Patterns Of P53 Protein Expression Research Articles

Clinicopathologic Aspects of Squamous Cell Carcinoma of the Uterine Cervix: Role of PTEN, BCL2 and P53

Background: Squamous cell carcinoma (SCC) of the uterine cervix is a leading cause of morbidity and mortality among women. The alterations of Phosphatase and tensin homolog (PTEN), B-cell lymphoma 2 (Bcl2) and p53 expression seem to be significant in the development of various types of cancers. The altered expressions of PTEN, Bcl2 and p53 and their involvement in cancer of the uterine cervix are not well recognized. Aim: This study aimed at examining the expression patterns of PTEN, Bcl2 and p53 proteins and comparing them with the grade and stage of cervical cancer. Materials and Methods: Tissue blocks of SCC and ten cases of inflammatory lesions of the uterine cervix were examined immunohistochemically for the expression of PTEN, Bcl2 and p53 proteins. Results: Loss of PTEN expression was identified in 45.33% of cervical SCC and high expression was found in inflammatory lesions (p ≤ 0.05). PTEN expression was significantly associated with the clinical stage of SCC (61.36% and 45.16% in stages I–II and III–IV, respectively) (p < 0.05), but not with the degree of differentiation of the SCC. The expression of Bcl2 was significantly high (60%) in cancer cases than in control cases (p < 0.05). Bcl2 did not show any significant association with the histologic type and clinical stage of the SCC of the uterine cervix. The expression of p53 protein was significantly high (57.33%)) in cancer tissue, and no expression was noted in control cases (p < 0.05). Moreover, the expression pattern of p53 protein in cervical cancer tissue samples was not linked with the patient age, grade and stage of the cervical SCC (p > 0.05). Conclusion: The reduced expression of PETN and overexpressions of Bcl2 and p53 might play an indispensable role in carcinogenesis of cervical SCC. Moreover, a relationship was detected between PTEN expression and clinical stage of the cervical SCC.

Pattern of p53 protein expression is predictive for survival in chemoradiotherapy-naive esophageal adenocarcinoma.

IntroductionTP53 mutations are considered to be the driving factor in the initiation of esophageal adenocarcinoma (EAC). However, the impact of this gene and its encoded protein as a prognostic marker has not been definitely established yet.MethodsIn total, 204 chemoradiotherapy (CRT)-naive patients with EAC were included for p53 protein expression evaluation by immunohistochemistry (IHC) on the resection specimens, categorized as overexpression, heterogeneous or loss of expression, and correlated with disease free survival (DFS) and overall survival (OS) using multivariable Cox regression analysis. In a subset representing all three IHC subgroups mutational status of selected candidate genes (n=33) and high throughput methylation profiling (n=16) was assessed.ResultsCompared to heterogeneous p53 expression, loss and overexpression were both independently predictive for adverse DFS and OS. TP53 mutational status significantly correlated with the IHC categories (p=0.035). Most of the EAC with loss- or overexpression harbored TP53 mutations (18/20, representing nonsense and missense mutations respectively). In contrast, 6/13 EAC with heterogeneous expression were TP53 wild type, of which two demonstrated MDM4 or MDM2 amplification. Combined genomic hypomethylation and high frequency of intra-chromosomal breaks was found in a selection of EAC without p53 overexpression.ConclusionP53 expression pattern is prognostic for DFS and OS in this historical cohort of CRT-naive EAC. P53 IHC is an informative readout for TP53 mutational status in EAC with either loss- or overexpression, but not in case of a heterogeneous p53 pattern. Different EAC pathogenesis might exist, related to p53 and other candidate gene status, DNA hypomethylation and intrachromosomal breaks.

Distinctive patterns of p53 protein expression and microsatellite instability in human colorectal cancer

Although evidence suggests an inverse relationship between microsatellite instability and p53 alterations in colorectal cancer, no study has thoroughly examined the use of p53 immunohistochemistry in phenotyping colorectal cancers. We investigated the value of p53 immunohistochemistry in microsatellite instability-positive colorectal cancers prescreening and attempted to clarify the relationship between DNA mismatch repair system and p53 pathway. In a series of 104 consecutive colorectal cancers, we performed p53 immunohistochemistry, TP53 mutational analysis, DNA mismatch repair system efficiency evaluation (DNA mismatch repair system immunohistochemistry, microsatellite instability status, MLH1/MSH2 germ line, and BRAF, murine double minute 2, and p21 immunohistochemistry. Microsatellite instability high was observed in 25 of 104 colorectal cancers, with DNA mismatch repair system protein loss (24/25) and germ line (8/25) or BRAF mutations (8/25). p53 immunohistochemistry revealed 3 distinct patterns of expression: complete negative immunostaining associated with truncating TP53 mutations (P < .0001), diffuse overexpression associated with missense TP53 mutations (P < .0001), and restricted overexpression characterized by a limited number of homogenously scattered strongly positive tumor cells in 36.5% of colorectal cancers. This latest pattern was associated with wild-type TP53 and microsatellite instability high colorectal cancers (P < .0001) including all Lynch tumors (8/8), but its presence among 22% of DNA mismatch repair system-competent colorectal cancers decreased its positive predictive value (55.2% [95% confidence interval, 45%-65%]). It was also correlated with murine double minute 2 overexpression (P < .0001) and inversely with p21 loss (P = .0002), independently of microsatellite instability status. In conclusion, a restricted pattern of p53 overexpression is preferentially associated with microsatellite instability high phenotype and could, therefore, be of clinical use as signal for microsatellite instability analysis in a large-scale tumor screening. Its association with concomitant murine double minute 2 overexpression suggests an alternative mechanism of p53 pathway deregulation.

Occurrence of multipolar mitoses and association with Aurora-A/-B kinases and p53 mutations in aneuploid esophageal carcinoma cells

BackgroundAurora kinases and loss of p53 function are implicated in the carcinogenesis of aneuploid esophageal cancers. Their association with occurrence of multipolar mitoses in the two main histotypes of aneuploid esophageal squamous cell carcinoma (ESCC) and Barrett's adenocarcinoma (BAC) remains unclear. Here, we investigated the occurrence of multipolar mitoses, Aurora-A/-B gene copy numbers and expression/activation as well as p53 alterations in aneuploid ESCC and BAC cancer cell lines.ResultsA control esophageal epithelial cell line (EPC-hTERT) had normal Aurora-A and -B gene copy numbers and expression, was p53 wild type and displayed bipolar mitoses. In contrast, both ESCC (OE21, Kyse-410) and BAC (OE33, OE19) cell lines were aneuploid and displayed elevated gene copy numbers of Aurora-A (chromosome 20 polysomy: OE21, OE33, OE19; gene amplification: Kyse-410) and Aurora-B (chromosome 17 polysomy: OE21, Kyse-410). Aurora-B gene copy numbers were not elevated in OE19 and OE33 cells despite chromosome 17 polysomy. Aurora-A expression and activity (Aurora-A/phosphoT288) was not directly linked to gene copy numbers and was highest in Kyse-410 and OE33 cells. Aurora-B expression and activity (Aurora-B/phosphoT232) was higher in OE21 and Kyse-410 than in OE33 and OE19 cells. The mitotic index was highest in OE21, followed by OE33 > OE19 > Kyse-410 and EPC-hTERT cells. Multipolar mitoses occurred with high frequency in OE33 (13.8 ± 4.2%), followed by OE21 (7.7 ± 5.0%) and Kyse-410 (6.3 ± 2.0%) cells. Single multipolar mitoses occurred in OE19 (1.0 ± 1.0%) cells. Distinct p53 mutations and p53 protein expression patterns were found in all esophageal cancer cell lines, but complete functional p53 inactivation occurred in OE21 and OE33 only.ConclusionsHigh Aurora-A expression alone is not associated with overt multipolar mitoses in aneuploid ESCC and BAC cancer cells, as specifically shown here for OE21 and OE33 cells, respectively. Additional p53 loss of function mutations are necessary for this to occur, at least for invasive esophageal cancer cells. Further assessment of Aurora kinases and p53 interactions in cells or tissue specimens derived from non-invasive dysplasia (ESCC) or intestinal metaplasia (BAC) are necessary to disclose a potential causative role of Aurora kinases and p53 for development of aneuploid, invasive esophageal cancers.

Abstract P1-03-07: Differential Effect of Specific p53 Mutations on Breast Cancer Growth and Response to Hsp90 Inhibition In Vivo

Abstract Background p53 mutation influences breast cancer cell growth and patient prognosis. However, different p53 mutations impart specific functions to the mutant protein, including dominant negative or gain of function effects. Mutant p53 molecules R273H and R175H are commonly found in primary breast cancers and are present in the MDA-MB-468 and SKBR3 cell lines, respectively. To compare the direct effects of these two mutations in vivo in an identical cellular background, H1299 (p53-null) cells were constructed to express R273H or R175H p53 mutants. Methods Thirty female SCID mice were injected subcutaneously with 106 H1299 (p53-null), H1299/R273H or H1299/R175H cells in DMEM + Matrigel (50:50) suspension. Some mice were treated with an Hsp90 inhibitor, which is required for correct folding of many oncogenic proteins. Results Xenografts bearing R175H showed a mean lag phase (time between cell injection and tumors at exponential growth) of 21 days and a doubling time of 5 days, whereas tumors bearing H1299 (p53-null) or R273H mutation had a lag phase of 31 days with a doubling time of 7 days. Immunohistochemical examination demonstrated a highly heterogeneous pattern of p53 protein expression in the more aggressive R175H expressing cells compared with R273H expressing cells. Hsp90 inhibitor treatment reduced the growth of H1299 and R273H cells, but not R175H cells. Conclusions The specific p53 mutations directly influence the rate of tumor growth and the p53 protein staining pattern on immunohistochemistry. The differential effects of specific p53 mutations should be considered when interpreting clinical data involving p53 mutation such as in the EORTC 10994 trial, with implications for prognostic determination of individual breast cancer patients. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-03-07.

Aberrant P53 Expression and the Development of Gallbladder Carcinoma and Adenoma

Gallbladder carcinoma (GBC) is a highly lethal but relatively rare neoplasm of the digestive tract. The progression from gallbladder adenoma to carcinoma remains unclear. The p53 gene is the most frequently mutated tumor suppressor in human cancers. In this study, we analyzed the expression patterns of the p53 protein in 22 cases of GBC, 17 cases of precursor lesions (16 gallbladder adenomas and 1 cystadenoma), and 15 cases of normal epithelia using immunohistochemical analysis. The results were correlated with clinicopathologic characteristics. We found that p53 expression was significantly increased in 59.1% (13/22) of GBC cases and in 17.6% (3/17) of gallbladder adenoma cases (p = 0.009). There was no p53 expression in the 15 cases of normal epithelia, and a significant difference was shown between normal epithelium and GBC cases (p < 0.001). In addition, the expression pattern of p53 protein did not show any significant correlation with the histologic type and the differentiation grade of GBC. In conclusion, we suggest that the aberrant p53 expression may play a role in the occurrence of GBC.

Basal cell carcinoma and its development: insights from radiation-induced tumors in Ptch1-deficient mice.

Loss-of-function mutations in Patched (Ptch1) are implicated in constitutive activation of the Sonic hedgehog pathway in human basal cell carcinomas (BCCs), and inherited Ptch1 mutations underlie basal cell nevus syndrome in which a typical feature is multiple BCC occurring with greater incidence in portals of radiotherapy. Mice in which one copy of Ptch1 is inactivated show increased susceptibility to spontaneous tumor development and hypersensitivity to radiation-induced tumorigenesis, providing an ideal in vivo model to study the typical pathologies associated with basal cell nevus syndrome. We therefore examined BCC development in control and irradiated Ptch1(neo67/+) mice. We show that unirradiated mice develop putative BCC precursor lesions, i.e., basaloid hyperproliferation areas arising from both follicular and interfollicular epithelium, and that these lesions progress to nodular and infiltrative BCCs only in irradiated mice. Data of BCC incidence, multiplicity, and latency support the notion of epidermal hyperproliferations, nodular and infiltrative BCC-like tumors representing different stages of tumor development. This is additionally supported by the pattern of p53 protein expression observed in BCC subtypes and by the finding of retention of the normal remaining Ptch1 allele in all nodular, circumscribed BCCs analyzed compared with its constant loss in infiltrative BCCs. Our data suggest chronological tumor progression from basaloid hyperproliferations to nodular and then infiltrative BCC occurring in a stepwise fashion through the accumulation of sequential genetic alterations.

Immunohistochemical p53 expression patterns in sarcomatoid carcinomas of the upper respiratory tract.

Sarcomatoid carcinoma of the upper respiratory tract is a phenotypically complex neoplasm that has triggered much thoughtful discussion regarding histogenic origin and morphologic classification. In particular, its putative epithelial lineage and distinction from a pseudosarcomatous reaction are sometimes questioned. Little is known about the genetic alterations underlying sarcomatoid carcinoma. Although about 45% of conventional squamous cell carcinomas of the upper respiratory tract harbor p53 mutations, the p53 status of sarcomatoid carcinomas is not well established. p53 immunohistochemical analysis using the monoclonal antibody D07 was performed on 23 sarcomatoid carcinomas of the upper respiratory tract. Twenty tumors were biphasic, having dual epithelial and spindled components. In four of these biphasic tumors, the epithelial and spindled components were separately analyzed for p53 gene mutations by sequence analysis. p53 immunohistochemistry was also performed on 19 cases of postradiation stromal atypia. Strong and diffuse p53 staining was detected in 18 (78%) of the 23 sarcomatoid carcinomas. When the spindled component was compared with its corresponding epithelial component, identical patterns of p53 protein expression were noted in 19 (95%) of the 20 biphasic tumors. Weak p53 staining was observed in one (5%) of the 19 cases of postradiation stromal atypia. In the four biphasic tumors evaluated by DNA sequence analysis, p53 status was always the same in the paired epithelial and spindle cell components. These findings help further dispel the notion that sarcomatoid carcinoma represents a reactive spindle cell proliferation (pseudosarcoma) or a collision between a carcinoma and a sarcoma (collision tumor). Instead, the epithelial and spindled components share a common pathway of tumorigenesis despite their conspicuous divergence at the phenotypic level.

Spindle cell squamous carcinoma of the oesophagus: an analysis of 17 cases, with new immunohistochemical evidence for a clonal origin.

To study the morphological and immunohistochemical characteristics of spindle cell squamous carcinoma of the oesophagus, in order better to understand the histogenesis of this tumour. In this study we analysed the morphological and immunohistochemical characteristics of 17 cases of spindle cell squamous carcinoma of the oesophagus. Most tumours were polypoid, but tumours with an ulcerated and infiltrative pattern were also observed. Histologically, most tumours were of superficial type, with a characteristic morphological aspect consisting of two types of tumour cells, i.e. differentiated squamous cells, and spindle cells with transition zones between the two components. On immunohistochemistry, the squamous cells were positive for cytokeratin and the spindle cells showed variable expression of cytokeratin, vimentin and smooth muscle actin. p53 protein was over-expressed in 10 cases, both tumour cell types showing strong nuclear positivity. In most tumours, E-cadherin was expressed in the squamous cells and absent in the spindle cells. The similar pattern of p53 protein expression in the two tumour cell types of spindle cell squamous carcinoma of the oesophagus suggests their common origin. The change in adhesion molecule expression with loss of E-cadherin expression may be associated with the acquisition of spindle cell morphology by the squamous tumour cells.

Cellular events and the pattern of p53 protein expression following cyclophosphamide-initiated cell death in various organs of developing embryo

This study was aimed at characterizing the temporal patterns of cell responses and p53 protein expression in the limbs, head, and liver of embryos responding to cyclophosphamide (CP)-induced teratogenic insult. ICR murine embryos were examined 24, 48, or 72 h after injection of 40 mg/kg CP on day 12 of pregnancy. The cellular events and temporal pattern of p53 protein expression were determined by FACS analysis and by TUNEL (apoptosis) in the head, limbs, and liver of the embryos. All tested organs showed apoptosis and a significantly decreased proportion of live cells after 24 h. Subsequent events were organ-dependent. In the liver, there were no dysmorphic events at any time and excessive cell death had been almost compensated for by 48 h. Compensation was preceded by G(1) arrest and accompanied by an increased level of p53 protein in surviving cells. Excessive cell death in the head and the limbs resulted in structural anomalies. In the head, there was an increased level of p53 protein and G(1) arrest after 24 h and the number of live cells at 48 h was equal to that seen in earlier samples, despite apoptosis. In the limbs, however, only isolated viable cells were seen by 48 h, but there was no increased level of p53 protein or G(1) arrest. Results of this study suggest that the differential sensitivity of tested organ systems to CP may be associated with differences in cellular events following CP-initiated cell death. They also suggest that the input of p53 in determining the response of these organ systems to CP-induced teratogenic insult may be different. Teratogenesis Carcinog. Mutagen. 19:353-367, 1999.

P53, p16 and RB Expression in Adenosquamous and Squamous Cell Carcinomas of the Stomach

The expression of p53, p16 and RB proteins and their clinicopathologic correlation were investigated in 15 cases of primary gastric adenosquamous carcinoma and 2 cases of squamous cell carcinoma of the stomach. The male to female ratio of the patients was 13:4 and the average age was 55.7 years. None of the cases was early gastric carcinoma, and none of the adenocarcinoma components were of the diffuse or signet ring cell types. Fourteen cases showed metastasis to regional lymph nodes and/or other organs at the time of surgery. The adenocarcinoma component was metastasized to lymph nodes in 12 cases, and both adenocarcinoma and squamous cell carcinoma components were metastasized in three cases. The altered expression of p53 correlated with the advanced stage, but did not correlate with the depth of invasion, lymph node metastasis or recurrence. The altered expression of p16 and RB proteins did not correlate with any of the above clinico-pathologic factors. Both the adenocarcinoma and squamous cell carcinoma components revealed an inverse correlation between the expression pattern of p16 and RB proteins (p < 0.05). This suggests that the two proteins share a role in the carcinogenesis of these tumors. The expression pattern of p53 proteins in the adenocarcinoma and squamous cell carcinoma components was exactly the same in all of the cases. The expression patterns of p16 and RB protein were also identical in most of the cases. The expression patterns of all three proteins in the metastatic lesions were also identical to those in the primary lesions. The fact that the alteration of the three tumor suppressor gene products shares the same pattern suggests that squamous and adenocarcinoma components in the stomach originate from the same or a genetically related clone.

Cellular events and the pattern of p53 protein expression following cyclophosphamide‐initiated cell death in various organs of developing embryo

Cellular events and the pattern of p53 protein expression following cyclophosphamide‐initiated cell death in various organs of developing embryo

Time course comparison of cell-cycle protein expression following partial hepatectomy and WY14,643-induced hepatic cell proliferation in F344 rats.

During recent years, there has been an extensive research focus in the area of cell-cycle control in eukaryotes and the relationship that exists between cell proliferation and cancer. The eukaryotic cell-cycle is governed by signal transduction pathways mediated by complexes of cyclin dependent kinases (CDK) and their partner cyclin proteins. This study was performed to identify differences in cell-cycle control protein expression following physical and chemical stimuli of hepatic cell growth. Protein levels of cell cycle mediators, cyclin dependent kinases (CDK 1,2,4,5), cyclin proteins (A,B,D1-D3 and E), proliferating cell nuclear antigen (PCNA), tumor suppressor proteins (p53 and Rb), and CDK inhibitory proteins (p16Ink4, p21Waf1 and p27Kip1) were examined in F344 rats following 70% partial hepatectomy or a single dose of WY14,643 over 96- and 48-h time courses, respectively. CDK1 (p34cdc2) and PCNA protein concentrations, quantified by ELISA, were significantly increased beginning at the 24-h time point and maximal at 48 h (6.9- and 3.7-fold for partial hepatectomy and 4.2- and 3.3-fold for WY14,643, respectively). Differential effects were observed with the G1 cell-cycle mediators CDK4, CDK5, and cyclin D3, p21Waf1 and p27Kip1 CDK inhibitory protein concentrations rose in accordance with the induction of DNA synthesis and histone H1 kinase activity. In addition, there were dramatic differences in p53 protein expression patterns following partial hepatectomy versus WY14,643 dosing. Because non-genotoxic hepatocarcinogens are known to induce cellular proliferation, data generated from this study may aid in elucidating the specific hepatocarcinogenic signal transduction pathways stimulated by non-genotoxic carcinogens.

P53 nuclear protein overexpression in colorectal cancer: a dominant predictor of survival in patients with advanced hepatic metastases.

To determine whether p53 protein expression is similar within primary colorectal cancer (CRC) and synchronous regional and distant metastases and to assess whether p53 nuclear protein expression could predict outcome in patients with synchronous unresectable liver metastases treated by hepatic artery infusional (HAI) chemotherapy. Paraffin sections from tumor and corresponding normal mucosa representative of 50 consecutive advanced CRC cases were examined for p53 nuclear protein expression by immunohistochemistry using the monoclonal antibody PAb 1801. Patterns of p53 nuclear expression were correlated with standard clinicopathologic variables and outcome, including response to HAI and survival. In a subset analysis, the pattern of nuclear p53 immunoreactivity was compared between primary CRC and lymph node and liver metastases. Positive nuclear immunoreactivity for p53 protein was found in 72% of cases. The pattern of p53 protein expression in lymph node and liver metastases was identical to that of the primary tumor. The median survival time was 21.0 months in patients with p53-positive tumors and 53.2 months in patients with p53-negative tumors (Wilcoxon test P = .038). Two-year survival rates were 41.7% and 78.6%, respectively (P < .01). No significant difference was found in the response rates to HAI chemotherapy between the two groups. By multivariate analysis, p53 protein status was the single best predictor of survival, with a relative risk of 6.312. Our results indicate that nuclear p53 protein status in primary CRC is similar to that in metastatic sites and may be the dominant predictor of survival in patients with advanced hepatic metastases.

Immunohistochemical Determination of P53 Protein Nuclear Accumulation in Prostatic Adenocarcinoma

Abnormalities of the TP53 gene are currently the most common genetic alterations associated with human malignancy. The study of altered patterns of p53 protein expression in primary prostate cancer has to date yielded a much lower incidence of alteration compared to bladder, colon, lung and breast cancer. However, the analysis of prostate cancer metastases has been limited. The objective of our study was to determine the prevalence of p53 nuclear accumulation in primary, metastatic and hormone refractory prostatic adenocarcinoma, and to characterize its relationship with conventional clinicopathological variables. We used 2 antibodies (mouse monoclonal PAb 1801 and rabbit polyclonal CM-1) and an immunohistochemical method in 93 paraffin embedded tumors (48 primary tumors, 29 lymph node metastases and 16 bone metastases) to assess p53 nuclear accumulation. Overall, p53 nuclear accumulation was observed in 19 tumors (20%), including 17 with PAb 1801 and CM-1 immunoreactivities, and 2 with CM-1 immunoreactivity only. The pattern of p53 immunoreactivity was heterogeneous in most tumors, with only 3 cases exhibiting homogeneous staining. Primary, lymph node and bone metastases exhibited p53 nuclear staining in 9 of 48 (19%), 2 of 29 (7%) and 8 of 16 (50%) cases, respectively (p = 0.003). In 6 of 10 primary hormone refractory tumors (60%) and in 3 of 38 primary hormone naive tumors (8%) p53 nuclear immunoreactivity was expressed (p = 0.002). P53 nuclear accumulation was significantly more common in higher grade primary tumors (p = 0.007).Our results suggest that p53 nuclear accumulation is relatively uncommon in prostate cancer. However, p53 nuclear accumulation appears to be associated with advanced stages of disease, as illustrated by its relatively higher occurrence in hormone refractory tumors and bone metastases. Furthermore, the significantly greater prevalence of p53 accumulation in bone metastases is currently the highest reported for prostate cancer.