Immunohistochemical demonstration of p63 in DMBA-induced hamster buccal pouch squamous cell carcinogenesis

Predicting the radiosensitivity of HPV-negative oropharyngeal squamous cell carcinoma using miR-130b

BACKGROUND

Human papillomavirus (HPV)-negative oropharyngeal squamous cell carcinoma shows a higher rate of radiation resistance than HPV-positive oropharyngeal squamous cell carcinoma (OPSCC). Radioresistant HPV-negative OPSCC is associated with unfavourable outcomes, but validated prognostic biomarkers remain lacking.

AIMS/OBJECTIVES

This study investigated biomarkers for radioresistant HPV-negative OPSCC.

MATERIAL AND METHODS

The Cancer Genome Atlas included miRNA sequence and mRNA sequence data from 528 HNSCC tumours. Of these, we used gene expression data for HPV-negative head and neck squamous cell carcinoma for which data were available on the effects of radiation, and compared miRNA sequence and mRNA sequence data between radioresistant and radiosensitive groups. We subsequently estimated downstream miRNA from the results. Finally, we validated miRNAs related to the outcomes of radiotherapy in our clinical cases.

RESULTS

Investigation of miRNA sequence revealed expression of miR-130b as the greatest difference between radiosensitive and radioresistant groups. We subsequently evaluated miR-130b expression in our clinical OPSCC cases. Values of miR-130b >5.372 (low expression), determined from receiver operating characteristic curve analyses, were associated with significantly longer progression-free survival and overall survival (p = .006, p = .04, respectively).

CONCLUSIONS AND SIGNIFICANCE

Our results suggest that miR-130b has potential as a biomarker for the radiosensitivity of HPV-negative OPSCC.

A Model for Induction of Dysplasia in Hamster Mucosal Pouch

Induction of premalignant lesions in animal models is of high value for research purposes. This study aimed to induce dysplasia in hamster mucosal pouch for investigation of dysplastic lesions using dimethylbenz(a)anthracene. The buccal pouch of 10 hamsters was painted with dimethylbenz(a)anthracene for 10 weeks every other day. At 5 and 10 weeks, they underwent histopathological analysis. Clinically, there was no change until week 7; after which mucosal thickening occurred. Hamsters scarified at 5 weeks and 10 weeks demonstrated mild and moderate dysplasia, respectively. dimethylbenz(a)anthracene is a useful tool for inducing dysplastic lesions in the buccal pouch mucosa of hamsters.

Prognostic Role of Epithelial-Mesenchymal Transition Markers "E-Cadherin, β-Catenin, ZEB1, ZEB2 and p63" in Bladder Carcinoma

Background

This study aimed to investigate the expression of epithelial-mesenchymal markers’ E-cadherin, β-catenin, zinc-finger E-box-binding homeobox 1 (ZEB1), zinc-finger E-box-binding homeobox 2 (ZEB2) and p63 in transitional cell carcinoma (TCC) and squamous cell carcinoma (SCC) variants of bladder carcinoma (BC) and their correlation with clinicopathological parameters of prognostic importance.

Methods

In this retrospective study, 91 patients were enrolled (66 with TCC and 25 with SCC). All patients had full clinical and follow-up data and available paraffin blocks. Immunohistochemical analysis was performed and correlated with clinicopathological factors.

Results

In TCC cases, reduced E-cadherin, β-catenin positivity and p63 expression rate were evident in the sitting of increased expression of ZEB1 and ZEB2. Patients with ZEB2 positive tumors were more likely to die compared to those with negative ZEB2 (P = 0.024). Moreover, in patients with muscle-invasive BCs, an intense p63 expression was associated with poor overall survival (OS) (P < 0.001). For patients with SCC, there was a reduction in E-cadherin and β-catenin positivity with elevated p63 expression and concomitant increased ZEB1 and ZEB2 expression. Poor prognosis was evident in association with reduced E-cadherin, positive nuclear β-catenin/reduced membranous β-catenin, ZEB1 and ZEB2 positive cases as well patients with elevated p63 expression (P < 0.001). TCC and SCC cases showed similar poor prognosis in association with elevated p63 expression (P < 0.001).

Conclusions

In both TCC and SCC variants, epithelial-mesenchymal transition (EMT) process is evident; however, its molecular mechanism shows some variations, specifically this notably different p63 expression pattern among two carcinoma variants with the similar impact of elevated p63 expression pattern on prognosis.

p63 Expression and its Relation to Epithelial Cells Proliferation in Dentigerous Cyst, Odontogenic Keratocyst, and Ameloblastoma

The current controversy about the classification of odontogenic keratocyst reflects the shortage in the understanding of the odontogenic cysts and tumors. The aim of the present study was to investigate p63 immunoexpression and its relation to the proliferation of the epithelial lining in dentigerous cyst (DC), odontogenic keratocyst (OKC), and follicular type of ameloblastoma (AB). The study involved 36 samples, which are DC (n = 12), OKC (n = 9), and AB (n = 15). p63 protein expression was evaluated by immunohistochemistry. The results on Ki-67 expression were obtained from our previous studies and correlated with p63 expressions. p63 was expressed differently in the studied lesions with various distribution in different study samples. Statistical analysis using Kruskal-Wallis test showed a significant difference in the expression of p63 protein among DC, OKC, and AB (p = 0.048). Subsequently, Mann-Whitney U test revealed the expression of p63 protein was significantly higher in OKC than DC (p = 0.018). Interestingly, Spearman's correlation analysis showed a positive correlation between the expression of p63 and Ki-67 in the odontogenic epithelium of DC (σ = 0.757, P = 0.004) and OKC (σ = 0.741, P = 0.022). While no such a positive correlation was found between the two studied markers in AB group (σ = 0.006, P = 0.983). In conclusion, the present results indicated various expression and correlation of p63 with the proliferation of odontogenic epithelial cells in DC, OKC, and AB. This diversity could reflect a different role and pathways of ΔNp63 in odontogenic tumor than that in odontogenic cyst. These together will help in better understanding the pathogenesis and biological behavior of odontogenic cysts and tumors.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Diagnostic utility of p63 (Ab-1) and (Ab-4) tumor markers in the squamous cell carcinomas of head and neck

P63 is a gene product required in cell cycle regulation which plays vital roles in tumor differentiation. Aims of the present study were to assess the frequency, pattern, sensitivity and specificity of two p63 protein clones P63 4A4 and P63 4A4+Y4A3 in squamous cell carcinomas (SCCs). Thirty cases of head and neck region SCC diagnosed on the basis of HandE staining were examined along with 60 cases of head and neck region biopsies other than squamous cell carcinoma, negative on HandE staining, were taken as control. Immunostaining was performed on slides according to the Thermo Scientific UltraVision LP detection System. P63 4A4+Y4A3 clone is more sensitive 96.6% in comparison to 86% in P63 4A4 with having greater NPV of 98.3%. The results signify the importance of P63 4A4+Y4A3 marker over the old markers and may be used as a confirmatory marker of squamous cell carcinoma.

Immunohistochemical expression of p63, epidermal growth factor receptor (EGFR) and notch-1 in radicular cysts, dentigerous cysts and keratocystic odontogenic tumors

The aim of this study was to assess the immunohistochemical expression of p63 protein, epidermal growth factor receptor (EGFR) and Notch-1 in the epithelial lining of radicular cysts (RC), dentigerous cysts (DC) and keratocystic odontogenic tumors (KOT). For this study, 35 RC, 22 DC and 17 KOT were used. The clinical and epidemiological data were collected from the patient charts filed in the Oral Pathology Laboratory, University of Ribeirão Preto, Brazil. Immunohistochemical reactions against the p63, EGFR and Notch-1 were performed in 3-µm-thick histological sections. The slides were evaluated according to the following criteria: negative: <5% of positive cells, low expression: 5-50% of positive cells, and high expression: >50% of positive cells. Moreover, the intensity of EGFR and Notch-1 expressions was also evaluated. Fisher's exact test and Spearman's correlation coefficients were used for statistical analysis, considering a significance level of 5%. Almost all cases demonstrated p63, EGFR and Notch-1 expressions. The p63 expression was significantly higher in KOT (p<0.001). Positive correlation between these immunomarkers was observed. These findings suggest the participation of p63, EGFR and Notch-1 in the development, maintenance and integrity of cystic odontogenic epithelial lining, favoring lesion persistence. The high expression of p63 in KOT suggests that it may be related to their more aggressive biological behavior and marked tendency to recurrence.

DMBA-induced hamster buccal pouch carcinoma and VX2-induced rabbit cancer as a model for human oral carcinogenesis

In this article, we have described and compared the advantages and disadvantages of two potential animal cancer models (the hamster buccal pouch cancer model and the VX2-induced rabbit cancer model) for human squamous cell carcinomas of the oral mucosa. Currently, no animal cancer model is perfectly applicable to human oral squamous cell carcinomas. This is because the hamster buccal pouch cancer model has a different etiology and genetic constitution compared with human oral carcinomas. In addition, the VX2-induced rabbit cancer model is not produced in situ and, consequently, its natural behavior is totally reliant on the location of transplantation. Nonetheless, with the use of these two animal cancer models together, researchers could evaluate different aspects of the cellular and molecular biological characteristics or assess potential novel treatment regimens for squamous cell carcinomas of the human oral mucosa.

Overexpression of p63 is associated with radiation resistance and prognosis in oral squamous cell carcinoma

BACKGROUND

The tumor suppressor homologue p63 is expressed in basal and parabasal layers of intraoral mucosa. Full length transcripts with transactivational domain (TA forms) present with homology to p53 and implicate functions governing cell proliferation, differentiation and apoptosis control. To date studies show an increase of p63 expression in oral dysplasia and additionally high expression levels correlated with poor prognosis for patients with OSCC, whereas a possible link to radiation resistance of tumors has not been investigated yet. In the present study we tested the hypothesis for p63 being a marker of radioresistance and overall survival in OSCC.

METHODS

p63 Expression was labeled by immunohistochemistry in pre-treatment biopsies collected from 33 patients with OSCC. Quantification of the labeling index (Li) based on the relation of p63 positive cells to overall tumor cell count. Histological examination of the resection specimen allowed categorization of the radiation response. Statistical analyses of the association between Li and radiation response were performed. Survival analysis utilized Kaplan-Meier estimates and additionally a Cox regression model was built for p63 (Li), T stage, N-stage and chemotherapy and presented as hazard ratios.

RESULTS

All tumors had enhanced p63 expression. The median Li was 63.1% (range 36-87%). Tumors with a p63 positive cell count>63.1% showed increased resistance to radiation (p=0.027). Overall survival was higher (p=0.001) for patients with low Li (<median value) than those with high Li (>median value) and multivariate Cox regression analysis confirmed the significance of p63 as a prognostic marker of survival.

CONCLUSIONS

The results of this analysis advocate p63 expression in pre-treatment tumor tissue to be a marker of radiation resistance in OSCC, with high expression levels being associated with poor radiation response and shorter survival. The promising results of this biomarker should now be confirmed by a study with larger patient counts.

Immunohistological evaluation of Ki-67, p63, CK19 and p53 expression in oral epithelial dysplasias

BACKGROUND

Oral squamous cell carcinoma develops through a multistep of genetic mutations, and the process can be morphologically recognized as oral epithelial dysplasia. To evaluate the hypothesis that distributional alterations of proliferating and stem cells may be a useful index to estimate the grading and development of epithelial dysplasia, we examined the distribution patterns according to stratified cell layers.

METHODS

Sixty-two oral dysplasia cases according to the histological grades were immunohistologically examined and the nuclear expression of Ki-67 and p63 antigens was counted according to epithelial layers as labeling index.

RESULTS

The Ki-67 labeling index in the basal and suprabasal layers and that of p63 in the basal layer showed a significant difference between low- and high-grade groups of epithelial dysplasia.

CONCLUSION

The architectural alteration of proliferating cell and stem cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of oral epithelial dysplasias.

p63 expression in odontogenic cysts

A total of 123 cases of odontogenic cysts, distributed as follows: 30 follicular (FC), 35 radicular (RC), 53 keratocysts, 1 glandular odontogenic and 4 calcifying odontogenic cysts, were analysed by immunohistochemistry for expression of p63, a component of p53 protein family. In RCs p63 positivity was not only in basal and parabasal layers but also in the intermediate layer and about 1/3 of cases displayed a percentage of stained cells comprised between 0 and <5%, and about 2/3 between >5% and <50%. In FCs positivity was confined to basal and parabasal layers of the epithelium and in the majority of FCs the stained cells were comprised between 0 and <5%. OKCs displayed the most intense and diffuse p63 labeling. In conclusion, these data suggest that p63 expression may be useful to identify cysts type with more aggressive and invasive phenotype supporting the hypothesis of a suprabasal proliferative compartment in OKCs.

p63 overexpression associates with poor prognosis in head and neck squamous cell carcinoma

p63 belongs to a protein family that includes 2 structurally related proteins, p53 and p73. The aim of this study was to investigate the biologic role of p63 in oral tumorigenesis and its possible role as prognostic marker in oral cancer. Ninety-four cases of oral squamous cell carcinoma and 10 cases of normal mucosa were analyzed for p63 expression by immunohistochemistry. Normal oral mucosa showed a basal and parabasal expression of p63. Five (5.3%) cases of oral cancer showed less than 10% of positive tumor cells; in 33 (35.1%) cases the positive tumor cells comprised between 10% and less than 30%, in 36 (38.3%) cases the positive tumor cells comprised between 30% and less than 50%, and in 20 (21.3%) cases the positive tumor cells were more than 50%. There was also a statistically significant correlation between p63 expression and tumor differentiation: p63 expression was amplified in poorly differentiated tumors (P < .05). When analyzed for prognostic significance, patients with perineural infiltration had poorer survival rates than the group with no perineural infiltration (P < .05) and patients with increased p63 expression had poorer survival rates than the group with reduced p63 expression (P < .05). The statistical analysis showed no significant correlation between p63 expression, sex, age, tumor size, staging, recurrence, and metastasis. Cases with diffuse p63 expression were more aggressive and poorly differentiated and related to a poorer prognosis. These data suggest that p63 expression may be useful to identify cases of oral squamous cell carcinoma with more aggressive and invasive phenotype providing novel diagnostic and prognostic information on individual patient survival with oral cancers.

Expression of p63 protein and mRNA in oral epithelial dysplasia

BACKGROUND

Abnormalities in the TP53 are regarded as the most consistent findings in oral squamous cell carcinoma. Two related members of the TP53 family, p73 and p63, have shown remarkable structural similarity to TP53, indicating possible functional and biological interactions. The aim of the present study was to investigate the expression of p63 protein and mRNA in oral epithelial dysplasia.

METHODS

Immunohistochemical p63 staining was compared for samples from 90 male patients with buccal epithelial dysplasias and 15 healthy individuals with normal buccal mucosa and 15 subjects with reactive epithelial hyperplasia of the oral mucosa secondary to traumatic insult. The buccal lesions consisted of mild, moderate and severe epithelial dysplasias (30 samples in each category). The mRNA expression using reverse transcription polymerase chain reaction (RT-PCR) was also included for a subset of available fresh tissue specimens (four samples in each category of mild and moderate epithelial dysplasia; five samples in severe epithelial dysplasia; five samples in each of normal and reactive epithelial hyperplasia).

RESULTS

Nuclear p63 staining was demonstrated predominantly in the basal layers of the epithelium of the normal buccal mucosa and reactive epithelial hyperplasia specimens. For epithelial dysplasia lesions, however, staining was not restricted to the basal layers, extending to the middle spinous layer for samples in the mild category, with p63 immunoexpression observed across almost the full thickness of the dysplastic epithelium for analogous moderate and severe specimens. Compared with normal/reactive hyperplastic mucosa, p63 staining in the dysplastic mucosa was significantly increased. The severity of dysplasia was increased with the increase of p63 staining. Furthermore, Delta Np63mRNA was identified in all of the fresh tissue samples whereas expression of transactivation (TA) isotype was not detected. A subset of moderate epithelial dysplasia and severe variant showing p63-positive staining has undergone malignant transformation to squamous cell carcinomas in about 5 years follow-up.

CONCLUSION

Our results indicate that impaired p63 immunoexpression (predominantly Delta N isoform) is associated with the severity of oral epithelial dysplasias and up-regulation of p63 may play a role in the early stage of human oral tumorigenesis.

Assessment of p63 expression in oral squamous cell carcinomas and dysplasias

OBJECTIVES

p63, a p53 homologue, may be associated with tumorigenesis in epithelial tissues through its inhibition of p53 transactivation functions. We sought to determine the pattern and levels of p63 expression in oral dysplasias and carcinomas using standard immunohistochemical staining. We also assessed and compared expression of p53 and a cell proliferation marker in these lesions.

STUDY DESIGN

This retrospective cross-sectional survey (n=67) included hyperkeratosis (10), mild dysplasia (9), moderate dysplasia (11), severe dysplasia/in situ carcinoma (10), squamous cell carcinoma (SCC) (22 [9 well differentiated, 7 moderately differentiated, 6 poor differentiated]), and normal mucosa (5). Serial sections were stained immunohistochemically with antibodies to p63 (4A4 recognizing all p63 isotypes), p53 (DO-7), and Ki-67 (MIB-1) proteins. In preinvasive lesions, both the percentage of positive cells and staining patterns (negative, basal, suprabasal) were assessed. In oral SCCs, the percentage of positive cells was assessed. Statistical analysis was done using the Tukey-Kramer multiple comparisons test.

RESULTS

A suprabasal p63 staining pattern was evident in keratinocyte nuclei in the entire range of noninvasive lesions studied, including normal mucosa. Most nuclei in invasive SCCs stained positive. When all grades of dysplasia were combined, the percent of p63 positive cells was significantly greater than hyperkeratosis (P < .01), and well-differentiated SCC (P < .001). Moderately differentiated SCC had statistically significant more positive cells than well-differentiated SSC (P < .01). Comparison of serial sections showed different p63 staining patterns compared to p53 or Ki-67 staining patterns.

CONCLUSIONS

We conclude that p63 is expressed in oral carcinomas and dysplasias, as determined by immunohistochemical staining with a primary antibody to all isotypes. Neither staining pattern nor percentage of stained cells could be used to differentiate the lesions studied. The statistically significant differences found between some groups are not likely to be of diagnostic value. p63 is not coexpressed with p53 expression or Ki-67 suggesting functional independence. When antibodies to the p63 isotypes become available, oral dysplasias and carcinomas should be reassessed.

Differential expression of p53, p63 and p73 protein and mRNA for DMBA-induced hamster buccal-pouch squamous-cell carcinomas

Abnormalities in the p53 gene are regarded as the most consistent of the genetic abnormalities associated with oral squamous-cell carcinoma. Two related members of the p53 gene family, p73 and p63, have shown remarkable structural similarity to p53, suggesting possible functional and biological interactions. The purpose of this study was to investigate the differential expression of p73, p63 and p53 genes for DMBA-induced hamster buccal-pouch squamous-cell carcinoma. Immunohistochemical analysis for protein expression and reverse transcriptase-polymerase chain reaction (RT-PCR) for mRNA expression were performed for 40 samples of hamster buccal pouches, the total being separated into one experimental group (15-week DMBA-treated; 20 animals) and two control groups (untreated and mineral oil-treated; 10 animals each). Using immunohistochemical techniques, nuclear staining of p53 and p73 proteins was detected in a subset of hamster buccal-pouch tissue specimens treated with DMBA for a period of 15 weeks, whereas p63 proteins were noted for all of the 20 hamster buccal-pouch tissue specimens treated with DMBA for 15 weeks as well as for all of the untreated and mineral oil-treated hamster buccal-pouch tissue specimens. Differential expression of p63, p73 and p53 protein for the experimental group was as follows: p63+/p73+/p53+ (n = 14; 70%); p63+/p73+/p53- (n = 2; 10%); p63+/p73-/p53- (n = 4; 20%) and p63+/p73-/p53- (untreated [n = 10] and mineral oil-treated mucosa [n = 10]; 100% each). Upon RT-PCR, DeltaNp63mRNA was detected within all of the 20 hamster buccal-pouch tissue specimens treated with DMBA for 15 weeks, whereas expression of TAp63 was not detected. Furthermore, p73 mRNA was identified for 16 of the hamster buccal-pouch tissue specimens treated with DMBA for 15 weeks, whereas p53 mRNA was noted for 14 15-week DMBA-treated pouches. The proportional (percentage) expression of DeltaNp63, p73 and p53 mRNA for the hamster buccal-pouch tissue specimens treated with DMBA for 15 weeks was noted to be consistent with the findings using immunohistochemical techniques. A significant correlation between p53, p63 and p73 expression (protein and mRNA) was demonstrated for the hamster buccal-pouch carcinoma samples. Our results indicate that both p73 and p63 may be involved in the development of chemically induced hamster buccal-pouch carcinomas, perhaps in concert with p53.