Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neoplastic transformation is commonly associated with altered glycosylation of proteins and lipids. To understand the basis for altered mucin glycosylation, we have examined the distribution of RER markers, a cis-Golgi resident protein, and the GalNAc alpha-O-Ser/Thr epitope (Tn) in human colon cancer cells and in normal colon. In cultured mucin-producing colon cancer cells, Gal-NAc alpha-O-Ser/Thr was found in mucin droplets and in RER cisternae. In addition, the Golgi apparatus was disorganized in a proportion of cells and a 130 kDa cis-Golgi resident protein was also abnormally redistributed to the RER. The distribution of the MUC2 intestinal apomucin, protein disulphide isomerase, Gal-NAc alpha-O-Ser/Thr, and the 130 kDa cis-Golgi resident protein was analysed in normal colon and in colon cancer tissues. In normal colon, MUC2 apomucin and protein disulphide isomerase were located in the RER, whereas the cis-Golgi resident protein and GalNAc alpha-O-Ser/Thr were detected only in the cis-Golgi compartment. In contrast, the two Golgi markers colocalized with the MUC2 apomucin and protein disulphide isomerase in the RER of colon cancer cells. On the basis of these results, we propose that in colon cancer cells a redistribution of molecules normally present in the Golgi apparatus takes place; this alteration may contribute to the abnormal glycosylation of proteins and lipids associated with neoplastic transformation.
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PMID:cis-Golgi resident proteins and O-glycans are abnormally compartmentalized in the RER of colon cancer cells. 769 49

Hereditary nonpolyposis colorectal cancer (HNPCC) (Lynch syndrome) accounts for a small proportion of the total colorectal cancer burden, yet represents the most common form of dominantly inherited colon cancer. Until recently, the diagnosis has been based on family history of colorectal and other intra-abdominal cancers. This has been problematic since chance clustering of such tumors cannot be excluded. On the other hand, not every HNPCC patients shows a dramatic family history of cancer. Genetic mapping of a locus for HNPCC to chromosome 2p and the observation that HNPCC tumors show instability of short tandem repeat sequences (replication errors, RER) rapidly led to the cloning of the predisposing gene, human MSH2 (hMSH2). Mutations of hMSH2 have been demonstrated to segregate in large HNPCC families with the cancer phenotype, thus providing convincing evidence that the gene indeed, when mutated, predisposes its carriers to colorectal and other intra-abdominal tumors. Localization of a second locus for HNPCC to chromosome 3p and the subsequent cloning of another predisposing gene, human MLH1 (hMLH1) give hope that a great majority of families can soon be diagnosed by molecular genetic methods.
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PMID:Genes involved in hereditary nonpolyposis colorectal carcinoma. 797 3

Microsatellite instability was analysed in 93 primary breast tumours at 13 chromosomal loci frequently altered in breast cancer. RER (replication errors) were observed at a low (5%) frequency in sporadic, familial and hereditary breast tumours, as well as in breast tumours from patients with multiple primary cancers. Our study suggests that the RER+ phenotype is rare in breast tumours, and that breast cancer is not included in the hereditary non-polyposis colon cancer (HNPCC) syndrome. Moreover, the RER+ tumours revealed an atypical pattern of microsatellite alteration as compared with those usually seen in HNPCC tumours. In agreement with the findings in HNPCC tumours, all RER+ breast tumours were diploid, although having a similar frequency of allelic imbalance as RER- tumours. Thus, mismatch repair deficiency is rare in breast cancer, is most likely caused by somatic mutations, and possibly in a set of DNA repair genes different from that involved in the HNPCC syndrome.
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PMID:Infrequent occurrence of microsatellite instability in sporadic and familial breast cancer. 865 65

The replication-error positive (RER+) phenotype characterizes tumour cells with microsatellite instability. This 'mutator phenotype' is thought to induce spread mutations throughout the genome, thus increasing the risk of tumour development. Here we analyse spontaneously arising mutations at the tetranucleotide CCGG ( Msp I recognition site), at positions 14 067-14 070 of the p53 gene sequence, in three colon cancer cell lines, two with microsatellite instability and one without this characteristic. This restriction site covers hot-spot codon 248, which is often mutated in colon carcinomas. Using the Msp I RFLP-PCR assay we found that the mean mutation frequency at this site was not different among the cell lines considered. Taking the substitutions separately, none of the mutations involving codon 248 arose with significantly higher frequency in each of the RER+ cell lines (HCT116 and DLD1) compared with the RER-one (SW480). Only the CG transversion at nt 14 067 (codon 247) occurred with a slightly higher, but biologically insignificant, frequency in one of the RER+ cell lines (HCT116). Our in vitro data support the previously reported lack of correlation between microsatellite instability and p53 mutations in RER+ tumour specimens.
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PMID:Mutation frequencies at codon 248 of the p53 tumour suppressor gene are not increased in colon cancer cell lines with the RER+ phenotype. 927 85

Up to 15% of all colorectal cancers are considered to be replication error positive (RER(+)) and contain mutations at hundreds of thousands of microsatellite repeat sequences. Recently, a number of intragenic mononucleotide repeat sequences have been demonstrated to be targets for inactivating genes in RER(+)colorectal tumors. In this study, thermostable DNA ligases were tested for the ability to detect alterations in microsatellite sequences in colon tumor samples. Ligation profiles on mononucleotide repeat sequences were determined for four related thermostable DNA ligases, Thermus thermophilus ( Tth ) ligase, Thermus sp. AK16D ligase, Aquifex aeolicus ligase and the K294R mutant of the Tth ligase. While the limit of detection for point mutations was one mutation in 1000 wild-type sequences, the ability to detect a single base deletion in a 10 base mononucleotide repeat was one mutation in 100 wild-type sequences. Furthermore, the misligation error increased exponentially as the length of the mono-nucleotide repeat increased, and was 10% of the correct signal for a 19 base mononucleotide repeat. A fluorescent ligase-based assay [polymerase chain reaction/ligase detection reaction (PCR/LDR)] correlated with results obtained using a radioactive assay to detect instability within the TGF-beta Type II receptor gene. PCR/LDR was also used to detect the APCI1307K mononucleotide repeat allele which has a carrier frequency of 6.1% in Ashkenazi Jewish individuals. In a blind study, 30 samples that had been typed for the presence of the APCI1307K allele were tested. The PCR/LDR results correlated with those obtained using sequencing and allele-specific oligonucleotide hybridization for 16 samples carrying the mutation and 13 wild-type samples. Ligation assays that characterize mononucleotide repeats can be used to rapidly detect somatic mutations in tumors, and to screen for individuals who have a hereditary predisposition to develop colon cancer.
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PMID:Ligase-based detection of mononucleotide repeat sequences. 1057 92

Hereditary non-polyposis colon cancer (HNPCC) is an autosomal dominant disorder featuring familial clustering of colorectal and/or endometrial cancer, and other malignancies. Except for a rare case report, Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) have not been considered part of HNPCC. Recent murine models for HNPCC have shown an increased incidence of B- and T-cell lymphoma, as well as tumors of the gastrointestinal tract and other organ systems, involving defects in genes resulting in faulty mismatch repair (MMR) of DNA. These MMR genes include MLH1, MSH2, MSH3, MSH6, PMS1 and PMS2. We sought to analyze the occurrence of NHL and HD in families with clusters of colorectal cancers (CRC). Probands from 21 kindreds were classified as HNPCC (3), HNPCC-like (5), and HNPCC-variant (13); seen and followed by Clinical Genetics at Memorial Hospital the kindreds were assessed for the occurrence of NHL or HD. Of the 21 pedigrees, a total of 37 patients were identified who were diagnosed with leukemia, lymphoma, or HD. Fourteen of the 37 patients with a diagnosis of NHL or HD were further classified and showed varying histologies ranging from chronic lymphocytic leukemia/small lymphocytic lymphoma (2), mycosis fungoides (1), follicular lymphoma (1), extranodal marginal zone lymphoma of MALT type (2), diffuse large B-cell lymphoma (4), nodular sclerosis HD (3), and mixed cellularity HD (1). Microsatellite instability studies were performed on 6 cases but none showed evidence of replication error repair defects. Immunohistochemical stains performed on paraffin sections from these 6 representative cases showed differential protein expression of MLH1, MSH2, MSH6, and PMS2 when compared to normal reactive tissues from the same patient but showed no significant differences when compared to controls of non-familial, sporadic lymphomas. These results suggest that lymphomas arising in the setting of familial CRC do not bear the molecular hallmarks of HNPCC. Further studies are needed to explain the differential patterns of expression of RER-associated proteins in lymphomas, as well as the association of lymphomas and possibly renal cell cancers in a subset of kindreds in which CRC clustering is evident.
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PMID:Analysis of mismatch repair defects in the familial occurrence of lymphoma and colorectal cancer. 1240 Jun 5

A new intestinal antiproliferative factor (IAF) with an approximate molecular weight of 120 kDa has been purified from the human small intestine. This factor blocks the progression of human colon adenocarcinoma cells HT-29 from the G1 to the S phase. IAF, specific of the lower part of the digestive tract, was detected rather late in mouse embryonic development. For determination of the specific intestinal cell producing IAF, long-term differentiated mucus-secreting HT-29 Cl 16E and enterocytic HT-29 Cl 19A cell lines were used. IAF is synthesized exclusively in the intestinal goblet cells; it is processed in the RER and Golgi complex before being excreted in secretory vesicles independently of mucin secretion. IAF can be considered a growth inhibitor of intestinal proliferation for the same reason as TGF-beta. However, two features differentiate it from TGF-beta: (1) the intestinal cell type synthesizing it, and (2) the delay in its expression in embryonic development. Particular interest was paid to IAF expression in pathological conditions using human colon biopsies. IAF was consistently recovered in biopsies from patients with inflammatory bowel diseases and benign tumors, but it was never detected in malignant tumors. IAF could represent a marker of colon cancer owing to its absence from malignant tumors.
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PMID:Immunolocalization of a new intestinal antiproliferative factor in human intestinal epithelial cells. 1245 77

MMTV induces the mouse mammary tumor through the dysregulation of Notch, Wnt, or Fgf signaling pathway. Activation of Notch signaling pathway leads to transcriptional activation of Hes family genes through the interaction between Notch intracellular domain and RBPSUH (CSL). Hes family proteins are mammalian homologs of Drosophila Hairy and Enhancer of split. Hes family of transcriptional repressors with basic Helix-loop-helix (bHLH) and Orange domains are implicated in the cell fate determination of stem cells (or precursor cells) by suppressing the expression of tissue-specific transcriptional activators. Human HES1, HES4, HES6, and HES7 genes have been reported by other groups. Here, we identified and characterized human HES2, HES3 and HES5 genes by using bioinformatics. FLJ33803 (AK091122.1) was the representative human HES2 cDNA. HES2 gene, encoding a 173-aa protein, was located within human genome sequence AL031848.11. HES3 gene, encoding a 186-aa protein, was identified within human genome sequence AL031847.17. HES5 gene, encoding a 166-aa protein, was identified within human genome sequence AL139246.20. HES2 and HES3 genes were mapped to human chromosome 1p36.31, while HES5 gene to 1p36.32. HES2 mRNA was expressed in placenta, pancreatic cancer, colon cancer with RER, cervical cancer, and in head and neck tumors. HES5 mRNA was expressed in fetal heart, and brain tumors. Human HES family proteins were found consisting of bHLH, Orange, Proline-rich domains, and WRPW motif. Phylogenetic analyses revealed that HES family proteins were distantly related except a paralog pair of HES1 and HES4. HES family genes are pharmacogenomic targets in the field of regenerative medicine and oncology.
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PMID:Identification and characterization of human HES2, HES3, and HES5 genes in silico. 1525 53