Barrett's esophagus (BE) can progress to dysplasia and esophageal adenocarcinoma (EAC), accompanied by mutations in TP53 that increase the stability of its product, p53.
These TCRs mediated recognition of commercially available ovarian cancer, uterine carcinoma, and myeloma cell lines, as well as an NIH patient-derived esophageal adenocarcinoma line that endogenously expressed p53p.R175H and HLA-A*0201.
Separate meta-analyses of case-control and cohort studies of BE patients who had baseline biopsies with p53 immunostaining revealed consistent, strong, and significant associations between aberrant p53 immunostaining and progression to high-grade dysplasia or esophageal adenocarcinoma.
Sections of formalin-fixed paraffin-embedded tissue from the initial biopsies of 275 patients with BM, who had no high-grade dysplasia (HGD) or oesophageal adenocarcinoma (EAC), were stained for p53 by immunohistochemistry.The mean follow-up was 41 months. p53-positive biopsies were divided into four groups: scattered positive cells, multifocal scattered positive cells, aggregates of positive cells, and multifocal aggregates of positive cells.
Patients with OAC and TP53 gene mutations have reduced overall survival compared with patients without these mutations, and this effect is independent of tumour stage.
Parental tumour and MFD-1 carried four somatically acquired mutations in three recurrent mutated genes in OAC: TP53, ABCB1 and SEMA5A, not present in FLO-1 or OE33.
Esophageal adenocarcinoma is characterized by evolution of punctuated and catastrophic somatic chromosomal alterations and high levels of overall mutations but few recurrently mutated genes aside from TP53.
Barrett's esophagus is thought to progress to esophageal adenocarcinoma (EAC) through a stepwise progression with loss of CDKN2A followed by TP53 inactivation and aneuploidy.
Frequent somatic mutations in the tumor suppressor genes CDKN2A and TP53 were recently reported in EA tumors, while somatic alterations at 9p (CDKN2A) and 17p (TP53) have been implicated as predictors of progression from BE to EA.
Following co-culture with visceral adipose tissue explants, expression of genes involved in tumour cell invasion and metastasis (matrix metalloproteinase (MMP)2 and MMP9) were upregulated between 10-fold (MMP2) and 5000-fold (MMP9), and expression of tumour suppressor p53 was downregulated 2-fold in OAC cell lines.
In subgroup analyses based on pathological type, the Pro variant was significantly associated with an increased esophageal squamous cell carcinoma (ESCC) risk in all four genetic comparison models (ORPro vs. Arg=1.26, 95% CI: 1.08-1.47, POR=0.003; OR Recessive genetic model=1.42, 95% CI: 1.07-1.88, POR=0.015; ORDominant genetic model=1.25, 95% CI: 1.10-1.42, POR=0.001; ORHomozygote model=1.55, 95% CI: 1.14-2.10, POR=0.005), whereas the association between TP53Arg72Pro polymorphism and esophageal adenocarcinoma risk was still uncertain owing to the limited studies included in this meta-analysis.
The p53 mutations are a predictor of significantly reduced postoperative survival following surgical resection of EADC, and would appear to be a clinically useful molecular prognostic biomarker.
No significant differences were found for patients with EADC who had p53 mutations (n = 21) compared with patients with wild-type p53 (n = 33) with respect to selected clinicopathologic variables (age, gender, tumor grade, stage, alcohol, or tobacco consumption) and dietary intake of folate or vitamin B(6).
To investigate the role of NO in esophageal adenocarcinoma (EADC), we studied patterns of p53 mutations, expression of inducible nitric oxide synthase (iNOS) and the tissue accumulation of nitrotyrosine (NTS), a stable reaction product of NO and a marker for cellular protein damage, in human premalignant and malignant esophageal epithelia.
A combination of 17p LOH, 9p LOH, and DNA content abnormalities provided better EA risk prediction than any single TP53, CDKN2A, or DNA content lesion alone.
Mutations in p53 were identified in 75% (30/40) of the esophageal adenocarcinoma. p53 protein overexpression, detected by immunohistochemistry, was found in 58% (23/40) of the esophageal adenocarcinoma, 60% (6/10) of Barrett's esophagus with high-grade dysplasia, 12% (1/8) of Barrett's esophagus with low-grade dysplasia, and 0% of Barrett's esophagus without dysplasia.
17p (TP53) loss of heterozygosity (LOH) has been reported to be predictive of progression from Barrett's esophagus to esophageal adenocarcinoma, but the mechanism by which TP53 LOH develops is unknown.
In the present study, 132 samples of esophageal adenocarcinoma and 58 samples of normal esophageal tissue were investigated for MGMT hypermethylation status by methylation-specific real-time PCR and results were correlated to clinicopathological parameters, patient's survival, p53 mutation and expression of p53 protein and MGMT protein.