Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009402 (colorectal cancer)
 53,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Results of the application of apparatus AKA-2 for the formation of compressive anastomoses under complicated conditions are discussed. Among them are: acute and chronic ileus, peritonitis, diabetes mellitus etc. Common negative factors for all the patients were symptoms of secondary immune deficiency and specific endogenous intoxication resulting from chronic internal irradiation by radionuclides (consequences of the disaster in Chernobyl atomic power station in 1986). In 1987-1990 operations were performed on 84 patients. Compressive colonic anastomoses were made with apparatus AKA-2. All the patients lived in Kiev and neighbouring regions from 1986. From the patients operated upon 81% had colorectal cancer localized in left portions of the colon, 19% of the patients had inflammatory diseases of the colon. The application of compressive colonic anastomoses under the complicated conditions proved to be sufficiently reliable in the nearest and late terms of observations.
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PMID:[Compression anastomoses of the large intestine under complicated conditions]. 809 92

Cyclooxygenase-2 (COX-2) overexpression and mutations of p53 (a known COX-2 regulator) are inversely associated with microsatellite instability-high (MSI-H) and CpG island methylator phenotype (CIMP) characterized by extensive promoter methylation, is associated with MSI-H. However, no studies have comprehensively examined interrelations between COX-2, p53, MSI, and CIMP. Using MethyLight, we measured DNA methylation in five CIMP-specific gene promoters [CACNA1G, CDKN2A (p16/INK4A), CRABP1, MLH1, and NEUROG1] in relatively unbiased samples of 751 colorectal cancer cases obtained from two large prospective cohorts; 115 (15%) tumors were CIMP-high (> or = 4 of 5 methylated promoters), 251 (33%) were CIMP-low (1 to 3 methylated promoters), and the remaining 385 (51%) were CIMP-0 (no methylated promoters). CIMP-high tumors were much less frequent in COX-2+/p53+ tumors (4.6%) than in COX-2+/p53- tumors (19%; P < .0001), COX-2-/p53+ tumors (17%; P = .04), and COX-2-/p53- tumors (28%; P < .0001). In addition, COX-2+/p53+ tumors were significantly less common in MSI-H CIMP-high tumors (9.7%) than in non-MSI-H CIMP-low/CIMP-0 tumors (44-47%; P < .0001). In conclusion, COX-2 and p53 alterations were synergistically inversely correlated with both MSI-H and CIMP-high. Our data suggest that a combined analysis of COX-2 and p53 may be more useful for the molecular classification of colorectal cancer than either COX-2 or p53 analysis alone.
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PMID:Combined analysis of COX-2 and p53 expressions reveals synergistic inverse correlations with microsatellite instability and CpG island methylator phenotype in colorectal cancer. 1682 91

p21 (CDKN1A/CIP1/WAF1), one of the cyclin-dependent kinase inhibitors, plays a key role in regulating the cell cycle and is transcriptionally regulated by p53. Down-regulation of p21 is caused by TP53 mutations in colorectal cancer. CpG island methylator phenotype (CIMP) appears to be a distinct subtype of colorectal cancer with concordant methylation of multiple gene promoters and is associated with a high degree of microsatellite instability (MSI-H) and BRAF mutations. However, no study to date has evaluated the relationship between p21 expression and CIMP in colorectal cancer. The purpose of this study was to examine the inter-relationships between p21, p53, CIMP, MSI and KRAS/BRAF status in colorectal cancer. We utilized 737 relatively unbiased samples of colorectal cancers from two large prospective cohort studies. Using quantitative real-time PCR (MethyLight), we measured DNA methylation in five CIMP-specific gene promoters [CACNA1G, CDKN2A (p16/INK4A), CRABP1, MLH1 and NEUROG1]. CIMP-high (>or=4/5 methylated promoters) was diagnosed in 118 (16%) of the 737 tumours. We also assessed expression of p21 and p53 by immunohistochemistry. Among the 737 tumours, 371 (50%) showed p21 loss. Both p21 loss and p53 positivity were inversely associated with CIMP-high, MSI-H and BRAF mutations. The associations of p21 with these molecular features were still present after tumours were stratified by p53 status. In contrast, the associations of p53 positivity with the molecular features were no longer present after tumours were stratified by p21 status. When CIMP-high and non-CIMP-high tumours were stratified by MSI or KRAS/BRAF status, CIMP-high and MSI-H (but not BRAF mutations) were still inversely associated with p21 loss. In conclusion, down-regulation of p21 is inversely correlated with CIMP-high and MSI-H in colorectal cancer, independent of TP53 and BRAF status.
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PMID:Down-regulation of p21 (CDKN1A/CIP1) is inversely associated with microsatellite instability and CpG island methylator phenotype (CIMP) in colorectal cancer. 1685 May 2

The CpG island methylator phenotype (CIMP or CIMP-high) with extensive promoter methylation seems to be a distinct epigenotype of colorectal cancer. However, no study has comprehensively examined features of colorectal cancer with less extensive promoter methylation (designated as "CIMP-low"). Using real-time polymerase chain reaction (MethyLight), we quantified DNA methylation in five CIMP-specific gene promoters [CACNA1G, CDKN2A (p16), CRABP1, MLH1, and NEUROG1] in 840 relatively unbiased, population-based colorectal cancer samples, obtained from two large prospective cohort studies. CIMP-low (defined as 1/5 to 3/5 methylated promoters) colorectal cancers were significantly more common among men (38 versus 30% in women, P = 0.01) and among KRAS-mutated tumors (44 versus 30% in KRAS/BRAF wild-type tumors, P = 0.0003; 19% in BRAF-mutated tumors, P < 0.0001). In addition, KRAS mutations were significantly more common in CIMP-low tumors (47%) than in CIMP-high tumors (with > or =4/5 methylated promoters, 12%, P < 0.0001) and CIMP-0 tumors (with 0/5 methylated promoters, 37%, P = 0.007). The associations of CIMP-low tumors with male sex and KRAS mutations still existed after tumors were stratified by microsatellite instability status. In conclusion, CIMP-low colorectal cancer is associated with male sex and KRAS mutations. The hypothesis that CIMP-low tumors are different from CIMP-high and CIMP-0 tumors needs to be tested further.
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PMID:CpG island methylator phenotype-low (CIMP-low) in colorectal cancer: possible associations with male sex and KRAS mutations. 1706 27

Cytoplasmic mislocalization of p27 (CDKN1B/KIP1) is caused by activated AKT1 and has been associated with poor prognosis in various cancers. CIMP in colorectal cancer is characterized by extensive promoter methylation and is associated with MSI-MSI-H and BRAF mutations. We have recently shown a positive correlation between MSI/CIMP and loss of nuclear p27. However, no study has examined cytoplasmic p27 mislocalization in relation to CIMP and MSI in colorectal cancer. Using MethyLight assays, we quantified DNA methylation in 8 CIMP-specific gene promoters (CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1) in 853 colorectal cancer samples obtained from 2 large prospective cohorts. We assessed expressions of nuclear and cytoplasmic p27 and nuclear p53 by immunohistochemistry. Cytoplasmic p27 expression was inversely associated with loss of nuclear p27 (P < .0001), CIMP-high (P < .0001), MSI-H (P < .0001), and BRAF mutations (P < .0001). The inverse association of cytoplasmic p27 with CIMP-high (or MSI-H) was independent of MSI (or CIMP) status. In addition, the inverse association of cytoplasmic p27 with CIMP-high was independent of KRAS/BRAF status. BRAF and CDKN2A (p16) methylation were not correlated with cytoplasmic p27 after stratification by CIMP status. The inverse associations of cytoplasmic p27 with MSI-H and CIMP-high were much more pronounced in p53-negative than p53-positive tumors. In conclusion, cytoplasmic p27 expression is inversely associated with MSI-H and CIMP-high, particularly in p53-negative tumors, suggesting interplay of functional losses of p27 and p53 in the development of various molecular subtypes of colorectal cancer.
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PMID:Cytoplasmic localization of p27 (cyclin-dependent kinase inhibitor 1B/KIP1) in colorectal cancer: inverse correlations with nuclear p27 loss, microsatellite instability, and CpG island methylator phenotype. 1723 30

The transforming growth factor-beta receptor type 2 gene (TGFBR2) is mutated in most microsatellite instability-high (MSI-H) colorectal cancers. Promoter methylation of RUNX3 (runt-related transcription factor 3; encoding a transcription factor downstream of the TGF-beta pathway) is observed in colorectal cancer with CpG island methylator phenotype (CIMP), which is characterized by extensive promoter methylation and is associated with MSI-H and BRAF mutations. However, no study to date has examined interrelationship between TGFBR2 mutation, RUNX3 methylation, and CIMP in colorectal cancer. Using 144 MSI-H colorectal cancers derived from 2 large prospective cohort studies, we analyzed a mononucleotide repeat of TGFBR2 and quantified DNA methylation (by MethyLight technology) in 8 CIMP-specific promoters (RUNX3, CACNA1G [calcium channel, voltage-dependent, T type alpha-1G subunit], CDKN2A [p16], CRABP1 [cellular retinoic acid binding protein 1], IGF2 [insulin-like growth factor 2], MLH1, NEUROG1 [neurogenin 1], and SOCS1 [suppressor of cytokine signaling 1]). Among the 144 MSI-H tumors, the presence of TGFBR2 mutation (overall 72% frequency) was correlated positively with CIMP-high (with >/=6/8 methylated promoters; P < .0001), RUNX3 methylation (P = .0004), BRAF mutation (P = .0006), and right colon (P = .05); inversely with KRAS mutation (P = .006); but not significantly with sex, tumor differentiation, and p53 status (assessed by immunohistochemistry). After stratification by sex, location, tumor differentiation, RUNX3 status, KRAS/BRAF status, or p53 status, CIMP-high was persistently correlated with TGFBR2 mutation. In contrast, RUNX3, KRAS, or BRAF status was no longer correlated with TGFBR2 mutation after stratification by CIMP status. In conclusion, TGFBR2 mutation is associated with CIMP-high and indirectly with RUNX3 methylation. Our findings emphasize the importance of analyzing global epigenomic status (for which CIMP status is a surrogate marker) when correlating a single epigenetic event (eg, RUNX3 methylation) with any other molecular or clinicopathologic variables.
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PMID:TGFBR2 mutation is correlated with CpG island methylator phenotype in microsatellite instability-high colorectal cancer. 1727 Feb 39

Overexpression of fatty acid synthase (FASN), a key enzyme for de novo lipogenesis, is observed in many cancers including colorectal cancer and is associated with poor clinical outcomes. Cellular FASN expression is physiologically upregulated in a state of energy excess. Obesity and excess energy balance have been known to be risk factors for colorectal cancer. High degree of microsatellite instability (MSI-H) is a distinct phenotype in colorectal cancer, associated with CpG island methylator phenotype (CIMP). Previous data suggest that obesity or altered energy balance may potentially modify risks for MSI-H cancers and microsatellite stable (MSS) cancers differently. However, the relationship between MSI and FASN overexpression has not been investigated. Using 976 cases of population-based colorectal cancer samples from 2 large prospective cohort studies, we correlated FASN expression (by immunohistochemistry) with MSI, KRAS and BRAF mutations, p53 expression (by immunohistochemistry), and CIMP status [determined by MethyLight for 8 CIMP-specific gene promoters including CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1]. Marked (2+) FASN overexpression was observed in 110 (11%) of the 976 tumors and was significantly more common in MSI-H tumors (21% [28/135]) than MSI-low (5.6% [4/72], P = .004) and MSS tumors (11% [72/678], P = .001). The association between FASN overexpression and MSI-H persisted even after stratification by CIMP status. In contrast, FASN overexpression was not correlated with CIMP after stratification by MSI status. Fatty acid synthase overexpression was not significantly correlated with sex, tumor location, p53, or KRAS/BRAF status. In conclusion, FASN overexpression in colorectal cancer is associated with MSI-H, independent of CIMP status.
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PMID:Fatty acid synthase overexpression in colorectal cancer is associated with microsatellite instability, independent of CpG island methylator phenotype. 1735 Jun 69

The CpG island methylator phenotype (CIMP) is a distinct epigenetic phenotype in colorectal carcinoma with concordant methylation in multiple promoter CpG islands. The relationship between CpG island methylation and clinical outcomes among colorectal cancer patients treated with chemotherapy has been a controversial subject. Utilizing real-time polymerase chain reaction (PCR; MethyLight technology), we quantified DNA methylation in 13 CpG island loci (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, SOCS1, MINT1, MINT31, IGFBP3, MGMT, and WRN) in 30 metastatic microsatellite stable colorectal carcinomas in phase I/II clinical trials of combination chemotherapy (5-fluorouracil, irinotecan, leucovorin, and gefitinib). Tumor response was assessed by CT scans performed at baseline and every 6 weeks thereafter. Overall CIMP-high status (either >or=9/13 or >or=7/13 methylated markers; identifying 3 or 5 CIMP-high tumors, respectively) and methylation in CACNA1G, IGF2, MLH1, NEUROG1, RUNX3, MINT31, and WRN were associated with worse survival (all p < 0.01). Although not statistically significant, there was a trend toward resistance to chemotherapy among tumors with CpG island methylation. In conclusion, CpG island methylation may predict poor survival in metastatic microsatellite stable colorectal carcinoma treated with chemotherapy. Additional studies are necessary to examine the role of DNA methylation in treatment efficacy.
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PMID:CpG island methylation, response to combination chemotherapy, and patient survival in advanced microsatellite stable colorectal carcinoma. 1737 56

The CpG island methylator phenotype (CIMP or CIMP-high) with extensive promoter methylation is a distinct phenotype in colorectal cancer. However, a choice of markers for CIMP has been controversial. A recent extensive investigation has selected five methylation markers (CACNA1G, IGF2, NEUROG1, RUNX3, and SOCS1) as surrogate markers for epigenomic aberrations in tumor. The use of these markers as a CIMP-specific panel needs to be validated by an independent, large dataset. Using MethyLight assays on 920 colorectal cancers from two large prospective cohort studies, we quantified DNA methylation in eight CIMP-specific markers [the above five plus CDKN2A (p16), CRABP1, and MLH1]. A CIMP-high cutoff was set at > or = 6/8 or > or = 5/8 methylated promoters, based on tumor distribution and BRAF/KRAS mutation frequencies. All but two very specific markers [MLH1 (98% specific) and SOCS1 (93% specific)] demonstrated > or = 85% sensitivity and > or = 80% specificity, indicating overall good concordance in methylation patterns and good performance of these markers. Based on sensitivity, specificity, and false positives and negatives, the eight markers were ranked in order as: RUNX3, CACNA1G, IGF2, MLH1, NEUROG1, CRABP1, SOCS1, and CDKN2A. In conclusion, a panel of markers including at least RUNX3, CACNA1G, IGF2, and MLH1 can serve as a sensitive and specific marker panel for CIMP-high.
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PMID:Evaluation of markers for CpG island methylator phenotype (CIMP) in colorectal cancer by a large population-based sample. 1759 25

O-6-methylguanine-DNA methyltransferase (MGMT) repairs inappropriately methylated guanine residues in DNA. MGMT promoter methylation and gene silencing are common events in colorectal cancer, and may or may not co-exist with the CpG island methylator phenotype (CIMP). To date, no study has examined the relationship between MGMT promoter methylation and common MGMT single nucleotide polymorphisms (SNPs), which have been associated with colorectal cancer risk. Utilizing real-time polymerase chain reaction (MethyLight technology), we quantified DNA methylation in MGMT and eight other markers (a CIMP diagnostic panel including CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1 in 182 colorectal cancers collected from two prospective cohorts, the Nurses' Health Study and the Health Professionals Follow-up Study. We genotyped four MGMT germline SNPs in normal DNA and assessed microsatellite instability (MSI), 18q loss of heterozygosity and KRAS and BRAF status in tumors. The presence of a common MGMT promoter SNP (NM_002412.2:c.-56C>T) (rs16906252) was strongly associated with MGMT methylation (multivariate odds ratio 18.0; 95% confidence interval, 6.2-52.1, P < 0.0001). The presence of the c.-56C>T SNP was also associated with loss of MGMT expression in tumors (assessed by immunohistochemistry) (P = 0.009). This promoter SNP was not correlated with KRAS, BRAF, CIMP or MSI status. None of the other three non-promoter SNPs was significantly associated with any molecular changes tested. In conclusion, we have found a strong association between the germline polymorphism (c.-56C>T) of the MGMT promoter and promoter methylation/silencing of MGMT in colorectal cancer. Our data provide compelling evidence for common susceptibility for MGMT promoter CpG island methylation.
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PMID:MGMT germline polymorphism is associated with somatic MGMT promoter methylation and gene silencing in colorectal cancer. 1762 91


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