Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is a growing body of evidence that the occurrence of neuroendocrine (NE) differentiation in prostate carcinoma correlates with poor prognosis, tumor progression, and androgen-independence. In the present study, the expression of common NE markers, i.e., chromogranin A (ChGA), serotonin (5HT), neuron-specific enolase (NSE) and adrenomedullin (AM), was retrospectively examined in formalin-fixed, paraffin-embedded prostate tissue samples obtained from patients with adenocarcinoma and from patients with nodular hyperplasia of the prostatic gland (NHPG) (33 and 28, respectively). The statistical analysis of the results (tested the equality of matched pairs of observations using the Wilcoxon matched-pairs signed ranks test) revealed a more prominent expression of ChGA in benign epithelial cells adjacent to adenocarcinomatic lesions (Peri-PAC) than in the adenocarcinoma (PAC) (p = 0.0049). A similar pattern of expression was detected for 5HT (p = 0.000). When comparing the expression of ChGA and 5HT in tissue samples originating in cancer patients with those obtained from NHPG samples, more ChGA and 5HT were expressed in Peri-PAC than in NHPG (p = 0.0004 and 0.002, respectively). The results obtained raise the possibility that adenocarcinoma cells urge some adjacent benign epithelial cells to differentiate into NE cells, which, in turn, may promote tumor growth and invasion.
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PMID:Augmented expression of chromogranin A and serotonin in peri-malignant benign prostate epithelium as compared to adenocarcinoma. 1546 96

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

Gene mutations in APC, K-ras, and p53 are thought to be essential events for colorectal cancer development. Recent data seem to indicate that K-ras and p53 mutations rarely co-exist in the same tumor, indicating that these alterations do not represent a synergistic evolutionary pathway. Moreover, an inverse relation between K-ras gene activation and BRAF mutations has been demonstrated, suggesting alternative pathways for colorectal cancer transformation. To reconstruct the chronological modulation of these gene mutations during cell transformation and colorectal cancer progression, mutations of p53, K-ras, and BRAF genes were analyzed by Single Strand Conformation Polymorphism (SSCP) or sequencing analysis in 100 colorectal cancer samples, evenly distributed among different Dukes' stages. We found mutations in p53, K-ras, and BRAF genes in 35%, 30%, and 4% of tumors, respectively, and observed a minimal or no co-presence of these gene alterations. Moreover, the frequency of molecular p53 mutations increased as tumor stage increased, suggesting an important role for this gene in the progression of colorectal cancer. Conversely, K-ras or BRAF genes were not related to tumor stage or location. These data seem to indicate the absence of a co-presence of the genes, highlighting the possibility of multiple pathways for colorectal tumor progression. Moreover, mutations in p53, K-ras, and BRAF are not present in about one-third of colorectal cancers and therefore other gene mutations need to be investigated to better understand molecular mechanisms at the basis of cell transformation and the progression of colorectal cancer.
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PMID:Mutation analysis of p53, K-ras, and BRAF genes in colorectal cancer progression. 1570 78

Patients with Barrett's esophagus (BE) are at increased risk of developing esophageal adenocarcinoma (EAC). Clinical neoplastic progression risk factors, such as age and the length of the esophageal BE segment, have been identified. However, improved molecular biomarkers predicting increased progression risk are needed for improved risk assessment and stratification. Using real-time quantitative methylation-specific PCR, we screened 10 genes (HPP1, RUNX3, RIZ1, CRBP1, 3-OST-2, APC, TIMP3, p16, MGMT, p14) for promoter hypermethylation in 77 EAC, 93 BE, and 64 normal esophagus (NE) specimens. A subset of genes manifesting significant differences in methylation frequencies between BE and EAC was then analysed in 20 dysplastic specimens. All 10 genes except p14 were frequently methylated in EACs, with RUNX3, HPP1, CRBP1, RIZ1, and OST-2 representing novel methylation targets in EAC and/or BE. p16, RUNX3, and HPP1 displayed increasing methylation frequencies in BE vs EAC. Furthermore, these increases in methylation occurred early, at the interface between BE and low-grade dysplasia (LGD). To demonstrate the silencing effect of hypermethylation, we selected the EAC cells BIC1, in which the HPP1 promoter is natively methylated, and subjected them to 5-aza-2'-deoxycytidine (Aza-C) treatment. Real-time RT-PCR indicated increased HPP1 mRNA levels after 3 days of Aza-C treatment, as well as decreased levels of methylated HPP1 DNA. Hypermethylation of a subset of six genes (APC, TIMP3, CRBP1, p16, RUNX3, and HPP1) was then tested in a retrospective longitudinal study of 99 BE and nine LGD specimens obtained from 53 BE patients undergoing surveillance endoscopy. Only high-grade dysplasia (HGD) or EAC were defined as progression end points. Two patient groups were compared: eight progressors (P) and 45 nonprogressors (NP), using Cox proportional hazards models to determine the relative progression risks of age, BE segment length, and methylation events. Multivariate analyses revealed that only hypermethylation of p16 (odds ratio (OR) 1.74, 95% confidence interval (CI) 1.33-2.20), RUNX3 (OR 1.80, 95% CI 1.08-2.81), and HPP1 (OR 1.77, 95% CI 1.06-2.81) were independently associated with an increased risk of progression, whereas age, BE segment length, and hypermethylation of TIMP3, APC, or CRBP1 were not independent risk factors. In combined analyses, risk was detectable up to, but not earlier than, 2 years preceding neoplastic progression. Hypermethylation of p16, RUNX3, and HPP1 in BE or LGD may represent independent risk factors for the progression of BE to HGD or EAC. These findings have implications regarding risk stratification, early EAC detection, and the appropriate endoscopic surveillance interval for patients with BE.
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PMID:Inactivation of p16, RUNX3, and HPP1 occurs early in Barrett's-associated neoplastic progression and predicts progression risk. 1582 39

The identification of specific protein markers for colorectal cancer would provide the basis for early diagnosis and detection, as well as clues for understanding the molecular mechanisms governing cancer progression. In this report, we describe the proteomic analysis of the samples of colorectal cancer corresponding to seven patients. We have used the highly sensitive two-dimensional differential gel electrophoresis (2-D DIGE) coupled with mass spectrometry (MS) for the identification of proteins differentially expressed in tumoral and neighboring normal mucosa. We have detected differences in abundance of 52 proteins with statistical variance of the tumor versus normal spot volume ratio within the 95th confidence level (Student's t-test; p < 0.05). Forty-one out of 52 analyzed proteins were unambiguously identified by matrix-assisted laser desorption/ionization-time of flight MS coupled with database interrogation as being differentially expressed in colorectal cancer. An ontology analysis of these proteins revealed that they were mainly involved in regulation of transcription (synovial sarcoma X5 protein, metastasis-associated protein 1), cellular reorganization and cytoskeleton (cytokeratins, vimentin, beta actin), cell communication and signal transduction (annexins IV and V, relaxin, APC), and protein synthesis and folding (heat shock protein 60, calreticulin, cathepsin D, RSP4) among others. Preliminary studies demonstrated that the differentially expressed proteins found by 2-D DIGE could be confirmed and validated by immunoblotting and immunohistochemistry analyses in those few cases where antibodies were available. We believe that the incorporation of more samples and new datasets will permit the definition of a collection of proteins with a potential interest as biomarkers for colorectal cancer.
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PMID:Proteomic expression analysis of colorectal cancer by two-dimensional differential gel electrophoresis. 1592 90

Tumor affects myelopoiesis by inhibiting the process of differentiation/maturation of antigen-presenting cells from their myeloid precursors and by stimulating an accumulation of immature myeloid cells in cancer patients and tumor-bearing mice. These immature myeloid cells can contribute greatly to tumor progression and promote tumor evasion from immune attack: i) by inhibiting development of adaptive immune responses against tumor in lymphoid organs; ii) by migrating into tumor site and differentiating there into highly immune suppressive tumor-associated macrophages. Immature myeloid cells and tumor-associated macrophages utilize different JAK/STAT signaling pathways and different mechanisms to control T cell responses, which include increased production of TGF-beta, reactive oxygen species, peroxynitrites, as well as enhanced L-arginine metabolism. Understanding of precise mechanisms, which tumors use to affect differentiation of APC from myeloid cell precursors and inhibit T cell responses, could help to develop new approaches for cancer therapy and substantially improve efficiency of existing cancer vaccination strategies.
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PMID:Role of immature myeloid cells in mechanisms of immune evasion in cancer. 1604 43

The Wnt/beta-catenin pathway is involved in various cellular activities--including determination, proliferation, migration and differentiation--in embryonic development and adult homeostasis. The deregulation or constitutive activation of the Wnt/beta-catenin pathway may lead to cancer formation. This review focuses on the role of the Wnt/beta-catenin canonical signaling pathway in the melanocyte lineage, and more specifically, in melanoma. Several components of the Wnt/beta-catenin pathway, such as APC, ICAT, LEF1 and beta-catenin are modified in melanoma tumors and cell lines, leading to activation of this signaling. A hallmark of the activation of this pathway is the presence of beta-catenin in the nucleus. Indeed, beta-catenin is found in about 30% of human melanoma nuclei, indicating a potentially specific role for this signaling pathway in this aggressive type of cancer. Beta-catenin can induce ubiquitous genes such as myc or cyclinD1, cell lineage-restricted genes such as Brn2 and melanocyte-specific genes such as Mitf-M and Dct. The Mitf-M and Brn-2 genes encode transcription factors. Mitf plays a critical role in melanocyte survival, proliferation and differentiation. Brn-2 is involved in melanoma proliferation. Determining how the Wnt/beta-catenin signaling pathway, alone or with other pathways, orchestrates the induction of target genes involved in a diverse range of activities represents a major challenge in research into melanoma formation and tumor progression.
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PMID:The WNT/Beta-catenin pathway in melanoma. 1614 65

Aberrant activation of the Wnt signaling pathway has been reported during neoplastic progression in Barrett's esophagus (BE). However, mutations in APC and CTNNB1 genes were rarely observed. In this study, expression pattern of Wnt ligands, Frizzled receptors and APC, as well as the methylation status of the APC, SFRP1 and SFRP2 promoter genes were investigated in normal esophageal mucosa and in preneoplastic and neoplastic lesions of BE patients. Promoter methylation of APC was found in all BE samples and in 95% of esophageal adenocarcinomas (EAC). Full methylation of APC correlated with lack of expression. In EAC, nuclear translocation of beta-catenin was observed regardless of the expression of APC. WNT2 expression was higher in dysplasia and EAC than in BE, with 20/26 (77%) of the EAC showing high expression of WNT2. SFRP1 methylation occurred in all BE samples and in 96% of EAC, while SFRP2 was methylated in 73% of the normal squamous esophageal mucosa samples. In conclusion, (1) alterations of key regulators of the Wnt signaling are frequent in the pathogenesis of BE; (2) the APC and SFRP1 genes are inactivated by promoter methylation in BE; (3) the WNT2 gene is upregulated along the progression from low-grade dysplasia to EAC.
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PMID:Alterations of the Wnt signaling pathway during the neoplastic progression of Barrett's esophagus. 1640 29

The development and progression of gastric cancer involves a number of genetic and epigenetic alterations of tumor suppressor and tumor-related genes. The majority of differentiated carcinomas arise from intestinal metaplastic mucosa and exhibit structurally altered tumor suppressor genes, typified by p53, which is inactivated via the classic two-hit mechanism, i.e. loss of heterozygosity (LOH) and mutation of the remaining allele. LOH at certain chromosomal loci accumulates during tumor progression. Approximately 20% of differentiated carcinomas show evidence of mutator pathway tumorigenesis due to hMLH1 inactivation via hypermethylation of promoter CpG islands, and exhibit high-frequency microsatellite instability. In contrast, undifferentiated carcinomas rarely exhibit structurally altered tumor suppressor genes. For instance, while methylation of E-cadherin is often observed in undifferentiated carcinomas, mutation of this gene is generally associated with the progression from differentiated to undifferentiated carcinomas. Hypermethylation of tumor suppressor and tumor-related genes, including APC, CHFR, DAP-kinase, DCC, E-cadherin, GSTP1, hMLH1, p16, PTEN, RASSF1A, RUNX3, and TSLC1, can be detected in both differentiated and undifferentiated carcinomas at varying frequencies. However, the significance of the hypermethylation varies according to the analyzed genomic region, and hypermethylation of these genes can also be present in non-neoplastic gastric epithelia. Promoter demethylation of specific genes, such as MAGE and synuclein Y, can occur during the progressive stages of both histological types, and is associated with patient prognosis. Thus, while the molecular pathways of gastric carcinogenesis are dependent on histological background, specific genetic alterations can still be used for risk assessment, diagnosis, and prognosis.
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PMID:Alterations of tumor suppressor and tumor-related genes in the development and progression of gastric cancer. 1648 17

The vast majority of colorectal cancers display genetic instability, either in the chromosomal instability (CIN) or microsatellite instability (MIN) forms. Although CIN tumors are per definition aneuploid, MIN colorectal cancers, caused by loss of mismatch repair function, are usually near diploid. Recently, biallelic germ line mutations in the MYH gene were found to be responsible for MYH-associated polyposis (MAP), an autosomal recessive predisposition to multiple colorectal polyps, often indistinguishable from the dominant familial adenomatous polyposis (FAP) syndrome caused by inherited APC mutations. Here, we analyzed MYH- and APC-mutant polyps by combining laser capture microdissection, isothermal genomic DNA amplification, and array comparative genomic hybridization. Smoothed quantile regression methods were applied to the MAP and FAP genomic profiles to discriminate chromosomes predominantly affected by gains and losses. Up to 80% and 60% of the MAP and FAP polyps showed aneuploid changes, respectively. Both MAP and FAP adenomas were characterized by frequent losses at chromosome 1p, 17, 19, and 22 and gains affecting chromosomes 7 and 13. The aneuploid changes detected at early stages of MYH-driven tumorigenesis may underlie accelerated tumor progression, increased cancer risk, and poor prognosis in MAP.
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PMID:Chromosomal instability in MYH- and APC-mutant adenomatous polyps. 1651 May 66


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