p53 expression in oral cancer: observations of a South Indian study

Oral cancers constitute a significant proportion of hospital admissions among cancer patients in India. The aim of this study was to elucidate the role of tumour suppressor gene p53 in the pathogenesis of oral squamous cell carcinoma by immunohistochemistry. Though extensive studies on p53 alterations in oral cancers have been done in Western countries and some Asian countries, only a few studies have emerged from India, especially the Southern states. This study would therefore be helpful in providing an Indian perspective, with particular reference to South Indian states. A total of 110 cases of oral squamous cell carcinoma, 35 dysplastic lesions, 15 hyperplastic lesions, and 50 samples of normal mucosa were assessed for p53 expression. Out of 110 cases of oral carcinoma, 40 (36%) were p53 positive. Among 35 cases of dysplastic lesions studied, 6 (17%) showed p53 positive staining. None of the hyperplastic lesions and normal oral lesions showed any evidence of p53 positivity. However, in 9 out of 40 (23%) cases of positive infiltrating squamous cell carcinomas, the adjacent or overlying non-tumourous epithelium demonstrated focal areas of p53 positive staining in the basal and parabasal layers of the epithelium. In addition, in 7 out of 110 (6%) cases, cytoplasmic staining was observed. In these samples, nuclei were not stained. Our results indicate that p53 over-expression may be involved in only a certain proportion of oral carcinomas. The fact that 6% of the dysplastic lesions were p53 positive, and adjacent non-tumourous epithelium of 23% infiltrating squamous cell carcinomas showed positive staining for p53 in the progenitor compartment of the epithelium indicates that p53 immunoreactivity could be used to detect early tumours as well.     

Correlation between morphology and telomerase activity in cells from exfoliative lung cytologic specimens

BACKGROUND: Telomerase is a ribonucleoprotein that compensates for the erosion of telomeres (chromosomal termini). Telomerase activity is detected in more than 85% of cancerous lesions and is therefore considered a novel marker of cancer. The authors compared cytologic morphology and telomerase activity at the cellular level to obtain further insight into their association. METHODS: The authors used bronchial washing and brushing materials obtained from 18 patients with lung carcinomas (6 squamous cell, 8 adenocarcinoma, 2 large cell, 1 small cell, and 1 metastasis from colon carcinoma) and 20 patients with nonmalignant disease. An in situ telomeric repeat amplification protocol (TRAP) assay was performed, and routine Papanicolaou-stained slides using the same sample were assessed. RESULTS: Nuclear fluorescent signals at the nuclear area, corresponding to telomerase activity, shown by the in situ TRAP assay were only detected in samples containing morphologically malignant cells. No nuclear fluorescence was seen in the keratinizing component of well-differentiated squamous cell carcinoma. Nuclear staining was not seen in metaplastic or basal hyperplastic cells. Cytoplasmic fluorescence was only found in macrophages and polymorphonuclear leukocytes. CONCLUSIONS: Nuclear fluorescence corresponding to telomerase activity was not demonstrated in metaplastic or basal hyperplastic cells, thus indicating that detection of telomerase activity is closely associated with the presence of malignant cells, but not premalignant lesions, in lung carcinoma patients. Moreover, in some samples with cancer, cells failed to show telomerase activity, suggesting the limitation of this method for the detection of malignant cells in certain lung carcinoma patients.     

Chemoprotective effect of progesterone on carcinoma formation in mice and rats

The protective effect of progesterone on the development of chemically induced carcinomas (squamous cell carcinomas in mice and basal cell carcinomas in rats) by 3-methylcholanthrene [(MCA) CAS: 56-49-5] was studied. Progesterone administration decreased the average number, size, and weight of carcinomas by 45-50% as compared to those of tumors treated with MCA alone at any time interval. DNA radioactivity and autoradiographic studies with the use of [3H]thymidine showed an inhibition of DNA synthesis in the neoplastic cell nuclei following a concomitant administration of progesterone and MCA (18.4%) as compared to the DNA synthesis following administration of MCA alone (35.0%). Electron microscopic and cytologic observations revealed salient ultrastructural findings following progesterone administration, with advanced cytolysis, tumefied mitochondria, large populations of secondary lysosomes, and autophagic formations; also, cell differentiation tended to be of a glandular-adenomatoid type following progesterone and MCA administration as compared to the characteristic squamous cell and basal cell carcinomas after treatment with MCA alone. In addition, scanning electron microscopic observations revealed advanced cytolytic areas with several disintegrated neoplastic cells and cell debris intermingled with red blood cells, following progesterone and MCA administration. The present findings demonstrate that progesterone in pharmacologic doses exerts important chemoprotective effects on carcinoma formation, possibly by interfering with MCA metabolism and inhibiting DNA synthesis in the epidermal neoplastic cells, and thus plays an important role in tumorigenesis.     

Expression of hyaluronan in normal and dysplastic bronchial epithelium and in squamous cell carcinoma of the lung

A series of 85 lung/bronchial tissue samples from 76 patients consisting of normal, metaplastic and dysplastic epithelium and different types of lung carcinomas were analyzed for the distribution of hyaluronan (HA), using a biotinylated hyaluronan binding complex as an HA-specific probe. The normal pseudo-stratified columnar bronchial epithelium was either negative for HA or displayed a weak staining around the basal cells. The epithelia of serous and mucous bronchial glands were HA negative whereas the submucosal connective tissue was strongly positive. In metaplastic, dysplastic and carcinoma in situ lesions the whole epithelium from basal to uppermost cells expressed HA on plasma membranes. Epithelial HA was also found in squamous cell carcinomas, but not in adenocarcinomas, carcinoid tumors or small cell carcinomas of the lung. Whereas epithelial HA was present in all lesions of the squamous cell type, the staining intensity displayed great local variability in 50% of the cases with severe dysplasia, carcinoma in situ and squamous cell carcinomas. In squamous cell carcinomas, such an irregular staining pattern was significantly associated with poor differentiation. Our results indicate that the expression of HA in different bronchial lesions and lung tumors is restricted to those showing squamous cell differentiation, being absent from other types of lung carcinomas. The increase of HA-depleted areas in poorly differentiated squamous cell carcinomas emphasizes the important role of HA in tumor differentiation. HA on carcinoma cell surface may influence tumor growth and metastatic behavior. Int. J. Cancer (Pred. Oncol.) 79:251–255, 1998.© 1998 Wiley-Liss, Inc.     

Expression of p53 in premalignant and malignant squamous epithelium.

Using three antibodies (JG8, CM-1 and 1081) directed to the p53 protein, strong positivity was found in 16/47 (34.0%) of mucosal squamous cell carcinomas of the head and neck and in two squamous carcinoma cell lines (LICR-LON- HN5 and HN6Rr). The presence of the mutant p53 was confirmed in the cell lines as substitutions in exon 7 (codon 238, TGT greater than AGT) and exon 5 (codon 152, CCG greater than CTG) respectively. Positive staining was seen only in the undifferentiated cells and progressively lost as the cells keratinized, both in the tumour specimens and in the cell lines. Similar results were seen in areas of dysplasia, well removed from the site of the primary tumour. Staining of epidermal lesions showed positivity in 2/12 (16.6%) cases of Bowen's disease, 0/12 (0.0%) cases of solar keratosis, 0/10 (0.0%) basal cell carcinomas and in 3/20 (15.0%) squamous cell carcinomas. These results are discussed in relation to the multifocal origin of squamous cell carcinomas, the role of p53 mutations in squamous cell carcinomas from different sites and the significance of the 'basal' distribution of p53 as a normal growth regulator. The possible significance of the distribution of p53 in squamous epithelium as it relates to papilloma virus infection is also considered.     

p53 Protein Accumulation in Non-Invasive Lesions Surrounding p53 Mutation Positive Invasive Breast Cancers

p53 mutation is a common event in sporadic breast cancer being found in 15–50% of invasive carcinomas. The purpose of this study was to determine the earliest histologic stage at which p53 mutation could be detected with a widely used anti-p53 antibody (DO7, Novocastra) which recognizes both wild type and mutant forms. p53 expression was assessed immunohistochemically in 12 primary breast carcinomas with known p53 mutations and in all pre-malignant epithelial lesions surrounding these invasive cancers. Strong p53 nuclear staining was found in all of the tumors known to have missense mutations and none of the tumors with truncation mutations. In cases with intense staining in the invasive carcinoma, a similar quality of staining was also seen in all areas of DCIS (ductal carcinoma in situ) and was representative of missense p53 mutations. Lighter nuclear staining intensity was observed in up to 40% of cells in areas of hyperplasia and in up to 30% of normal breast lobules irrespective of the type of mutation found in the invasive carcinoma. This weak staining was not specific to mutated p53 and may indicate increased amounts of normal p53 protein.We conclude that p53 inactivation occurs prior to invasion in breast carcinogenesis, with mutations being uniformly identified in DCIS associated with p53-mutated invasive carcinomas. In contrast, there is no evidence that epithelial hyperplasia or epithelial cells of the terminal duct lobular unit harbor the same mutations as their associated invasive carcinoma.     

ACCELERATED PAPER: Immunohistoselective sequencing (IHSS) of P 53 tumor suppressor gene in human oesophageal precancerous lesions

Accumulation of p53 protein occurs in human oesophageal precancerouslesions and even in near-normal oesophageal epithelium. In someinstances, p53 gene mutations have been detected. In many ofthe cases of p53 protein accumulation in early lesions, however,p53 mutations were not detected due to either the lack of mutationor the low abundance of cells with a mutation. In order to enrichp53 immunostain-positive cells for single strand conformationpolymorphism (SSCP) analysis and DNA sequencing, an immunohisto-selectivesequencing (IHSS) method was developed. Anti-p53 antibody-peroxidasestained oesophageal tissue sections were subjected to ultraviolet(UV) irradiation to damage the DNA in p53 immunostain-negativecells. The immunostain protected p53 immunostain-positive cellsfrom the UV light and thus preserved the DNA in those cellsfor PCR amplification. Comparison of the SSCP results from sectionswith and without UV treatment showed that the IHSS method selectivelyenriched p53 immunostain-positive cells. With this method, wecould analyse mutations in samples with as few as 30 p53 immunostain-positivecells per tissue section. Analysis was carried out on tissueswith precancerous lesions from six surgically-resected oesophagealspecimens and 13 oesophageal biopsies from symptom-free subjects.The results of mutation analysis for some of the samples wereconfirmed by microdissection to enrich the p53-positive cells.The mutations in tissues with precancerous lesions were comparedwith those in the corresponding squamous cell carcinomas. TheIHSS method is shown to be a simple and effective way to analysemutations in p53 immunostain-positive cells. IHSS may also bea general method for molecular analysis of biological specimensafter immuno-histochemical staining.     

Inhibition of DNA synthesis and neoplastic cell growth by vitamin A (retinol)

The inhibitory effect of vitamin A alcohol (retinol) on the DNA synthesis and neoplastic cell growth of chemically induced carcinomas (squamous cell carcinomas in Swiss male albino mice and basal cell carcinomas in inbred SD rats) by 3-methylcholanthrene [(MCA) CAS: 56-49-5] was studied. A marked inhibition of squamous cell carcinomas and basal cell carcinomas was observed following a combined administration of MCA and vitamin A (retinol) compared to the finding for animals treated with MCA alone (P less than .001). DNA radioactivity and autoradiographic studies with the use of [3H]thymidine showed a marked inhibition of DNA synthesis (twofold to threefold) in the neoplastic cell nuclei following a concomitant administration of vitamin A (retinol) and MCA (12%) as compared to the DNA synthesis following administration of MCA alone (31%) (P less than .001). Electron microscopic and cytologic observations revealed an advanced cytolysis and disorganization of neoplastic cells with reduction of polysomes, tonofilaments, and lysosome populations and mitochondrial alterations following vitamin A and MCA administration as compared to characteristic squamous neoplastic cells and basal neoplastic cells following MCA treatment alone. In addition, scanning electron microscopy revealed advanced changes of cell surfaces with reduction of microvilli and disorganization of cytoarchitecture. The present findings demonstrate that vitamin A exerts its anticarcinogenic effect by inhibiting DNA synthesis, disrupting cell surfaces, and possibly interfering with MCA metabolism in epidermal cells.     

Infrequent p53 mutations in arsenic-related skin lesions

Oral arsenic exposure increases the risk for a variety of benign and malignant skin lesions, but the molecular mechanism of the carcinogenic effect is poorly understood. Arsenic-related squamous cell carcinomas of the skin can develop either de novo or progress from Bowen's disease lesions. Arsenic-related basal cell carcinomas develop usually in non-sun-exposed areas and are multiple. Because p53 tumor suppressor protein is a protective cellular molecule against environmental carcinogens and mutations in the p53 gene are frequent in nonmelanoma skin cancers, we studied p53 in 23 premalignant or malignant skin lesions from seven patients with a history of arsenic medication. The eighth patient studied (with six lesions) had a long standing exposure to UV radiation. Accumulation of the p53 protein was detected (with a monoclonal DO-7 antibody) in 78% of the lesions from cases with arsenic exposure. Two of the six (30%) arsenic-related premalignant lesions and in addition one UV related carcinoma in situ lesion were clearly and repeatedly positive when p53 exons 5 to 8 were screened by a nonradioactive single-strand conformation polymorphism (SSCP) analysis. Only one of the arsenic-related lesions was confirmed by sequencing to have a mutation (a CC to TT double transition). No indications of mutations were found among the 18 basal cell carcinoma or two squamous cell carcinoma lesions studied. Our results suggest that the frequent accumulation of p53 protein in arsenic-related skin lesions is not due to p53 mutations. which may not be a prerequisite in the development of arsenic-induced skin cancers.     

Use of p63 for distinction of glandular versus squamous lesions in cervicovaginal specimens

BACKGROUND: Differentiating primary glandular from high-grade squamous intraepithelial lesions (HSIL) that involve endocervical glands is not an uncommon diagnostic problem in liquid-based gynecological cytology. Squamous and atypical glandular cell lesions may show similar cytomorphologic features. The aim of this study was to evaluate the use of p63 as a marker of basal and/or squamous cell derivation in this differential diagnosis. METHODS: Of 59,257 liquid-based cervicovaginal specimens collected over a 3-year period, 149 were diagnosed as atypical glandular cells of uncertain significance (AGUS) or adenocarcinoma and had histological follow-up. Ten cases (8AGUS and 2 adenocarcinomas) were proven to be high-grade dysplasia on cervical biopsies and the remaining cases represented glandular pathology. Slides from discrepant cases were stained with p63 antibody. In addition, the authors stained 25 control cases (10 adenocarcinomas, 10 HSIL, and 5 negative cervicovaginal specimens). RESULTS: In all 10 discrepant cases, the abnormal groups originally interpreted as glandular in origin showed a homogeneous strong nuclear staining for p63 that indicated their squamous origin. Nuclei of isolated HSIL cells and basal cells from atrophic smears were also positive for p63. Benign and malignant glandular cells were uniformly negative. Isolated metaplastic, intermediate, and superficial squamous cells were likewise negative for this antibody. CONCLUSIONS: p63 is a useful immunocytochemical marker for differentiating primary glandular pathology from HSIL in cervicovaginal specimens. It also detects isolated HSIL cells ("litigation cells"). This antibody is not expressed in AGUS, adenocarcinoma, or normal glandular cells. p63 stains basal cells and may be a diagnostic pitfall in atrophic cervicovaginal specimens.     

P53 expression during multistage human oral carcinogenesis

This study examined the immunohistochemical expression of p53 in human oral premalignancies and squamous cell carcinomas (SCC), and analyzed the relationship between the expression of p53 and the degree of dysplasia. p53 staining was observed in 15 of the 27 oral premalignant lesions (56%), including mild dysplasia, and 7 of the 10 oral SCC (70%), but in none of the 10 hyperplastic oral lesions. With increasing degrees of dysplasia and the appearance of SCC, not only was there an increase in the percentage of cases demonstrating p53 staining, but also an increase in the staining intensity of the positive cells and expansion of these positive cells. The results suggest that mutation of p53 is an early event during oral cancer development and p53 protein may be used as an early adjunct marker for identification of those premalignant lesions with higher malignant potential.     

建立大鼠周边型肺鳞癌模型的方法和体会

本文用甲基胆蒽(MCA)十二乙基亚硝胺(DEN)的碘化油溶液诱发100只Wistar大鼠周边型肺鳞癌。方法上主要是利用气管插管给药后,再灌以0.2ml空气,将致癌剂送至深部气道。系列活杀动物观察结果表明,致癌剂引起的末梢肺组织病变在经历了上皮的立方化、复层化后,发展为浸润性鳞癌。电镜观察结果示这类鳞癌可能起自Ⅱ型肺泡上皮细胞。文中还就本实验中可能遇到的问题及其解决方法进行了讨论。     

Topographical analysis of p53 expression and DNA ploidy in early bronchial squamous cell carcinoma and preneoplastic lesions.

The significance of p53 mutations and DNA aneuploidy in carcinoma cells has been investigated on the basis of a multi-step development theory of carcinogenesis. It has, however, not been determined whether these alterations can be used as diagnostic markers for the early detection of bronchial squamous cell carcinoma (BSqCC). To address this problem, we topographically investigated p53 alterations and DNA aneuploidy in 24 X-ray-negative, early BSqCC patients with various preneoplastic lesions and in 25 non-carcinoma patients with preneoplastic lesions. Bronchial lesions (n=88) were morphologically classified as hyperplasia (HP, n=5), squamous metaplasia (SM, n=23), low-grade dysplasia (LGD, n=14), high-grade dysplasia (HGD, n=11), intraepithelial carcinoma including 'carcinoma in situ' (CIS) (IEC, n=15), and microinvasive carcinoma (MIC, n=20). Immunohistochemistry for the p53 protein and image cytometry for DNA ploidy detection were performed in serial sections of each lesion. Overexpression of p53 protein was detected in 36, 73, and 65% of the HGD, IEC, and MIC lesions, respectively. Aneuploid DNA profiles were found only in carcinoma lesions, 33% in IEC and 85% in MIC. The topographical analysis revealed two types of early BSqCCs, one with adjacent preneoplastic lesions (sequential type, n=8) and another without such lesions (de novo type, n=16). The p53 protein was frequently overexpressed in both types (sequential type, 79%; de novo type, 62%). In the sequential type, however, the p53 protein was overexpressed in HGD lesions that were directly adjacent to p53-overexpressing carcinoma lesions without exception. The present topographical study suggests that p53 mutations play an important role in the carcinogenesis of BSqCC and that p53-overexpressing HGD lesions in sequential types should be regarded as 'truly' preneoplastic lesions that actually develop into carcinomas. In addition, our study demonstrated that DNA aneuploidy might occur at times after p53 alteration with increasing frequency, as invasive growth begins. Such combination analysis of p53 immunohistochemistry and nuclear DNA ploidy in routine histology may contribute to estimates of malignant potential in preneoplastic and intraepithelial squamous lesions and provide additional information for early detection of BSqCC.     

Association between p53 mutation and clinicopathological features of non-small cell lung cancer

Genetic alterations in exons 5-8 of the p53 gene, determined by single-strand conformation polymorphism and sequencing analyses, and the clinicopathological characteristics of 108 patients with non-small cell lung cancer were compared. Mutations in this gene were found in 37 of the 108 patients (34%): in 30% (23/76) of those with adenocarcinomas, 46% (12/26) of those with squamous cell, 33% (1/3) of those with large cell and 33% (1/3) of those with adenosquamous carcinomas. No associations between the incidence of p53 mutations and the histological or cytological subtypes of adenocarcinomas were found. The analysis of types of mutations, however, showed that GC transversion was relatively common in papillary and clara subtypes, whereas it accounted for only 17% at most of p53 mutations in tubular and bronchial surface epithelial cell subtypes of adenocarcinomas. Univariate analyses revealed that large tumor size, high nodal stage and positive vascular invasion of non-small cell lung cancers, and high nodal stage and high-grade nuclear atypia of adenocarcinomas were associated significantly with p53 mutations. Multivariate analyses showed that the tumor sizes of non-small cell lung cancer correlated with p53 mutations with marginal significance (P = 0.099) whereas nuclear atypia of adenocarcinomas correlated significantly (P = 0.028). No differences between the overall or relapse-free survival rates of patients with and without p53 mutations in non-small cell lung cancers or adenocarcinomas were found. These findings indicate that p53 mutations in adenocarcinomas of the lung are associated with the malignant phenotype of tumor cells, but not with patient survival.      

Clonal Heterogeneity in Human Esophageal Squamous Cell Carcinomas on DNA Analysis

Cancers are thought to arise through multistep accumulation of somatic mutations in the progeny of a single cell. Multiple mutations may induce molecular intratumor heterogeneity. Therefore, we examined molecular clonal heterogeneity in esophageal squamous cell carcinomas. Twenty-four esophageal squamous cell carcinomas and associated lymph node metastases were examined for microsatellite alterations, and abnormalities of the p53 and transforming growth factor-β type II receptor ( TGF-β RII ) genes. There were eight cases (33%) showing different patterns of loss of heterozygosity in primary tumors and metastatic lymph nodes with microsatellite markers. On the other hand, the abnormalities of p53 were identical in all these cases. No mutation was detected in the simple repeated sequences of the TGF-β RII gene. These results indicate that molecular clonal heterogeneity exists in esophageal squamous cell carcinomas. Therefore, care is necessary in preoperative genetic diagnosis using biopsy samples.     

Heterogeneous nuclear ribonucleoprotein B1 as early cancer biomarker for occult cancer of human lungs and bronchial dysplasia

Heterogeneous nuclear ribonucleoprotein (hnRNP) B1 is a RNA-binding protein of Mr 37,000. We previously reported that hnRNP B1 was specifically overexpressed in the nuclei of human lung cancer cells, particularly in squamous cell carcinoma (E. Sueoka et al., Cancer Res., 59: 1404-1407, 1999). We extended this study to determine whether hnRNP BL was overexpressed in roentgenographically occult cancers of the lungs and premalignant lesions of squamous cell carcinomas, such as bronchial dysplasia. The additional object of our study was to examine the usefulness of hnRNP B1 as a potential diagnostic marker for squamous cell carcinoma of various organs, such as the oral cavity and esophagus in humans. Surgically resected specimens of bronchial dysplasia, lung cancers, and various human squamous cell carcinomas, collected at two hospitals in Japan, were subjected to immunohistochemical staining with anti-hnRNP B1 antibody. Overexpression of hnRNP B1 protein was observed in 100% of stage I lung cancer tissues, but it was not found in normal bronchial epithelium. Squamous cell carcinoma of the lungs showed stronger staining than other histological types, and elevation of hnRNP B1 was found in both roentgenographically occult lung cancers and bronchial dysplasia. Furthermore, cytological examination with anti-hnRNP B1 antibody detected cancer cells in sputum, suggesting the potential of hnRNP B1 protein as a new biomarker for the very early stage of lung cancer in humans. Because strong staining of hnRNP B1 was also observed in various squamous cell carcinomas of oral and esophageal tissues as shown in our recent reports, overexpression of hnRNP B1 seems to be a common event in the carcinogenic processes of squamous cell carcinoma. These results suggest that hnRNP B1 protein could be a useful diagnostic biomarker for both the very early stages of lung cancer and various squamous cell carcinomas in humans.     

p53 immunohistochemistry in transitional cell carcinoma and dysplasia of the urinary bladder correlates with disease progression.

Immunohistochemically detectable p53 protein using a polyclonal antibody (CM-1) was studied in 42 carcinomas of which 11 were grade I, 22 grade II and nine grade III carcinomas. Additionally 14 urothelial dysplasias were studied. In 11 of these a diagnosis of transitional cell carcinoma was established before and in one after the dysplasia diagnosis. Twenty-one out of 42 (50%) cases of transitional cell carcinoma were positive for the p53 protein. Eleven out of 14 (78%) dysplasias and 10/12 (83%) related carcinomas were p53 positive. One out of 11 grade I (9%), 12/22 grade II (55%) and 8/9 grade III (89%) tumours showed positivity for p53. There were significantly more p53 positive cases in grade II-III tumours than in grade I tumours (P = 0.004). There were significantly more p53 positive cases in stage T2-T4 tumours than in stage T1 tumours (P = 0.035). In only one case among the 11 dysplastic lesions following the treatment of a carcinoma the dysplastic lesion was p53 negative while the preceding carcinoma was p53 positive. All dysplasias and 28 carcinomas were also immunostained for laminin and type IV collagen to evaluate the continuity of basement membranes (BMs). Clearly disrupted BMs were observed only in grade III carcinomas. These cases showed the most p53 immunopositivity. The results show a strong association of p53 staining between dysplasias and transitional cell carcinomas of the urinary bladder indicating that these lesions might share similar p53 changes. The correlation to grade, clinical stage and to disrupted BM suggests that p53 mutations may be associated with the evolution of aggressive growth characteristics in transitional cell carcinomas or, alternatively, that p53 positive tumours of a more aggressive type from the start. Whether p53 staining can be used as an adjunct in the assessment and follow-up of epithelial changes of patients treated for a p53 positive bladder carcinoma deserves to be studied.     

Multiparameter flow cytometry for simultaneous assessment of p53 protein expression and cellular DNA content in oral squamous cell carcinomas: evidence for the development of aneuploid clones from p53-deficient diploid progenitor cells

Diploid tumour cells regularly continue to progress after the development of aneuploid cell populations in head and neck squamous cell carcinomas. The coexistence of aneuploid clones with their diploid progenitor cells provides a unique opportunity to study the order of appearance of p53 mutation and aneuploidy in the same tumour. Multiparameter flow cytometry was therefore applied to 22 oral squamous cell carcinomas to simultaneously assess cellular DNA content and p53 protein expression on a single-cell basis. Concurrent measurements of cytokeratin expression served to identify tumour cells of epithelial origin. One of 5 diploid and 2 of 17 aneuploid carcinomas were p53-negative. For 15 p53-positive aneuploid tumours, overexpression of p53 protein was identified for the aneuploid clones as well as for coexisting diploid tumour cell populations in 14 cases. On the understanding that coexisting diploid and aneuploid tumour cell populations have a common clonal origin, these results provide evidence that aneuploid tumour clones typically develop from p53-deficient diploid progenitor cells. Loss of wild-type p53 function may therefore contribute to the development of aneuploidy in head and neck cancer.