Lack of molecular markers to predict malignant potential of oral precancer

Biomarkers of malignant transformation in oral leukoplakia: from bench to bedside

Oral leukoplakia is a common precursor lesion of oral squamous cell carcinoma, which indicates a high potential of malignancy. The malignant transformation of oral leukoplakia seriously affects patient survival and quality of life; however, it is difficult to identify oral leukoplakia patients who will develop carcinoma because no biomarker exists to predict malignant transformation for effective clinical management. As a major problem in the field of head and neck pathologies, it is imperative to identify biomarkers of malignant transformation in oral leukoplakia. In this review, we discuss the potential biomarkers of malignant transformation reported in the literature and explore the translational probabilities from bench to bedside. Although no single biomarker has yet been applied in the clinical setting, profiling for genomic instability might be a promising adjunct.

Tissue biomarkers for predicting the risk of oral cancer in patients diagnosed with oral leukoplakia: A systematic review

OBJECTIVES

We performed a systematic review to evaluate the published biomarkers related to oral leukoplakia (OL), aiming to identify the biomarkers that indicate any future risk of cancer in patients with oral leukoplakia.

METHODS

A search strategy was developed for three main electronic databases: PubMed, Cochrane Library, and EBSCO, and also for Google Scholar, until February 28, 2020. The study selection was performed in a two-phase process aiming at studies assessing tissue biomarkers for "malignant transformation of OL." Risk of bias analysis of included studies was performed using the Quality in Prognosis Studies Tool.

RESULTS

From 3,130 articles initially identified by searching databases, a total of 46 studies were included in this systematic review, with a combined sample of 3,783 patients, of whom 1,047 presented with malignant transformation of a previously diagnosed OL as reported by the authors. The cancer incidence in the whole group was 27.6% (range: 5.4% to 54.1%). The studies were derived from different geographic areas, including Asia (n = 21), Europe (n = 15), North America (n = 9), and Oceania (n = 1). There were 49 different molecular biomarkers evaluated in the 46 included studies: p53 and podoplanin proteins were the most frequently reported, followed by abnormalities at particular chromosomal loci (e.g., LOH). Risk of bias analysis revealed concerns associated with "measurement of prognostic factor," "study confounding" and "statistical analysis and reporting."

CONCLUSIONS

Substantial heterogeneity and lack of standardized reporting of data among the studies were identified. The most promising biomarkers reported to have a significant association with the malignant transformation in OL included podoplanin and chromosomal loci abnormalities. A critical examination of the follow-up studies on OL published so far indicated that tissue biomarkers that could predict the risk of oral cancer in patients with OL are still in a discovery phase.

Expression of Survivin in Oral Potentially Malignant Disorders: An Immunohistochemical Study

AIM

The aim of this study was to compare the immunohistochemical expression of survivin in oral potentially malignant disorders (OPMDs) and evaluate its prognostic significance among oral leukoplakia (OL), oral submucous fibrosis (OSMF), and oral lichen planus (OLP).

MATERIALS AND METHODS

The study material consisted of 60 formalin-fixed paraffin-embedded tissue samples: 15 cases each of OL, OSMF, OLP, and normal oral mucosal epithelium as control. Survivin expression was analyzed immunohistochemically, and data analysis was accomplished using Statistical Package for Social Sciences, version 22.0 (SPSS Inc., Chicago, IL). Fisher's chi-square test was opted to compare the study groups.

RESULTS

Survivin was expressed in all the OPMDs including OL, OSMF, and OLP, but was absent in normal oral tissue samples. Higher immunoreactivity and survivin staining was observed in OLP compared to OL and OSMF whereas OL showed a significant difference in the distribution of survivin immunoexpression against OLP. An increased nuclear expression of survivin along with distribution in the basal and parabasal layers was evident in all OPMDs.

CONCLUSION

Survivin was expressed more in OLP in comparison to OSMF and OLP, indicating unfavorable prognosis. OL showed increased expression in comparison to OSMF, showing unfavorable prognosis. On the basis of this study, it was concluded that survivin may be used as an important diagnostic and prognostic marker for OPMDs.

Oral potentially malignant disorders: risk of progression to malignancy

Oral potentially malignant disorders (OPMDs) have a statistically increased risk of progressing to cancer, but the risk varies according to a range of patient- or lesion-related factors. It is difficult to predict the risk of progression in any individual patient, and the clinician must make a judgment based on assessment of each case. The most commonly encountered OPMD is leukoplakia, but others, including lichen planus, oral submucous fibrosis, and erythroplakia, may also be seen. Factors associated with an increased risk of malignant transformation include sex; site and type of lesion; habits, such as smoking and alcohol consumption; and the presence of epithelial dysplasia on histologic examination. In this review, we attempt to identify important risk factors and present a simple algorithm that can be used as a guide for risk assessment at each stage of the clinical evaluation of a patient.

Genomic profile of oral squamous cell carcinomas with an adjacent leukoplakia or with an erythroleukoplakia that evolved after the treatment of primary tumor: A report of two cases

Oral leukoplakia and erythroleukoplakia are common oral potentially malignant disorders diagnosed in the oral cavity. The specific outcome of these lesions remains to be elucidated, as their malignant transformation rate exhibits great variation. The ability to predict which of those potentially malignant lesions are likely to progress to cancer would be vital to guide their future clinical management. The present study reported two patients with tongue squamous cell carcinoma: Case study 1 was diagnosed with a simultaneous leukoplakia and case study 2 developed an erythroleukoplakia following the primary tumor treatment. Whole genome copy number alterations were analyzed using array comparative genomic hybridization. The present study determined more genomic imbalances in the tissues from leukoplakia and erythroleukoplakia compared with their respective tumors. The present study also identified in tumor and potentially malignant lesions common alterations of chromosomal regions and genes, including FBXL5, UGT2B15, UGT2B28, KANSL1, GSTT1 and DUSP22, being some of these typical aberrations described in oral cancer and others are linked to chemoradioresistance. Several putative genes associated with hallmarks of malignancy that may have an important role in predicting the progression of leukoplakia and erythroleukoplakia to squamous cell carcinoma, namely gains in BNIPL, MCL1, STAG2, CSPP1 and ZNRF3 genes were also identified.

Evaluation of Different Laser-Supported Surgical Protocols for the Treatment of Oral Leukoplakia: A Long-Term Follow-Up

PURPOSE

The aim of this study was to evaluate the long-term success rate of oral leukoplakia treatments by using different laser-supported surgical protocols.

PATIENTS AND METHODS

Overall, 2347 diagnosed homogeneous oral leukoplakias were treated with CO₂ laser and were included in this study. Different surgical protocols (P) were used: P1 (SV = superficial scanning) was a complete superficial vaporization of the leukoplakia by a scanning mode in two passages respecting an overlapping. Only the visible white area was treated in one surgical session independently of the lesion size. P2 (CR1x1) was a complete excision of the lesions until a tissular depth of 1 mm and 1 mm of surrounding healthy-like tissue were attained. The visible white area was treated in one surgical session independently of the lesion size. P3 (CR1x3) was a complete excision of the lesions until a minimum tissue depth of 1 mm and 3 mm of surrounding healthy-like tissue were obtained. The visible white area was treated in one surgical session independently of the lesion size. P4 (PR1x3) was similar to the third one, but for patient comfort, the large lesions of leukoplakias (lesion size higher than 20 mm), the complete surgical excision of the leukoplakia was performed in multiple sessions that were spaced by 1 month (partial surgical removal of 10 mm per session). All patients were recalled at 2 and 8 weeks after surgery, and then every 2 months during the first year, every 4 months during the second year, and once a year for the follow-up period of 6 years. A biopsy was done once a year during the follow-up period in the surgical site when needed. The control consisted of checking the nature and the aspect of the healed mucosa to exclude an eventual recurrence of leukoplakia.

RESULTS

The percentage of permanent success after 6 years of follow-up was 5.7%, 69.7%, 97.8%, and 71.9%, respectively, for the first surgical protocol (SV), the second (CR 1 × 1), the third (CR 1 × 3), and the fourth (PR 1 × 3). The appearance of malignant transformation after laser treatment (during the follow-up period of 6 years) was 20%, 1%, and 0.2%, respectively, for the groups treated by the following protocols: 1 (SV), 2 (CR 1 × 1), and 4 (PR 1 × 3). Only in the third group CR1x3, no dysplasia or malignant transformation was noted. On the contrary, the appearance of malignant transformation in failed treated cases was 21.21% for the protocol 1 (SV), 3% for the protocol 2 (CR 1 × 1), and 0.6% for the protocol 4 (PR 1 × 3).

CONCLUSIONS

The results of this long-term follow-up of treated patients with oral homogeneous leukoplakias pointed out that the surgical laser protocol respecting the complete excision of leukoplakias, in one session, by the removal of a minimum of 1 mm in lesion depth and 3 mm of surrounding healthy-like tissues (CR 1 × 3) offers significantly the highest success rate.

Screening for oral cancer-a perspective from the Global Oral Cancer Forum

Screening for oral cancer should be defined as the application of a test to people who are apparently free of disease to identify those who may have oral cancer and to distinguish them from those who may not. The aim of the test is not to be diagnostic but to identify changes that may be the earliest signs of impending disease. Defined in this way, screening is an ongoing public health measure, often funded by governments. A screening program must do no harm and must be cost effective. Governments demand that strict evidence of benefits and cost effectiveness be met before a program may be implemented. Although many studies have investigated the utility of potential screening tests, there have been few evaluations of screening programs and only one randomized controlled trial. Systematic reviews have concluded that there is insufficient evidence to show that oral cancer screening can reduce mortality from oral cancer, and to date, no country has implemented a formal oral cancer screening program. This paper reviews this evidence and tries to identify the barriers to screening and suggests areas of focus for future research.

The impact of clinical prognostic factors on the survival of patients with oral squamous cell carcinoma

PURPOSE

This study investigated prognostic factors and useful predictors for survival in patients with oral squamous cell carcinoma.

PATIENTS AND METHODS

The medical records of all patients with oral squamous cell carcinoma who underwent curative surgery with or without adjuvant radiation from 2009 through 2011 were retrospectively reviewed.

RESULTS

Seventy-seven patients (63 men and 14 women) were enrolled. The 2-year disease-free and overall survival rates were 67.5% and 74%, respectively. Multivariate analyses showed that a diagnostic delay longer than 2 months (hazard ratio [HR]=4.43; 95% confidence interval [CI], 1.26-15.51; P=.02), T3 or T4 tumor (HR=4.40; 95% CI, 1.91-10.12; P=.001), neck metastasis (HR=1.96; 95% CI, 1.21-4.37; P=.01), and stage III or IV disease (HR=3.94; 95% CI, 1.64-9.47; P=.002) were independent adverse factors for survival rate.

CONCLUSION

Oral squamous cell carcinoma is an important health issue associated with poor survival. A diagnostic delay longer than 2 months, T3 or T4 tumor, neck metastasis, and stage III or IV disease were independent adverse factors for subsequent survival rate and locoregional recurrence in patients with oral squamous cell carcinoma.

Cyclin D1 an early biomarker in oral carcinogenesis

BACKGROUND

Dysregulation of cell cycle is a fundamental hallmark of cancer progression. Cyclin D1, part of complex molecular system regulating G1-S point of cell cycle is overexpressed in variety of tumors.

AIMS

To look for its immunohistochemical expression in clinically normal mucosa from patients with and without tobacco habits, leukoplakia; and correlate its expression to individual atypical morphologic features, as seen in hematoxylin and eosin (H and E) sections of leukoplakia exhibiting dysplasia.

MATERIALS AND METHODS

We examined the expression of cyclin D1 in immunohistochemically stained sections of 15 normal buccal mucosa without any habits (group 1), 30 clinically normal mucosa from tobacco habituιs (group 2) and 30 leukoplakias exhibiting dysplasias (group 3). Descriptive statistical analysis performed. Results presented on Mean ± Standard deviation and in number (%). Adjusted Wald 95% Confidence Interval (CI) computed, percentages of morphological features assessed by Laplace estimate. Mann-Whitney U, Kruskal-Wallis test used to find the percentage expression of cyclin D1.

RESULTS

Expression of cyclin D1 in group 3 was significantly higher than in group 1 and 2 (P < 0.001, P = 0.028), expression in group 2 was significantly higher than in group 1 (P = 0.003) and were statistically significant. Generally expression of cyclin D1 was confined to lower one-third of epithelium and was highest in mild dysplasias. Among 13 atypical morphologic features, cyclin D1 expression consistently correlated with basilar hyperplasia.

CONCLUSION

The altered pattern of cyclin D1 expression here may be an early event in conversion of normal epithelium into dysplastic epithelium and may serve as a biomarker of oral carcinogenesis. Its expression may be increased in tobacco habitués. Basilar hyperplasia should be given additional weightage in the grading system in predicting the fate of affected epithelium.

MicroRNAs in Head and Neck Cancer

microRNAs (miRs) are small noncoding single-stranded RNAs, about 19–25 nucleotides long. They have been shown to be capable of altering mRNA expression; thus some are oncogenic or tumour suppressive in nature and are regulated by cellular and epigenetic factors. The molecular pathogenic pathway of many cancers has been modified since the discovery of miRs. Head and neck squamous cell carcinoma (HNSCC), the sixth most common cancer in the world, has recently been associated with infection by the human papillomavirus (HPV). miR expression profiles are altered in the transition from dysplasia to carcinoma, with some changes being specific to the underlying risk factor. This difference is particularly significant in HPV-positive HNSCC where host miRs are modulated by the virus, creating a different profile to HPV-negative HNSCC. Saliva, as an easily collected proximal biofluid containing numerous miRs, presents an attractive noninvasive diagnostic tool in detecting HNSCC and determining prognosis. Furthermore, miRs may play a role in the analysis of surgical margins for residual tumour extension and in the development of novel miR-based therapeutic targets and agents.

The relevance of EGFR overexpression for the prediction of the malignant transformation of oral leukoplakia

The present study evaluated the relevance of EGFR overexpression in prediction of malignant transformation of oral leukoplakia (OLP). The retrospective study comprised paraffin-embedded tissue samples of OLP that transformed into oral squamous cell carcinoma (OSCC) (n=53) and tissue samples of OLP that did not transform into OSCC (n=45) during a follow-up period of 5 years. EGFR overexpression was assessed immunohistochemically. A significantly different expression rate of EGFR was determined between transformed and non-transformed OLP (p=0.017). A statistically significant increase of EGFR expression for low dysplasia lesions in group I compared to group II was proven (D0, p=0.013; D1, p=0.049). By calculation of ROC curve and determination of highest Youden index the optimal threshold value [cut-off point (COP) = 44.96] for distinguishing the transformed from non-transformed lesions was estimated (critical expression rate of EGFR). Using the determined COP the correlation between high-risk lesions and the detection of increased expression rates were significant (p=0.001). In the future, the assessment of EGFR overexpression in OLP may allow identifying OLP lesions with an increased risk of malignant transformation that may have been regarded harmless when only the grade of dysplasia had been taken into account.

Oral squamous cell carcinoma in relation to field precancerisation: pathobiology

Squamous cell carcinoma of the oral cavity evolves within a field of precancerized oral epithelium containing keratinocytes at different stages of transformation. Following acquisition of additional genetic alterations, these precancerous keratinocytes may become cancerous.Persons with apparently successfully treated oral squamous cell carcinoma are at high risk of developing a new carcinoma at, or close to the site of the treated tumour. This second carcinoma may have developed either from malignant keratinocytes left behind at surgery (recurrence), or from transformed keratinocytes within the field of precancerized epithelium from which the primary carcinoma had arisen (new carcinoma).The cells of the new carcinoma may have genetic changes in common with the cells of the original carcinoma because both are descended from a proliferating monoclone within the precancerized field; but if the new cancer originates from a different clone, it may have a dissimilar genetic profile even if the original and the new carcinoma are closely contiguous.The purpose of this article is to review the pathobiology of oral squamous cell carcinoma in relation to fields of precancerised oral epithelium.

Evaluation of MAGE-A expression and grade of dysplasia for predicting malignant progression of oral leukoplakia

The risk of the malignant transformation of oral leukoplakia (OLP) is difficult to predict by histopathology. Melanoma-associated antigen-A (MAGE-A) expression is restricted to malignant cells and may be useful for the more accurate estimation of the potential malignant transformation of pre-malignant lesions. The aim of the present study was to investigate whether the expression of MAGE-A can be used to predict the malignant transformation of OLP. Paraffin-embedded tissue samples of OLP from 74 patients followed-up for at least 5 years were included. A total of 24 progressing and 50 non-progressing OLP, 18 corresponding tumor and 30 healthy mucosa specimens were analysed for MAGE-A 1, 3, 4, 6 10 and 12 expression by nested real‑time RT-PCR and graded for dysplasia. In total, 46% of the progressing lesions expressed at least 1 out of the examined MAGE-A antigens, whereas no expression was detected in any of the non-progressing OLP and normal specimens. The correlation between malignant transformation and MAGE-A expression was statistically significant (p=0.00001). Furthermore, 42% of the progressing OLPs without dysplasia (D0) expressed at least 1 antigen. The correlation between the grade of dysplasia and MAGE-A staining in the malignant transformation group was not significant (p=0.08). The detection of at least 1 MAGE-A antigen may allow the identification of high-risk lesions that may progress into carcinoma with time. Therefore, the investigation of MAGE-A expression should be assessed in order to obtain a more accurate evaluation of the potential cancer risk of OLP.

Antiproliferative effects of goniothalamin on Ca9-22 oral cancer cells through apoptosis, DNA damage and ROS induction

Goniothalamin (GTN), a plant bioactive styryl-lactone, is a natural product with potent anti-tumorigenesis effects for several types of cancer. Nonetheless, the anticancer effect of GTN has not been examined in oral cancer. The present study was designed to evaluate its potential anticancer effects in an oral squamous cell carcinoma (OSCC) model and to determine the possible mechanisms with respect to apoptosis, DNA damage, reactive oxygen species (ROS) induction, and mitochondrial membrane potential. Our data demonstrated that cell proliferation was significantly inhibited by GTN in Ca9-22 OSCC cancer cells in concentration- and time-dependent manners (p<0.05). For cell cycle and apoptotic effects of GTN-treated Ca9-22 cancer cells, the sub-G1 population and annexin V-intensity significantly increased in a concentration-dependent manner (p<0.001). For the analysis of DNA double strand breaks, γH2AX intensity significantly increased in GTN-treated Ca9-22 cancer cells in concentration-response relationship (p<0.05). Moreover, GTN significantly induced intracellular ROS levels in Ca9-22 cancer cells in a concentration- and time-dependent manner (p<0.05). For membrane depolarization of mitochondria, the DiOC(2)(3) (3,3'-diethyloxacarbocyanine iodide) intensity of GTN-treated Ca9-22 cancer cells was significantly decreased in concentration- and time-dependent relationships (p<0.001). Taken together, these results suggest that the anticancer effect of GTN against oral cancer cells is valid and GTN-induced growth inhibition and apoptosis influence the downstream cascade including ROS induction, DNA damage, and mitochondria membrane depolarization. Therefore, GTN has potential as a chemotherapeutic agent against oral cancer.

Detection of MAGE-A expression predicts malignant transformation of oral leukoplakia

The study aimed at checking if MAGE-A expression in oral leukoplakia (OLP) lesions is related to malignant transformation. The 48 samples of OLP that transformed to oral squamous cell carcinoma (OSCC) (group 1) and 50 samples of OLP that did not transform to OSCC (group 2) were included in the study. The expression of MAGE-A was restricted to group 1. The correlation between malignant transformation and MAGE-A occurrence in OLP was statistically significant (p < .0001). Detection of MAGE-A may allow identifying OLP with a high risk of malignant transformation giving a view to a new approach to prevention of oral cancer.

Oral Leukoplakia as It Relates to HPV Infection: A Review

Leukoplakia is the most common potentially malignant lesion of the oral cavity and can be categorised according to its clinical appearance as homogeneous or nonhomogenous. Tobacco and areca nut use, either alone or in combination are the most common risk factors for oral leukoplakia, but some oral leukoplakias are idiopathic. Some leukoplakias arise within fields of precancerized oral epithelium in which the keratinocytes may be at different stages of cytogenetic transformation. Leukoplakias may unpredictably regress, may remain stable, or may progress to carcinoma. There is a greater risk of carcinomatous transformation of idiopathic leukoplakia, of non-homogenous leukoplakia, of leukoplakia affecting the floor of the mouth; the ventrolateral surface of the tongue and the maxillary retromolar and adjoining soft palate (collectively called high-risk sites), of leukoplakia with high-grade epithelial dysplasia, and of leukoplakia in which the keratinocytes carry cytogenetic alterations associated with carcinomatous transformation. Although there appears to be some link between human papillomavirus (HPV) and oral leukoplakia, there is little evidence to support a causal relationship either between HPV infection and oral leukoplakia or between HPV-infected leukoplakic keratinocytes and their carcinomatous transformation.

Cell transformation and the evolution of a field of precancerization as it relates to oral leukoplakia

Potentially malignant oral leukoplakias arise within precancerized epithelial fields consisting of cytogenetically altered keratinocytes at various stages of transformation. The evolution of a clone of keratinocytes culminating in a precancerous phenotype is a function of the number of mutagenic events, rather than the sequential order in which they occur. The altered molecular configurations of the transformed precancerous keratinocytes may confer upon them a growth advantage in relation to the unaltered neighbouring keratinocytes. Replicative clonal expansion of these keratinocytes results in the progressive replacement of the surrounding normal keratinocytes by the fitter clone or clones of altered cells. The precancerized oral epithelial field may have a clinically normal appearance and microscopically may be normal or may show dysplasia. Oral leukoplakias arising within a precancerized epithelial field in which the keratinocytes show DNA aneuploidy or loss of heterozygosity at certain specific chromosomal loci have the potential to progress to carcinoma. The pathogenic mechanisms that drive the carcinomatous transformation of oral leukoplakias, in which cytogenetic alterations in the keratinocytes cannot be detected, are unknown.

Morphometry of the basal cell layer of oral leukoplakia and oral squamous cell carcinoma using computer-aided image analysis

Objectives:

To study and compare the changes in nuclear and cellular size, shape and nuclear–cytoplasmic ratio of the cells in the basal layer of oral leukoplakia and well-differentiated oral squamous cell carcinoma (SCC) with normal buccal mucosa, using computer-aided image analysis in tissue sections.

Study design:

This was a retrospective study conducted on tissue sections on a total number of 70 cases to determine the various morphometric parameters. The data collected in this study were analyzed statistically by computing descriptive statistics, viz., percentage, mean, standard deviation, standard error of mean, 95% confidence interval for mean. The difference in the control and study groups for various diagnostic variables was compared by means of analysis of variance (ANOVA), Student’s t-test for independent samples, wherever applicable. Mann–Whitney U-test and Kruskal–Wallis test were used where the data were found to be asymmetrical and the standard deviations were also different. The results were considered statistically significant whenever P ≤ 0.05.

Results:

Our results were significant for the morphometric parameter, size. The values of nuclear perimeter and area, cellular perimeter and area increased gradually from the normal buccal mucosa to leukoplakia, reaching the highest value in SCC. There was statistically significant difference in the nuclear and cellular areas to differentiate between leukoplakia and squamous cell carcinoma. Two variables which were used to study the shape, “form perimeter (PE)” and “contour index (CI)”, showed significant difference between normal buccal mucosa and leukoplakia and between normal buccal mucosa and SCC. The morphometric parameter, nuclear–cytoplasmic ratio, in our results showed an increase in leukoplakia and SCC compared to normal buccal mucosa, but the difference was not significant between leukoplakia and SCC.

Conclusion:

The morphometric parameter, size, was useful to differentiate between normal, potentially malignant leukoplakia and SCC.

Reference spectra from squamous epithelium and connective tissue allow whole section proteomics analysis

We reasoned that micro-dissection of tumour cells for protein expression studies should be omitted since tumour-stroma interactions are an important part of the biology of solid tumours. To study such interactions in head and neck squamous cell carcinoma (HNSCC) development, we generated reference protein spectra for normal squamous epithelium and connective tissue by SELDI-TOF-MS. Calgranulins A and B, Annexin1 and Histone H4 were found to be strongly enriched in the epithelium. The alpha-defensins 1-3 and the haemoglobin subunits were identified in the connective tissue. Tumour-distant epithelia, representing early pre-malignant lesions, showed up-regulated expression of the stromal alpha-defensins, whereas the epithelial Annexin 1 was down-regulated. Thus, tumour microenvironment interactions occur very early in the carcinogenic process. These data demonstrate that omitting micro-dissection is actually beneficial for studying changes in protein expression during development and progression of solid tumours.

Analysis of immunohistochemical expression of k19 in oral epithelial dysplasia and oral squamous cell carcinoma using color deconvolution-image analysis method

K19 is an intermediate filament protein that has been investigated in oral squamous cell carcinoma (OSCC), but that has not been correlated with the amount of keratin produced within well-differentiated OSCC grade. The aim of the present study was to objectively analyze K19 immunoexpression in OSCC and to validate the utility of K19 in differentiation among grades of oral epithelial dysplasia (OED). Formalin-fixed tissues of 36 primary OSCC (22 well, 10 moderately, 4 poorly differentiated), 43 OED (23 mild, 8 moderate, 12 severe), and 11 normal oral epithelium (NOE) were included. K19 was immunostained using HRP-DAB method. The percentage of K19-positive area was found using color deconvolution program in ImageJ(®) image analysis system (public domain software, National Institutes of Health, Bethesda, MD, USA) and analyzed using independent samples t tests and ANOVA test. K19 scores in NOE, mild, moderate and severe OED were: 1.8, 3.4, 21, and 50.3%, respectively, with significant association with the grade (t test P < 0.05). Well-differentiated OSCC with <30% keratin pearl formation expressed significantly higher K19 scores compared to well-differentiated OSCC with >30% keratin pearls (28.6 and 1.2%, respectively, P < 0.05). K19 scores in moderately and poorly differentiated OSCC were 60.8 and 61.3%, respectively. K19 scores significantly differentiated between two subgroups of tumors within well-differentiated OSCC grade and reflected histologic differentiation as well as probably predicting the clinical outcome. Combining K19 immunostain with the regular H&E stain may be helpful to facilitate and assure assigning a more accurate grade for OED.

PCNA and p53 expression in oral leukoplakia with different degrees of keratinization

Leukoplakias are oral lesions that may have many clinical and histological aspects and they are usually associated with malignancy when dysplastic alterations are shown. However, these transformations may occur in non-dysplastic lesions that show harmless clinical aspect. For this reason, the proposal was to study the p53 and PCNA immunohistochemical expression in non-dysplastic leukoplakias, trying to correlate the results only with the epithelial keratinization degree. For this, 24 leukoplakias degrees I, II and III of Grinspan were used, all of them located in oral mucosa. Most of the leukoplakias showed p53 and PCNA expression in their different keratinization degrees. The p53 marking was confined to the basal and parabasal layers, while the PCNA marking occurred in practically all epithelial layers. The expression pattern of these markers was histologically and statistically similar between the lesions with these keratinization variations. It was evident that non-dysplastic epithelium of leukoplakias showed submicroscopical signs of alterations that lead to malignant transformation, and that the keratinization degree did not correlate to a greater risk of this event.

Evaluation of myofibroblasts in oral epithelial dysplasia and squamous cell carcinoma

BACKGROUND

Carcinogenesis is accompanied by a number of changes in the adjacent stroma including the appearance of myofibroblasts. The purpose of this study was to evaluate and compare the presence of myofibroblasts in normal mucosa, oral epithelial dysplasia, and different grades of oral squamous cell carcinoma.

METHODS

The study sample consisted of three groups, including 40 oral squamous cell carcinomas, 15 dysplasias, and 15 sections of normal oral epithelium. Vimentin, desmin, and alpha-smooth muscle actin were used to identify myofibroblasts.

RESULTS

The percentage and intensity of alpha-smooth muscle actin were examined, and positive immunostaining was observed in the myofibroblasts of all squamous cell carcinomas; however these cells did not stain in the dysplasias or normal epithelium specimens. The presence of myofibroblasts was significantly higher in oral squamous cell carcinomas compared to both, dysplasias and normal mucosa cases (P < 0.001). A significant difference was not observed between the different grades of oral squamous cell carcinoma (P = 0.2).

CONCLUSIONS

These findings show the presence of myofibroblasts in the stroma of oral squamous cell carcinoma but not dysplasia and normal mucosa, suggesting further investigation to clarify the role of myofibroblasts in the carcinogenesis of this tumor.

The significance of Epstein Barr virus (EBV) & DNA topoisomerase II alpha (DNA-Topo II alpha) immunoreactivity in normal oral mucosa, oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC)

Background

Head and neck cancer including oral cancer is considered to develop by accumulated genetic alterations and the major pathway is cancerization from lesions such as intraepithelial dysplasia in oral leukoplakia and erythroplakia. The relationship of proliferation markers with the grading of dysplasia is uncertain. The involvement of EBV in oral carcinogenesis is not fully understood.

Aim

The present study was designed to investigate the role of EBV and DNA Topoisomerase II∝ (DNA-Topo II∝) during oral carcinogenesis and to examine the prognostic significance of these protein expressions in OSCCs.

Methods

Using specific antibodies for EBV and DNA-Topo II∝, we examined protein expressions in archival lesion tissues from 16 patients with oral epithelial dysplasia, 22 oral squamous cell carcinoma and 20 normal oral mucosa by immunohistochemistry. Clinical information was obtained through the computerized retrospective database from the tumor registry.

Results

DNA-Topo II∝ was expressed in all examined specimens. Analysis of Variance ANOVA revealed highly significant difference (P < 0.01) in young aged labial tissues and significant (P ≤ 0.05) in gingival and not significant (P > 0.05) in inferior surface of tongue and in hard palatal tissues. Significant differences were observed between OEDs and NSE (P < 0.001) and SCCs and controls (P < 0.001), also, significant differences could be observed between SCCs and OEDs. DNA-Topo II∝ expression was significantly higher in tumors of low differentiation versus tumors of moderate and high differentiation (P < 0.001), DNA-Topo II∝ expression was correlated with age, tumor size, tumor stage, node metastasis and tumor differentiation, but not with gender and tumor site. None of normal squamous epithelium (NSE) expressed EBV. Heterogenous reactivity for EBV was observed through the series of dysplasia and squamous cell carcinoma. Its expression increased progressively with lymph node metastasis and low tumor differentiation, but no significant association could be observed with other clinicopathological parameters. EBV protein expression was increased with elevated Topo II-∝ LI in OEDs and OSCCs. A tendency to positive correlation between EBV and Topo II∝ expression was observed in OEDs but not in OSCCs.

Conclusion

EBV and DNA Topo II-αLI expression are possible indicators in oral carcinogenesis and may be valuable diagnostic and prognostic indices in oral carcinoma.

Predictive Role of p53 Protein as a Single Marker or Associated to Ki67 Antigen in Oral Carcinogenesis

p53 over-expression has been proposed as a reliable marker associated to oral carcinogenesis, although only about 50% of oral carcinomas (OSCC) are associated with p53 over-expression and even p53-negative lesions can progress to OSCC. The aim of the study was to determine whether the combination of p53 over-expression and p53 low-expression associated with Ki67 over-expression (high Ki67/p53 ratio) could lead to a more sensitive parameter. Immunohistochemical expression of Ki67 and p53 was measured in 54 specimens from OSCC; 27 specimens from moderate/severe epithelial dysplasia; 32 specimens from oral leukoplakias without epithelial dysplasia, and 13 specimens with normal epithelium. p53 over-expression was found in 31 (53%) samples from OSCC, in 10 (37%) samples from severe dysplasias, and in 5 (15%) samples from non-dysplastic lesions, while the combination of high p53 values with high Ki67/p53 ratio was observed in 93% of OSCC, in 81% of dysplastic lesions, and in 50% of non-dysplastic lesions. This parameter may have a clinical implication to detect early lesions with an impairment of p53 pathway, and probably at risk of progress to OSCC.

Management of oral epithelial dysplasia: a review

One of the goals of the fourth meeting of The World Workshop on Oral Medicine (WWOM IV) included a review of the pathophysiology and future directions for the clinical management of patients with oral epithelial dysplasia, excluding the lips and oropharynx. In the pathophysiology review of dysplasia since WWOM III (1998-2006), a wide range of molecular changes associated with progression of dysplasia to squamous cell carcinoma were found. These include loss of heterozygosity, dysregulation of apoptosis, aberrant DNA expression, and altered expression of numerous tissue markers. Based on the literature search, no single molecular pathway has been identified as the primary factor in progression of dysplasia to squamous cell carcinoma. A systematic review of medical (i.e., nonsurgical) management strategies for the treatment of dysplastic lesions has shown promising results in short-term resolution of dysplasia in the small number of studies that met eligibility criteria for review. However, because of the limited periods of follow-up reported in these studies, it remains unclear as whether resolution of dysplasia would actually be a long-term benefit of these interventions. This question is particularly germane when it is considered in the context of prevention of future development of squamous cell carcinoma. Because of the lack of randomized controlled trials that have shown effectiveness in the prevention of malignant transformation, no recommendations can be provided for specific surgical interventions of dysplastic oral lesions either.

Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low risk) of oral epithelial dysplasia and to compare it with the WHO classification 2005. The accuracy of the new system for predicting malignant transformation was also assessed. Ninety-six consecutive oral epithelial dysplasia biopsies with known clinical outcomes were retrieved from the Oral Pathology archives. A pilot study was conducted on 28 cases to determine the process of classification. Four observers then reviewed the same set of H&E stained slides of 68 oral dysplastic lesions using the two grading systems blinded to the clinical outcomes. The overall inter-observer unweighted and weighted kappa agreements for the WHO grading system were Ks = 0.22 (95% CI: 0.11-0.35), Kw = 0.63 (95% CI: 0.42-0.78), respectively, versus K = 0.50 (95% CI: 0.35-0.67) for the new binary system. Interestingly, all pathologists showed satisfactory agreement on the distinction of mild dysplasia from severe dysplasia and from carcinoma in situ using the new WHO classification. However, assessment of moderate dysplasia remains problematic. The sensitivity and specificity of the new binary grading system for predicting malignant transformation in oral epithelial dysplasia were 85% and 80%, respectively and the accuracy was 82%. The new binary grading system complemented the WHO Classification 2005 and may have merit in helping clinicians to make critical clinical decisions particularly for the cases of moderate dysplasia. Histological grading of dysplasia using established criteria is a reproducible prognosticator in oral epithelial dysplasia. Furthermore, the present study showed that more consensus scoring on either the degree of dysplasia, assessment of risk or the presence of each morphological characteristic by a panel should be encouraged.

Interventions for treating oral leukoplakia

BACKGROUND

Oral leukoplakia is a relatively common oral lesion that in a small but significant proportion of cases changes into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment should be to prevent such malignant transformation.

OBJECTIVES

To assess effectiveness, safety and acceptability of treatments for leukoplakia.

SEARCH STRATEGY

The following databases were searched for relevant trials: Cochrane Oral Health Group's Trials Register (to April 2006), CENTRAL (TheCochrane Library 2006, Issue 1), MEDLINE (from 1966 to December 2005), and EMBASE (from 1980 to December 2005). Handsearching was performed for the main oral medicine journals. References of included studies and reviews were checked. Oral medicine experts were contacted through an European mailing list (EURORALMED).

SELECTION CRITERIA

Randomised controlled trials (RCTs), enrolling patients with a diagnosis of oral leukoplakia, were included. Any surgical or medical (topical and systemic) treatment was included. The primary outcome considered was malignant transformation of leukoplakia. Other outcomes considered were clinical resolution, histological modification and frequency of adverse effects.

DATA COLLECTION AND ANALYSIS

Data were collected using a specific extraction form. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. The validity of included studies was assessed by two review authors, on the basis of the method of allocation concealment, blindness of the study and loss of participants. Data were analysed by calculating risk ratio. When valid and relevant data were collected, a meta-analysis of the data was undertaken.

MAIN RESULTS

The possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has never been studied by means of a RCT with a no treatment/placebo arm. Twenty-five eligible RCTs of non-surgical interventions were identified: 11 were excluded for different reasons, five were ongoing studies, leaving nine studies to be included in the review (501 patients). Two studies resulted at low risk of bias, six at moderate risk of bias and one at high risk of bias. Vitamin A and retinoids were tested by five RCTs, two studies investigated beta carotene or carotenoids, the other drugs tested were bleomycin (one study), mixed tea (one study) and ketorolac (one study). One study tested two treatments. Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with the placebo. Treatment with beta carotene, lycopene and vitamin A or retinoids, was associated with significant rates of clinical resolution, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients, since drop-out rates were similar between treatment and control groups.

AUTHORS' CONCLUSIONS

To date there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion, however relapses and adverse effects are common.

Use of fuzzy neural networks in modeling relationships of HPV infection with apoptotic and proliferation markers in potentially malignant oral lesions

To evaluate in oral leukoplakia the relationship between HPV infection and markers of apoptosis (bcl-2, survivin) and proliferation (PCNA), also conditionally to age, gender, smoking and drinking habits of patients, by means of Fuzzy neural networks (FNN) system 21 cases of oral leukopakia, clinically and histologically diagnosed, were examined for HPV DNA presence, bcl-2, survivin and PCNA expression. HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR: MY09-MY11/GP5-GP6), and the HPV genotype determined by direct DNA sequencing. All markers were investigated by means of standardised immunohistochemistry procedure. Data were analysed by chi-square test, crude OR and the 95% CI; in blindness, FNN was applied. HPV DNA was found in 8/21 OL (38.1%); survivin, PCNA, and tobacco smoking were associated in univariate analysis (p = 0.04) with HPV DNA status. HPV-18 was the most frequently detected genotype (6/8), followed by HPV-16 (2/8). FNN revealed that survivin and PCNA, both being expressed in all of OL HPV+ve, were associated with HPV infection. In conclusion, the FNN allowed to hypothesise a model of specific variables associated to HPV infection in OL. The relevance of survivin and PCNA suggest that they may be involved in HPV-mediated deregulation of epithelial maturation and, conversely, that HPV may have a role in the expression level of these two markers. FNN system seems to be an effective tool in the analysis of correlates of OL and HPV infection.

Oral erythroplakia--a review

Oral erythroplakia (OE) is considered a rare potentially malignant lesion of the oral mucosa. Reports entirely devoted to OE are very few, and only two reviews none of which are of recent date have been published. Only the true, velvety, red homogeneous OE has been clearly defined while the terminology for mixed red and white lesions is complex, ill-defined and confusing. A recent case control study of OE from India reported a prevalence of 0.2%. A range of prevalences between 0.02% and 0.83% from different geographical areas has been documented. OE is predominantly seen in the middle aged and elderly. One study from India showed a female:male ratio of 1:1.04. The soft palate, the floor of the mouth and the buccal mucosa is commonly affected. A specific type of OE occurs in chutta smokers in India. Lesions of OE are typically less than 1.5 cm in diameter. The etiology of OE reveals a strong association with tobacco consumption and the use of alcohol. Histopathologically, it has been documented that in OE of the homogenous type, 51% showed invasive carcinoma, 40% carcinoma in situ and 9% mild or moderate dysplasia. Recently, genomic aberrations with DNA aneuploidy has been demonstrated. p53 mutations with different degrees of dysplasia may play a role in some cases of OE. Transformation rates are considered to be the highest among all precancerous oral lesions and conditions. Surgical excision is the treatment of choice. Data on laser excision are not available. Recurrence rates seem to be high, reliable data are, however, missing. More studies on OE are strongly needed to evaluate a number of so far unanswered questions. The natural history of OE is unknown. Do OEs develop de novo or are they developing from oral leukoplakia through several intermediate stages of white/red lesions? The possible role of fungal infection (Candida micro-organisms) is not clear as is the possible role of HPV co-infection in the development of OE. More data on incidence and prevalence, biological behaviour and adequate treatment are urgently needed.

Genetic portrait of mild and severe lingual dysplasia

Squamous cell carcinoma is the most frequent malignant tumor of the oral cavity and often arises from premalignant lesions. Traditional methods used by the pathologist are subjective and lack the sensitivity to predict accurately which precancers may progress with time. Therefore, it is important to search for markers that may identify progression of premalignant lesions. Microarray technology can be use with this aim. Here, we define the genetic expression profile of lingual dysplasia (DS) progression. By using cDNA microarray containing 19.2K clones and a baseline of 11 normal tissues, we compared 5 mild and 4 severe DS. We identified 270 genes differentially expressed in normal tissue vs. mild DS (i.e. 161 up- and 109 down-regulated) and 181 genes differentially expressed in mild vs. severe DS (i.e. 63 up- and 118 down-regulated). The described genes cover a broad range of functional activities: (a) anti-oxidative, (b) DNA-repair, (c) inflammatory response, (d) cell-adhesion/mobility, (e) extracellular matrix depolymerization, and (f) cell-cycle regulation. The data reported better define DS progression and can help in classifying premalignant lesions.

Expression of cell cycle markers and human papillomavirus infection in oral squamous cell carcinoma: Use of fuzzy neural networks

Our aim was to evaluate in oral squamous cell carcinoma (OSCC) the relationship between some cell cycle markers and HPV infection, conditionally to age, gender and certain habits of patients, and to assess the ability of fuzzy neural networks (FNNs) in building up an adequate predictive model based on logic inference rules. Eighteen cases of OSCC were examined by immunohistochemistry for MIB-1, PCNA and survivin expression; presence of HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR, MY09-MY11/GP5-GP6), and HPV genotype was determined by direct DNA sequencing. Data were analyzed by traditional statistics (TS) and FNNs. HPV DNA was found in 9/18 OSCCs (50.0 %) without any significant higher risk of HPV infection with respect to the sociodemographic variables considered (p > 0.2), apart from tobacco smoking, reported in 44.4% of OSCC HPV-positive vs. 100% HPV-negative subjects (p = 0.029). Regarding cell cycle markers, TS and FNN revealed that survivin was expressed significantly more in HPV-negative than in HPV-positive OSCC [root mean-square error (RMSE) = 5.89 x 10(-6), % predicted 100.0]; furthermore, smoking played a protective role for survivin expression in HPV-positive cases (OR = 0.019, 95%CI 0.001-0.723, RMSE = 0.20, % of prevision 94.4). FNN, although on a small sample size, allowed us to confirm data by TS and to hypothesize a different cell cycle pattern for HPV-positive vs. HPV-negative OSCC. In the latter cases, the relevance of apoptotic vs. proliferative markers suggested that they may be related to the different supposed outcome of HPV-negative OSCC and that HPV may have a protective role in the expression level of survivin, especially in tobacco smokers.

Novel management of oral cancer: a paradigm of predictive oncology

The rationale for molecular-targeted prevention of oral cancer is strong. Oral cancer is a major global threat to public health with 300,000 new cases diagnosed worldwide on an annual basis. Notably, the great morbidity and mortality rates of this devastating disease have not improved in decades. Oral cancer development is a tobacco-related multistep and multifocal process involving field carcinogenesis and intraepithelial clonal spread. Biomarkers of genomic instability, such as aneuploidy and allelic imbalance, can accurately measure the cancer risk of oral premalignant lesions or intraepithelial neoplasia (IEN). Retinoid-oral IEN studies (e.g., retinoid acid receptor-beta, p53, genetic instability, loss of heterozygosity, and cyclin D1) have advanced the overall understanding of the biology of intraepithelial carcinogenesis and preventive agent molecular mechanisms and targets, important advances for monitoring preventive interventions, assessing cancer risk, and pharmacogenomics. Clinical management of oral IEN varies from watchful waiting to complete resection, although complete resection does not prevent oral cancer in high-risk patients. New approaches, such as interventions with molecular-targeted agents and agent combinations in molecularly defined high-risk oral IEN patients, are urgently needed to reduce the devastating worldwide consequences of oral cancer.

Loss of heterozygosity at 9q33 and hypermethylation of the DBCCR1 gene in oral squamous cell carcinoma

The DBCCR1 gene at chromosome 9q33 has been identified as a candidate tumour suppressor, which is frequently targeted by promoter hypermethylation in bladder cancer. Here, we studied the possible involvement of DBCCR1 in the development of oral squamous cell carcinoma. DNA from 34 tumours was examined for loss of heterozygosity (LOH) at three markers surrounding DBCCR1 and for hypermethylation of the DBCCR1 promoter, using methylation-specific PCR and methylation-specific melting-curve analysis. LOH was found in 10 of 31 cases (32%), and DBCCR1 hypermethylation was present in 15 of 34 cases (44%). Hypermethylation of DBCCR1 was also present in three of seven epithelial tissues adjacent to the tumours, including two hyperplastic and one histologically normal epithelia. Furthermore, of four oral leukoplakias with dysplasia, one showed LOH at 9q33 and two showed DBCCR1 hypermethylation. These data suggest that LOH at 9q33 and hypermethylation of the DBCCR1 promoter are frequent and possibly early events in oral malignant development.

p53-Positive Tumor-Distant Squamous Epithelia of the Head and Neck Reveal Selective Loss of Chromosome 17

OBJECTIVES/HYPOTHESIS

The progression of clinically manifest premalignant lesions in the head and neck region to primary or second primary cancer is characterized by numerical and structural chromosomal aberrations. However, many tumors arise from histologically inconspicuous mucosal sites. The objective was to investigate whether chromosomal aberrations can be detected in tumor-distant mucosa and whether they can help predict the risk of second primary malignancy.

STUDY DESIGN

A retrospective series of 72 clinically healthy, arbitrarily taken mucosal samples from 53 patients with squamous cell carcinoma of the head and neck was studied. A previous analysis of the p53 protein status had revealed both p53-positive and p53-negative samples.

METHODS

The samples were analyzed by fluorescence in situ hybridization (FISH) using centromeric probes specific for the chromosomes 1, 10, 17, and 18.

RESULTS

Tumor-distant mucosa generally showed increased numerical chromosomal aberrations, which consisted mainly of monosomies. In the group of patients with p53-positive epithelia, all aberrations including gains of chromosomes (trisomies, tetrasomies) were more frequent. Monosomy for chromosome 17 was most significantly and selectively enhanced in this group (Wilcoxon Scores [rank sum] test, P =.0002).

CONCLUSION

Detectable chromosomal aberrations occur in clinically healthy epithelia in patients at risk for secondary head and neck cancer. Specifically, unbalanced chromosome 17 monosomy in conjunction with p53 protein overexpression may constitute a valuable biomarker for progressive "field cancerization."

Interventions for treating oral leukoplakia

BACKGROUND

Oral leukoplakia is a relatively common oral lesion that in a small but significant proportion of cases changes into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment should be to prevent such malignant transformation.

OBJECTIVES

To assess effectiveness, safety and acceptability of treatments for leukoplakia.

SEARCH STRATEGY

The following databases were searched for relevant trials: Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE, EMBASE. Handsearching was performed for the main oral medicine journals. References of included studies and reviews were checked. Oral medicine experts were contacted through an European mailing list (EURORALMED).

SELECTION CRITERIA

Randomised controlled trials (RCTs), enrolling patients with a diagnosis of oral leukoplakia, were included. Any surgical or medical (topical and systemic) treatment was included. The primary outcome considered was malignant transformation of leukoplakia. Other outcomes considered were clinical resolution, histological modification and frequency of adverse effects.

DATA COLLECTION AND ANALYSIS

Data were collected using a specific extraction form. Malignant transformation of leukoplakia, demonstrated by histopathological examination, was the main outcome considered. Secondary outcomes included clinical resolution of the lesion and variation in dysplasia severity. The validity of included studies was assessed by two reviewers, on the basis of the method of allocation concealment, blindness of the study and loss of participants. Data were analysed by calculating relative risk. When valid and relevant data were collected, a meta-analysis of the data was undertaken.

MAIN RESULTS

The possible effectiveness of surgical interventions, including laser therapy and cryotherapy, has never been studied by means of a RCT. Nineteen potentially eligible RCTs of non-surgical interventions were identified: eight were excluded for different reasons, four were ongoing studies, leaving seven studies to be included in the review. Two studies resulted at low risk of bias, four at moderate risk of bias and one at high risk of bias. Vitamin A and retinoids were tested by five RCTs (245 patients), the other drugs tested were bleomycin (one study), mixed tea (one study) and beta carotene (one study). Malignant transformation was recorded in just two studies: none of the treatments tested showed a benefit when compared with the placebo. Treatment with beta carotene and vitamin A or retinoids, was associated with significant rates of clinical resolution, compared with placebo or absence of treatment. Whenever reported, a high rate of relapse was a common finding. Side effects of variable severity were often described; however, interventions were well accepted by patients, since drop-out rates were similar between treatment and control groups.

REVIEWERS' CONCLUSIONS

To date there is no evidence of effective treatment in preventing malignant transformation of leukoplakia. Treatments may be effective in the resolution of lesion, however relapses and adverse effects are common.

Chronic hyperplastic candidosis/candidiasis (candidal leukoplakia)

Chronic hyperplastic candidosis/candidiasis (CHC; syn. candidal leukoplakia) is a variant of oral candidosis that typically presents as a white patch on the commissures of the oral mucosa. The major etiologic agent of the disease is the oral fungal pathogen Candida predominantly belonging to Candida albicans, although other systemic co-factors, such as vitamin deficiency and generalized immune suppression, may play a contributory role. Clinically, the lesions are symptomless and regress after appropriate antifungal therapy and correction of underlying nutritional or other deficiencies. If the lesions are untreated, a minor proportion may demonstrate dysplasia and develop into carcinomas. This review outlines the demographic features, etiopathogenesis, immunological features, histopathology, and the role of Candida in the disease process. In the final part of the review, newer molecular biological aspects of the disease are considered together with the management protocols that are currently available, and directions for future research.

Prognosis of oral pre-malignant lesions: significance of clinical, histopathological, and molecular biological characteristics

The concept of a two-step process of cancer development in the oral mucosa, i.e., the initial presence of a precursor subsequently developing into cancer, is well-established. Oral leukoplakia is the best-known precursor lesion. The evidence that oral leukoplakias are pre-malignant is mainly derived from follow-up studies showing that between < 1 and 18% of oral pre-malignant lesions will develop into oral cancer; it has been shown that certain clinical sub-types of leukoplakia are at a higher risk for malignant transformation than others. The presence of epithelial dysplasia may be even more important in predicting malignant development than the clinical characteristics. Three major problems, however, are attached to the importance of epithelial dysplasia in predicting malignant development: (1) The diagnosis is essentially subjective, (2) it seems that not all lesions exhibiting dysplasia will eventually become malignant and some may even regress, and (3) carcinoma can develop from lesions in which epithelial dysplasia was not diagnosed in previous biopsies. There is, therefore, a substantial need to improve the histologic assessment of epithelial dysplasia or, since epithelial dysplasia does not seem to be invariably associated with or even a necessary prerequisite for malignant development, it may be necessary to develop other methods for predicting the malignant potential of pre-malignant lesions. As a consequence of these problems, numerous attempts have been made to relate biological characteristics to the malignant potential of leukoplakias. Molecular biological markers have been suggested to be of value in the diagnosis and prognostic evaluation of leukoplakias. Markers of epithelial differentiation and, more recently, genomic markers could potentially be good candidates for improving the prognostic evaluation of precursors of oral cancer. As yet, one or a panel of molecular markers has not been determined that allows for a prognostic prediction of oral pre-cancer which is any more reliable than dysplasia recording. However, these new markers could be considered complementary to conventional prognostic evaluation.

Prognostic relevance of molecular markers of oral cancer--a review

The aim of the present article was to review the current knowledge on the prognostic value of tumour marker in the treatment of oral squamous cell carcinoma (OSCC). The literature of the past 5 years (1997-August 2002) was screened. One hundred and sixty-nine articles were included in this review, twenty-nine molecular markers of relevance were identified. Tumour markers were allocated to four groups according to their function: (i) Enhancement of Tumour Growth: Cell cycle acceleration and proliferation, (ii) Tumour Suppression and Anti-Tumour Defence: Immune response and apoptosis, (iii) Angiogenesis, (iv) Tumour Invasion and Metastatic Potential: Adhesion molecules and matrix degradation. Data showed that the prognostic relevance of most tumour markers is still not quite clear. Only 12 of 23 reports on the prognostic relevance of markers for cell cycle acceleration and proliferation indicated a significant association with prognosis while 20 of 29 studies on markers for tumour suppression and anti-tumour response showed prognostic relevance. Markers of angiogenesis exhibited only minor importance for the prognosis and treatment of OSCC. Results on markers of tumour invasion and metastatic potential appeared to be too premature for a statement regarding their prognostic value. In general, the location of markers within the tumour and not their quantitative assessment as such is emphasized. Particularly, the analysis of the invasive front of the tumour with regard to the occurrence of molecular markers is supposed to be of great importance for prognostication.

Progress in determining the malignant potential of oral lesions

The dilemma in managing patients with potentially malignant oral lesions and field change is of deciding which mucosal lesions or areas will progress to carcinoma. Although dysplasia may be predictive, this is not invariable, and there can be considerable inter- and intraexaminer variation in that diagnosis. Recent data on molecular and DNA changes in potentially malignant lesions suggest that it is now feasible to identify those lesions that are truly potentially malignant.

TP53 and head and neck neoplasms

Head and neck cancer is an important health problem around the world, accounting for approximately 500,000 new cases each year of head and neck squamous cell carcinoma (HNSCC). Carcinogenesis of head and neck results from a dysregulation of cellular proliferation, differentiation, and cell death. The major etiologic agents are tobacco and alcohol consumption and for some cases, human papilloma virus (HPV) infection. All three factors are associated with the disruption of a cellular pathway essential for the maintenance of cellular integrity, the p53 pathway. The objective of this review is to point out the specificity of p53 gene (TP53) alterations in head and neck cancer in relation with chemocarcinogenesis and to discuss whether or not the determination of p53 alterations will be of clinical relevance in the management of head and neck cancer in terms of prognosis and response to treatments.

Genomic gain of PIK3CA and increased expression of p110alpha are associated with progression of dysplasia into invasive squamous cell carcinoma

PIK3CA, encoding the catalytic subunit p110alpha of phosphatidylinositol 3-kinase (PI3K), is activated in malignant diseases. However, the role of the PIK3CA gene aberrations for tumourigenesis of head and neck squamous cell carcinoma (HNSCC) is to date unclear. The present study was designed to determine the genomic aberration of PIK3CA in invasive HNSCC and dysplastic precursor lesions by fluorescence in situ hybridization (FISH) with a YAC probe, containing the PIK3CA gene, on isolated interphase nuclei from histomorphologically well-defined regions of formalin-fixed tissue sections and to compare these data with protein and mRNA expression of p110alpha. The mRNA and protein levels of p110alpha were assessed, respectively, by in situ hybridization and immunohistochemistry on consecutive tissue sections. Copy number gains at 3q26 were observed in one of six low-to-moderate dysplasias (17%) and in seven of nine high-grade dysplasias (78%), as well as in 11 carcinomas (100%). In addition, one of seven high-grade dysplasias (14%) and 6 of 11 carcinomas (55%) had amplifications of 3q26. The majority of cases with copy number gain in more than 50% of the cells and/or amplification in more than 10% of cells showed increased p110alpha mRNA and protein expression, whereas only two cases (18%) (one high-grade dysplasia and one carcinoma) with no gain or low-level gain displayed increased p110alpha protein expression. These data suggest that 3q26 copy number gain and amplification represent early genomic aberrations in HNSCC carcinogenesis. In addition, p110alpha mRNA and protein expression in HNSCC may be regulated by these genomic aberrations as well as by epigenetic events.