Differential Transcriptional Regulation of Polymorphic p53 Codon 72 in Metabolic Pathways

p53 is a transcription factor that is activated under DNA damage stress and regulates the expression of proapoptotic genes including the expression of growth arrest genes to subsequently determine the fate of cells. To investigate the functional differences of polymorphic p53 codon 72, we constructed isogenic lines encoding each polymorphic p53 codon 72 based on induced pluripotent stem cells, which can endogenously express each polymorphic p53 protein only, encoding either the arginine 72 (R72) variant or proline 72 (P72) variant, respectively. We found that there was no significant functional difference between P72 and R72 cells in growth arrest or apoptosis as a representative function of p53. In the comprehensive analysis, the expression pattern of the common p53 target genes, including cell cycle arrest or apoptosis, was also increased regardless of the polymorphic p53 codon 72 status, whereas the expression pattern involved in metabolism was decreased and more significant in R72 than in P72 cells. This study noted that polymorphic p53 codon 72 differentially regulated the functional categories of metabolism and not the pathways that determine cell fate, such as growth arrest and apoptosis in cells exposed to genotoxic stress.

Polymorphism of p53 Codon 72 Gene on Cervical Cancer Incidence in Malay Population

In Indonesia, the cases of cervical cancer are estimated at around 50 per 100.000 people. It wasestimatedthattherearemore than1 millionwomenworldwidewho have cervical cancer,andmostofthemhavenot been diagnosed yet or do not have access to screening and medical treatment. P53 codon 72polymorphism can affect the risk of cervical cancerthrough the regulationofproliferationandcellapoptosis.Thepurpose of this research was to investigate the association between p53 codon 72 polymorphism and cases ofcervical cancer. This research was observational analytic research. The research was done by examining in thelaboratory of Molecular Biology, Faculty of Medicine, Universitas Sriwijaya by using a case-control studyapproach.Thesampleoftheresearchconsistedof 70subjects,andtheyweredividedintotwogroups:35in casegroup and 35 in the control group. The determination of genotype and allotype was done by using PCR-RFLPtechnics. The results of the research showed there was a significant difference between p53 codon 72polymorphism between the case group and control group. The results of genotypes of p53 codon 72polymorphism in the case group were seven respondents (20.0%) with Pro/Pro genotype, five respondents(14.3%) with Arg/Arg genotype, and 23 respondents (65.7%) with Pro/Arg. While in control group, there were 28respondents (80.0%) with Pro/Pro genotype, 0 respondent (0.0%) with Arg/Arg genotype, and 7 respondents(20%) with Pro/Arg. The frequency of the Prolin allele in case group was 37 (52.9%), and the Arginin allele was 33(47.1%), while the frequency of the Prolin allele in the control group was 63 (90%), and the Arginin allele was 7(10%).TheChi-Squareofgenotypewas valued0.000,OR1,304andCI95%1,071-5,891,whiletheallelewas valued0.000,OR8.027 andCI95% 3.228-19.962. Therewas an associationbetweengenotypeand allele of p53 codon72polymorphismandcasesofcervicalcancer

Prospective study of biomarkers in squamous cell carcinoma of the anal canal (SCCAC) and their influence on treatment outcomes: Five-year long-term results.

4053 Background: Chemoradiation (CRT) is a curative treatment for SCCAC. However, some patients (pts) present primary CRT resistance. As a rare tumor, there is a lack of prospective studies of prognostic factors in this setting. Methods: This prospective cohort study was aimed to evaluate predictive biomarkers (Ki-67, PD-L1, Human papillomavirus (HPV), HIV status, and tumor DNA mutations) in SCCAC. We published the 6 months (m) response rate (RR) of this cohort showing that HIV- were 5.7 times more likely to achieve response 6m post CRT (OR 5.72, CI 95% 2.5-13.0, P < 0.001). Now we report the long-term follow-up results of 5-year progression-free survival (PFS) and overall survival (OS). Eligible pts had T2-4/N0-3/M0 disease and were candidates to standard CRT. DNA mutations were analyzed by next-generation sequencing (NGS). HPV positivity was tested by PapilloCheck Test. KI-67 and PD-L1 were evaluated by immunohistochemistry. Results: 78 pts were recruited from Jan/2011 to Dec/2015. 75 were evaluable for PFS and OS. The median age was 57 years; 49 (65%) were stage III, and 9 (12%) were HIV+. HPV was evaluated in 67 and found in 47 (70.1%); HPV16 was the most common. PD-L1 was tested in 61; 10 (16.4%) had positive expression > 1%. Ki-67 was performed in 65, with a median of 50% (range 1-90%). The median follow up is 66m. 5-year PFS and OS rates were 63.3% (95% CI 51.2-73.2%) and 76.4% (95% CI 64.8-84.6%), respectively. In a multivariate analysis, age (HR 1.06, P = 0.022, IC 95% 1.01-1.11) and absence of complete response at 6m (HR 3.36, P = 0.007, IC 95% 1.39-8.09) was associated with inferior OS. The OS rate was 62.5% in HIV+ group (95% CI 22.9-86%) in comparison with 78% (95% CI 65.7-86.3%) among HIV- pts, although this difference was not statistically significant (P = 0.400). A tendency to inferior OS was observed among pts with p53 codon 72 polymorphism (HR 2.83, P = 0.181, 95% CI 0.61-13.02). Other tumor mutations, HPV, Ki-67 expression, and PD-L1 expression, were not associated with PFS and OS. Conclusions: HIV- pts were 5.7 times more likely to achieve response 6m post CRT. The absence of complete response at 6m was the main factor associated with poor 5-year OS. New strategies of follow up and complementary treatment should be studied in late responders and HIV+ pts to ensure the success of curative treatment. Clinical trial information: 36211 .

Genetic analysis ofTP53gene mutations in exon 4 and exon 8 among esophageal cancer patients in Sudan

BackgroundEsophageal carcinoma (EC) represents the 1strank among all gastrointestinal cancers in Sudan. Despite little publications, there is a deep absence of literature about the molecular pathogenesis of EC considering TP53 gene from Sudanese population.AimsIn this study, we performed the expression analysis on p53 protein level by immunohistochemical staining and examined its overexpression with p53 mutations in exons 4 and 8 among esophageal cancer patients in Sudan.Material and MethodsFixed tissue with 10% buffered formalin was stained by Hematoxlin and Eosin (H&E), Alcian blue-Periodic Acid Schiff (PAS) and Immunohistochemistry stain. PCR-RFLP was used to study the frequencies of p53 codon 72 R/P polymorphism. Conventional PCR and sanger sequencing were applied for exon 4 and exon 8. Then detection and functional analysis of SNPs and mutations were performed using various in bioinformatics tools.ResultNuclear accumulations for p53 protein was detected in all of the esophageal carcinomas examined while no accumulations were observed in normal control sections. Four patients with immune-positive for p53 showed no mutations in p53 gene (exon4 and exon8). The incidence of the homozygous mutant variant Pro/Pro was higher in esophageal cancerous patients comparing to healthy control subject 20(71. 4%) vs. 1(10%), respectively (p=0.0026). In exon 4, no mutation was detected other than NG_017013.2:g. 16397C>G. While in exon 8, g.18783-18784AG>TT, g.18803A>C, g.18860A>C, g.18845A>T and g.18863_ 18864 InsT were observed.Conclusionwe found a significant association between the overexpression of TP53 protein and mutation in exon 4 and 8. A silent mutation P301P was detected in all of examined cases. Two patients who diagnosed with small cell sarcoma have shared the same mutations in exon8. Further studies with large sample size are required to demonstrate the usefulness of these mutations in the screening of EC especially SCCE.