Normal P53 Expression Research Articles

Oligo-Fucoidan prevents IL-6 and CCL2 production and cooperates with p53 to suppress ATM signaling and tumor progression

Low-molecular-weight Fucoidan (Oligo-Fucoidan) is a sulfated polysaccharide that has a variety of biological effects and has also been shown to have beneficial health effects. However, the molecular mechanisms underlying the therapeutic effects of Oligo-Fucoidan in patients with cancer remain unclear. Using human colorectal cancer HCT116 cells with (p53+/+) or without (p53−/−) normal p53 expression, we found that Oligo-Fucoidan treatment reduces the occurrence of spontaneous DNA lesions. Etoposide induces double strand DNA breaks. Subsequent administration of Oligo-Fucoidan to etoposide-treated cells promotes p53 accumulation, p21 expression and significant decreases in ataxia-telangiectasia-mutated (ATM), checkpoint kinase 1 (Chk1) and γ-H2AX phosphorylation in p53+/+ cells compared with p53−/− cells. Similarly, co-administration of Oligo-Fucoidan with etoposide inhibits ATM, Chk1 and γ-H2AX phosphorylation, particularly in the presence of p53. Furthermore, Oligo-Fucoidan supplementation increases cancer cell death and attenuates the adverse effects induced by etoposide that decreases production of the pro-inflammatory cytokine IL-6 and chemokine CCL2/MCP-1. Importantly, Oligo-Fucoidan decreases the tumor-promoting M2 macrophages in microenvironment as well as collaborates with p53 and works in combination with etoposide to prevent HCT116 tumorigenicity. Our results first demonstrate that p53 enables Oligo-Fucoidan to effectively inhibit tumor progression, and Oligo-Fucoidan minimizes the side effects of chemotherapy and alters tumor microenvironment.

Study on the relationship between MCT-1 and p53 in laryngeal squamous cell carcinoma

Objective:The aim of this study is to investigate the expression and clinical significance of monocarboxylate transporter 1 (MCT-1) and p53 in laryngeal squamous cell carcinoma (LSCC). Method:Immunohistochemical staining of MCT-1 and p53 was carried out in 41 cases of laryngeal squamous cell carcinoma embedded in paraffin, and the relationship between positive expression and clinicopathological data was evaluated. All data were analyzed by SPSS software (Windows version 21.0). Result:In normal mucosa p53 expression was absent; while, the basal "stem cell" layer is highly enriched in MCT-1. The positive expression of MCT-1 and p53 in the 41 cases of LSCC was 73.2% and 61.0% respectively. The differential expressions of MCT-1 and p53 in LSCC and normal tissues had significant difference (P=0.002, P=0.028). In the well-differentiated tumor tissues, MCT-1 was mainly expressed in the highly invasive cancerous cells. In poorly differentiated tumors, cells in the nests diffusely stain strongly for MCT-1. Of the 41 cases of LSCC, MCT-1 and p53 was significantly associated with histologic grade (P=0.046, P=0.047), clinical stage (P=0.023, P=0.044) and lymph node metastasis (P=0.044, P=0.005). However, over expression of MCT-1 and p53 had no relation with age (P=0.945, P=0.364), gender (P=1.0, P=1.0) and tumor location (P=0.456, P=0.51). Spearman analysis is shown a positive correlation with MCT-1 and p53 (r=0.418, P=0.006). Conclusion:MCT-1 is an importer of L-lactate and ketone bodies into cells, and high expression of MCT-1 induces high OXPHOS and low glycolytic states. We show here that MCT-1 is the best marker of the basal stem cell layer of normal mucosa, and its expression correlate with high p53 expression in LSCC. Therefore, MCT-1 is a new target for the development of anticancer drugs for laryngeal squamous cell carcinoma.

Somatostatin receptor expression related to TP53 and RB1 alterations in pancreatic and extrapancreatic neuroendocrine neoplasms with a Ki67-index above 20%

Somatostatin receptor 2A expression is a feature of well-differentiated neuroendocrine neoplasms and is important for their diagnosis and therapy. Little is known about somatostatin receptor 2A expression in poorly differentiated neuroendocrine neoplasms in relation to TP53 and RB1 status and how these features may contribute to the separation of well from poorly differentiated neuroendocrine neoplasms with a proliferation index above 20%. This study investigates the expression of somatostatin receptors, p53 and Rb1, and TP53 alterations in pancreatic and extrapancreatic well and poorly differentiated neuroendocrine neoplasms (Ki67-index >20%). Thirty-seven poorly differentiated neuroendocrine neoplasms of pancreatic (n=12) and extrapancreatic origin (n=25) as well as 10 well-differentiated neuroendocrine neoplasms of the pancreas (n=9) and rectum (n=1) with a Ki67-index >20% were immunostained for synaptophysin, chromogranin A, Ki67, CD56, p53, Rb1, ATRX, DAXX, progesterone receptor, somatostatin receptor 2A, somatostatin receptor 5, and cytokeratin 20, and sequenced for TP53, exons 5–9. Somatostatin receptor 2A was positive in 6/37 of poorly differentiated and in 8/10 of well-differentiated neuroendocrine neoplasms. One well-differentiated and two poorly differentiated neuroendocrine neoplasms expressed somatostatin receptor 5. Abnormal nuclear p53 and Rb1 staining was found in 29/37 and 22/37 poorly differentiated neuroendocrine neoplasms, respectively, whereas all well-differentiated neuroendocrine neoplasms showed normal p53 and Rb1 expression. TP53 gene alterations were restricted to poorly differentiated neuroendocrine neoplasms (24/34) and correlated well with p53 expression. All cases were progesterone receptor negative. Somatostatin receptor 2A expression is not limited to well-differentiated neuroendocrine neoplasms but also occurs in 16% of poorly differentiated neuroendocrine neoplasms from various sites. Most poorly differentiated neuroendocrine neoplasms are characterized by TP53 alterations and Rb1 loss, usually in the absence of somatostatin receptor 2A expression. In the pancreas, these criteria contribute to separate well-differentiated neuroendocrine neoplasms with a Ki67-index above 20% from poorly differentiated neuroendocrine neoplasms.

Differentiated squamous intraepithelial lesion (dSIL)-like changes in the epidermis overlying anogenital melanocytic nevi: A diagnostic pitfall.

Differentiated squamous intraepithelial lesion (dSIL) is morphologically and immunohistochemically analogous in the whole anogenital region. dSIL is a premalignant lesion frequently misinterpreted histopathologically as a benign dermatosis. The authors describe a peculiar change in the basal cell layer of the epidermis/epithelium overlying anogenital melanocytic nevi that may histopathologically imitate dSIL. The aim of this study is to familiarize the pathologists with this pitfall to avoid its possible overdiagnosis as dysplasia. Further, we tried to explore the biological characteristics of the dSIL-like changes and to focus on the differential diagnostic aspects. Seventy cases of anogenital nevi were retrieved from our registry. All cases were stained with hematoxylin and eosin (H&E) and reviewed. Cases in which the epidermis overlying nevi featured atypical appearing basal keratinocytes in otherwise fully differentiated epithelium, variable degrees of acanthosis and parakeratosis were selected for additional investigation. Thirty cases meeting the above described criteria were identified. The patients were 8 males and 22 females, with age at the time of diagnosis ranging from 4 to 68years. Follow-up data were available for 28 patients (range 0.5-19years, mean 5.1), and to date, no signs of epithelial malignancy have been recorded. Immunohistochemically (IHC), the epidermis overlying nevi showed insignificant positivity for p53 in all tested cases. Melanocytic markers (S-100 protein, SOX10, Melan A) and cytokeratin AE1/3 labeled melanocytes and keratinocytes, respectively, enabling their distinction, especially in nevi featuring a junctional component. Differentiated squamous intraepithelial lesion-like changes seem to occur relatively often in the epidermis overlying anogenital melanocytic nevi. Since morphologically they are virtually identical to the "true" dSIL, their distinction largely depends on p53 expression in basal keratinocytes with normal p53 expression in dSIL-like changes and diffuse nuclear/p53-null immunostaining in the "true" dSIL serving as an essential differential diagnostic tool. dSIL-like alterations seem to have no malignant potential, as to date, none of the patients included in this study have shown any signs of epithelial malignancy.

A protein and mRNA expression-based classification of gastric cancer

The overall survival of gastric carcinoma patients remains poor despite improved control over known risk factors and surveillance. This highlights the need for new classifications, driven towards identification of potential therapeutic targets. Using sophisticated molecular technologies and analysis, three groups recently provided genetic and epigenetic molecular classifications of gastric cancer (The Cancer Genome Atlas, ‘Singapore-Duke' study, and Asian Cancer Research Group). Suggested by these classifications, here, we examined the expression of 14 biomarkers in a cohort of 146 gastric adenocarcinomas and performed unsupervised hierarchical clustering analysis using less expensive and widely available immunohistochemistry and in situ hybridization. Ultimately, we identified five groups of gastric cancers based on Epstein–Barr virus (EBV) positivity, microsatellite instability, aberrant E-cadherin, and p53 expression; the remaining cases constituted a group characterized by normal p53 expression. In addition, the five categories correspond to the reported molecular subgroups by virtue of clinicopathologic features. Furthermore, evaluation between these clusters and survival using the Cox proportional hazards model showed a trend for superior survival in the EBV and microsatellite-instable related adenocarcinomas. In conclusion, we offer as a proposal a simplified algorithm that is able to reproduce the recently proposed molecular subgroups of gastric adenocarcinoma, using immunohistochemical and in situ hybridization techniques.

Alterations in PTEN, MDM2, TP53 and AR protein and gene expression are associated with canine prostate carcinogenesis

The PTEN, AR, MDM2 and p53 protein network plays a central role in the development of many human cancers, thus eliciting the development of targeted cancer therapeutics. Dogs spontaneously develop tumours, and they are considered a good model for comparative oncology initiatives. Due to the limited information on these proteins in canine tumours, this study aimed to investigate gene and protein alterations in PTEN, AR, MDM2 and p53 in canine prostate cancer (PC). Protein expression was evaluated by immunohistochemistry (15 normal, 22 proliferative inflammatory atrophy (PIA) and 19 PC samples) and Western blotting (2 normal prostate tissue, 2 BPH, 2 PIA samples and 2 PC samples) and gene expression by RT-qPCR (10 normal, 10 PIA and 15 PC samples) of formalin-fixed tissue. We identified nuclear and cytoplasmic expression of PTEN and p53 in all samples, with only nuclear staining found for MDM2 and AR. Our results revealed high expression of MDM2 in PC and PIA samples compared to normal samples, whereas PTEN, P53 and AR expression was down-regulated in PC compared to normal tissue. All tumour samples (n=19) showed loss of nuclear PTEN expression, and all cancer mimickers showed positive nuclear staining. Therefore, nuclear PTEN staining could be a good diagnostic marker for differentiating between malignant lesions and mimickers. Canine prostate carcinogenesis involves increased expression of MDM2 in association with decreased expression of PTEN, p53 and AR, such as occurs in hormone refractory PC in men. Thus, dogs may be an important model for studying advanced stage PC.

Massively Parallel Sequencing Identifies Recurrent Mutations in TP53 in Thymic Carcinoma Associated with Poor Prognosis

The characterization of the molecular alterations in thymic epithelial tumors may lead to a better understanding of tumorigenesis, new therapeutic targets, and biomarkers in these tumors. Paired tissue (tumor and matched normal) from 15 thymic carcinomas (TCA) and six B3 thymomas were evaluated by exon capture of 275 cancer-related genes, followed by deep coverage next-generation sequencing, which identifies somatic sequence variants, small insertions and deletions, and copy number alterations involving all exons of the captured genes. Non-silent somatic mutations were identified in 12 of 15 (80%) TCA with a median of one mutation per tumor (range 0-26). Recurrent mutations were identified in tumor suppressor genes TP53 (n = 4), SMAD4 (n = 2), and CYLD (n = 2); and chromatin remodeling genes KDM6A (n = 3), SETD2 (n = 2), MLL3 (n = 2), and MLL2 (n = 2). Tumors with TP53 mutation appeared to exhibit more aggressive behavior. Therefore, the role of P53 was evaluated by immunohistochemistry in an additional ten cases. P53 overexpression correlated with TP53 mutation. These tumors had a higher rate of recurrence and death of disease compared to carcinoma with normal p53 expression (p = 0.02 for disease-free survival and p = 0.05 for overall survival). Among the B3 thymomas, mutations were identified in four of six tumors. Mutations in BCOR (BCL6 co-repressor) were seen in three thymomas and MLL3 (involved in histone methylation) in one tumor. Next-generation sequencing of cancer genes in thymic epithelial tumors revealed a low frequency of mutation, with different patterns between TCA and B3 thymomas. TP53 and BCOR were the most frequently mutated genes in TCA and B3 thymomas, respectively. Alterations in p53 are associated with worse prognosis in TCA.

Pifithrin-alpha has a p53-independent cytoprotective effect on docosahexaenoic acid-induced cytotoxicity in human hepatocellular carcinoma HepG2 cells

Pifithrin-alpha (PFT) is an inhibitor of p53 and is known to protect against a variety of p53-mediated genotoxic agents. In this report, we examined the inhibitory effects of PFT against docosahexaenoic acid (DHA)-induced cytotoxicity in the human hepatocellular carcinoma (HCC) cell line HepG2. PFT significantly abrogated DHA-induced cytotoxicity in wild-type HepG2 cells (normal expression of p53) and after p53-knockdown by siRNA, as well as in Hep3B (p53 null) and Huh7 (p53 mutant) cells. DHA-induced cytotoxicity is mediated by induction of oxidative stress, and PFT inhibited this event, but it does not exert antioxidant effects. PFT significantly suppressed the release of cytochrome c from mitochondria to cytosol, as well as changes in the mitochondrial membrane potential (ΔΨM) by DHA. Therefore, protection of mitochondria by PFT is crucial for its inhibition of DHA-induced cytotoxicity. Although it has been reported that PFT is able to block p53 function, our data suggest that PFT also has a p53-independent inhibition mechanism. This work provided insights into the mechanisms of PFT action on DHA-induced cytotoxicity in HCC.

Influence of RNA interference in p53 gene on the expressions of genes involved in ultraviolet B-induced premature senescence and photocarcinogenesis in human skin fibroblasts

Objective To evaluate the effect of RNA interference in p53 gene on the expressions of genes involved in ultraviolet B (UVB)-induced premature senescence and photocarcinogenesis in human skin fibroblasts (HSFs).Methods A previously established HSF cell clone with repressed expression of p53,which was named as HSF-p53,was cultured and irradiated with a subcytotoxic dose (10 mJ/cm2) of UVB once a day for five consecutive days.The HSFs with normal expression of p53 served as the control.Subsequently,β-galactosidase (SA-β-gal)-staining was performed to estimate the degree of senescence,quantitative real-time PCR array was performed to determine the mRNA expressions of photocarcinogenesis-and senescence-associated genes,including p53,p21,p19,p16,pRb,fibronectin,osteonectin,smooth muscle 22 (SM22),bax,bcl-2,hypoxia-inducible factor-1 α (HIF-1α),vascular endothelial growth factor(VEGF),and human double minute-2 (hdm2).Statistical analysis was carried out by Student's t test using the software SPSS 10.0.Results The percentage of SA-β-gal-positive cells in irradiated HSF-p53 was 19.70％ ± 0.85％,significantly higher than that in unirradiated HSF-p53 (12.77％ ± 0.81％,t =6.45,P ＜ 0.05),but lower than that in irradiated control HSFs (50.48％ ± 5.30％,t =7.86,P ＜ 0.05),and similar to that in unirradiated control HSFs (18.50％ ± 0.45％,t =2.57,P ＞ 0.05).Compared with the control HSFs,the HSF-p53 showed decreased expressions of p21,p19,fibronectin,osteonectin,SM22 and bax genes (all P ＜ 0.05),but increased expressions of bcl-2,HIF-1α,VEGF and hdm2 genes (all P ＜ 0.05),and a similar expression of p16 gene (P ＞ 0.05); the repeated UVB radiation significantly promoted the expressions of p16 and pRb genes (both P ＜ 0.05),but had no obvious effect on the expressions of the other genes in HSF-p53 compared with unirradiated HSF-p53 (all P ＞ 0.05).Conclusions The inhibition of p53 expression may decelerate the UVB-induced premature senescence in HSFs,which may be involved in the p53-dependent tumor suppression. Key words: Genes, p53; RNA interference; Aging, premature; Ultraviolet rays; Fibroblasts

Telomere Shortening: A Biological Marker of Sporadic Colorectal Cancer with Normal Expression of p53 and Mismatch Repair Proteins

Uncontrolled growth of cells, a main criterion of cancer, is merged with pathologic telomere length alteration. Thereby, measurement of telomere length could provide important information on cell proliferation and senescence in cancer tissues. Telomere shortening and its potential correlation with clinicopathological predictive markers in sporadic colorectal cancer (CRC) with normal expression of mismatch repair (MMR) proteins (including Mlh1, Msh2, Pms2, and Msh6) and normal p53 expression was completely explored. Relative telomere length (RTL) was quantitatively measured in a cohort of 164 samples (68 patients with sporadic CRC and 96 healthy unrelated controls). Our results demonstrated a significant shortening of RTL in the tumor-derived tissue of patients compared with the control group (p<0.001). Interestingly, significant telomere shortening was observed in tumors from an ascending and sigmoid colon in comparison with tumors located in a descending colon. Additionally, the telomere length was significantly shorter in those with lymph node metastasis (p<0.05). The results suggest that pathological telomere shortening, leading to genome instability and lymphatic transformation, could serve as a potential sensitive detection and also as a classification marker for facilitating diagnosis and management of CRC.

ARID1A loss correlates with mismatch repair deficiency and intact p53 expression in high-grade endometrial carcinomas

BAF250a (ARID1A) loss is a frequent event in high-grade endometrial cancers. It has been proposed that ARID1A is a driver gene, with ARID1A mutations occurring secondary to deregulated mismatch repair mechanism in gastric cancers, representing an alternative oncogenic pathway to p53 alteration. The prognostic significance of ARID1A loss is controversial. In this study, we investigated the frequency of BAF250a immunohistochemical loss in a cohort of high-grade endometrial cancers (n=190) and correlated it with mismatch repair (hMLH1, hMSH2, hMSH6, and hPMS2) and p53 protein expression. The 190 cases consisted of 82 high-grade endometrioid, 88 serous, 10 clear cell, and 10 mixed (carcinosarcomas and mixed histology). There was BAF250a loss in 55/190 (29%) cancers, most commonly in high-grade endometrioid carcinomas (46 vs 9% in serous carcinomas, P<0.0001). Loss of any mismatch repair proteins was observed in 63/190 (33%) cancers, most commonly in high-grade endometrioid carcinomas (57 vs 10% in serous carcinomas, P<0.0001). Aberrant p53 expression was found in 86/190 (45%) cancers, more commonly in serous carcinomas (77 vs 18% in high-grade endometrioid carcinomas, P<0.0001). BAF250a loss was associated with mismatch repair loss (P<0.0001) and normal p53 expression (P<0.0001). These associations were maintained in the subset analysis within the high-grade endometrioid (P=0.026 and P=0.0083, respectively) and serous carcinoma cases (P=0.0031 and P<0.0001, respectively). Survival analysis revealed a superior progression-free survival (P=0.017) for patients with BAF250a loss within the entire cohort but not within the high-grade endometrioid and serous subtypes. Additionally, data from The Cancer Genome Atlas were extracted to correlate mutations in ARID1A, TP53, and MMR genes; we found that ARID1A mutations were negatively associated with TP53 mutations but were unrelated to mismatch repair gene mutations. In conclusion, BAF250a loss is more common in high-grade endometrioid carcinomas than in other high-grade endometrial cancers and is associated with mismatch repair deficiency and normal p53 expression.

Immunohistochemical Evaluation of Cell Cycle Regulators: Impact on Predicting Prognosis in Stage T1 Urinary Bladder Cancer

Background and Objective. The cell cycle is regulated by proteins at different checkpoints, and dysregulation of this cycle plays a role in carcinogenesis. Matrix metalloproteinases (MMPs) are enzymes that degrade collagen and promote tumour infiltration. The aim of this study was to evaluate the expression of various cell cycle regulators and MMPs and to correlate such expression with progression and recurrence in patients with stage T1 urothelial carcinoma of the bladder (UCB). Patients and Methods. This population-based cohort study comprised 201 well-characterized patients with primary stage T1 urothelial carcinoma of the bladder. Immunohistochemistry was performed on formalin-fixed material to quantify expression of cell cycle regulators and two MMPs. Results. Normal expression of p53 and abnormal expression of MMP9 were associated with greater risk of tumour recurrence. Also, normal p16 expression was related to a lower risk of tumour progression. MMP2, p21, cyclin D1, and pRb showed no significant results that could estimate progression or recurrence. Conclusions. Normal p16 expression is associated with a lower risk of tumour progression, but immunohistochemistry on cell cycle regulators and MMPs has little value in predicting the prognosis in stage T1 UCB.

Significance of mortalin expression in gastric cancer with normal p53.

25 Background: Gastric cancer still has the highest morbidity rate and the second highest mortality rate. As chemotherapy confers only a minimal survival advantage, the prognosis of patients with advanced or recurrent gastric cancer remains poor. Studying the mechanisms and underlying molecules that drives gastric cancer malignant, could contribute to finding a remedy for gastric cancer. Mortalin is a heat non-inducible member of the heat shock protein 70 family. Mortalin binds to p53 and prevents p53 from entering the nucleus, as well as cell stress. To understand the significance of mortalin in gastric cancer, we investigated the expression of mortalin and p53. Methods: The expression of mortalin and p53 were examined by immunohistochemical staining of 182 clinical samples of gastric cancer. Results: Mortalin-positive and aberrant-p53-positive samples were found in 75.2% and 62.6% of cases, respectively. Mortalin-positive tumors were deeper in invasion and had more lymph node and liver metastases compared with mortalin-negative tumors (p &lt; 0.01, p &lt; 0.05, respectively). Mortalin-positive tumors had worse prognosis compared with mortalin-negative tumors (p = 0.035). Moreover, in tumors with normal p53 expression, mortalin-positive tumors had especially worse prognosis compared with mortalin-negative tumors (p = 0.013). With multivariate analysis, mortalin expression appeared to be an independent prognostic factor in gastric cancer with expression of normal p53 (p = 0.0174). Conclusions: Mortalin has a great impact on gastric cancer with normal p53. Therefore, mortalin is a target molecule for treatment of gastric cancer, as well as a promising prognostic factor, especially in tumors with normal p53.

Long-term results of ablation with antireflux surgery for Barrett’s esophagus: a clinical and molecular biologic study

The initial results from ablation therapy for metaplastic/dysplastic Barrett's esophagus (BE) are promising, but the results of extended follow-up evaluation are seldom reported. Neodymium:yttrium-aluminum-garnet laser ablation and successful antireflux surgery for 18 patients with metaplastic BE primarily resulted in the total histologic eradication of BE in 15 patients (83%). After antireflux surgery, the healing of gastroesophageal reflux disease (GERD) was objectively verified in all the patients. At late follow-up evaluation, endoscopy, conventional histology, molecular oxidative stress analyses in comparison with normal control conditions (8-hydroxydeoxyguanosine [8-OHdG], superoxide dismutase [SOD], glutathione [GSH], myeloperoxydase [MP]), and immunohistochemistry (p53, and Cdx2, caudal-related homeobox gene 2, marking intestinal differentiation) of the neosquamous epithelium were performed. At the end of the follow-up period (range, 3-15 years; mean, 8 years), intestinal metaplasia without dysplasia was detected histologically in eight patients (44%). Six patients had macroscopic BE (mean length, 3.5 cm; range 1-10 cm). The neosquamous epithelium was histologically normal, with no underlying columnar tissue. The fundoplication was endoscopically normal in 14 patients (82%). The 8-OHdG level was higher in the neosquamous epithelium than in the control conditions in the distal esophagus (4.3 vs. 0.52; P = 0.0002) and the proximal esophagus (1.8 vs. 0.95; P = 0.006). Likewise, SOD activity was higher in the neosquamous epithelium (0.38 vs. 0.12; P = 0.0005), whereas MP activity and GSH levels remained normal. Three patients showed slight nuclear p53 expression (typical in normal inflammatory reactions), whereas Cdx2 positivity was confined to one case with recurrent intestinal metaplasia. The neosquamous mucosa, generated by the ablation of BE and the treatment of GERD with fundoplication, was stable during long-term follow-up evaluation in two-thirds of the patients with initial eradication. It had normal p53 expression and no Cdx2 protein expression. The oxidative stress of the neosquamous esophagus remained high, although the clinical significance of this is unclear.

Immunohistochemical analysis of vascular endothelial growth factor (VEGF) and p53 expression in pterygium from Tunisian patients

A pterygium is characterized by abnormal fibrovascular corneoconjunctival tissue. A number of investigations have attempted to elucidate this incompletely understood pathology. Since vascular endothelial growth factor (VEGF) and p53 are known to participate in tumor vascularization, our purpose was to study VEGF and p53 expression in active primary and recurrent pterygium from Tunisian patients. To this end, 15 cases of active primary pterygium and five cases of recurrent pterygium from Tunisia were studied by immunohistochemistry. Antibodies raised against VEGF and p53 were used to analyze the distribution and expression of these markers in pterygium and normal human conjunctiva were used as negative control. VEGF and p53 proteins were found in all cases of primary pterygium in epithelial, fibroblast and vascular endothelial cells. Active primary and recurrent pterygium have different patterns of expression. In primary pterygium, an important variability of p53 and VEGF expression was observed. However, in recurrent pterygium, p53 immunoreactivity was weak to moderate, whereas VEGF immunoreactivity was strong. In normal human conjunctiva, VEGF and p53 expression was weak to negative. The overexpression of VEGF in active primary and recurrent pterygium suggests that angiogenesis may play a role in pterygium pathogenesis and the expression of p53 in active primary pterygium, which might be associated with its mutated form, supports the hypothesis that actinic radiation may be involved in the genesis of pterygium. Thus, VEGF and p53 may be useful biomarkers for understanding the physiopathology of pterygium.

P53 Protein Expression Status and Recurrence in Men Treated with Radiation and Androgen Suppression Therapy for Higher-Risk Prostate Cancer: A Prospective Phase II Cancer and Leukemia Group B Study (CALGB 9682)

It has been hypothesized that abnormal p53 protein expression is associated with a worse prognosis after radiation (RT) and androgen suppression therapy (AST). This hypothesis was prospectively tested. Between May 1997 and April 2001, 180 men with clinical stage T1c-T3cN0M0 adenocarcinoma of the prostate were registered on a study evaluating whether the endorectal magnetic resonance imaging (eMRI)-defined change in tumor volume (TV) during neoadjuvant (n) AST was associated with prostate-specific antigen (PSA) outcome. Of these, 141 had sufficient tissue to perform immunohistochemical detection of the p53 protein expression status and 113 had complete eMRI information. Multivariable Cox regression analysis was used to assess whether p53 protein expression status predicted time to PSA failure adjusting for known prognostic factors. After a median follow-up of 6.9 years and adjusting for PSA level, Gleason score, clinical stage, and eMRI-defined TV change during nAST, men with abnormal compared with normal p53 expression were at increased risk of PSA failure (hazard ratio [HR]: 2.8; 95% confidence interval [CI]: 1.3-5.9; P = 0.008 for the 141; HR: 2.4; 95% CI: 1.1-5.4; P = 0.03 for the 113). Adjusted estimates of PSA failure were significantly higher (P = 0.03) in men with abnormal compared with normal p53 expression. At 5 years, these respective estimates were 33% and 18%. Maximizing local control and randomized trials evaluating the impact on survival of adding novel agents to maximal local therapy are warranted in men whose prostate cancer demonstrates abnormal p53 expression.

Significance of PML and p53 protein as molecular prognostic markers of gallbladder carcinomas

Molecular markers for cancers are not only useful for cancer detection and prognostic prediction, but may also serve as potential therapeutic targets. In order to identify reliable molecular markers for prognostic prediction in gallbladder carcinoma (GBC), we evaluated the immunohistochemical expression of 15 proteins, namely p53, p27, p16, RB, Smad4, PTEN, FHIT, GSTP1, MGMT, E-cadherin, nm23, CD44, TIMP3, S100A4, and promyelocytic leukemia (PML) in 138 cases of GBC using the tissue microarray method. The prognostic significance was analyzed for each protein. Overexpression of p53 and S100A4, and loss of p27, p16, RB, Smad4, FHIT, E-cadherin and PML expression were associated with poor survival. In particular, PML and p53 showed considerable potential as independent prognostic markers. Patients with normal PML and p53 expression displayed favorable outcomes, compared to those showing abnormal expression of either or both proteins (49% vs. 23% in a 5-year survival rate; 60 months vs. 11 months in median survival, respectively; P=0.009). Thus, PML and p53 are potential candidates for development as clinically applicable molecular prognostic markers of GBC, and may be effective therapeutic targets for the disease in the future.

Regenerative capacity of neural precursors in the adult mammalian brain is under the control of p53

The question of whether or not stem cell loss drives aging in the brain has not been fully resolved. Here, we used mice over-expressing the short isoform of p53 (ΔNp53 or p44) as a model of aging to gain insight into the cellular mechanisms underlying age-related functional deficits in the brain. By BrdU labeling, we observed an accelerated decline in the number of subventricular zone proliferating cells with age in p44Tg mice compared to mice with normal p53 expression. A 2–3-fold reduction in the number of slowly dividing stem cells was evident in the subventricular zone of 9–12-month-old p44Tg mice, but not in younger p44Tg mice or in normal mice. Consequently, the supply of new olfactory bulb neurons was also reduced. The number and size of neurospheres generated from subventricular zone cells from p44Tg mice was significantly reduced, and cells derived from these neurospheres had limited self-renewal and amplification capacities. At the cellular level, p44 lengthened the cell cycle and affected cell cycle reentry properties, evident by an increased proportion of cells in G0. At the functional level, p44 expression resulted in impaired olfactory discrimination in 15–16-month-old mice. This phenotype is driven by constitutive activation of p53 and constitutive expression of p21 Cip1/waf1 in neural stem cells. Our results demonstrate that p53 plays a crucial role in the maintenance of the regenerative capacity of the brain by regulating the proliferation of stem and progenitor cells.

P53 expression between 13–27 weeks old human male fetus gonads

P53 is a tumor suppressor gene and a critical component of cellular mechanisms that respond to genotoxic stresses. During normal fetal development, some of these cells lose their genomic stability because of intensive cell proliferation. They arrest cell cycle progression and repair genomic stability by p53 induction or die via apoptosis. If p53 is overexpressed, some structures may have different abnormalities. This study was conducted to investigate normal p53 expression in human male gonads during second trimester. Twenty one normal human male fetuses' testes in 2nd trimester were processed and immunohistochemistry was applied. The spermatogonia with nuclear and perinuclear staining, were accepted as p53 (+). The number of p53 (+) spermatogonia was counted in randomly 10 different seminiferous tubules. The results suggest that p53 expression in gonads of human male fetuses significantly increases in the 20th week.

Tumor suppressor and genetic instability during development of esophageal adenocarcinoma

Genomic instability (GIN) occurs in majority of human solid tumors, particularly in GI cancers. The significance and molecular regulators of GIN remain poorly understood. The roles of p53 and APC in protecting the genomic integrity have been well investigated, largely from studies in vitro. Precancerous Barrett's esophagus (BE) provides an important in vivo model to investigate GIN in human. This study was undertaken to determine GIN in relation to changes in p53 and APC in BE. We analyzed specimens from endoscopic biopsies or esophagectomies in patients with BE (10 cases) or with BE-associated esophageal adenocarcinoma (10 cases), with normal gastro-esophageal junction (5 cases) as controls. Chromosomal enumeration probe Cep 7, 11, 12, 17 and 18 were detected by fluorescence in situ hybridization (FISH). Expression of tumor suppressor p53 and APC were determined by the sensitive avidin-biotin immunohistochemistry. Up-regulation of p53, an indicator of p53 mutations, was observed in BE with high grade dysplasia (HGD), which increased further in BE associated esophageal cancer (EC). The expression of wildtype APC was decreased in BE with HGD and in advanced EC. Chromosomal abnormalities of all probes tested were found in each BE associated EC (100%). Numeric changes of chromosome 7, 11 and 12 were observed in BE stage in 14%, 64% and 43% of cases, respectively. Interestingly, aneusomy of chromosome 11 and 12 were found in BE without pathological dysplasia, in the presence of normal expression of p53 and APC. Our results suggest that GIN is an early event that occurs at precancerous stage prior to changes in tumor suppressor p53 and APC in BE-associated cancer progression.