and poor outcomes in non-small cell lung cancer by targeting FHIT. 2490 76


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