Avaliação da expressão do gene MGMT nos tecidos normal e neoplásico de doentes com câncer colorretal

Cordeiro, Adriana Teixeira; Silva, Camila Morais Gonçalves da; Júnior, Waldemar Bartchewsky; Ribeiro, Marcelo Lima

doi:10.1590/s0100-69912012000100010

Cited by 3 publications

(2 citation statements)

References 23 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…O 6 -methylguanine DNA methyltransferase (MGMT) is a DNA repair enzyme expressed by all normal human cells, it prevents DNA mutations and damage due to alkylating agents, then undergoes self-inactivation.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, MGMT epigenetic silencing is linked to its lack of expression through the methylation process. Loss of MGMT expression has a significant role in carcinogenesis in various tumors as gliomas, non-small cell lung carcinoma, and diffuse large B-cell lymphoma [5], [6], [7]. Temozolomide (TMZ), an alkylating chemotherapeutic drug, is widely used to treat glioblastoma patients.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

Ahmed

Bayoumi

Abdallah

et al. 2021

Open Access Maced J Med Sci

View full text Add to dashboard Cite

Introduction: There is an urgent need to identify predictive features and markers for colorectal carcinoma (CRC) progression and treatment. This study aimed to assess O6-methylguanine DNA methyltransferase (MGMT) expression in CRC and correlate with the clinico-pathological aspects of the tumor, also to evaluate the relationship between different histopathologic parameters and tumor progression. Material and Methods: The study was carried on 70 colectomy using formalin fixed paraffin embedded tumor tissue. Immunohistochemistry was used to detect MGMT expression, and clinico-pathologic aspects as well as Tumor budding, type of desmoplastic reaction, inflammatory lymphocytic milieu, pattern of invasive front and necrosis were assessed Then correlated with MGMT expression and tumor progression, using parametric and nonparametric statistical methods. Results: MGMT Loss of expression was detected in 42.9% of CRC cases. MGMT expression status was significantly correlated with tumor stage and metastatic status (p<0.05), while it was not correlated with other clinic-pathologic features, (p>0.05). Desmoplastic reaction (DR), tumor budding, stromal tumor infiltrating lymphocytes (TIL-S) and necrosis were correlated with tumor stage (p<0.05). DR correlated with tumor budding (p<0.05). Both types of TIL and Crohn’s-like lymphoid reaction (CLR) showed a mutual correlation (p<0.05). Conclusion: MGMT high expression and histopathologic parameters as DR, tumor budding, inflammatory lymphocytic milieu and necrosis could be correlated with CRC progression.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

Ahmed

Bayoumi

Abdallah

et al. 2021

Open Access Maced J Med Sci

View full text Add to dashboard Cite

show abstract

Prognostic impact of MGMT promoter methylation and MGMT and CD133 expression in colorectal adenocarcinoma

et al. 2014

View full text Add to dashboard Cite

BackgroundNew biomarkers are needed for the prognosis of advanced colorectal cancer, which remains incurable by conventional treatments. O6-methylguanine DNA methyltransferase (MGMT) methylation and protein expression have been related to colorectal cancer treatment failure and tumor progression. Moreover, the presence in these tumors of cancer stem cells, which are characterized by CD133 expression, has been associated with chemoresistance, radioresistance, metastasis, and local recurrence. The objective of this study was to determine the prognostic value of CD133 and MGMT and their possible interaction in colorectal cancer patients.MethodsMGMT and CD133 expression was analyzed by immunohistochemistry in 123 paraffin-embedded colorectal adenocarcinoma samples, obtaining the percentage staining and intensity. MGMT promoter methylation status was obtained by using bisulfite modification and methylation-specific PCR (MSP). These values were correlated with clinical data, including overall survival (OS), disease-free survival (DFS), tumor stage, and differentiation grade.ResultsLow MGMT expression intensity was significantly correlated with shorter OS and was a prognostic factor independently of treatment and histopathological variables. High percentage of CD133 expression was significantly correlated with shorter DFS but was not an independent factor. Patients with low-intensity MGMT expression and ≥50% CD133 expression had the poorest DFS and OS outcomes.ConclusionsOur results support the hypothesis that MGMT expression may be an OS biomarker as useful as tumor stage or differentiation grade and that CD133 expression may be a predictive biomarker of DFS. Thus, MGMT and CD133 may both be useful for determining the prognosis of colorectal cancer patients and to identify those requiring more aggressive adjuvant therapies. Future studies will be necessary to determine its clinical utility.

show abstract

Fish Oil Contaminated with Persistent Organic Pollutants Induces Colonic Aberrant Crypt Foci Formation and Reduces Antioxidant Enzyme Gene Expression in Rats

Hong

Hoh

Kang

et al. 2017

The Journal of Nutrition

View full text Add to dashboard Cite

Epidemiologic, clinical, and experimental studies have suggested that fish oil (FO), a rich source of n-3 (ω-3) polyunsaturated fatty acids, protects against colon cancer. However, this message is confounded by the FDA's warning that the consumption of certain types of fish should be restricted because of contamination with persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides. We examined FO contaminated with POPs (PCBs, dichlorodiphenyltrichloroethane, and chlordane) compared with unmodified FO on the risk factors of colon cancer development. Male Sprague-Dawley rats aged 28 d ( = 30) were allocated into 3 groups and fed 15% corn oil (CO), FO, or POP-contaminated FO for 9 wk with a subcutaneous injection of colon carcinogen azoxymethane at weeks 3 and 4. Colonic aberrant crypt foci (ACF) and cell proliferation were enumerated, and the gene expression of inflammation, antioxidant enzymes, and repair enzymes were determined with the use of real-time quantitative polymerase chain reaction analysis. FO-fed rats had a lower number of ACF (mean ± SE: 29 ± 4.0 for FO compared with 53 ± 8.4 for CO and 44 ± 4.6 for POP FO) and higher-multiplicity ACF than the CO and POP FO groups (4.7 ± 0.9 for FO compared with 11 ± 1.5 for CO and 9.6 ± 1.8 for POP FO) ( < 0.05). FO feeding lowered the proliferation index compared with the CO and POP FO feeding groups (18% ± 1.1% for FO compared with 25% ± 1.6% for CO and 23% ± 0.7% for POP FO) ( = 0.009). Superoxide dismutase [2.4 ± 0.6 relative quantification (RQ) for FO compared with 1.2 ± 0.2 RQ for CO and 1.3 ± 0.3 RQ for POP FO] and catalase gene expression (10 ± 2.0 RQ for FO compared with 5.4 ± 1.1 RQ for CO and 6.6 ± 1.5 RQ for POP FO) were higher in the FO group than in the CO and POP FO groups ( < 0.05). There were no differences between CO and POP FO on the variables. These results indicate that POPs in FO reduce the preventive effects of FO on colon carcinogenesis by increasing preneoplastic lesion formation through the downregulation of antioxidant enzyme expression and increasing cell proliferation in rats.

show abstract

Avaliação da expressão do gene MGMT nos tecidos normal e neoplásico de doentes com câncer colorretal

Cited by 3 publications

References 23 publications

MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

Prognostic impact of MGMT promoter methylation and MGMT and CD133 expression in colorectal adenocarcinoma

Fish Oil Contaminated with Persistent Organic Pollutants Induces Colonic Aberrant Crypt Foci Formation and Reduces Antioxidant Enzyme Gene Expression in Rats

Contact Info

Product

Resources

About