High Levels Of P53 Expression Research Articles

Association of p53 protein expression with the presence of a 17p13 locus deletion of the TP53 gene and with the survival of patients with diffuse large B-cell lymphoma

Background. A significant role in the pathogenesis, resistance to treatment and progression of many types of lymphomas, including diffuse large B-cell lymphoma, is assigned to the TP53 gene. Literature data on the prognostic significance of the expression of its product, the p53 protein, and its association with aberrations at the 17p13 locus are ambiguous.
 Aim. To assess the relationship of p53 protein expression with the presence of a 17p13 locus deletion of the TP53 gene and the survival of patients with diffuse large B-cell lymphoma.
 Material and methods. The study included 75 patients with newly diagnosed diffuse large B-cell lymphoma who received R-CHOP therapy. The calculation of the relative content of tumor cells expressing p53 was carried out using immunohistochemical and morphometric methods on biopsy samples of lymph nodes. The 17p13/TP53 deletion was determined by fluorescent in situ hybridization. The threshold level of p53-positive tumor cells, corresponding to 43%, was calculated by ROC analysis. The association between p53 protein expression and the presence of a 17p13 deletion was assessed using Fisher's (F) and Pearson's 2 tests. The correlation dependence was evaluated by the Cramer method (V). Five-year overall and progression-free survival was calculated using the KaplanMeier method. Differences between the indicators were considered statistically significant at p 0.05.
 Results. The frequency of 17p13/TP53 deletion was higher in patients with high expression of p53 (43%) compared to the group of patients with low expression: 87.5 and 12.5%, respectively (p=0.018). A direct correlation between a high level of p53 expression (43%) and the presence of a 17p13/TP53 deletion was found (p=0.018). Five-year overall and progression-free survival in patients with a proportion of p53-positive cells 43% was significantly lower than in patients with its subthreshold value: 54.5 versus 81.0% (p=0.014) and 45.5 versus 66.7% (p=0.022), respectively.
 Conclusion. High expression of the p53 protein is associated with the presence of a 17p13 locus deletion and a low five-year survival rate in patients with diffuse large B-cell lymphoma.

Tumor immune microenvironment and apoptotic markers in breast cancer patients carrying <I>BRCA1</I> gene mutations

Background. It is suggested that defects in BRCA1 / 2 genes contribute to a high mutational load and high immunogenicity, which modulates immune microenvironment. At the same time, it was shown that BRCA1 / 2-associated breast cancer tumors do not belong to the category of immunoactive ones. These tumors have low expression of immune response genes and exhibit an immunosuppressive type of microenvironment. This indicates the need of antitumor immune response modulation and maintaining of the optimal balance of tumor CD4/CD8 T-lymphocytes ratio. In addition, there is evidence of the additional evaluation of TP53 mutation in these tumors and disruption of the cell death process, which can also be a factor of resistance to therapy, including PARP inhibitors, and serve as a therapeutic target.Materials and methods. The prospective study included 20 patients with BRCA1-associated breast cancer. BRCA1 / 2 mutations (BRCA1 185delAG, 4153delA, 5382insC, 3819delGTAAA, 3875delGTCT, 300T>G, 2080delA, BRCA2 6174delT) were detected in by real-time polymerase chain reaction. Immunohistochemical study was performed on paraffin embedded tissue blocks by an automated method on a ThermoScentific immunohistotainer using monoclonal antibodies. The expression of markers of tumor-infiltrating CD4+ and CD8+ T-lymphocytes, markers of macrophages (CD68, CD163), apoptosis (Bcl-2, p53), cell adhesion markers (E-cadherin, β-catenin) in breast cancer in carriers of BRCA1 mutations was assessed.Results. High CD4/CD8 ratio, which characterizes immunosuppressive microenvironment, occurred in 75 % of cases. BRCA1 5382insC mutation is associated with high level of CD4+ TILs (p˂0.05), G2 is associated with a low CD4/CD8 ratio (p = 0.039) and a high level of CD163 (p = 0.02, AUC = 0.739); T1 correlates with high levels of CD8+ TILs (p = 0.038) and high levels of CD163 (p = 0.033). High Ki-67 is associated with a lack of Bcl-2 expression (p = 0.04) and a low level of E-cadherin (p = 0.02). Negative expression of Bcl-2 occurred in 75 % of cases. High level of p53 expression has been described as the main type of expression in these tumors, suggesting a combination of TB53 and BRCA1 mutations and a violation of cell death mechanism of in these tumors.Conclusion. Breast cancer tumors of patients with hereditary mutations in BRCA1 gene demonstrate immunosuppressive type of microenvironment and a violation of the cell death mechanism. The main directions of future therapy of these tumors may include tumor immune microenvironment modification and activation of cell death mechanisms.

47P Immune tumor microenvironment and markers of apoptosis in breast cancer in carriers of hereditary mutations in the BRCA1 gene

Tumor immune microenvironment is currently recognized as an important participant in carcinogenesis, influencing the behavior of tumor cells and treatment efficacy. It is suggested that defects in BRCA1/2 genes contribute to a high mutation load and high immunogenicity, which modulates immune microenvironment. At the same time, it was shown that BRCA1/2-associated breast cancer tumors do not belong to the category of immunoactive ones. In addition, there is evidence of the additional evaluation of TP53 mutation in these tumors and disruption of the cell death process, which can also be a factor of resistance to therapy. 40 patients with breast cancer with BRCA1 mutations 185delAG, 4153delA, 5382insC, 3819DELGTAA, 3875delGTCT, 300T>G, 2080delA and BRCA2 (6174delT)) determined by real-time polymerase chain reaction (PCR) were included. Immunohistochemical study was performed using monoclonal antibodies to Ki67, p53, CD8, CD4, CD68, CD163, BCL2. In the presented study patients with BRCA1-associated breast cancer, had high low tumor CD4/CD8 ratio in 50% of cases, which characterizes an immunosuppressive microenvironment. Mutation BRCA1 5382insC is associated with high level of CD4+ T-lymphocytes (p˂0.05), G3 is associated with a low CD4/CD8 ratio (p=0.056) and a low levels of CD68+M1, CD163+M2-macrophages (p=0,022, p=0.002); T1 correlates with high levels of CD8+ TILs (p=0.038) and high levels of CD163 (p=0.033). High Ki-67 is associated with a lack of BCL2 expression (p=0.04). Negative expression of BCL2 occurred in 52.5% of cases. A high level of p53 expression is described as the main type of expression in these tumors, suggesting a combination of TB53 and BRCA1 mutations and a violation of the mechanism of cell death in these patients. The immunosuppressive type of microenvironment prevails in the tumors of breast cancer patients with hereditary mutations in the BRCA1 gene, where a violation of the mechanism of cell death in BRCA1-deficient breast cancer was revealed. The main directions of future therapy of these tumors may be modification of the immune microenvironment and activation of the mechanisms of cell death.

Focal p53 protein expression and lymphovascular invasion in primary prostate tumors predict metastatic progression

TP53 is one of the most frequently altered genes in prostate cancer. The precise assessment of its focal alterations in primary tumors by immunohistochemistry (IHC) has significantly enhanced its prognosis. p53 protein expression and lymphovascular invasion (LVI) were evaluated for predicting metastatic progression by IHC staining of representative whole-mounted prostate sections from a cohort of 189 radical prostatectomy patients with up to 20 years of clinical follow-up. Kaplan–Meier survival curves were used to examine time to distant metastasis (DM) as a function of p53 expression and LVI status. TP53 targeted sequencing was performed in ten tumors with the highest expression of p53 staining. Nearly half (49.8%) of prostate tumors examined showed focal p53 expression while 26.6% showed evidence of LVI. p53(+) tumors had higher pathologic T stage, Grade Group, Nuclear Grade, and more frequent LVI. p53 expression of > 5% and LVI, individually and jointly, are associated with poorer DM-free survival. TP53 mutations were detected in seven of ten tumors sequenced. Four tumors with the highest p53 expression harbored likely pathogenic or pathogenic mutations. High levels of p53 expression suggest the likelihood of pathogenic TP53 alterations and, together with LVI status, could enhance early prognostication of prostate cancer progression.

Detection of p53 Protein in Leukemic Cells by Flow Cytometry.

Although the alterations of TP53 gene are rare in malignant hematological disorders, these genetic alterations have strong correlations with unfavorable prognostic factors and are found in relapse acute lymphoid leukemia (ALL), relapse acute myeloid leukemia (AML), blastic crisis of chronic myeloid leukemia (CML) and evolution from chronic lymphoid leukemia to Richter's syndrome (CLL/SR). Most methods currently used to study TP53 gene employ molecular biology techniques such as single strand conformation polymorphism (PCR-SSCP) and direct DNA sequencing. Both techniques detect TP53 gene mutation but not p53 protein expression and are time-consuming and difficult to apply in the clinical setting. In the last years, p53 protein expression has emerged as a potential prognostic marker, which can be used to study TP53 gene alterations in malignant diseases. The aim of this work was to validate flow cytometry (FC) technique to detect p53 expression in different types of leukemias and analyze the relationship between p53 expression and status of disease. We studied p53 protein expression in 223 blood and bone marrow samples: 72 patients with CML, 54 in chronic phase (CML-CP), 7 in accelerated phase (CML-AP) and 11 in blastic crisis (CML-BC); 64 patients with CLL (34 at diagnosis and 9 with Richter's syndrome), 44 patients with ALL (36 at diagnosis and 8 in relapse) and 43 AML (27 de novo, 7 in relapse and 9 secondary AML). p53 protein expression was observed in 63 out of 223 patient's samples: 14/64 CLL (21.9%), 13/44 ALL (29.5%), 19/43 AML (44.2%) and 17/72 LMC (23.6%). The highest levels were detected in the advanced phases of CLL, ALL and CML. In addition, in AML cases, high levels of p53 expression were detected in secondary and relapse disease and also in de novo AML cases. Our results demonstrated that p53 expression levels are strongly associated with advanced disease. Based on these results flow cytometry can be a reliable approach to study p53 protein expression in leukemic patients. Further studies are needed to ascertain the role of p53 expression as a prognostic marker of disease progression.

Downregulation of Sirt1 is correlated to upregulation of p53 and increased apoptosis in epicardial adipose tissue of patients with coronary artery disease.

The higher expression level of p53 in epithelial adipose tissue (EAT) has previously been reported in atherosclerosis. Since we hypothesized that the expression of p53 is modulated by Sirt1, the aim of this study was to determine the expression levels of Sirt1 and p53 and to investigate their correlation to apoptosis in EAT of patients with coronary artery disease (CAD). Thirty-five patients with more than 50 % stenosis in at least one of the main coronary arteries were considered as CAD group while 29 patients with no clinical signs of atherosclerosis who underwent open-heart surgery for valve replacement were classified as control group. EAT biopsy samples were collected from all participants during surgery. Sirt1, p53, Bax, and Bcl-2 gene expression levels were determined in EAT by qRT-PCR and Western blotting was carried out to assess Sirt1 and p53 protein levels. Hematoxylin and eosin staining was used for histopathological analysis. mRNA and protein levels of Sirt1 in EAT were significantly lower in patients with CAD compared with control group, whereas CAD patients showed greater p53 gene and protein expressions. In addition, inverse correlations were observed between Sirt1 and p53 at both mRNA and protein levels. The Bax and ratio of Bax/Bcl-2 gene expressions were higher in CAD group, but no difference was observed in Bcl-2 expression. Histopathological analysis showed apoptotic bodies and infiltrated immune cells in EAT of CAD group. Our results suggest that the Sirt1-p53 axis may involve in atherosclerosis by promotion of apoptosis.

Structural equation modelling analysis determining causal role among methyltransferases, methylation, and apoptosis during human pregnancy and abortion

The human implantation failure during first trimester leads to spontaneous abortions. Spontaneous abortions are consecutive and occur twice or thrice (with or without prior live births) due to factors which are either maternal or fetal. However, it also constitutes of unknown etiology; known as unexplained recurrent spontaneous abortions (URSA). In this study, the medical terminated human normal early pregnancies (NEP) of the first trimester were taken as control samples, the normal decidual sample whose molecular and epigenetic changes were compared with that of decidua of human URSA subjects. Apoptosis-related genes reported in consecutive recurrent pregnancy loss became the basis for this study. So, in this study, we evaluated the hypothesis that “p53 methylation level through methyltransferases (G9aMT and DNMT1) implicates the fate of embryo towards sustenance or cessation of pregnancy”. Further, the interaction between P53, BAX, BCL-2, CASPASE-6, G9aMT, DNMT-1, and methylated p53 expression level(s) during the first trimester of both URSA and NEP are included in this study. The degree of p53 methylation during the first trimester is found to be significant and positively correlated with that of G9aMT (p < 0.05), BCL-2 (p < 0.001), and DNMT1 (p < 0.001) at both transcript and protein level. A significant and negative correlation (with p-value < 0.001) between the degree of p53 methylation during the first trimester and that of the expression level of TUNEL assay (Apoptosis), P53, BAX, and CASPASE-6 are also observed in the present study. A positive correlation between apoptosis and a higher level of p53 expression (which is possibly due to low degree of p53 methylation) is observed both at the transcript and protein level in URSA which is in line with our findings. The analysis performed using structural equation modelling (SEM) further throws light on the causal relationship between sustenance of pregnancy or URSA during the first trimester of a human pregnancy and degree of methylation of p53 which is closely correlated with the interaction between G9aMT, DNMT1, BCL-2, BAX, P53, CASPASE-6, and apoptosis.

The presence of Merkel cell carcinoma polyomavirus is associated with a distinct phenotype in neoplastic Merkel cell carcinoma cells and their tissue microenvironment.

AimsMerkel cell carcinoma (MCC) is an aggressive primary neuroendocrine tumor of the skin, associated with Merkel cell polyomavirus (MCPyV) in 49–89% of cases, depending on the country of origin and the techniques of detection. The presence of MCPyV defines heterogeneity in MCC; MCPyV-negative cases bear a much higher mutational load, with a distinct ultraviolet signature pattern featuring C > T transitions, as a consequence of exposure to ultraviolet light radiation. MCC stroma has not been thoroughly studied, although MCC patients benefit from therapy targeting PD1/PDL1.Methods and resultsIn this study, using Tissue Microarrays and immunohistochemistry, we have analyzed a series of 219 MCC cases in relation to the presence of MCPyV, and confirmed that the presence of MCPyV is associated with changes not only in the neoplastic cells, but also in the composition of the tumor stroma. Thus, MCPyV, found in 101/176 (57,4%) analyzable cases, exhibits changes in its tumor morphology, the density of the inflammatory infiltrate, the phenotype of the neoplastic cells, and the cell composition of the tumor stroma. MCPyV presence is negatively correlated with a higher level of p53 expression, and associated with a very high frequency (86%) of HLA-I expression loss, a higher apoptotic index, and a stroma richer in T-cells, cytotoxic T-cells, macrophages, PDL1-positive macrophages, and B-cells.ConclusionsOur findings provide evidence of the basic heterogeneity of MCC, supporting the hypothesis that the presence of MCPyV may induce a rich inflammatory response, which is at least partially avoided through loss of HLA-I antigen expression. On the other hand, MCPyV-negative cases show a much higher frequency of stronger p53 expression and, probably, p53 alterations.

P14.76 Characteristics of anaplastic oligodendrogliomas short-term survivors: a POLA network study

Abstract BACKGROUND Although patients with 1p/19q codeleted anaplastic oligodendrogliomas (AO) usually have a prolonged survival, some patients have a poorer outcome. The aim of the present study was to analyze their characteristics. MATERIAL AND METHODS The characteristics of AO patients with a survival &lt; 5 years included in the POLA network were analyzed and compared to those of AO patients with a survival &gt; 5 years. RESULTS In January 2019, among the 519 patients AO patients included in the POLA network, 55 patients were short-term survivors and 146 patients had a survival &gt; 5 years. Among the 55 AO short-term survivors, 44 patients (80%) died from tumor progression and 11 patients (20%) from another cause (suicide n=2, toxicity n=2, intercurrent disease n=6, other n=1). Compared to &gt; 5 years survivors, short-term survivors were older (57 years vs 48 years, p&lt;0.001) and less frequently presented with isolated seizures (9% vs 33%, p=0.0017). They presented with tumors that more frequently involved multiple lobes (66% vs 47%, p=0.03), had a higher rate of nuclear atypia (80% vs 48%, p&lt;0.001), a higher proliferative index (Ki67, 26% vs 18%, p&lt;0.001), a higher level of p53 expression (10.8% vs 3.9% p&lt;0.001), and had a higher rate of chromosomal abnormalities (91% vs 71% p=0.008). Compared to &gt; 5 years survivors, short-term survivors less frequently underwent a surgical resection (64% vs 89% p&lt;0.001) and their initial treatment more frequently consisted in temozolomide chemotherapy alone (41% vs 20% p=0.008). CONCLUSION AO short-term survivors are associated with distinct clinical, radiological, histological and molecular characteristics at diagnosis.

The Expressions of MDM2 and P53 Protein are Adverse Prognostic Factors in Patients with Esophageal Squamous Cell Carcinoma

Background: Esophageal squamous cell carcinoma (ESCC) is the fourth most prevalent malignancy in China and causes a high rate cancer-related death. In the present study, we aimed to examine the expression levels of MDM2 and P53 in different cell populations of tumor environments and explore their association with survivals of ESCC patients. Method: The protein expression and amplification of MDM2 and P53 were measured by immunochemistry and fluorescence in situ hybridization (FISH) in tumor specimens from 157 resected ESCC. Correlation analyses and independent prognostic outcomes were determined using Pearson's chi-square test and Cox regression analysis. Findings: We found that high expression levels of MDM2 in tumor cells were correlated with M status (P = 0.027), and high expression levels of P53 in tumor cells were positively closely correlated with N status (P = 0.005), M status (P = 0.008) and clinical stage (P = 0.003). The Kaplan-Meier survival analysis showed the ESCC patients with lower expression levels of MDM2 or P53 in tumor cells had better DFS and OS. Besides, the patients with the double high expression levels of MDM2 and P53 in tumor cells had worst DFS and OS compared to the patients with single high expression level of MDM2 or P53 in tumor cells or double low expression level of MDM2 and P53 in tumor cells (P<0.001 and P <0.001, respectively). Furthermore, the multivariate Cox model analysis determined the expression of MDM2, P53 and combined expression of MDM2 and P53 in tumor cells were independent predictors for DFS and OS in ESCC patients. Interpretation: The present study indicates that high expression of MDM2 and P53 are independently significant prognostic indicator of a higher rate of clinical stage and poor survival in patients with surgically resected ESCC. Funding Statement: The authors state: No specific funding was disclosed. Declaration of Interests: The authors have declared that they have no conflict of interest. Ethics Approval Statement: This study was approved by the Research Ethics Committee of the Sun Yat-Sen University Cancer Center. Informed consent was obtained from all patients prior to specimen collection.

Genital basal cell carcinoma, a different pathogenesis from sun-exposed basal cell carcinoma? A case-control study of 30 cases.

Genital basal cell carcinoma (BCC) accounts for <1% of all BCCs. We aimed to elucidate the pathogenesis of genital BCC. We retrospectively evaluated cases of pathologically diagnosed genital BCC between 1990 and 2016 in an Asian tertiary referral center. The control group was composed of consecutive cases, from 2016, of BCCs occurring in sun-exposed areas. Presence of human papillomavirus (HPV) was evaluated by polymerase chain reaction (PCR). Immunohistochemical p16 and p53 staining was performed and analyzed. We found 33 genital BCCs (33/1837, 1.8%) over 26 years. The mean follow-up duration was 30.0 ± 33.2 months. Genital BCCs had a larger size (14.05 vs 8.92 mm, P = 0.014), more common presence of ulcers (61.3% vs 32.0%, P = 0.035), shorter epidermal p53 clone (0.33 vs 1.20 mm, P = 0.007), and high p53 expression levels. Most cases (29/30, 96.7%) showed negative or faint spotty p16 staining. Patient age, tumor depth, presence of pigment, or histology subtype did not differ significantly. Thirty genital BCCs were negative for HPV. HPV infection is mostly likely not involved in genital BCC pathogenesis. A greater level of p53 expression in genital BCCs implicates pathways other than ultraviolet (UV)-specific p53 mutations in their pathogenesis.

P53 expression and subcellular survivin localization improve the diagnosis and prognosis of patients with diffuse astrocytic tumors.

Diffuse astrocytic tumors are the most frequently occurring primary central nervous system (CNS) tumors. Their histological sub-classification into diffuse astrocytoma (DA), anaplastic astrocytoma (AA) and glioblastoma (GB) is challenging and the available prognostic factors are limited to age and tumor subtype. Biomarkers that may improve the histological sub-classification and/or serve as prognostic factors are, therefore, urgently needed. The relationship between survivin and p53 in diffuse astrocytic tumor progression and survival is currently unclear. Here, we aimed to assess the relevance of these proteins in the accuracy of the histological sub-classification of these tumors and their respective treatment responses. One hundred and thirty-three formalin-fixed paraffin-embedded diffuse astrocytic tumor samples were included. The tumor samples were histologically reviewed and subsequently assessed for p53 and survivin expression and the presence of the IDH R132H mutation by immunohistochemistry. p53 expression levels and survivin subcellular localization patterns were correlated with histological classification and clinical outcome. We found that age and histological subtype were the only features with a prognostic impact. In addition, we found that high p53 expression levels and a nuclear survivin localization correlated with the AA subtype, whereas cytoplasmic survivin localization correlated with the GB subtype. We also found that patients carrying tumors with a high cytoplasmic survivin expression, a high nuclear survivin expression or a high p53 expression, and who did not receive radiotherapy, exhibited poorer short-term and long-term overall survival rates. Our data suggest that subcellular survivin localization and p53 expression may be employed as valuable tools to improve the accuracy of the histological sub-classification of diffuse astrocytic tumors. Patients whose tumors overexpress these proteins may benefit from radiotherapy, irrespective age and/or histological classification.

Exosomes Transfer p53 between Cells and Can Suppress Growth and Proliferation of p53-Negative Cells

Exosomes are nanosized vesicles that are secreted by many types of cells. We have found that exosomes secreted by HEK293 and HT-1080 can suppress growth and proliferation of p53-deficient cells. Upon overexpression of exogenous p53-GFP in HEK293 cells, we observed p53 protein in exosomes that were secreted by these cells. We also found endogenous p53 in exosomes that were secreted by HT-1080 cells with a higher level of p53 expression. We were able to detect endogenous p53 protein in exosomes that originated from human plasma and were transferred to p53-deficient cells. Our findings indicate that p53 protein can be transferred between cells and may play an important physiological role.

SC27.03 Transforming KRAS into a Clinically Relevant Biomarker

SC27.03 Transforming KRAS into a Clinically Relevant Biomarker

Comparative immunohistochemical characteristic of expression levels of Ki-67, p53, caspase 3 in non-invasive and invasive intestinal-type gastric adenocarcinoma

Aim. Comparison analysis of expression levels of Ki-67, p53, and caspase 3 was performed between the tumor cells and the stromal cells of non-invasive intestinal-type gastric adenocarcinoma on the one hand and the tumor cells and the stromal cells of invasive intestinal-type gastric adenocarcinoma on the other hand.Materials and methods. For this purpose, pathohistological and immunohistochemical studies were used. The surgical material of 10 patients with non-invasive (pTis, pT1) intestinal-type gastric adenocarcinoma and 10 patients with invasive (pT2, pT3, pT4) intestinal-type gastric adenocarcinoma were analyzed.Results. It was established that intestinal-type gastric adenocarcinoma is characterized by the medium Ki-67 labeling index, the low expression level of p53, the low expression level of caspase 3 in the tumor cells, and also the low Ki-67 labeling index and the extremely low expression level of caspase 3 in the stromal cells. The tumor cells of invasive intestinal-type gastric adenocarcinoma are characterized by the 2 times higher expression level of p53, than the tumor cells of non-invasive intestinal-type gastric adenocarcinoma. Moreover, direct correlation between the medium Ki-67 labeling index of the tumor cells and the low Ki-67 labeling index of the stromal cells, and also direct correlation between the medium Ki-67 labeling index in the tumor cells of intestinal-type gastric adenocarcinoma and the low expression level of p53 in these cells were identified.Conclusions. These data demonstrate a significantly more activity of proliferation and apoptosis in the tumor cells of intestinal-type gastric adenocarcinoma, in comparison with the stromal cells of this tumor. Invasive intestinal-type gastric adenocarcinoma differs by the 2 times higher expression level of p53, in comparison with the same index for non-invasive carcinoma. Furthermore, a tight association between proliferative processes in the tumor cells and in the stromal cells of intestinal-type gastric adenocarcinoma, and also an association between proliferative processes and accumulation of mutant protein p53 in the tumor cells of intestinal-type gastric adenocarcinoma were identified.

Comparison of immunohistochemical characteristics of expression estrogen receptors-alpha, progesterone receptors, p16, p53, Ki-67 and caspase 3 in invasive endometrial adenocarcinoma of different grade.

Background. Endometrial cancer occupies the sixth place among newly diagnosed neoplasm in women each year. Objective. Immunohistochemical characterization of the expression of the estrogen receptors-α, progesterone receptors, p16, p53, Ki-67, caspase-3 by the cells of invasive endometrioid endometrial adenocarcinomas of various grade. Methods. The invasive endometrioid endometrial adenocarcinoma (stage pT1-4MxNxG1-3) in the uteruses of 56 perimenopausal women with the verified diagnosis of endometrial cancer were analyzed. For this purpose, immunohistochemical and morphometrical studies were used. Results. The expression levels of p16 and Ki-67 significantly reduce in the tumor cells (р&lt;0,05). The caspase-3 expression level significantly increased in the tumor stromal cells with FIGO (International Federation of Gynecology and Obstetrics) grade increasing (p&lt;0.05). The FIGO grade of the invasive endometrioid endometrial carcinoma has significant relations with the expression levels of the estrogen receptor-α (γ=-0,68), progesterone receptors (γ=-0,78), p53 (γ=-0,45 in the group of adenocarcinomas with low and high expression levels of p53; γ=0,75 in the adenocarcinomas group with overexpression of p53 ), p16 (γ=0,76), Ki-67 (γ=0,34), caspase-3 (γ=-0,84) in the tumor cells and estrogen receptor -α (γ = -0,36), caspase-3 expression levels in tumor stromal cells (γ = 0,84). Conclusion. With increasing of FIGO grade of the invasive endometrioid endometrial adenocarcinoma the sensitivity of tumor cells to regulatory signals of estrogen and progesterone decreases. The expression level of p16 increases, which indicates the violations of p16-associated cell cycle control mechanism. The proliferation level of tumor cell increases and the level of tumor cells apoptosis decreases.

Effects of p53 on aldosterone-induced mesangial cell apoptosis in vivo and in vitro.

Aldosterone (ALD) is a well-known hormone, which may initiate renal injury by inducing mesangial cell (MC) injury in chronic kidney disease (CKD); however, the molecular mechanism remains unknown. The aim of the present study was to investigate the effects of p53 on ALD-induced MC apoptosis and elucidate the underlying molecular mechanism. For the in vivo studies, rats were randomly assigned to receive normal saline or ALD for 4 weeks. The ratio of MC apoptosis was analysed by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay. In addition, the expression level and localisation of p53, a well-known cell apoptosis-associated key protein, were detected by immunofluorescence. For the in vitro studies, rat MCs were incubated in medium containing either buffer (control) or ALD (10−6 M) for 24 h. The cell apoptosis ratio was assessed by flow cytometry, and the expression level of p53 was assessed by reverse transcription quantitative polymerase chain reaction and western blotting. In order to confirm the role of p53 in ALD-regulated cell apoptosis, a rescue experiment was performed using targeted small interfering (si)RNA to downregulate the expression of p53. The ALD-treated rats exhibited greater numbers of TUNEL-positive MCs and higher expression levels of p53 when compared with the control group. Furthermore, the ratio of MC apoptosis and the p53 expression level were significantly increased following ALD exposure, compared with the control group. Additionally, in the rescue experiment, the effects of ALD on MC were blocked by downregulating the expression level of p53 in MCs. The present study hypothesized that ALD may directly contribute to the occurrence of MC apoptosis via p53, which may participate in ALD-induced renal injury.

Mutant p53 accumulates in cycling and proliferating cells in the normal tissues of p53 R172H mutant mice.

The tumour suppressor p53 is regulated primarily at the protein level. In normal tissues its levels are maintained at a very low level by the action of specific E3 ligases and the ubiquitin proteosome pathway. The mutant p53 protein contributes to transformation, metastasis and drug resistance. High levels of mutant p53 can be found in tumours and the accumulation of mutant p53 has previously been reported in pathologically normal cells in human skin. We show for the first time that similarly elevated levels of mutant p53 can be detected in apparently normal cells in a mutant p53 knock-in mouse model. In fact, in the small intestine, mutant p53 spontaneously accumulates in a manner dependent on gene dosage and cell type. Mutant p53 protein is regulated similarly to wild type p53, which can accumulate rapidly after induction by ionising radiation or Mdm2 inhibitors, however, the clearance of mutant p53 protein is much slower than wild type p53. The accumulation of the protein in the murine small intestine is limited to the cycling, crypt base columnar cells and proliferative zone and is lost as the cells differentiate and exit the cell cycle. Loss of Mdm2 results in even higher levels of p53 expression but p53 is still restricted to proliferating cells in the small intestine. Therefore, the small intestine of these p53 mutant mice is an experimental system in which we can dissect the molecular pathways leading to p53 accumulation, which has important implications for cancer prevention and therapy.

Prognostic role of serum p53 antibodies in lung cancer.

BackgroundMutations in the TP53 (Tumour Protein 53) gene can lead to expression of mutant p53 proteins that accumulate in cancer cells and can induce circulating p53 antibodies in cancer patients. Our aim was to evaluate the presence and prognostic role of these antibodies in lung cancer patients and to investigate whether they were related to p53 expression or TP53 mutations in tumour tissues.MethodsA total of 201 lung cancer patients were evaluated for p53 antibodies by ELISA (Enzyme-Linked Immunosorbent Assay) and control was obtained from 54 patients with non-malignant disorders; p53 expression was evaluated in 131 of the lung cancer patients by immunohistochemistry and TP53 mutations were then investigated in 53 tumours positively staining for p53 and in 12 tumours without p53 overexpression, whose DNA was available for direct sequencing.ResultsOur results show that 20.4% of cancer patients have positive levels of p53 antibodies, while none of the controls resulted positive. High levels of p53 expression are detected in 57.3% of cases and a significant correlation between serum p53 antibodies and high levels of p53 expression in the corresponding tumours is observed. In non-small cell lung cancer, p53 antibodies are significantly associated with poorly differentiated tumours; furthermore, high levels of p53 expression significantly correlated with squamous cell carcinoma and tumours with highest grade. Survival time of non-small cell lung cancer patients low/negative for serum p53 antibodies was significantly longer compared to patients with positive levels (p = 0.049); in particular, patients with squamous cell carcinoma, but not adenocarcinoma, low/negative for these antibodies show a significant better survival compared to serum-positive patients (p = 0.044).ConclusionsIn our study, detection of serum p53 antibodies in non-small cell lung cancer patients has been shown to be useful in identifying subsets of patients with poor prognosis. A significant correlation between the presence of serum p53 antibodies in lung cancer patients and p53 overexpression in the corresponding tumours was also observed. We did not find a significant correlation between levels of serum p53 antibodies and TP53 mutations in the corresponding tumours.

Elevated p53 expression levels correlate with tumor progression and poor prognosis in patients exhibiting esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is the most common histological subtype of esophageal cancer and one of the most aggressive types of malignancy, with a high rate of mortality. Early diagnosis and treatment may improve the prognosis of ESCC and, thus, survival rates. As a significant tumor suppressor, p53 is closely associated with apoptosis and the differentiation of cancer cells. The present study evaluated the expression levels of the p53 protein and the clinical significance in patients presenting with ESCC. The p53 protein expression level of 64 paired ESCC and tumor-adjacent normal tissues was evaluated using western blot analysis. In addition, immunohistochemistry (IHC) was performed to detect the p53 expression level in specimens from 118 paraffin-embedded cancerous tissues. The correlation of the p53 expression level with the clinicopathological parameters and prognosis of the ESCC patients was also analyzed. The p53 protein was identified to be highly expressed in the ESCC tissue, with western blot analysis demonstrating that the expression level of p53 in the cancerous tissue was 1.89 times that of the tumor-adjacent normal tissue (P<0.001); furthermore, IHC indicated that there was a marked positive expression of p53 in the ESCC tissue (49.15%). The expression level of p53 protein was identified to be significantly correlated with the tumor grade (P<0.001), N stage (P=0.010). Additionally, the higher level of p53 expression was found to be associated with a poor survival rate in the ESCC patients (P=0.0404). The univariate analysis showed that the survival time of patients was significantly correlated with the T stage (RR=3.886, P<0.001), N stage (lymph node metastasis; RR=3.620, P<0.001) and TNM stage (RR=3.576, P<0.001). Furthermore, the multivariate analysis revealed that the T stage (RR=3.988, P<0.001) and N stage (RR=4.240, P=0.004) significantly influenced the overall survival of the ESCC patients.