Prognostic significance of p53 and p63 immunolocalisation in primary and matched lymph node metastasis in oral squamous cell carcinoma

Prediction of Lymphovascular and Perineural Invasion of Oral Squamous Cell Carcinoma by Combined Expression of p63 and Cyclin D1

OBJECTIVES

 The aim of this study was to determine the value of immune expression of p63 and cyclin D1 in the prediction of lymphovascular invasion (LVI) and perineural invasion (PNI) in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

 Clinical and histopathologic features of 65 subjects with histologically confirmed OSCC were collected. Tissue microarray blocks representing all subjects were prepared for the immunohistochemical quantification of the nuclear expression of p63 and cyclin D1 using immune ratio plugin of image J software. Image analysis was performed by two independent pathologists. Independent samples t-test, analysis of variance, and receiver operating characteristic curve tests were used for statistical analysis. The level of significance was set at p≤ 0.05.

RESULTS

 The optimum cutoff value for the prediction of LVI for p63 and cyclin D1 was found to be 100 and 93.2, respectively, while the optimum cutoff value for the prediction of PNI for p63 and cyclin D1 was found to be 95.9 and 94, respectively. p63 and cyclin D1 expression correlated with several clinicopathologic features of the studied population. p63 expression was a significant predictor of moderate/poorly differentiated OSCC compared with well-differentiated OSCC. A parallel combination of positive p63 and cyclin D1 increased the specificity of predicting LVI from 89.1% and 67.4% for either p63 or cyclin D1, respectively, to 93.5% with a positive predictive value of 92.5%. Similarly, the parallel combination of the two markers raised the specificity of predicting PNI from 70% and 77.5% for either p63 or cyclin D1, respectively, to 90% with a positive predictive value of 86.3%.

CONCLUSION

 Combined overexpression of nuclear markers p63 and cyclin D1 can be considered as a valuable independent predictor of LVI and PNI, and hence tumor progression, in OSCC.

Human Papilloma Virus Increases ΔNp63α Expression in Head and Neck Squamous Cell Carcinoma

P63, and in particular the most expressed ΔNp63α isoform, seems to have a critical role in the outcome of head and neck cancer. Many studies have been conducted to assess the possible use of p63 as a prognostic marker in squamous cell carcinoma cancers, but the results are still not well-defined. Moreover, a clear relationship between the expression of ΔNp63α and the presence of high-risk HPV E6 and E7 oncoproteins has been delineated. Here we describe how ΔNp63α is mostly expressed in HPV-positive compared to HPV-negative head and neck cancer cell lines, with a very good correlation between ΔNp63α mRNA and protein levels.

Expression of p63 and CD44 in oral squamous cell carcinoma and correlation with clinicopathological parameters

Squamous cell carcinoma (SCC) is the sixth most frequent malignant tumor of the head and neck region. Despite advances in therapeutic options over the last decades, the rate of mortality and morbidity has not been improved markedly. A small subset of cells, cancer stem cells (CSCs), with self-renewal properties have become a major focus of current cancer research. CD44 and p63 are identified as candidate stem cell markers in normal squamous epithelium and SCC. The role of these markers in oral squamous cell carcinoma (OSCC) is still debatable. The aim of this study was to evaluate immunohistochemical expression of these markers in OSCC samples and also correlates the expression of these markers with some clinicopathological parameters of prognostic significance including histological grading, TNM staging, overall survival (OS) rate as well as patients' age, gender, and tumor location. CD44 and p63 were expressed in all studied lesions with different degrees. Statistically significant difference was observed between CD44 and p63 expression with tumor grade and stage with higher expression in high grade and advanced OSCCs. No significant relationship was detected between markers immunoreactivity and patients age, gender, tumor location as well as OS. These markers can possibly advance our understanding of the initiating mechanisms and pathogenesis of OSCC and also result in novel therapeutic target in cancer treatment.

Elevated ΔNp63α Levels Facilitate Epidermal and Biliary Oncogenic Transformation

Unlike its family member p53, TP63 is rarely mutated in human cancer. However, ΔNp63α protein levels are often elevated in tumors of epithelial origin, such as squamous cell carcinoma and cholangiocarcinoma. To study the oncogenic properties of ΔNp63α in vivo, we generated transgenic mice overexpressing ΔNp63α from the Rosa26 locus promoter controlled by keratin 5-Cre. We found that these mice spontaneously develop epidermal cysts and ectopic ΔNp63α expression in the bile duct epithelium that leads to dilatation of the intrahepatic biliary ducts, to hepatic cyst formation and bile duct adenoma. Moreover, when subjected to models of 7,12-dimethylbenz[a]anthracene-based carcinogenesis, tumor initiation was increased in ΔNp63α transgenic mice in a gene dosage-dependent manner although ΔNp63α overexpression did not alter the sensitivity to 7,12-dimethylbenz[a]anthracene-induced cytotoxicity in vivo. However, keratinocytes isolated from ΔNp63α transgenic mice displayed increased survival and delayed cellular senescence compared with wild-type keratinocytes, marked by decreased p16^Ink4a and p19^Arf expression. Taken together, we show that increased ΔNp63α protein levels facilitate oncogenic transformation in the epidermis as well as in the bile duct.

A genetic programming approach to oral cancer prognosis

Background

The potential of genetic programming (GP) on various fields has been attained in recent years. In bio-medical field, many researches in GP are focused on the recognition of cancerous cells and also on gene expression profiling data. In this research, the aim is to study the performance of GP on the survival prediction of a small sample size of oral cancer prognosis dataset, which is the first study in the field of oral cancer prognosis.

Method

GP is applied on an oral cancer dataset that contains 31 cases collected from the Malaysia Oral Cancer Database and Tissue Bank System (MOCDTBS). The feature subsets that is automatically selected through GP were noted and the influences of this subset on the results of GP were recorded. In addition, a comparison between the GP performance and that of the Support Vector Machine (SVM) and logistic regression (LR) are also done in order to verify the predictive capabilities of the GP.

Result

The result shows that GP performed the best (average accuracy of 83.87% and average AUROC of 0.8341) when the features selected are smoking, drinking, chewing, histological differentiation of SCC, and oncogene p63. In addition, based on the comparison results, we found that the GP outperformed the SVM and LR in oral cancer prognosis.

Discussion

Some of the features in the dataset are found to be statistically co-related. This is because the accuracy of the GP prediction drops when one of the feature in the best feature subset is excluded. Thus, GP provides an automatic feature selection function, which chooses features that are highly correlated to the prognosis of oral cancer. This makes GP an ideal prediction model for cancer clinical and genomic data that can be used to aid physicians in their decision making stage of diagnosis or prognosis.

Prognostic molecular markers in cancer - quo vadis?

Despite the tremendous number of studies of prognostic molecular markers in cancer, only a few such markers have entered clinical practise. The lack of clinical prognostic markers clearly reflects limitations in or an inappropriate approach to prognostic studies. This situation should be of great concern for the research community, clinicians and patients. In the present review, we evaluate immunohistochemical prognostic marker studies in oral squamous cell carcinomas (OSCC) from 2006 to 2012. We comment upon general issues such as study design, assay methods and statistical methods, applicable to prognostic marker studies irrespective of cancer type. The three most frequently studied markers in OSCC are reviewed. Our analysis revealed that most new molecular markers are reported only once. To draw conclusions of clinical relevance based on the few markers that appeared in more than one study was problematic due to between-study heterogeneity. Currently, much valuable tissue material, time and money are wasted on irrelevant studies.

High expression of p63 is correlated to poor prognosis in squamous cell carcinoma of the tongue

BACKGROUND

p63 proteins are important in formation of the oral mucosa. Normal oral mucosa shows a balance between the six protein isoforms, whereas an imbalance between them is seen in squamous cell carcinomas (SCC). There is controversy over the clinical impact of p63 in SCC, which may relate to different expression in different areas. In addition, p63 isoforms can act as p53-like molecules (TAp63) or can inhibit p53 functions (ΔNp63) and expression of these isoforms varies in different tumours. Here, we chose to concentrate on the most common intra-oral sub-site, SCC of the mobile tongue.

METHODS

Total p63, ΔNp63 and TAp63 were analysed separately using immunohistochemistry. The percentage of cells and intensity of expression of different isoforms of p63 was evaluated using a quick score method and correlated with clinical data in a group of 87 patients with tongue SCC.

RESULTS

All tumours expressed p63 in at least 60% of the cells when using two different antibodies detecting all 6 isoforms. p63 expression correlated significantly with 2-year survival (P = 0.018), with fewer patients surviving 2 years if their tumours expressed p63 with strong intensity in at least 80% of the cells (quick score 18). Looking at 5-year survival, this was even more emphasized. ΔNp63 was expressed in all tumours, whereas expression of TAp63 was seen only in 59/87 patients, usually at very low levels.

CONCLUSIONS

Based on the present data, we recommend using expression of p63 as an additional factor contributing prognostic information in analysis of SCC in the tongue.

Role of p63 in cancer development

Since their initial identification p53 homologues p63 and p73 have been expected to play a role in cancer development due to their close homology to p53, notoriously one of the most mutated genes in cancer. However soon after their discovery the awareness that these genes were rarely mutated in cancer seemed to indicate that they did not play a role in its development. However a large number of data collected in the following years indicated that altered expression rather than mutation could be found in different neoplasia and play a role in its biology. In particular p63 due to its fundamental role in epithelial development seems to play a role in a number of tumors of epithelial origin. In this review we summarize some of the evidence linking p63 to carcinogenesis.

Prognostic significance of immunohistochemical biomarkers in oral squamous cell carcinoma

Advances in understanding of the molecular mechanisms underlying oral squamous cell carcinoma (OSCC) have resulted in an increasing number of biomarkers that can be used to predict the behaviour of this disease. The authors conducted a literature review of studies examining the role of immunohistochemistry-based protein biomarkers in predicting OSCC outcome. Only articles published in PubMed-indexed journals over the past 5 years were considered. 22 molecular biomarkers were identified and classified into five groups based on their biological functions: cell cycle acceleration and proliferation; tumour suppression and apoptosis; hypoxia; angiogenesis; and cell adhesion and matrix degradation. The cell cycle acceleration and proliferation biomarkers showed the most divergent prognostic findings. Studies on tumour suppression and apoptosis biomarkers were the most prevalent. There were only a few studies examining molecular biomarkers of hypoxia and angiogenesis, and studies examining cell adhesion and matrix degradation biomarkers have shown that this group has the greatest potential for assessing prognostic parameters. Amongst the several proteins analysed, the immunohistochemical expression levels of epithelial growth factor receptor (EGFR), p53, and matrix metalloproteinases (MMPs) have demonstrated the greatest potential for survival prediction in OSCC, but this review demonstrates that their prognostic relevance is debatable and requires further standardisation.

Comparison of p53 and epidermal growth factor receptor gene status between primary tumors and lymph node metastases in non-small cell lung cancers

BACKGROUND

To obtain insight into the cancer progression and metastatic process, we evaluate p53/epidermal growth factor receptor (EGFR) somatic aberrations in non-small-cell lung cancers to compare accumulated genetic alterations between primary tumors and lymph node metastases.

MATERIALS AND METHODS

A total of 56 primary lung cancers with corresponding lymph node metastases were identified to investigate somatic mutations and altered expressions of p53 and EGFR for clonality assessment. Genomic DNA was extracted from macrodissected cells of paraffin-embedded primary tumor and metastatic lymph node tissues. Overexpression and somatic mutations in exons of p53 (exons 5-8) and tyrosine kinase domain of EGFR (exons 18-21) were examined by immunohistochemical staining and DNA sequencing, respectively.

RESULTS

p53 and EGFR mutation/overexpression status were different between primary tumors and lymph node metastases in 5.4/7.2% and 28.6/33.9%, respectively. In most cases, the p53 and EGFR mutations usually preceded lymph node metastasis, and these gene statuses in the primary cancer and their lymph node metastasis were concordant (92.9 and 69.6%, respectively), which further supported the hypothesis that when these p53 mutations occur before the establishment of lymph node metastasis, they subsequently persist in the metastatic nodes. The expressions of p53 and EGFR showed 7.1 and 33.9% discordance in that order.

CONCLUSIONS

Our results reveal that p53 and EGFR mutations usually precede lymph node metastasis. The higher prevalence of EGFR heterogeneity existing in the primary tumor is not reflected in all lymph node metastasis and thus might have therapeutic implications when adjuvant therapy is considered.

Prognostic value of quantitative p63 immunostaining in adenoid cystic carcinoma of salivary gland assessed by computerized image analysis

BACKGROUND

In a long-term retrospective immunohistochemical study of adenoid cystic carcinoma (ACC) of salivary gland, we investigated the relation of p63 immunodetection to prognosis. Although it is generally agreed that the solid pattern is the most aggressive pattern of growth, ACCs with predominantly cribriform or tubular patterns have an unpredictable clinical course, with a relatively favorable 5-year survival but a low 20-year survival.

METHODS

Formalin-fixed paraffin sections from 35 cases of ACC showing a predominantly better differentiated histopathology, ie, cribriform or tubular patterns of growth, were immunostained for p63. Automated image analysis was used to quantify p63 positivity, using a modification of a previously developed algorithm.

RESULTS

Patients alive for more than 10 years had a lower extent of p63 expression than those who died of disease. Kaplan-Meier analysis revealed that separation of patients with morbidity and mortality from those alive with no evidence of disease, could be achieved at a cutoff of 35% p63 positivity (P = .0031, log-rank test). Multivariate analysis using the Cox proportional hazard model revealed p63 and tumor stage to be independent predictors of survival (P = .012 and P = .0003, respectively).

CONCLUSIONS

To our knowledge, the present study is the first to report prognostic significance of p63 in salivary gland ACC and the first report of a robust and well-studied immunohistochemical stain performable on routinely fixed and processed tissue with prognostic utility.

Ki-67 and p53 correlation prognostic value in squamous cell carcinomas of the oral cavity and tongue

Epidermoid carcinomas represent from 90% to 95% of oral cavity malignant neoplasias, making up 13,470 cases/year.

Aims

To correlate p53 and Ki-67 expressions in mouth and tongue carcinomas with lymph node status, gender, histological grade, tumor volume and pathological stage.

Materials and Methods

We carried out a retrospective study of 28 cases of mouth and tongue epidermoid carcinomas. They were submitted to immunohistochemical study in order to check the expression of p53 and Ki-67 antibodies and statistically compare them in terms of lymph node status, gender, histological grade, tumor volume and pathological staging.

Results

The individually analyzed p53 proved to have statistical significance (p < 0.05) when compared to tumor volume (p=0.029). Despite a strong tendency, the p53/tumor volume relation was not significant. When p53 + Ki67 were analyzed, tumor volume had p < 0.05 (p = 0.029).

Discussion

Literature shows that the expression of p53 and Ki-67 is related to the presence of metastasis to lymph nodes and a worse prognosis.

Conclusion

In oral cavity and tongue epidermoid carcinomas, p53 and Ki-67 are related to larger tumors, metastasis to lymph nodes and very likely to a worse prognosis.

p63 contributes to cell invasion and migration in squamous cell carcinoma of the head and neck

The transcription factor p63 is commonly over-expressed in squamous cell carcinomas of the head and neck (SCCHN). By microarray analysis of p63-siRNA-treated SCCHN cells we identified 127 genes whose expression relies on over-expression of p63. More than 20% of these genes are involved in cell motility. Chromatin immunoprecipitation and reporter assay revealed PAI-1 and AQP3 as direct p63 transcriptional targets. In addition to PAI-1, most of the key cell motility-related molecules are up-regulated by p63, such as MMP14 and LGALS1. Our findings indicate a contribution by p63 in cell invasion and migration, supporting an oncogenic role for p63 in SCCHN.