Análise comparativa do polimorfismo genético da glutationa transferase, do Helicobacter pylori e do vírus Epstein-Barr entre a área do tumor e as margens de ressecção proximal e distal do câncer gástrico.

Mac-Cormick, Thaís Messias; Carvalho, Carlos Eduardo; Neto, Guilherme Pinto Bravo; Carvalho, Maria da Glória da Costa

doi:10.1590/0100-6991e-20192068

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…DNA extraction from the tumor and surrounding tissue was performed as previously described by McCormick et al, 13 using the Ultra Pure™ Phenol: Chloroform: Isoamyl Alcohol kit (Invitrogen™, Carlsbad, United States) Cat. No.…”

Section: Methodsmentioning

confidence: 99%

hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study

Queiroz,

Silva,

Souza

et al. 2024

Sao Paulo Med. J.

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BACKGROUND: The human telomerase reverse transcriptase (hTERT) enzyme, encoded by the hTERT gene, synthesizes protective telomeric sequences on chromosomes and plays a fundamental role in cancer formation. Methylation of the hTERT gene has an upregulatory effect, increasing hTERT enzyme synthesis and allowing continuous tumor cell division. OBJECTIVE: In a group of patients with breast cancer, we aimed to analyze the methylation status of hTERT in the tumor, surrounding tissue, and circulating free deoxyribonucleic acid (cfDNA) of blood collected on the day of mastectomy and then approximately one year later. DESIGN AND SETTING: A prospective study was conducted at a university hospital in Rio de Janeiro, Brazil. METHODS: Samples were collected from 15 women with breast cancer on the day of mastectomy and approximately one year postoperatively. cfDNA was analyzed by sodium bisulfite conversion, followed by polymerase chain reaction, electrophoresis, and silver nitrate staining. RESULTS: Methylation of hTERT was detected in the tumors and surrounding tissues of all 15 patients. Five patients displayed hTERT methylation in the cfDNA from the blood of the first collection. Of the ten patients who returned for the second collection, three showed methylation. Two patients with methylation in the first collection did not display methylation in the second collection. One patient with no methylation in the first collection displayed methylation in the second collection, and one patient had a diminished level of methylation in the second collection. CONCLUSION: Only one-third of patients displayed methylation in their cfDNA, which may be related to the success of chemotherapy.

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Section: Methodsmentioning

confidence: 99%

hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study

Queiroz,

Silva,

Souza

et al. 2024

Sao Paulo Med. J.

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“…DNA extraction: Genomic DNA was extracted from fresh tumor tissue using the phenol:chloroform method, according to previously described by Maccormick et al 9 .…”

Section: Methodsmentioning

confidence: 99%

Epstein-Barr virus in gastric cancer and association with 30 bp del-latent membrane protein 1 polymorphism

Santos

Silva

Canêdo

et al. 2023

Rev. Assoc. Med. Bras.

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SUMMARY OBJECTIVE: This study aimed to determine the frequencies of Epstein-Barr virus, types 1 and 2 infection, and 30 bp del-latent membrane protein 1 viral polymorphism in gastric adenocarcinomas, as well as to investigate the association between Epstein-Barr virus infection and tumor location, type, and the patient's sex. METHODS: Samples were collected from 38 patients treated at a university hospital in Rio de Janeiro, Brazil. Epstein-Barr virus detection and genotyping were performed by polymerase chain reaction, followed by polyacrylamide gel electrophoresis and staining by the silver nitrate method. RESULTS: Overall, 68.4% of patients had Epstein-Barr virus-positive tumors. Of these, 65.4% presented infection by Epstein-Barr virus type 1, 23.1% by Epstein-Barr virus type 2, and 11.5% had coinfection with types 1 and 2. The 30 bp del-latent membrane protein 1 polymorphism was found in 42.3% of Epstein-Barr virus-positive tumors, 23.1% had the wild-type virus, and 23.1% had the wild-type and the polymorphism concomitantly. In 11.5% of Epstein-Barr virus-positive tumors, it was impossible to determine whether there was polymorphism or not. Tumor location in the antrum (22 of 38) and diffuse type (27 of 38) were predominant. There was no significant difference in Epstein-Barr virus infection or the 30 bp del-latent membrane protein 1 polymorphism between men and women. CONCLUSION: Epstein-Barr virus infection was found in 68.4% of tumors investigated in this study. To the best of our knowledge, this is the first article showing the coinfection of Epstein-Barr virus types 1 and 2 in gastric carcinoma in Brazil.

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“…The DNA extraction from tumor and non-tumor tissues was performed by the phenol:chloroform method 13…”

Section: Extraction Of Dna From the Tumor Surrounding Tissue And Bloo...mentioning

confidence: 99%

Molecular monitoring by CDKN2A/p16INK4A and RB1 gene methylation in breast cancer

Queiroz,

Silva,

Rosman

et al. 2024

Rev. Assoc. Med. Bras.

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OBJECTIVE: This prospective study aimed to provide a comprehensive analysis of the methylation status of two pivotal genes, CDKN2A/p16 INK4A (cyclin-dependent kinase inhibitor 2A) and RB1 (retinoblastoma transcriptional corepressor 1), in breast cancer patients. METHODS: Samples were obtained from 15 women diagnosed with breast cancer and who underwent a total mastectomy. DNA was extracted from the tumor, non-tumor tissue, and peripheral blood (circulating cell-free DNA). The methylation pattern of cell-free DNA extracted from blood collected on the day of mastectomy was compared with the methylation pattern of cell-free DNA from blood collected 1 year post-surgery. The methylation analysis was carried out by sodium bisulfite conversion and polymerase chain reaction, followed by electrophoresis. RESULTS: Methylation of CDKN2A/p16 INK4A was identified in 13 tumor samples and 12 non-tumor tissue samples. Two patients exhibited CDKN2A/ p16 INK4A methylation in the cell-free DNA of the first blood collection, while another showed methylation only in the cell-free DNA of the subsequent blood collection. Regarding RB1, 11 tumors and 8 non-tumor tissue samples presented methylation of the gene. CONCLUSION: This study presents a novel approach for monitoring breast cancer patients through the analysis of cell-free DNA methylation. This analysis can detect changes in methylation patterns before any visible sign of cancer appears in breast tissue and could help predict the recurrence of malignant breast tumors.

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Análise comparativa do polimorfismo genético da glutationa transferase, do Helicobacter pylori e do vírus Epstein-Barr entre a área do tumor e as margens de ressecção proximal e distal do câncer gástrico.

Cited by 5 publications

References 28 publications

hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study

hTERT gene methylation in circulating DNA, tumor, and surrounding tissue in breast cancer: a prospective study

Epstein-Barr virus in gastric cancer and association with 30 bp del-latent membrane protein 1 polymorphism

Molecular monitoring by CDKN2A/p16INK4A and RB1 gene methylation in breast cancer

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