Human p53 gene localized to short arm of chromosome 17

Prognostic Value of Numerical Chromosome Aberrations in Multiple Myeloma: A FISH Analysis of 15 Different Chromosomes

Recent observations indicate that chromosome aberrations are important prognostic factors in patients with multiple myeloma (MM) treated with high-dose chemotherapy. Nevertheless, the inherent problems of conventional cytogenetics have hampered the systematic evaluation of this parameter in series of patients treated with conventional chemotherapy. Fluorescence in situ hybridization (FISH) analysis is an attractive alternative for evaluation of numerical chromosomal changes. In the present study, we analyze the relationship between aneuploidies of 15 different chromosomes assessed by FISH and prognosis in a series of 63 patients with MM treated with conventional chemotherapy. After a median follow-up of 61 months (range, 6 to 109), 49% of patients are still alive with a median survival of 33 months. The overall incidence of numerical chromosome abnormalities was 70%. This incidence significantly increased when seven or more chromosomes were analyzed (53 patients), reaching 81%. Trisomies of chromosomes 6, 9, and 17 were associated with prolonged survival (P = .033, P = .035, and P = .026, respectively); by contrast, overall survival (OS) was lower in cases with monosomy 13 (as assessed by deletion of Rb gene,P = .0012). From the clinical point of view, loss of Rb gene was associated with a poor performance status; low hemoglobin levels; high creatinine, C-reactive protein, and lactic dehydrogenase serum levels; high percentage of bone marrow plasma cells (BMPC); extensive bone lytic lesions; and advanced clinical stage. Other chromosome abnormalities such as trisomy of chromosome 9 and 17 were associated with good prognostic features including high hemoglobin levels, early clinical stage, β2microglobulin less than 6 μg/mL, and low percentage of BMPC. A multivariate analysis for OS showed that S-phase PC greater than 3% (P = .010) and β2microglobulin serum levels greater than 6 μg/mL (P = .024), together with monosomy of chromosome 13 (P = .031) and nontrisomy of chromosome 6 (P = .048) was the best combination of independent parameters for predicting survival in patients with MM. According to these results, chromosomal analysis is of great use in patients with MM at diagnosis to have a correct prognostic evaluation for clinical decision making.

Nucleotide sequence of a highly conserved region of the canine p53 tumour suppressor gene

An evolutionary conserved region of the canine tumour suppressor gene, p53, was PCR amplified and its DNA sequence determined. The 1003 bp fragment consisted of exons 5 to 8 and the intervening introns. A high level of sequence homology was demonstrated with human sequences, with the evolutionary conserved domains II, III, IV and V being identical.

Li-Fraumeni syndrome and the role of the p53 tumor suppressor gene in cancer susceptibility

Mutation of the tumor suppressor gene p53 is a molecular genetic event frequently observed in human cancer, and inactivating missense mutations usually are accompanied by the resultant overexpression of mutant p53 protein. In gynecologic cancers, p53 is also often altered; the frequency varies depending on types of cancers and where they develop. Further, human papillomavirus oncoproteins that inactivate p53 and Rb proteins play important roles in the development of several gynecologic cancers. Individuals who are heterozygous for germline mutations of the p53 gene are strongly predisposed to a variety of cancers. The identification of these individuals may have profound value in the future when therapies or chemopreventive agents specific for the p53 alteration are available. The role of p53 tumor suppressor gene in gynecologic cancers and heritable cancer susceptibility syndromes including Li-Fraumeni and Lynch II syndromes is an active and important area of study.

Loss of heterozygosity at microsatellite marker sites for tumour suppressor genes in oesophageal adenocarcinoma

AIMS

Loss of cell cycle control is an important step in the development of human tumours. A number of tumour suppressor genes are involved in cell cycle control, including p16, p53 and Rb. The aim of this study was to seek evidence of deletions of these genes in oesophageal adenocarcinoma.

METHODS

Paired (tumour and normal squamous epithelium) frozen tissue samples from 12 patients were analysed by polymerase chain reaction (PCR) for loss of heterozygosity (LoH) at five microsatellite marker sites (two each for p16 and Rb, one for p53). Aneuploid tumour cell populations were sorted by flow cytometry prior to PCR, to eliminate stromal cell contamination.

RESULTS

Of the 12 tumours, 11 (92%) had LoH at one or more loci. LoH at the p53 locus occurred in nine of 12 tumours, at one or both p16 loci in seven of 11 tumours, and at one or both Rb loci in eight of 12 tumours. Five tumours had LoH at two tumour suppressor gene loci, and a further four tumours had LoH at loci for all three genes.

CONCLUSIONS

Allelic deletions of p53, p16 and Rb are common in oesophageal adenocarcinoma, and may be important in the development of this disease.

How is the mutational status for tumor suppressors p53 and p16(INK4A) in MFH of the bone?

Both tumor suppressor genes p53 and p16(INK4A) play a crucial role in the control of cell cycle and tumor development. In this study 19 malignant fibrous histiocytomas of the bone (MFH-b), a very rare sarcoma entity, were investigated for mutations in p53 and p16 genes by a PCR-SSCP-sequencing analysis. In the tumor samples two p53 mutations and two polymorphisms (one in the p53 gene and one in the p16 gene) were found. The occurrence rate for p53 mutations and the absence of p16 mutations in MFH-b are comparable to the findings for MFH of soft tissues (MFH-st) and osteosarcomas, suggesting that p53 rather than p16 may play a role in tumorigenesis of MFH-b.

p53 protein expression in patients with hepatocellular carcinoma from the high incidence area of Guangxi, Southern China

Mutation of the p53 gene has been reported in hepatocellular carcinoma (HCC) occurring worldwide. The most frequent p53 mutation has been found in HCCs in regions with high hepatitis B virus (HBV) infection and intake of aflatoxin B1 (AFB1). The aim of our study was to examine p53 protein expression in HCCs from a high incidence area of Guangxi, Southern China, where HBV infection and dietary intake of AFB1 are high. Immunohistochemical staining of p53 protein was carried out using a polyclonal rabbit antibody (CM-1). Serial sections were also stained for hepatitis B surface antigen and core antigen. p53 Protein expression was detected in 13 (43.3%) of the 30 HCCs. Expression of p53 was found in 25.0% (1/4) of the < or = 5.0 cm diameter HCCs, in 36.8% (7/19) of the 5.1-10.0 cm diameter HCCs and in 71.4% (5/7) of the >10.0 cm diameter HCCs. Expression of p53 was observed more in moderately and poorly differentiated than in the well differentiated HCCs and more frequently seen in HCCs from younger patients. These data indicate that there is a close association between p53 protein expression and tumor size, histological grade and age of patients. Twenty-seven out of 30 cases (90.0%) were positive for HBV. No significant association between p53 expression and sex. HBV infection, cirrhosis or alpha-fetoprotein has been found.

Double immunostaining for p53 and molecular chaperone hsp72/73 in gastric carcinoma

AIMS

To examine the relation between the expression of p53 protein and the chaperone heat shock protein (hsp)72/73 in a population at high risk for gastric carcinoma, using single and double immunohistochemistry, and to compare the expression of these two proteins with clinicopathological features.

METHODS

Monoclonal antibodies were used to investigate the expression of p53 protein and hsp72/73 in 46 human gastric carcinomas. A double immunohistochemical technique was used in cases that showed p53/hsp72/73 coexpression.

RESULTS

p53 immunoreactivity was present in 11 tumours (24%), and hsp72/73 immunostaining was observed in 22 cases (48%). p53 expression was observed as nuclear staining in tumoral cells. hsp72/73 expression was demonstrated mainly as cytoplasmic staining, but six tumours also showed focal weak nuclear staining. Seven cases showed p53 and hsp72/73 coexpression with immunoreactivity for both proteins in the same neoplastic cells, three of them with focal areas of nuclear coexpression. p53 expression was seen more frequently in cases that showed a high intensity (+ + +) of hsp72/73 staining. No significant association was observed between the expression of the two proteins and clinicopathological features.

CONCLUSIONS

More than half of our cases may have some impairment in p53 protein growth suppressive function, as a result of p53 gene alterations or complex formation. The positive correlation between p53 expression and intensity of hsp72/73 supports the postulate of a p53 regulating function for the chaperone hsp72/73. A high intensity of hsp72/73 immunohistochemical staining could be used as an indirect marker of p53 gene abnormalities.

Correlation Between Mutation in P53, p53 Expression, Cytogenetics, Histologic Type, and Survival in Patients With B-Cell Non-Hodgkin's Lymphoma

In the biology of a cell, the central role of p53 in controlling functions such as G1/S transition (check point) and DNA damage repair, and as a trigger of apoptosis, is well established. Somatic mutations or other changes in P53 have been reported in numerous tumor types, and in some of these, they are associated with poor prognosis. In this study, we examined 237 cytogenetically characterized B-cell non-Hodgkin's lymphomas (B-NHLs) for somatic changes in P53 by Southern blot analysis, by single-strand conformation polymorphism analysis (SSCP) of exon 5 through 9, and by direct sequencing of SSCP variants to determine the frequency and types of mutations and their clinical significance. In a portion of these (173 tumors), we also studied p53 expression by immunostaining. On Southern blots, no gross change was identified in P53 and no mutation was identified in exon 9. In exons 5 through 8, 27 different mutations were identified in 25 patients (23 single-base substitutions, 3 deletions, 1 duplication). Mutations in P53 were identified in 25 of 237 tumors (10.5%), which included 1 of 45 small lymphocytic lymphomas (SLLs), 2 of 38 follicular small cleaved-cell lymphomas (FSCCs), 2 of 35 follicular mixed small cleaved-cell and large-cell lymphomas (FMxs), 1 of 4 follicular large-cell lymphomas (FLCs), 1 of 14 diffuse small cleaved-cell lymphomas (DSCCs), 2 of 17 diffuse mixed small- and large-cell lymphomas (DMxs), and 16 of 84 diffuse large-cell lymphomas (DLCCs); the difference between the histologic groups was significant (P < .01). Among mantle-cell lymphoma (MC) patients, 3 of 10 had mutations. In 16 patients, the mutation was identified in specimens obtained at diagnosis. Mutation of transition type and transversion type occurred at a relative frequency of 2:1. Thirty percent occurred at CpG dinucleotide sequences and the codon for arginine was most frequently affected. Nineteen of 99 tumors with complex cytogenetic abnormalities, but none of 69 tumors with simple cytogenetic abnormalities, had mutations (P < .001). Similarly, 11 of 25 tumors with an abnormality of 17p and 8 of 143 tumors with apparently normal 17p had mutations (P < .0001). Positive correlations were found between a mutation and p53 expression (P < .001), between missense type mutations and p53 expression (P < .005), and between 17p abnormalities and p53 expression (P < .05). Twenty-two of 49 patients without mutation and 14 of 17 patients with mutations died (P < .05), but there was no significant difference in median survival. Similarly, 21 of 26 p53 positive patients died, whereas only 1 of 24 p53-negative patients died on-study (P < .001). Among p53-negative patients, mutation (P < .01) was positively associated with a fatal outcome. These findings indicate that in B-NHL, somatic changes in P53 were present in diagnostic specimens of all histologic types, but at a higher frequency in DLC and MC tumors. P53 mutation and/or expression has a negative influence on survival, and therefore can serve as prognostic indicators. Immunostaining for p53 is an effective way to screen for P53 changes in these tumors.

Detection of apoptosis-related factors and apoptotic cells in ameloblastomas: analysis by immunohistochemistry and an in situ DNA nick end-labelling method

To clarify the possible role of apoptosis in odontogenic epithelium, apoptosis-related factors and apoptotic cells were examined by immunohistochemistry and an in situ DNA nick end-labelling method. Expression of bcl-2 protein was detected in both normal and neoplastic odontogenic epithelium, whereas expression of p53 protein was detected only in neoplastic but not in normal odontogenic epithelium. The prevalence of cases positive for Lewis(y) antigen in ameloblastomas was significantly lower than in enamel organs. Correlation between these factors and apoptotic cells presented by an in situ DNA nick end-labelling method was not clear. The number of apoptotic cells in ameloblastomas was significantly greater than in normal odontogenic epithelium, and apoptotic reactions in the granular cell type ameloblastoma tended to be more frequently detected than in other types of ameloblastomas. These results suggested that apoptotic cell death might play an important role in oncogenesis and/or tissue differentiation in odontogenic epithelium.

Mutations of p53 tumor-suppressor gene in angiosarcoma

Transgenic mice deficient for the p53 gene were reported to frequently develop angiosarcoma (AS), suggesting that alterations in the gene are associated with tumorigenesis of AS. However, little is known about genetic changes, including p53 gene alterations, in human AS because of its rarity. We analyzed p53 mutations on paraffin-embedded specimens from 33 patients with AS by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) followed by direct sequencing. Age of patients ranged from 18 to 91 (median 70) years, with a male to female ratio of 1.5:1. Sites of tumor were the head in 13 patients, the trunk in 4, the extremities in 4, the heart in 4, bones in 2 and others in 6. PCR-SSCP revealed aberrant mobility shifts of bands in 17 cases: 11 in exon 5, 5 in exon 7 and 4 in exon 8. Direct sequencing on these 17 cases revealed a total of 20 mutations. The frequency of p53 mutations was different by site of tumors: 7 of 13 in head, all 4 in extremities, 2 of 4 in heart and none of 4 in trunk. Our findings suggest that occurrence of p53 mutation is a major pathway for development of human AS.

Expression and mutations of p53 in salivary gland tumours

A series of 219 salivary gland tumours (103 carcinomas and 116 benign tumours) were analysed for p53 protein expression using immunohistochemistry, and for mutations in p53 gene using non-radioactive single strand conformation polymorphism (SSCP). p53 expression was present in 36% (42/116) of the benign tumours and in 54% (56/103) of the carcinomas. The highest prevalence of p53 expression was found in adenoid cystic carcinomas (69%), followed by mucoepidermoid carcinomas (67%). Of the benign tumours, pleomorphic adenomas showed the highest prevalence of p53 positivity (41%). In malignant tumours, expression of p53 bore no correlation to local recurrence, metastatic disease or survival of the patients. Exons 5 through 9 were analysed and four mutations were found in 20 cases of p53-immunopositive tumours and two in 20 p53-negative tumours. Each of the exons 5, 6 and 8/9 had two mutations, whereas no mutations were detected in exon 7.

Biphenotypic blast crisis of chronic myelogenous leukemia: abnormalities of p53 and retinoblastoma genes

The molecular mechanisms responsible for progression of chronic myelogenous leukemia (CML) to blast crisis have not been well defined. Blast crisis may be partially related to inactivation of tumor suppressor genes/such as p53 or retinoblastoma (Rb) gene. There is evidence for an association of blast cell phenotypes in CML with alterations of these genes: a strong association of myeloid phenotypes with abnormalities of the p53 gene and a weaker association of lymphoid phenotypes with abnormalities of the Rb system. We found a marked decrease in Rb gene product and rearrangements of the p53 gene simultaneously in two cases of biphenotypic blast crisis of CML (myeloid and B-lymphoid). These results support the association of blast cell phenotypes with alterations in tumor suppressor genes in CML blast crisis.

The 17p-syndrome: a distinct myelodysplastic syndrome entity?

The 17p- syndrome is a subset of myelodysplastic syndrome characterized by "typical" dysgranulopoïesis, combining a pseudo-Pelger-Hüet and a deletion of the short arm of chromosome 17. We describe two patients; one with de novo myelodysplastic syndrome (RAEB), one with secondary MDS (RAEB-T). Both showed a 17p- deletion resulting from tanslocations involving 17p associated with an additional complex cytogenetics, and both of them had a particular type of dysgranulopoiesis, combining pseudo-Pelger-Hüet anomaly.

p53: functions, mutations and sarcomas

The p53 gene is the most commonly altered gene in a multitude of human cancers. The alterations can be acquired somatically or transmitted through the germ-line. Bone and soft tissue sarcomas are frequently found to have acquired abnormalities in the p53 and mdm-2 genes. In soft tissue sarcoma, the amplification of the mdm-2 gene and the binding of its oncogene product to wild-type p53 protein functionally inactivates normal p53-regulated growth. Inherited mutations of the p53 gene are associated with the rare Li-Fraumeni familial cancer syndrome. Various tumor types arise in these families, with sarcomas of the bone and soft tissues and carcinoma of the breast being the most frequently observed. Transgenic mice with highly expressed mutated p53 have a higher incidence of tumors, including predominantly osteosarcomas and soft tissue sarcomas. In close similarity with the Li-Fraumeni syndrome, homozygously p53-null mice (transgenic mice carrying two non-functional p53 allele) are developmentally normal however they are susceptible to spontaneous tumor formation. This article reviews briefly the structure, function, and dysfunction of the p53 tumor-suppressor gene with particular focus on its role in the development of bone and soft tissue sarcoma.

Blastic transformation of p53-deficient bone marrow cells by p210bcr/abl tyrosine kinase

Blastic transformation of chronic myelogenous leukemia (CML) is characterized by the presence of nonrandom, secondary genetic abnormalities in the majority of Philadelphia1 clones, and loss of p53 tumor suppressor gene function is a consistent finding in 25-30% of CML blast crisis patients. To test whether the functional loss of p53 plays a direct role in the transition of chronic phase to blast crisis, bone marrow cells from p53+/+ or p53-/- mice were infected with a retrovirus carrying either the wild-type BCR/ABL or the inactive kinase-deficient mutant, and were assessed for colony-forming ability. Infection of p53-/- marrow cells with wild-type BCR/ABL, but not with the kinase-deficient mutant, enhanced formation of hematopoietic colonies and induced growth factor independence at high frequency, as compared with p53+/+ marrow cells. These effects were suppressed when p53-/- marrow cells were coinfected with BCR/ ABL and wild-type p53. p53-deficient BCR/ABL-infected marrow cells had a proliferative advantage, as reflected by an increase in the fraction of S+G2 phase cells and a decrease in the number of apoptotic cells. Immunophenotyping and morphological analysis revealed that BCR/ABL-positive p53-/- cells were much less differentiated than their BCR/ABL-positive p53+/+ counterparts. Injection of immunodeficient mice with BCR/ABL-positive p53-/- cells produced a transplantable, highly aggressive, poorly differentiated acute myelogenous leukemia. In marked contrast, the disease process in mice injected with BCR/ABL-positive p53+/+ marrow cells was characterized by cell infiltrates with a more differentiated phenotype and was significantly retarded, as indicated by a much longer survival of leukemic mice. Together, these findings directly demonstrate that loss of p53 function plays an important role in blast transformation in CML.

Immunohistochemical analysis of nm23-H1 in stage I non-small cell lung cancer: a useful marker in prediction of metastases

BACKGROUND

About 30% to 40% of patients with pathologic stage I non-small cell lung cancer die within 5 years after complete resection. The identification of subgroups with high risk of recurrence is important. The level of nm23-H1/nucleoside diphosphate kinase expression has been reported to correlate inversely with the metastatic potential of some tumors.

METHODS

We examined immunohistochemically the expression of nm23-H1 in 32 stage I non-small cell lung cancers to determine its value in predicting the outcome of the operation.

RESULTS

Twelve (37.5%) recurrences and ten deaths occurred in this series. There were eight (25%) distant and four (12.5%) locoregional recurrences. Of the 32 pathologic stage I non-small cell lung cancers, 10 (31.3%) were positive for nm23-H1 gene product. None of the patients with a higher nm23-H1 protein level had detectable distant metastases at the end of this study (chi 2 test, p < 0.05). The median follow-up time to date is only 35 months (range, 18 to 83 months), and so far no significant difference in overall survival rate has been observed between the groups with high and low nm23-H1 protein levels.

CONCLUSIONS

The level of nm23-H1 protein is more useful than the T status or histologic type for the prediction of distant metastases, whereby cases may be selected for postoperative adjuvant chemotherapy.

Immunostaining of p53 protein in ovarian carcinoma: correlation with histopathological data and clinical outcome

OBJECTIVE

The objective of this study was to analyze the incidence of immunohistochemically detectable p53 protein accumulation in epithelial ovarian carcinomas and to correlate these data with the clinical outcome so as to clarify further the role of p53 mutations in prognosis with these patients.

METHODS

Tumor tissues from 179 patients with epithelial ovarian carcinoma were used for immuno-histochemical analysis with monoclonal antibody DO1 and BP 53-12-1 on formalin-fixed, paraffin-embedded tissue.

RESULTS

A total of 78 cases (44%) showed positive nuclear p53 staining. The p53-positive cases were found in all histological types of epithelial ovarian tumors. p53 staining was found in tumors of all stages with a higher percentage of positive cases in stage IV ovarian carcinomas (not significant). Poorly differentiated carcinomas showed a significantly higher percentage of p53 protein expression than did highly differentiated tumors (P = 0.0002). Clinical follow-up of up to 14 years (median 25 months) showed a slightly but not significantly shortened disease-free and overall survival time for patients with p53-positive epithelial ovarian carcinomas.

CONCLUSIONS

We conclude from our data that p53 expression in ovarian carcinoma is associated with poor differentiation but not with the disease being in an advanced stage. There was a tendency for shortened disease-free and overall survival for patients with p53-positive tumors.

Expression of bcl-2 and p53 in Merkel cell carcinoma. An immunohistochemical study

Bcl-2 is a protooncogene thought to play a role in oncogenesis by inhibiting programmed cell death. It may interact with p53, a tumor-suppressor gene which induces apoptosis in certain circumstances. We have studied these gene products by immunohistochemistry in 15 cases of Merkel cell carcinoma, a tumor characterised by prominent apoptosis. Five cases showed moderate/strong staining for p53, with moderate/strong bcl-2 staining in 10 patients. In seven cases abundance of p53 and bcl-2 expression was mutually exclusive. Two patients died within 1 year of diagnosis and six had nodal recurrences. Gene expression and survival appear unrelated. The role of Bcl-2 and p53 in tumorigenesis is complicated and may be inter-related with other genes known to be involved in programmed cell death.

Lack of p53 immunoreactivity in pancreatic endocrine tumors

Abnormal expression of the p53 tumor suppressor gene has been implicated in many human epithelial tumors. However recent evidence has revealed the absence of p53 gene abnormalities or overexpression in some human endocrine cancers. This study examines the immunohistological expression of the p53 gene product using the monoclonal antibody DO-7, an antibody directed against both wild and mutant forms of p53 protein, and a streptavidin-biotin-peroxidase method, in pancreatic endocrine tumors (n = 16). None of the cases of pancreatic endocrine tumors showed evidence of p53 immunostaining. This finding is in contrast to that in pancreatic adenocarcinomas in which increased p53 immunoreactivity has been previously observed. These observations suggest that the p53 gene may not be important in the development of endocrine tumors of the pancreas.

P53 tumour suppressor gene expression in hyperparathyroidism

BACKGROUND

Mutations of the p53 tumour suppressor gene lead to the loss of control of normal cellular proliferation and differentiation and have been shown to be associated with the development of malignancy.

METHOD

Archival paraffin resection specimens from 86 cases of hyperparathyroidism treated surgically using the rabbit polyclonal CMI antibody were investigated to detect p53 immunoreactivity in these sections.

RESULTS

Eighteen of the 86 sections examined (21%) showed nuclear immunoreactivity. No correlation was detected between tumour histology and p53 immunoreactivity (P = 0.45), nor was there any correlation between tumour clonality and immunoreactivity (P = 0.54). Multiple endocrine neoplasia type 1 (MEN 1) status did not correlate with p53 immunoreactivity. A significant correlation between p53 immunoreactivity and preparathyroidectomy calcium levels of > 1.5 mmol/L was detected (P < 0.005) although no correlation was noted between p53 immunoreactivity and higher levels of preparathyroidectomy intact parathyroid hormone (PTH) levels.

CONCLUSION

A relationship is postulated between abnormal serum calcium regulation and p53 mutation in hypercalcaemic states associated with hyperparathyroidism.

Spindle cell hepatocellular carcinoma. A clinicopathologic and immunohistochemical analysis of 15 cases

BACKGROUND

Spindle cell hepatocellular carcinoma (SpHCC) has rarely been reported, and its clinicopathologic characteristics, histogenesis, and prognosis after hepatic resection have yet to be clarified.

METHODS

Fifteen cases of SpHCC, including 13 surgically resected patients and 2 autopsy cases, were studied clinicopathologically and immunohistochemically.

RESULTS

In 13 resected patients, all except 1 were male and the serum alpha-fetoprotein (AFP) was positive in 6 (46%). Portal venous invasion and intrahepatic metastases were frequent. In an immunohistochemical analysis of 13 SpHCC tumors, cytokeratin CAM 5.2 and AFP were positive in 8 (62%) tumors and 3 (23%) tumors in both ordinary HCC and spindle cell components, respectively. The spindle cell components, but not ordinary HCC components, revealed a positive reaction for vimentin in 8 (62%) tumors, S-100 protein and HAM-56 in 3 (23%) tumors, HHF-35 in 2 (15%) tumors, and alpha-smooth muscle actin, desmin, and KP-1 in 1 (8%) tumor, respectively. p53 overexpression was found in two SpHCC tumors. The survival curve after hepatic resection in the 13 patients with SpHCC was significantly worse than that of the 371 patients with Stage II-IV ordinary HCC (P < 0.001).

CONCLUSIONS

These results suggest that SpHCC represents a sarcomatous transformation of HCC. The spindle cell components revealed an immunohistochemical expression of several markers of mesenchymal cells. In addition, poor survival after hepatic resection was documented.

p53 immunohistochemistry of odontogenic keratocysts in relation to recurrence, basal-cell budding and basal-cell naevus syndrome

Mutation of the p53 tumour suppressor gene can produce a more stable protein that does not inhibit mitosis, accumulates in the nucleus and can then be detected immunohistochemically in many human tumours using antibody CM-1. The protein has also been detected in odontogenic keratocysts. Routinely processed material from 30 odontogenic keratocysts was immunostained with antibody CM-1. Ten were recurrences and five were associated with the basal-cell naevus syndrome (Gorlin-Goltz syndrome). p53 protein was found in 50% (15/30) of the odontogenic keratocysts, in 53.3% (8/15) of non-recurrent cysts, in 40% (4/10) of recurrent cysts and in 60% (3/5) of those associated with the basal-cell naevus syndrome. Staining was weak and speckled and limited to occasional basal and suprabasal cells. There was no statistically significant difference in staining between these groups and no correlation between expression and the presence of satellite cysts, basal-cell budding or islands of odontogenic epithelium. The low levels of expression may represent physiological expression of wild-type p53 protein rather than mutant or complexed p53 protein.

p53 in cutaneous melanoma: immunoreactivity and correlation with prognosis

p53 protein immunoreactivity was investigated in cutaneous Spitz naevi (n = 7), superficial spreading (n = 21) and nodular (n = 6) melanomas using the monoclonal antibody DO-7. Nuclear immunostaining for p53 protein was observed in 41% of all the melanomas but not in any of the Spitz naevi studied. This difference in p53 immunoreactivity appeared statistically significant (P = 0.0001; chi 2 test). There were also differences in p53 immunoreactivity between superficial spreading and nodular melanomas (P = 0.001, chi 2 test), where up to 38% of superficial spreading melanomas and 50% of nodular melanomas had demonstrated p53 nuclear immunostaining. An apparently significant correlation was observed between melanomas with poor prognostic histological indices and p53 immunoreactivity (P = 0.0016; chi 2 test). In conclusion, increased p53 protein immunoreactivity is found in melanomas and is associated with poorer prognosis. The differences in p53 immunohistological expression between cutaneous melanomas and Spitz naevi suggest that alterations of the protein may be important in the pathogenesis of the tumour.

The prognostic significance of accumulation of p53 protein in stage III non-small cell lung cancer treated by radiotherapy

In the present study the prognostic significance of accumulation of nuclear p53 protein on survival and freedom from local progression was investigated. Formalin-fixed, paraffin-embedded sections obtained by bronchoscopy or mediastinoscopy were used to examine the expression of nuclear p53 protein using immunohistochemistry. In 37 cases (57%), overexpression of the p53 protein was detected. No relation was found between p53 expression and other pretreatment variables. Response to radiotherapy was found in 11 p53-negative cases (65%) versus 10 p53-positive cases (42%). Freedom from local progression was significantly better in the p53-negative cases as compared with the p53-positive cases. The p53-negative cases who responded to radiotherapy showed an excellent freedom from local progression rate after 2 years of 100%, whereas all p53-positive cases without response to radiotherapy showed local progression within 24 months. Overall survival between p53-negative and -positive cases did not differ, however the disease-specific survival was found to be worse in the p53-positive cases as compared to the negative cases (median survival 8.4 vs. 14.4 months (P < 0.05)). No correlation was found between p53 expression and the frequency of distant metastases. In conclusion, the results of this study suggest that p53 protein expression may be of prognostic value on freedom from local progression in non-small cell lung carcinoma.

Intracranial germ cell tumors: detection of p53 gene mutations by single-strand conformation polymorphism analysis

Using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis, p53 gene mutation was examined in 12 intracranial germ cell tumors (5 yolk sac carcinomas and 7 germinomas), many of which were derived from young patients in the first to the second decade. A total of 10 mutations were detected in 4 of the 12 cases and, in 3 of them, the mutations were multiple or tandem. Among the 10 mutations, 7 were missense, 1 was splicing and 2 were silent. The 7 missense mutations were located at previously proposed hot spot codons or in their vicinity or, when outside the hot spots, at a codon encoding an amino acid conserved in most vertebrates. These findings suggested that all 7 missense mutations may actually give rise to functional alteration of the p53 protein. The splicing mutation was considered to be a germ-line mutation, though its biological effect was equivocal, since the neoplastic tissue contained an additional mutation. The pattern of the mutations was predominancy of G:C-A:T transition with frequent involvement of the CpG site. These mutations were more frequently detected in yolk sac carcinomas (60%; 3/5 cases) than in germinomas (14%; 1/7 cases), suggesting that the contribution of the p53 mutation to carcinogenesis differed with the histological type of the intracranial germ cell tumor.

Cloning and characterization of two processed p53 pseudogenes from the rat genome

We have cloned, by the polymerase chain reaction (PCR), two rat genomic fragments of 1.3 and 1.2 kb, both of which hybridize to a human p53 cDNA probe. Nucleotide sequencing revealed that they are two intronless rat p53 pseudogenes (designated as psi R53-1 and psi R53-2, respectively), representing a start-to-stop-codon-length copy of the processed transcript of the rat p53 gene. Further PCR analysis of DNA from rat organs (skin, kidney, etc.) of two different strains demonstrated that psi R53-1 and psi R53-2 were formed in the germ-line. As psi R53-1 and psi R53-2 share 85 and 83% homology with the rat p53 cDNA, it is thus estimated that psi R53-1 was created approx. 10 million years (Myr) ago and psi R53-2 arose 12 Myr ago. Moreover, GenBank scanning indicated that a 95-bp insert in psi R53-1, as compared with the cDNA, was 90% homologous with a sequence of mouse alternatively spliced p53 mRNA, where the spliced p53 mRNA contains an additional 96 nt derived from intron 10. Although the rat alternatively spliced p53 mRNA has so far not been described, our data suggest that these two processed pseudogenes may have been generated by integration of different mRNA intermediates into germ-line DNA.

p53 protein immunoreactivity in cancers of the gallbladder, extrahepatic bile ducts and ampulla of Vater

Immunohistochemical expression of the p53 protein was investigated in carcinoma of the gallbladder (n = 13), common bile duct (n = 7) and ampulla of Vater (n = 9) using the polyclonal, CM1, and monoclonal, DO7, antibodies (Novocastra). This was compared with cases of chronic cholecystitis (n = 11) and preneoplastic lesions of the gallbladder (n = 4) and ampulla (n = 3). Nuclear immunostaining for p53 protein was found only in the poorly differentiated adenocarcinomas of the gallbladder (n = 9) and were associated with a shorter patient survival period (median: 18.6 mths). The moderately differentiated adenocarcinomas (n = 4) did not show p53 immunostaining and were associated with a longer median survival period (26 mths). The gallbladder dysplasias and adenoma also had no p53 protein immunoreactivity. The common bile duct carcinomas did not stain for p53. Focal p53 immunoreactivity was present in only one (11%) of the cases of ampullary carcinoma and in one (9%) of chronic cholecystitis. In summary, increased p53 immunostaining was associated with reduced patient survival and found more frequently in poorly differentiated adenocarcinoma of the gallbladder but not in the better differentiated carcinoma, chronic cholecystitis or preneoplastic lesions of the gallbladder. The differences in p53 immunohistological expression between gallbladder, common bile duct and ampullary carcinomas justify further investigation into the molecular mechanisms responsible for their development.

Differential in situ hybridization for determination of mutational specific expression of the p53 gene in human hepatoma cell lines

The codon 249 mutation specific expression of the p53 gene was determined in 7 human hepatocellular carcinoma (HCC) cell lines. Two 20-base oligomers complementary to bases 872-891 of human p53 cDNA with a single nucleotide difference in the third position of codon 249 were end-labelled with biotin-conjugated dATP using terminal deoxynucleotidyltransferase (TdT). The hybridized oligomer was visually detected in situ using streptavidin-alkaline phosphatase (AP) conjugate and AP substrate. Expression of the codon 249 mutant p53 was steady in PLC/PRF/5 and Mahlavu cells (derived from African patients), while Huh4, Huh6, Huh7 and HCC-M cells (derived from Japanese patients) expressed only the codon 249 wild-type p53. The transcripts of the p53 gene were undetectable in Hep3B cells (derived from an American patient). Hybridizations of the codon 249 specific oligomers were specific to the p53 transcripts, since the cells that expressed p53 gene homogeneously were stained in the cytoplasm only by differential hybridization with a codon 249 specific oligomer; moreover, hybridization with a labelled oligomer non-complementary to the p53 cDNA showed nuclear stainings. Thus, detection of the codon 249 mutant p53 mRNA by differential in situ hybridization is a specific method for studying the mutation-specific expression of the p53 gene in liver cancers at the cellular level, while simultaneously visualizing the cell morphology. The results also support the notion that the p53 gene codon 249 mutation may have etiological implications involving HCC from various geographic areas.

Immunohistochemical expression of the mutant p53 protein and nuclear DNA content during the transition from benign to malignant breast disease

Immunohistochemical expression of the cellular phosphoprotein p53 was investigated in archival, formalin-fixed, and paraffin-embedded surgical breast tissue specimens from 543 patients using the polyclonal antibody CM-1. Cytometric DNA assessments were performed on histopathologically or cytopathologically identified cell nuclei using image analysis. The series included five samples of normal resting breast parenchyma, 35 benign lesions including benign tumors, 54 hyperplastic lesions with and without atypia, 109 carcinomas in situ, and 340 invasive adenocarcinomas. In 56 of the latter cases specimens from corresponding lymph node metastases also were investigated. Mutant p53 protein expression was absent in normal resting parenchyma and in benign lesions, including benign tumors and epithelial hyperplasias. However, 14 of the 54 hyperplasias (26%) were found to be of DNA aneuploid type. Thirteen of 109 (12%) carcinomas in situ and 79 of 340 (23%) invasive neoplasms expressed the mutant p53 protein. Eight of nine (89%) p53 immunoreactive carcinomas in situ and 62 of 78 (80%) invasive carcinomas with p53 expression were DNA aneuploid. In invasive carcinomas p53 expression was absent in well differentiate neoplasms. In contrast, 58 of 158 (37%) poorly differentiated invasive carcinomas immuoreacted. Intraductal carcinomas of comedo type and poorly differentiated invasive carcinomas of comedo type expressed the mutant p53 protein in seven of 18 cases (39%) and in 14 of 22 cases (64%), respectively. The staining behavior of lymph node metastases was the same as that of the corresponding primary tumors. The present findings suggest that chromosomal alterations as indicated by DNA aneuploidy occur in precancerous lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

p53 immunohistochemical positivity as a prognostic marker in intracranial tumours

The frequency and scale of positive p53 immunohistochemistry in 107 intracranial tumours of different types was studied as a possible prognostic marker using a polyclonal antibody CM-1 which detects both the wild-type and mutated p53 proteins. Fifty of the tumours (46.7%) showed nuclear p53 positivity with different percentages of positive nuclei. The positivity was concentrated in glial tumours of which 52.8% were positive. Forty-two of seventy-four astrocytomas (56.8%), 4 of 12 oligodendrogliomas (33.3%), and 1 of 3 ependymomas (33.3%) showed p53-positive nuclei. Cytoplasmic positivity, found in 25 astrocytomas, was always associated with nuclear positivity. Some p53-positive nuclei were seen in 16.7% of the non-gliomatous tumours, but in all cases p53 positivity was seen in less than 1% of the nuclei. The patients with astrocytomas containing more than 5% p53-positive nuclei were younger (mean 27.3 years) (p = 0.016) and their tumours larger in diameter (mean 4.4 cm) (p = 0.05) than those with p53-negative astrocytomas (mean 41.0 years and mean 3.3 cm, respectively). In p53-positive (> or = 1% of nuclei) grade IV astrocytomas, survival time was significantly shorter (mean 7.2 months) than in p53-negative grade IV astrocytomas (mean 15.5 months (p = 0.024). The results indicate frequent p53 expression in intracranial tumours, especially in gliomas. The association of p53 positivity with young age, larger tumour size, and poor prognosis in high-grade astrocytomas suggests that p53 may be involved in the development of more aggressive types of intracranial tumours. According to these results, p53 immunohistochemical positivity may serve as a prognostic marker in high-grade astrocytomas.

Immunohistochemical detection of p53 protein in human prostatic cancer

Tissue sections from 73 radical-prostatectomy specimens were studied immunohistochemically for the presence of p53 protein. In seven specimens numerous tumor cells showed a strong nuclear immunostaining. An additional 27 revealed a more discrete and focal accumulation of p53 protein. Comparison of the pathologic characteristics of the p53-negative and -positive groups showed that the presence of p53 protein closely correlated with more advanced tumor stages (p < 0.00001), with higher primary (p = 0.0004), combined (p < 0.0001) and worst (p < 0.0001) Gleason grades, and with larger total (p = 0.0001) and high-grade (p < 0.0001) tumor volumes. No staining was found in areas of benign hyperplasia or in well-differentiated tumor zones. Our results suggest that the accumulation of p53 protein to immunohistochemically detectable concentrations is not a feature of low-grade cancer. This finding implies that abnormal p53 accumulation might be involved in the process of prostatic cancer progression.

Evidence for a second tumor suppressor gene on 17p linked to high S-phase index in primary human breast carcinomas

The short area of chromosome 17 is a frequent target for deletions in human tumors, including breast cancer. We have investigated by restriction fragment polymorphism analysis the pattern of loss of heterozygosity (LOH) at four loci on 17p13.1-17pter in a panel of 110 primary human breast carcinomas. A copy of the p53 gene was lost in 23% of the informative cases. Point mutations in the p53 gene were statistically associated with LOH at the same locus (p = 0.003) but not at other loci on 17p13.3-17pter. A second region bordered by the loci D17S5/D17S28 (17p13.3) and D17S34 (17pter) is also affected by LOH, independent of point mutations in the p53 gene. We propose the presence of a second tumor suppressor gene within this region. In support of this hypothesis is the significant association (p = 0.005) between LOH at the D17S5/D17S28, but not at the TP53 or D17S34 loci, and tumors having a high S-phase index.

Frequent mutations of p53 gene in oesophageal squamous cell carcinomas with and without human papillomavirus (HPV) involvement suggest the dominant role of environmental carcinogens in oesophageal carcinogenesis

Epidemiological evidence suggests that alcohol intake, use of tobacco, ingestion of mycotoxins and nitrosamines and nutritional deficiencies are high-risk factors for the development of oesophageal cancer. Similarly, viral infections have been postulated to play a role in some tumours. However, the molecular events underlying the development of oesophageal carcinoma are poorly understood as yet. Loss of p53 tumour-suppressor gene function has been found in different human malignancies, and it can occur in a variety of ways, including gene mutation and interaction with the E6 protein of oncogenic human papillomaviruses (HPVs). Because the oesophageal mucosa is potentially exposed to mutagens and HPVs, we studied DNA samples derived from nine HPV-positive squamous cell carcinomas and 12 HPV-negative tumours. Exons 5-9 of the p53 gene containing phylogenetically conserved domains were examined using the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique. HPV detection was done using DNA in situ hybridisation with biotin-labelled HPV DNA probes. Mutations were detected in eight (38%) out of the 21 cases. Three mutations were found in exons 5/6, three in exon 7 and two in exon 8/9. Six (50%) of the 12 HPV-negative carcinomas showed p53 mutations. Two (22.2%) of the nine HPV-positive carcinomas were found to contain p53 mutations as well; one contained HPV 16 DNA sequences and showed p53 mutation in exon 8/9, and the other was HPV 6/11 positive with the mutation in exon 5/6. Although mutations were more common in HPV-negative tumours (50.0% vs 22.2%), the difference in p53 mutations in HPV-positive and -negative tumours did not reach statistical significance (P = 0.1946). These data indicate that inactivation of the p53 gene is a frequent event in oesophageal squamous cell carcinomas and such an inactivation might be an important molecular pathway for the development of oesophageal cancer. The findings of p53 mutations in HPV-positive oesophageal carcinomas suggest that HPV and p53 mutation were not mutually exclusive events. The presence of frequent mutations of p53 gene in both HPV-positive and -negative oesophageal carcinomas suggests a dominant role of environmental carcinogens in oesophageal carcinogenesis.

Immunohistochemical Detection of p53 and c-erbB-2 Proteins: Prognostic Significance in Operable Breast Cancer

We examined the associations of p53 expression and/or c-erbB-2 expression with Ag-NOR counts and clinicopathologic variables in 111 breast cancer patients, and assessed whether expression of either p53or c-erbB-2 would be useful prognostic indicators. There was no significant association between p53 expression and c-erbB-2 expression, but p53 expression and c-erbB-2 expression, especially in combination, were shown to be significantly associated with Ag-NOR counts and axillary lymph node metastasis. Although p53 expression and c-erbB-2 expression were significant prognostic factors by univariate analysis, they did not appear to be independent prognostic factors by multivariate analysis, in which nodal status was introduced using the Cox model. When nodal status was excluded from the model, however, concurrent p53 and c-erbB-2 expression did have a significant prognostic value. Therefore, it was suggested that concurrent p53 and c-erbB-2 expression provides valuable prognostic information for breast cancer patients in whom axillary lymph node dissection has not been performed.

mRNA and protein expression of p53 mutations in human bladder cancer cell lines

We investigated mRNA and protein expression in p53 gene mutations in four human bladder cancer cell lines using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and Northern blot and Western blot analyses. The following mutations were identified in three of the four cell lines: a missense transversion at codon 110, a missense transition at codon 250 and a non-sense transversion at codon 126. These mutations were located outside previously identified hot spot codons and have rarely been reported in bladder cancer tissues or other neoplasms. Positive intranuclear p53 immunostaining in neoplastic cells in the two missense mutations and the premature stop codon in the non-sense mutation suggested the presence of structural and functional alterations in the p53 protein. Northern and Western blot analyses revealed either an intense or a weak p53 mRNA band together with an intense p53 protein band in the missense mutations, but no p53 mRNA or protein band in the non-sense mutation. A weak p53 mRNA band, but no distinct p53 protein band was observed in the cell line without a mutation and in normal control bladder cells. Our findings suggest that regulation of p53 expression in these cell lines differs at the post-transcriptional and/or post-translational level between the wildtype and the mutant p53 genes and also among different mutant p53 genes. The three cell lines with mutations were derived from high-grade carcinomas; the cell line without mutation was derived from a low-grade carcinoma.

Frequency and distribution of numerical chromosomal aberrations in prostatic cancer

Prostatic cancer frequently shows striking morphological heterogeneity and multifocal growth. To better understand the relationship between chromosomal changes and pathological characteristics, 31 routinely processed radical prostatectomy specimens were studied for the presence of numerical chromosomal aberrations by in situ hybridization with centromeric nucleic acid probes specific for chromosomes 7, 10, 17, X, and Y. In 24 of the cases preoperative core biopsy specimens were available and were examined with the probe for the X chromosome. In eight of the prostatectomy specimens chromosome numbers consistent with a normal male karyotype were found. Three cases, besides diploid chromosome numbers, showed a focal doubling of hybridization signals, consistent with tetraploidy. The other 20 cases displayed numerical chromosomal aberrations to a various degree. In this group the appearance of numerical chromosomal aberrations often showed considerable local heterogeneity, generally coinciding with morphological dedifferentiation, and was significantly correlated with tumor stage (P = .0004) as well as primary (P = .0068), worst (P = .0002), and combined (P < .0001) Gleason grades, total tumor volume (P = .0448), and the volume of tumor with Gleason grades 4 or 5 (P < .0001). In four of the 24 core biopsy specimens no residual tumor tissue was left for cytogenetic examination. In the remaining 20 biopsy specimens the presence or absence of numerical changes matched the result obtained on the corresponding prostatectomy specimen. We conclude that in prostatic cancer the presence of numerical chromosomal aberrations is associated with advanced disease. Especially in low differentiated tumors local heterogeneity in 2 chromosome numbers can be very marked. It is possible to forecast the presence or absence of numerical chromosomal changes on preoperative core biopsy specimens.

p53 alteration correlates with negative ER, negative PgR, and high histologic grade in breast cancer

Seventy tumors of invasive ductal carcinoma of the breast were examined for p53 alteration by the RT-PCR-SSCP method. Sixty-five samples (92.9%) were investigated in the regions of codons 101-200 and 201-300. In total, 16 samples (24.6%) showed p53 gene alteration. We found that p53 gene alteration showed a correlation with (1) a negative ER status, (2) a negative PgR status, and (3) a high histologic grade (especially numerous mitotic figures) of the tumor. However, we found no correlation between p53 gene alteration and the lymph node status or clinical stage. Thus, p53 gene alteration in breast cancer may occur in highly malignant breast cancer other than advanced clinical stage cancer or node-positive cancer.

Three synchronous carcinomas of the papilla of Vater, common bile duct and pancreas

Multiple carcinomas of the pancreatico-biliary tree are rare. A 53 year old Japanese man was diagnosed as having an adenocarcinoma in the papilla of Vater. During the operation, he was also found to have a polypoid mass in the common bile duct. While cutting the operative specimen into stepwise sections, a small tumor was also detected incidentally in the main pancreatic duct of the pancreatic head. Histologically, all three tumors proved to be papillary adenocarcinomas and were restricted to the mucosa. Immunohistochemically, all three tumors were positive for carcinoembryonic antigen, carbohydrate antigen 19-9, chromogranin A and serotonin, while they were negative for somatostatin. Immunoreactivity to the tumor suppressor gene p53 protein (PAb 1801) was found in all three tumors. A flow cytometric analysis of the cellular DNA content revealed all three tumors to be aneuploid. The above results suggested that these three tumors from different sites all had the same histological, immunohistochemical and flow cytometrical characteristics.

Introduction of wild-type p53 in a human ovarian cancer cell line not expressing endogenous p53

Utilizing a temperature sensitive p53 mutant (pLTRp53cGval135) which expresses mutant p53 at 37 degrees C and a wild-type like p53 at 32 degrees C, we transfected a human ovarian cancer cell line (SKOV3) which does not express endogenous p53. Among the different clones obtained, we selected three clones. Two were obtained from simultaneous transfection of p53 and neomycin resistance expression plasmids (SK23a and SK9), the other was obtained from transfection experiments utilizing the neomycin resistance gene only (SKN). Introduction of mutant p53 did not alter the morphology or growth characteristics of this ovarian cancer cell line. Upon shifting to the permissive temperature, a dramatic change in morphology and growth rate was observed in SK23a and SK9 cells that is associated with the presence of a wild-type like p53. SKN and SKOV3 cells maintained at 32 degrees C did not change morphology and only slightly reduced proliferation. Both SK23a and SK9 cells did not show evidence of apoptosis when measured up to 72 hours of maintenance at 32 degrees C. In contrast to what observed in other cell lines, SK23a and SK9 cells maintained at 32 degrees C were not blocked in G1, but they were accumulated in G2-M. This accumulation was transient and could be due either to a blockade or to a delay in the G2 progression. No down-regulation of c-myc was observed in p53 expressing clones when shifted to the permissive temperature. In these conditions gadd45 mRNA expression was highly stimulated in SK9 and SK23a cells but not in SKN cells. In both clones Gas1 mRNA was not detected either at 37 degrees C or 32 degrees C. This system represents a new and useful model for studying the effect of the absence of p53 (SKOV3 or SKN), presence of mutated p53 (SK23a and SK9 kept at 37 degrees C) or wild type p53 (SK23a and SK9 kept at 32 degrees C) on the mechanism of response of cancer cells to DNA damaging agents.

Correlation of p53 protein expression in human urothelial transitional cell cancers with malignant potential and patient survival

The p53 gene product has been detected frequently in various human malignancies. We have studied the expression of p53 protein in urothelial transitional cell cancers (TCCs) and examined its correlation with pathologic grade, stage(pT) and patient survival. Specimens from 69 surgically-resected TCCs (38 cases of urinary bladder cancer, 17 cases of ureteral cancer and 14 cases of renal pelvic cancer) were examined by immunohistochemical staining, using two anti-p53 monoclonal antibodies, PAb1801 and PAb240, and a polyclonal antibody, CM-1. Twenty-six TCCs (37.6%) were positively stained by at least one of the three antibodies. Statistical analysis showed a significant correlation between p53 expression and high pathologic grade (p < 0.05, p < 0.001) or progressive pathologic stage (p < 0.01). In addition, in 51 of the patients who were available for follow-up (23 cases of urinary bladder cancer, 13 cases of ureteral cancer, and 15 cases of renal pelvic cancer), the correlation between p53 protein expression and prognosis was examined. The survival of patients exhibiting positive p53 protein expression was significantly worse than those with p53-negative tumors (p < 0.05). These results suggest that an immunohistochemical test for p53 protein may be a useful method of evaluating the malignant potential of TCCs. Additionally, expression of p53 protein in TCCs is an indicator of a poor prognosis which should be considered in drawing up treatment strategies.

Analysis of p53 gene mutations in low- and high-grade astrocytomas by polymerase chain reaction-assisted single-strand conformation polymorphism and immunohistochemistry

Using polymerase chain reaction-assisted single-strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses, mutations in the p53 tumor suppressor gene were examined in 19 low- and high-grade gliomas. By PCR-SSCP and nucleotide analyses, p53 gene mutation was seen in 7 gliomas. Out of the 7 mutations, 3 were located at the CpG site of the previously proposed hot-spot codons 248 and 273, 2 were at codons 171 and 214 and the other 2 were in intron 5, 1 at the splice acceptor site and the other in the vicinity of the splice donor site. The latter 4 mutations have not, or only rarely, been observed in gliomas or in other tumors. However, their effect on the structural and functional alteration of the p53 protein was suggested by positive intranuclear p53 immunostaining in neoplastic cells in 3 mutations including the 1 at the splice acceptor site. In connection with glioma grading, the p53 gene mutation was shown to have occurred in both low- and high-grade gliomas, often in most of the neoplastic cells, as suggested by lack of distinct normal bands and ladders in SSCP and direct sequencing, respectively. The absence of recurrence and malignant transformation over a considerably long postoperative time in our low-grade glioma cases suggested that the p53 gene mutation might not be sufficient for the progression from low- to high-grade gliomas. The frequency of detection of mutation was 7/19(37%) by PCR-SSCP, 8/19(42%) by immunohistochemistry and 10/19(53%) by both methods. The results of PCR-SSCP and immunohistochemistry were consistent in 14 cases (73.7%), but not in 5 cases(26.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

The p53 tumor suppressor gene frequently is altered in gynecologic cancers

Mutation of the p53 tumor suppressor gene, often accompanied by overexpression of mutant p53 protein, is the most frequent molecular genetic event described thus far in human cancers. In adenocarcinomas of the ovary and endometrium, p53 overexpression is seen in approximately 10% to 15% of early and 40% to 50% of advanced cancers. Similar to many other types of human cancers, ovarian and endometrial cancers that overexpress p53 protein contain mutations in conserved regions of the p53 gene. These mutations are predominantly transitions, which suggests that they arise spontaneously rather than being caused by carcinogen exposure. Alteration of the p53 gene does not appear to be a feature of endometrial hyperplasias or benign or borderline ovarian tumors. Although mutation and overexpression of p53 rarely occur in cancers of the cervix, vulva, and vagina, it has been shown that human papillomavirus E6 oncoproteins bind to and inactivate p53 protein. Studies of the p53 gene have begun to provide insight into the molecular pathogenesis of gynecologic cancers.

P53 as a marker of the malignant cell in Hodgkin's disease

BACKGROUND

The p53 gene has a tumor-suppressor function. The mutated gene encodes for a protein which has a longer half-life than the normal p53 protein. This enables the detection of the mutated p53 protein by immunohistochemistry.

MATERIALS AND METHODS

In this study we examined 53 lymph nodes of patients with Hodgkin's disease for the presence of p53. The lymph nodes were stained with DO-1 and CM-1, two antibodies directed against the p53 protein.

RESULTS

DO-1 weakly stained 2/14 samples positively, and CM-1 10/25. When preincubated with Target Unmasking Fluid, CM-1 stained 51/53 samples positively. Although, only Hodgkin and Reed-Sternberg cells stained positively, p53-negative Hodgkin and Reed-Sternberg cells were also seen in the same sample.

CONCLUSION

Based on these results, we conclude that the p53 mutated protein is present in a high number of cases with Hodgkin's disease, which is suggestive for an important event in the pathophysiology of the disease. In addition, because of the absence of positive staining in the surrounding lymphocytes, these cells are unlikely to be part of the malignant clone.

Comparative analysis of p53 and c-myc expression and cell proliferation in human hepatocellular carcinomas--an enhanced immunohistochemical approach

Expression of p53 and c-myc was investigated and compared with cell proliferative activity in a series of 40 hepatocellular carcinomas (HCC), by means of enhanced immunohistochemistry. p53 expression was demonstrated in 5 out of 40 HCC (12.5%) with the incidence increasing in 5 out of 40 HCC (12.5%) with the incidence increasing in proportion to the histological grading of malignancy: thus, 0% of well-differentiated, 6.9% of moderately differentiated and 33.3% of poorly differentiated lesions were positive. The proliferating-cell nuclear antigen (PCNA) labeling index also showed a statistically significant increase with this grading. Distribution patterns of PCNA-positive cell were divided into four types: scatter, marginal, mosaic and diffuse. Four HCC cases, predominantly of the poorly differentiated type, exhibited the diffuse pattern. Generally, p53 overexpression corresponded well with PCNA positivity. In contrast, there was no correlation between c-myc overexpression, found in 19 out of 40 HCC (47.5%), and histological grading of HCC or PCNA labeling index. The distribution pattern of c-myc-positive HCC cells was also different from that of PCNA and p53. Our results suggest that p53 overexpression closely relates to proliferation of HCC cells. Furthermore, there may be a consistent difference in regulatory mechanisms between p53 and c-myc expression in multistep hepatocarcinogenesis.

Undifferentiated spindle cell carcinoma of the gallbladder: a clinicopathologic, immunohistochemical, and flow cytometric study of 11 cases

Eleven primary spindle cell carcinomas (SpCCs) of the gallbladder are reported. They occurred in eight women and three men ranging in age from 59 to 80 years (mean age, 66.5 years). Histologically, the tumors showed interlacing bundles of atypical spindle cells with eosinophilic cytoplasm, oval to elongated nuclei, and conspicuous nucleoli. Eight SpCCs contained tiny foci of neoplastic glands similar to those seen in adenocarcinoma, and two of these cases also had small foci of neoplastic squamous epithelium. A gradual transition between the squamous cell carcinoma and the spindle cell component was observed in one tumor. Immunohistochemically, all SpCCs were positive for at least one of the epithelial markers (epithelial membrane antigen, nine cases; AE1/AE3, nine cases; carcinoembryonic antigen, three cases; and EAB 903, one case), and the tumor cells also were immunoreactive to mesenchymal marker (vimentin, eight cases), muscle markers (alpha-smooth muscle actin, one case; desmin, one case), and histiocytic marker (HAM 56, one case). Abnormalities in tumor suppressor gene p53 expression also were found in two of the 11 SpCC cases using monoclonal antibody PAb 1801. In six cases for which data were available flow cytometry revealed aneuploidy in three SpCCs (50%). The survival curve of the SpCC cases (mean survival, 9 months) was less favorable than that of 224 cases of adenocarcinoma of the gallbladder (mean survival, 81 months) (P = .0011). These results indicate that SpCC of the gallbladder is an epithelial tumor with sarcomatoid components and its prognosis is unfavorable.

Correlation between p53 mutations and antibody staining in breast carcinoma

Abnormalities of the p53 gene and protein were examined in 81 primary breast carcinoma samples. Using a polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis, mutations in p53 exons 5-8 were identified in 13 of 81 tumours (16 per cent) and confirmed by DNA sequencing. Positive staining for p53 protein was detected in ten of 77 (13 per cent) of these tumours using polyclonal CM1 antibody on formalin-fixed tissue. Mutations detected by PCR-SSCP analysis were more common in grade III tumours (P = 0.015), but no correlation was found with tumour size, node status or level of epidermal growth factor receptor expression. A p53 mutation was associated with positive antibody staining in only two patients. Positive immunohistochemical staining using a p53 antibody may detect p53 protein expression, but this may not correlate directly with an underlying mutation in the hot spot region examined.