• The Korean Journal of Zoology
• /
• v.39 no.3
• /
• pp.231-238
• /
• 1996

Several types of human lung and pancreatic carcinoma cell lines were cultured and their chromosomal DNAs were extracted. These DNAs were then partially amplified by PCR (Polymerase Chain Reaction) and sequenced to analyze the types and frequency of mutations, and their possible relation in the oncogene, K-ras and suppressor gene, p53. Regardless of the cell line origin, 81% were found to possess at least one mutation. Among the cell lines analyzed, 54.5% of the mutations were found in either K-ras or p53. Except for one nonsense mutation, all mutations were missense with either base insertions or substitutions. Furthermore, besides the p53 codons Known to be mutated simultaneously with' ras to enhance tumor growth, p53 164-165 and 248 were found to be mutated simultaneously with K-ms. Regardless of the site of p53 mutation, all K-ras mutations found in these cases occurred at exon 1, codon 12.

• Korean Journal of Clinical Laboratory Science
• /
• v.55 no.2
• /
• pp.93-104
• /
• 2023

This study aimed to identify new markers that cause lung adenocarcinoma by analyzing mutation hotspots for the top five genes with high mutation frequency in lung adenocarcinoma in Koreans by next generation sequencing (NGS) analysis. The association between TP53 mutation types and patterns with smoking, a major cause of lung cancer, was examined. The clinicopathological characteristics of lung adenocarcinoma patients with TP53 P72R SNPs were analyzed. In Korean lung adenocarcinoma cases, regardless of the smoking status, the TP53 P72R SNP was the most frequently occurring mutational hotspot, in which the nucleotide base was transversed from C to G, and the amino acid was substituted from proline to arginine at codon 72 of TP53. An analysis of the clinicopathological characteristics of lung adenocarcinoma cases with TP53 P72R SNP revealed no significant correlation with the patient's age, gender, smoking status, and tumor differentiation, but a significant correlation with low stage (P-value =0.026). This study confirmed an increase in TP53 rather than EGFR, which was reported as the most frequent mutations in lung adenocarcinoma in Koreans through NGS. Among them, TP53 P72R SNP is the most frequent regardless of smoking status.

• Journal of Gastric Cancer
• /
• v.6 no.4
• /
• pp.214-220
• /
• 2006

Purpose: p53 is one of the most commonly mutated genes in human tumors. The aim of this study was to analyze p53 mutation in gastric cancer and its correlations with the clinicopathologic variables to clarify the usefulness of p53 mutation as a prognostic factor. Materials and Methods: Specimens from 331 patients with gastric cancer who underwent a gastrectomy between March 1999 and April 2001 at the Kyungpook National University Hospital were used. p53 gene mutations were assessed by using a polymerase chain-reaction single-strand conformation polymorphism (PCR-SSCP) analysis. The correlations between p53 gene mutation and clinocopathologic parameters were analyzed. Results: p53 mutations were found in 66 (19.9%) tumors. Among those 66 cases, mutations were seen in 23 tumors at axon 5, in 8 at exon 6, in 21 at exon 7, and in 17 at exon 8. Two mutations were shown in 3 tumors. Thiriy-six (23.1%) of 156 intestinal-type tumors and 19 (13.1%) of 145 diffuse-type tumors showed p53 gene mutation (P=0.007). The frequency of p53 gene mutation didn't show any significant differences according to age, sex, stage, location, or gross type. Exon 5 mutations showed more frequently in intestinal-type tumors than in diffuse-type tumors (9.7% vs. 2.8%, P=0.024), and p53 mutation were more frequent in lymph nodes metastasis group than lymph nodes non-metastasis group with statistical significance (25.0% vs 15.6%, P=0.034). The five-year survival rate showed no statistically significant difference with p53 mutation (P=0.704). Conclusion: p53 mutations assessed by PCR-SSCP had little value as a prognostic factor after gastrectomy in patients with gastric cancer.

• Journal of the Korean Chemical Society
• /
• v.47 no.5
• /
• pp.460-465
• /
• 2003

Structural alteration of p53 and overexpression of p53 protein are the most common genetic abnormalities in various kinds of human cancer. Mutations in the p53 tumor-suppressor gene are usually associated with an advanced development of colorectal cancer characterized by the transition from the adenoma to carcinoma stage. Mutations in exons 5-8 of the p53 gene were analyzed by the polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) and denaturing high performance liquid chromatography(DHPLC). SSCP analysis detected 7 mutations(C13109>T) in 50 colorectal cancer samples(14%) at exon 5, and DHPLC analysis detected 7 mutations (C13109>T) and 2 mutation(C13202>A, C13204>G) in 50 colorectal cancer samples(18%) at exon 5. All of 9 mutations were proved by sequencing analysis. We conclude that DHPLC is a highly sensitive and specific method for p53 gene mutations.

• Tuberculosis and Respiratory Diseases
• /
• v.40 no.4
• /
• pp.395-403
• /
• 1993

Background: The cell cycle is composed of a series of steps which can be negatively or positively regulated by various factors. Alteration or inactivation of p53 by mutations, or by its interactions with oncogene products of DNA tumor viruses, can lead to cancer. Mutations of the p53 gene occur frequently in human primary lung cancers and the wild-type p 53 allele is often concomitantly deleted. These suggest that deprivation of suppressive role of the wild-type p53 may ensure tumor cell growth presumable by the mutant p53 gene. Methods: In an attempt to investigate this hypothesis, a mutant p53 gene was immunohistochemically demonstrated in the formalin-fixed paraffin-embedded tissue sections of lung cancers by using a monoclonal antibody p53 (Ab-3 and clone DO7). Results: The expression of p53 (DO7) was found in all four normal lung tissues, four small cell carcinomas, and four non small cell carcinomas in histologic types of lung cancer. In the six normal lung tissues the expressions of p53 (Ab-3) were not found. Contrarily, the expression of p53 (Ab-3) was found in the nuclei of lung cancers among fifteen (46.9%) of thirty-two cases studied. The expression of p53 (Ab-3) was disclosed in three case (37.5%) of eight small cell carcinomas and twelve cases (50.0%) of twenty-four non small cell carcinomas in histologic types of lung cancer. Conclusion: These findings suggest that expression of the mutant p53 is related to the one of events in the pathogenesis of human lung cancer and the role of the other oncogenes might be also related to the development of lung cancers.

• Journal of the Korean Chemical Society
• /
• v.48 no.1
• /
• pp.33-38
• /
• 2004

Mutation of p53 tumor suppressor gene in HNSCC (head and neck squamous cell carcinoma) has been proposed high rate. We extracted genomic DNA from 50 head and neck cancer. The DNA was amplified by PCR at exon 5-8 in p53 tumor suppressor gene. We have compared single strand conformation polymorphism (SSCP) and denaturing high performance liquid chromatography (DHPLC) method for analysis of p53 somatic mutation. As a result, 16 deleted mutations (32%) were detected by SSCP analysis and 17 deleted mutations (34%) were detected by DHPLC analysis at exon 8. All of 17 mutations were proved by sequencing. We conclude that DHPLC is a fast and simple screening method rather than SSCP analysis.

• The Journal of Natural Sciences
• /
• v.9 no.1
• /
• pp.31-37
• /
• 1997

Apoptosis is an important event in the anticancer drug therapy. p53 was demonstrated to serve a key component to lead tumor cell death by inducing apoptosis. However, recent study showed the presence of p53 independent apoptotic pathway (Gaftenhaus et al., 1996). We were curious to know it apoptosis induced by adriamycin, a genotoxic anticancer agent, involved p53 gene mutation. Thus this study investigated the p53 gene mutation status among HeLa cell population during apoptosis induced by adriamycin. Under our experimental condition, 12 hour treatment of 1 ${\mu}m$ adriamycin caused apoptosis which was monitored by DNA fragmentation assay. In order to see the p53 gene mutation status, exons of 5, 7 and 8 of p53 gene, where previously reported p53 mutation hot spots reside, were amplified by PCR and nucleotide sequence change was scanned. However, no nucleotide change was observed among apoptotic HeLa cell population. Therefore this study demonstrated that adriamycin induced apoptosis without causing p53 gene damage.

• The Journal of the Korean bone and joint tumor society
• /
• v.6 no.4
• /
• pp.143-151
• /
• 2000

Purpose : The p53 tumor suppressor gene is one of the most frequently altered genes in human malignancies. We try to explore the implication of p53 alteration in Ewing's sarcoma. Materials and Methods : We analyzed 35 paraffin blocks to explore the deletion and sequence alterations of p53. Results : Quantitative PCR analysis showed that 2 tumors showed a homozygous deletion of the gene. Mutational analysis of exons 4 to 9 of p53 by PCR-SSCP revealed that 3 tumors carry sequence alterations in exons 5 or 8, and DNA sequencing analysis identified missense point mutations. Conclusion : Taken together, our data demonstrate that p53 is genetically altered in a small fraction of Ewing's sarcoma.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.1 s.60
• /
• pp.15-26
• /
• 1998

p53 is the most frequently mutated gene in female breast cancer tissues and the prognosis of breast cancer could be changed by mutation of the gene. This study was performed to examine risk factors for breast cancer subtypes classified by p53 mutation and to investigate the roles of p53 gene mutation in carcinogenesis of breast cancer. The study subjects were 81 breast cancer patients and 121 controls who were matched to cases 1:1 or 1:2 age, residence, education level and menopausal status. All the subjects were interviewed by a well-trained nurse with standardized questionnaire on reproductive factors, and wire asked to fill the self-administrative food frequency questionnaire. p53 gene mutation in the cancer tissue was screened using polymerase chain reaction (PCR)-single strand conformational polymorphism (SSCP) method. Mutation type was identified by direct sequencing of the exon of which mobility shift was observed in SSCP analysis. Mutations were detected in p53 gene of 25 breast cancer tissues. By direct sequencing, base substitutions were found in 20 cancer tissues (10 transition and 10 transversion), and frame shift mutations in 5 (4 insertions and 1 deletion). For the whole cases and controls, risk of breast cancer incidence decreased when the parity increased, and increased when intake amount of total calory, fat, or protein increased. Eat and protein were statistically significant risk factors for breast cancer with p53 mutation. For breast cancer without p53 mutation, protein intake was the only significant dietary factor. These results suggest that causes of p53 positive breast lancer would be different from those of p53 negative cancer, and that dietary factors or related hormonal factors induce mutation of p53, which may be the first step of breast cancer development or a promoter following some unidentified genetic mutations.

• Journal of Life Science
• /
• v.28 no.4
• /
• pp.488-495
• /
• 2018

The p53 gene plays a critical role in the transcriptional regulation of cellular response to stress, DNA damage, hypoxia, and tumor development. Keeping in mind the recently discovered manifold physiological functions of p53, its involvement in the regulation of cancer is not surprising. In about 50% of all human cancers, inactivation of p53's protein function occurs either through mutations in the gene itself or defects in the mechanisms that activate it. This disorder plays a crucial role in tumor evolution by allowing the evasion of a p53-dependent response. Many recent studies have focused on directly targeting p53 mutants by identifying selective, small molecular compounds to deplete them or to restore their tumor-suppressive function. These small molecules should effectively regulate various interactions while maintaining good drug-like properties. Among them, the discovery of the key p53-negative regulator, MDM2, has led to the design of new small molecule inhibitors that block the interaction between p53 and MDM2. Some of these small molecule compounds have now moved from proof-of-concept studies into clinical trials, with prospects for further, more personalized anti-carcinogenic medicines. Here, we review the structural and functional consequences of wild type and mutant p53 as well as the development of therapeutic agents that directly target this gene, and compounds that inhibit the interaction between it and MDM2.