Salivary Biomarkers and Their Application in the Diagnosis and Monitoring of the Most Common Oral Pathologies

Saliva is a highly versatile biological fluid that is easy to gather in a non-invasive manner—and the results of its analysis complement clinical and histopathological findings in the diagnosis of multiple diseases. The objective of this review was to offer an update on the contribution of salivary biomarkers to the diagnosis and prognosis of diseases of the oral cavity, including oral lichen planus, periodontitis, Sjögren’s syndrome, oral leukoplakia, peri-implantitis, and medication-related osteonecrosis of the jaw. Salivary biomarkers such as interleukins, growth factors, enzymes, and other biomolecules have proven useful in the diagnosis and follow-up of these diseases, facilitating the early evaluation of malignization risk and the monitoring of disease progression and response to treatment. However, further studies are required to identify new biomarkers and verify their reported role in the diagnosis and/or prognosis of oral diseases.

Different expression patterns of carbonic anhydrase IX in oral lichen planus and leukoplakia

Tumor hypoxia is an important indicator of cancer prognosis. Among the different genes that are upregulated by hypoxia is carbonic anhydrase IX, which combines carbon dioxide and water to form bicarbonate and hydrogen. Although expression of this enzyme is very low in normal tissues, carbonic anhydrase IX is overexpressed in several types of cancer. The aim of the present work was to analyze carbonic anhydrase IX expression in the two most frequent potentially malignant oral disorders: oral lichen planus and oral leukoplakia. Immunohistochemical analysis of oral lichen planus and oral leukoplakia biopsies was performed using anticarbonic anhydrase IX antibody. Samples of normal mucosa served as controls. Statistical analysis was performed by Fischer's exact test. The enzyme was detected in the epithelium of both lesions. The staining was more intense in the basal layer and decreased towards the surface in oral lichen planus. Conversely, the most intense reaction was observed in the superficial layers in leukoplakia, and staining intensity decreased towards the basal membrane. No carbonic anhydrase IX expression was seen in normal mucosa samples. Carbon anhydrase IX expression in lichen and leukoplakia epithelia shows that hypoxia plays a role in the pathogenesis of both lesions. The different distribution patterns provides further evidence of the different biological behavior of these two entities, which under certain circumstances can have similar clinical and histological features.

Nitric oxide synthase evaluation in oral precancerous and cancerous lesions

Nitric Oxide (NO) has been linked to several cardiovascular, neurological and immunological physiological and pathological functions. Several studies have shown that the eNOS, nNOS and iNOS effects on cancer cell growth and proliferation are related to the upregulation of the Wnt pathway and have a central role during metastasis development. Recent studies suggest that cancer cells undergo metabolic reprogramming, which drives cancer cell growth and progression. The aim of this study was to observe the NOS activity in the pathogenesis of oral precancerous and cancerous lesions. The results showed changes in eNOS activity levels, which increased from healthy oral mucosa to oral squamous cell carcinoma SCC, through different dysplasia levels. The iNOS activity levels increased in precancerous lesions compared to healthy mucosa, where iNOS was absent, while it decreased in SCC lesions. Moreover, a gradual increase of nNOS activity together with the progression of the lesions was also found. These results may suggest how NO could play a critical role during pathogenesis, growth and development of precancerous lesions to cancer degeneration.

Effect of methylxanthines (coffee/tea consumers) on oral precancer and oral cancer patients with smoking and smokeless tobacco habits

AIM

To study, whether the consumption of regular tea/coffee (methylxanthines) increases the risk of oral cancer in patients with smoking and smokeless tobacco habits.

MATERIALS AND METHODS

This study was conducted on a total of 90 oral cancer and precancerous patients, from western Maharashtra (India) males in the age group of 20 to 45 years who were with smoking and smokeless tobacco habits; also regular tea/coffee consumers were subjected to biochemical parameters such as aspartate transaminase (AST) and alanine transaminase (ALT) from saliva and serum of patients with oral precancer (submucous fibrosis, leukoplakia) and oral cancer patients and compared with 90-age and sex-matched controls. Individuals consent was taken to measure their biochemical parameters, by using Hafkenscheid method in whole saliva and serum. Statistical analysis of variance (ANOVA) with Tukey's correction for multiple group comparisons was performed using Student t-test.

RESULTS

Results show, that a statistically significant increase in value (p < 0.05) in ALT, AST in both saliva and serum was observed in precancerous and oral cancer patients among the study group as compared to the control group.

CONCLUSION

In the present study, there was increase in the levels of ALT, AST enzymes in both saliva and serum levels in the study group as compared to the control group which was statistically significant (p < 0.05) suggesting that long-term exposure of methylxanthines results in impairment of salivary gland antioxidant system which may affect the anticarcinogenic action of saliva.

CLINICAL SIGNIFICANCE

Oral fluids may be utilized effectively to study the variations in the biochemical constituents of saliva of leukoplakia, submucous fibrosis and oral cancer patients.

[Expression of survivin, caspase-3 in oral precancerous lesions and oral squamous-cell carcinoma]

OBJECTIVE

To investigate the roles of surviving and caspase-3 in the development of oral cancer.

METHODS

Archival tissue sections of 17 oral squamous cell carcinoma (OSCC), 28 oral leukoplakia with dysplasia, 10 normal oral mucosa were obtained from Capital Medical University School of Stomatology for immunohistochemical staining of markers of survivin and caspase-3. The cell apoptosis was detected with terminal deoxynucleotidyl transferase-mediated nucleotide shift enzyme (TdT) mediated d-UTP end labeling (TUNEL). Positively stained cells were counted and analyzed statistically to determine potential relationship between survivin, caspase-3 and cell apoptosis.

RESULTS

The expression of survivin was faint or negative in normal epithelial cells. The average positive rate of survivin was (1.05 ± 1.21)% in control group and (21.89 ± 10.45)% in OSCC. Caspase-3 was expressed in all the normal mucosa,but it obviously down-regulated in dysplasia and OSCC. The apoptosis index (AI) decreased from (0.89 ± 0.46)% in normal mucosa to (0.21 ± 0.12)% in OSCC.

CONCLUSIONS

Both survivin and caspase-3 are associated with carcinogenesis of the oral mucosa. Survivin may restrain cell apoptosis by inhibiting caspase-3.

Matrix metalloproteinase-2 matrix metalloproteinase-9 and inducible nitric oxide synthase in oral leukoplakia: immunohistochemistry and RT-PCR analysis

Oral leukoplakia is the most common and potentially malignant disorder of the oral mucosa. The definition of leukoplakia given by the World Health Organization is ?a white plaque that cannot be characterized either from a clinical or from a histopathological point of view?, thus the diagnosis of leukoplakia is based on the exclusion of other lesions of the oral mucosa. We believe it is necessary to identify molecular and immunohistochemical parameters that can contribute to discriminating between the different leukoplakia clinical subtypes coded by the epidemiology. In the present work we show the preliminary results of this research project. We investigated the expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and inducible nitric oxide synthase (iNOS) in a verrucous proliferative leukoplakia sample. By immunohistochemistry we detected the presence of all the three proteins both in the leukoplakia samples and in healthy oral mucosa, while the reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed in both samples only the expression of MMP-2 and MMP-9 but not iNOS.

Loss of expression of DNA repair enzyme MGMT in oral leukoplakia and early oral squamous cell carcinoma. A prognostic tool?

MGMT is a specific DNA repair enzyme that removes alkylating lesions and therefore plays an important role in maintaining normal cell physiology and genomic stability. Loss of expression of MGMT is associated with increased carcinogenic risk and sensitivity to methylating agents in different types of tumours. The expression of MGMT was immunohistochemically assessed in 12 normal oral mucosa, 38 oral leukoplakias and 33 early oral squamous cell carcinomas. The results were correlated with clinicopathological data. We found a significant loss of MGMT protein expression from leukoplakia when compared with early squamous cell carcinoma. We also observed a statistically significant relationship between smoking and the loss of MGMT protein expression. Loss of MGMT expression could be considered an early event in oral carcinogenesis with possible prognostic implications.

GSTM1 polymorphism and oral leukoplakia

BACKGROUND

Molecular epidemiological studies have now provided evidence that an individual susceptibility to cancer is mediated by genetic and environmental factors. Genetic polymorphisms have been described for enzymes involved in the metabolism of tobacco carcinogens and cancer risk is determined by the degree of expression and/or activity of enzymes involved in carcinogen activation or deactivation. The objective of this study was to investigate the GSTM1 null polymorphism and the risk for oral leukoplakia in individuals with tobacco-smoking habit in a Brazilian population.

METHODS

A total of 52 tobacco-smoking patients with oral leukoplakia and 52 tobacco-smoking controls were recruited in a Brazilian population. The GSTM1 genotypes were studied by polymerase chain reaction-based methods.

RESULTS

The frequency of the GSTM1 null genotype in the group with oral leukoplakia (57.7%) was statistically different from the controls (34.6%; OR: 2.57, 95% CI: 1.16-5.69, P < 0.05). The stratification of the samples according to the level of dysplasia showed increased prevalence of GSTM1 null genotype on lesions with moderate/severe histological dysplasia (68.2%) compared with the control group (31.9%). This difference was statistically significant (OR: 4.59, 95% CI: 1.29-16.33, P < 0.05).

CONCLUSION

In conclusion, the GSTM1 null genotype may increase the risk for oral leukoplakia development.

GSTT1 polymorphism and oral leukoplakia

BACKGROUND

Considering that tobacco is the main etiological factor in oral cancer and that oral leukoplakia is the most prevalent potentially malignant lesion, together with the fact that GSTT1 polymorphism increases the risk of oral squamous cell carcinoma, the purpose of this study was to investigate the GSTT1 null polymorphism and the risk of oral leukoplakia in individuals with tobacco smoking habits in a Brazilian population.

MATERIALS AND METHODS

The GSTT1 genotypes of 72 tobacco smoking patients with oral leukoplakia and 72 tobacco smoking healthy subjects were studied by PCR-based methods.

RESULTS

The frequency of the GSTT1 null genotype in the group with oral leukoplakia (48.6%) was statistically different from the controls (27.8%). After stratification, the frequencies of the null genotype in female patients, lesions with absent/mild grade of dysplasia and from low-risk sites were statistically different from the control.

CONCLUSION

The GSTT1 null genotype may increase the risk of developing oral leukoplakia.

Furin expression in squamous cell carcinomas of the oral cavity and other sites evaluated by tissue microarray technology

Furin is a proprotein convertase that activates many cancer development-related substrates such as growth factors, growth factor-receptors, adhesion molecules, and matrix degrading enzymes. Furin expression was studied in sections from tissue microarrays (TMA) and conventional paraffin blocks in a collection of squamous cell carcinomas (SCC) from three different sites. A total of 118 SCCs from the oral cavity, lung and esophagus as well as 34 precursor lesions (intraepithelial neoplasia) from the oral and bronchial mucosae were studied by immunohistochemistry. Furin expression was notably higher in most precursor lesions than in normal epithelia. Tumors from either the TMAs or the conventional blocks showed significant differences when compared to the mostly negative normal epithelia. High levels of furin expression were observed in approximately 50% SCCs of three different sites as well as in precursor lesions of the oral and bronchial mucosae. In addition another 30% showed low furin expression that was localized in all tumor cells including those in a basaloid position. Normal epithelia sometimes showed low level expression but the normal basal cells were always negative. These results show that furin is up-regulated in SCCs from three different organs and validates its use as a tumor marker in both invasive and pre-invasive neoplasia.

Correlation of telomerase activity, clinical prognosis and therapy in oral carcinogenesis

Telomerase activity is associated with most malignant tumors. To evaluate the role of telomerase reactivation as a diagnostic and prognostic marker in oral carcinogenesis activity was investigated in mortal and immortal cell lines in eight oral leukoplakias (OL) and 46 oral squamous cell carcinomas (OSCC). Activity was also investigated in 13 histopathologically unaffected mucosas from distant sites or tumor-free margins of the same patients using a modified, highly sensitive, non-radioactive telomeric repeat amplification protocol (TRAP). This was correlated with histopathological stages and the clinical course of the disease. 50% of OL and 46% of OSCC showed activity. One patient with positive, high dysplastic OL developed an OSCC 11 month later. One of three specimens of adjacent tissue presented activity and a recurrence occurred after 6 months. Out of 10 tissues of distal normal mucosa, 2 demonstrated activity which could also be proved in the corresponding tumor. Detection of telomerase reactivation may be a novel method for early detection of immortalised cell clones and malignant cells in histopathologically normal oral squamous epithelium.

[Telomerase activity in oral squamous cell carcinoma and leukoplakia]

Telomeres, the physical ends of eukaryotic chromosomes, are important to stabilize the chromosome and have a unique simple repetitive DNA sequence, TTAGGG in humans. In most normal somatic cells, telomere length becomes 50-100 bp shorter with every cell division, and the cells finally go into senescence, while most cancer cells have been reported to maintain the length and thus are immortalized. Telomeres are replicated by a special transcriptase, called telomerase, which is composed of a template RNA (hTR) and at least two component proteins: hTERT (hEST 2/hTRT) and hTEP 1 (hTLP 1/hTP1). In the present paper, I examined the status of telomerase activities in oral squamous cell carcinomas (OSCCs), precancerous lesions, and also cell lines established from OSCCs, by using a non-radioactive PCR-based TRAP (telomeric repeat amplification protocol) assay. Telomerase activities were detected in 23 of 30 OSCCs, 8 of 17 leukoplakias, 0 of 5 normal tissues, and in 8 of 8 OSCC cell lines and 0 of 5 normal human keratinocyte cultures. These results indicated that telomerase activity might have some association with carcinogenesis and might be used as a tumor marker in OSCC.

Expression of telomerase components in oral keratinocytes and squamous cell carcinomas

Telomerase activity was measured using a telomeric repeat amplification protocol (TRAP), and expressions of the telomerase components, telomerase associated protein 1 (hTEP1), human telomerase RNA component (hTR), and human telomerase reverse transcriptase (hTERT) were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) in cultured normal oral keratinocytes and oral squamous cell carcinoma (SCC) cells. Telomerase localization was analyzed by in situ hybridization (ISH) in normal, precancerous and cancerous oral tissues. There was a strong correlation of telomerase activity with the expression levels of hTERT but not with hTEP1 or hTR mRNA in the cultured cells. Not only hTEP1 and hTR but also hTERT expression were detected in the basal cells of normal oral mucosa, and the cells expressing these mRNAs were also seen in the upper layer of leukoplakia of gingiva, and a heterogeneous pattern of expression was observed in the oral SCC tissues. These results indicate that there are at least two steps in the increase of telomerase activity during carcinogenesis in oral squamous cells; a change in distribution of cells expressing these telomerase components and the over-expression of hTERT gene in individual cells.

[Glutathione-S-transferase expression in oral squamous cell carcinoma]

BACKGROUND

A large number of oral cancer patients shows poor or partial response to chemotherapy and the mechanisms are poorly understood. Glutathione-S-transferase (GST) is one of the molecules involved in resistance to natural product-based chemotherapeutics. It is an enzyme able to conjugate several substances (metabolites, drugs) to reduct glutathione. Today several isoenzymes of GST are known: GST-alpha, GST-mu, GST-pi, GST-theta. Over-expression of glutathione S-transferase-pi class isozyme is often associated with malignant transformation. Several studies reported that GST-pi staining patterns and their distribution may be helpful in identifying high-risk oral lesions. However, GST is surely involved in resistance to alchilant agents.

OBJECTIVE

To verify the possibility of implication of GST in oral cancerogenesis and in natural chemioresistance, the authors examined the protein expression patterns by immunohistochemistry in paraffin-embedded specimens of primary untreated oral cancers (OSCC).

METHODS

GST-a and GST-pi expression in 17 cases of OSCC at different degree of cellular differentiation have been evaluated by immunohistochemistry.

RESULTS

The GST-pi expression in primary tumours predominantly varied from mild to moderate levels. The GST-a expression was often quite similar to GST-pi expression with a few exceptions.

CONCLUSIONS

Expression of GST enzymes is an important signal for multidrug resistance: positive staining for both GST-pi and GST-a could constitute a hallmark of chemoresistant groups of OSSC.

Telomerase activity and in situ telomerase RNA expression in oral carcinogenesis

To investigate the role of telomerase in oral carcinogenesis, we assayed telomerase activity in various oral tissues by a modified telomeric repeat amplification protocol (TRAP) analysis. Also, using digoxigenin-labeled probes, we measured the in situ expression of human telomerase RNA component (hTR) in paired oral squamous cell carcinomas (OSCC) and adjacent non-cancerous matched tissue (NCMT). We detected telomerase activity in three OSCC cell lines, but not in primary oral keratinocytes. In patient samples, most OSCC (36/42, 86%) and oral premalignant lesions (8/12, 67%) possessed telomerase activity. In addition, 6 of 27 (22%) NCMT contained weak telomerase activity. In situ hybridization showed that hTR was expressed in almost all OSCC (23/27, 85%) as well as in the majority of NCMT (20/25, 80%). In most cases, accumulation of hTR was observed both in the nucleus and cytoplasm of epithelial cells. A correlation between hTR expression and more advanced tumor grade was observed. The appearance of telomerase activation and hTR expression during oral carcinogenesis was different. This study indicates that the activation of telomerase is an early and frequent event in OSCC.

Telomerase activity in premalignant and malignant lesions of human oral mucosa

Recent studies have demonstrated a strong association between carcinogenesis and re-activation of telomerase in various human tumors. In the present study, we have analyzed the telomerase activity in 105 oral mucosal samples, including normal mucosa and premalignant and malignant lesions, by using the telomeric repeat amplification protocol assay. The telomerase activity was detected in normal oral squamous epithelium and in 75% of the oral leukoplakias and oral carcinomas. Although the telomerase activity was observed in normal and hyperplastic squamous epithelium, it showed some relationship with certain clinico-pathological factors in malignant lesions. Telomerase activity was found to have a relationship with the grade of tumor differentiation. Of 34 well-differentiated squamous cell carcinomas, only 10 (30%) exhibited high telomerase activity, whereas in moderately or poorly differentiated squamous cell carcinomas, all seven (100%) tumors displayed high activity. In addition, the level of telomerase activity had an inverse correlation with the treatment response in the early-stage tumors, and the activity differed significantly between the tumors in the following intraoral sites: nonkeratinizing mucosa (buccal mucosa, alveolus, and floor of mouth) and tongue. This preliminary result shows that telomerase activity is present in normal oral squamous epithelium, as it is in normal hematopoietic cells and in carcinomas, and that telomerase activity has a relationship with degree of tumor differentiation and treatment response. Thus, assessing the telomerase activity may be a useful prognostic marker in oral squamous cell carcinomas.

Telomerase activity in oral leukoplakia and head and neck squamous cell carcinoma

The expression of telomerase, a ribonucleoprotein complex, is necessary to overcome cellular senescence, and it is associated with immortal cells and cancer. However, its role in precancerous lesions such as oral leukoplakias is less known. The purpose of this study is to investigate the presence of telomerase activity in oral leukoplakia and the relationship between the enzyme and multistep tumorigenesis. Telomerase activity was detectable in 14 of 16 human head and neck squamous cell carcinomas and 10 of 26 oral leukoplakia tissues. We also showed that the expression of telomerase in the premalignant lesions was associated with phenotypic progression, the degree of dysplasia. These results indicate that telomerase is activated frequently during the late stage of oral premalignancy and may play a crucial role in head and neck squamous cell carcinogenesis.

Immunocytochemical detection of ornithine decarboxylase (ODC) in paraffin-embedded tissues as a possible prognostic indicator for oral lesions

Intracellular levels of ornithine decarboxylase (ODC) are raised following mitogenic stimulus and in neoplasia. Because lesions of the oral cavity are often difficult to assess histologically, we have determined the value of immunocytochemical detection of ODC as a prognostic indicator in 74 routinely fixed and paraffin-embedded oral biopsies using peroxidase-antiperoxidase and immunogold-silver staining. The latter proved more sensitive, yielding positive reactions in 32 of 43 oral carcinomas (11/14 well differentiated, 16/21 moderately differentiated and 3/5 poorly differentiated) and 7/11 potentially malignant lesions, compared with 19/45 carcinomas and 1/15 potentially malignant lesions, by peroxidase anti-peroxidase. Hyperplastic lesions (n = 7) and normal non-keratinized buccal mucosa (n = 7) were all negative. Follow-up was possible in 13 of the carcinoma patients. Of 7 positive ODC reactions but clinically node-free at biopsy, 2 died and 2 had recurrences within 3 years, whereas all of 6 with no immunoreactivity were symptom-free after 3-5 years. Immunostaining for ODC may be helpful for the prognostic assessment of routinely processed oral lesions and in choosing treatment.

Immunohistochemical demonstration of epithelial glutathione S-transferase isoenzymes in normal, benign, premalignant and malignant human oral mucosa

The expression and localization of glutathione S-transferase (GST) isoenzymes in the epithelium of normal oral mucosa (n = 9), overlying reactive fibrous hyperplasia (n = 9), and of potentially malignant [leukoplakia (n = 25), submucous fibrosis (n = 12), verrucous hyperplasia (n = 16)] and malignant [squamous cell carcinoma (n = 36), verrucous carcinoma (n = 13)] oral lesions were examined immunohistochemically using polyclonal antibodies raised against GST isoenzymes (alpha, mu and pi) with the standard avidin-biotin-peroxidase complex (ABC) method. GST alpha, mu and pi were almost completely absent in the epithelium of normal oral mucosa and overlying benign fibrous tissues. GST alpha staining was cytoplasmic and focally positive, while GST mu staining was similar to but weaker than that seen for GST alpha. GST pi showed both cytoplasmic and nuclear staining and was expressed in 60% of leukoplakias with mild dysplasia (n = 15), 80% of leukoplakias with moderate to severe dysplasia (n = 10). 75% of submucous fibrosis samples (n = 12), 75% of verrucous hyperplasias (n = 16), 77% of verrucous carcinomas (n = 13), 81% of well-differentiated squamous cell carcinomas (n = 26) and 70% of moderate- to poorly-differentiated squamous cell carcinomas (n = 10). In addition, GST pi expression was independent of the state of differentiation of oral cancers. Since GST pi was significantly over-expressed in the oral premalignant and malignant lesions, the kinetics of GST pi-positive cells and the value of GST pi as a tumor marker in oral carcinogenesis need further investigation.

Immunological studies on the Epstein-Barr virus encoded alkaline deoxyribonuclease found in virus-producing lymphoblastoid cells

Antisera were raised against a purified recombinant form of the Epstein-Barr virus (EBV) alkaline deoxyribonuclease (DNase) expressed in Escherichia coli. These sera were shown to be reactive with lymphoblastoid cells expressing EBV antigens (B95-8, P3HR-1 and Raji). Immunostaining studies of cells expressing EBV antigens revealed that the DNase was a component of the restricted early antigen complex of EBV. Western blot analysis of these chemically induced cells revealed that the polypeptide associated with the EBV DNase has an Mr of approximately 55,000, slightly greater than that of the recombinant form, suggesting that the protein undergoes some form of posttranslational modification during virus replication. The DNase enzymic activities observed in B95-8, P3HR-1 and Raji cells following chemical induction were neutralized using the specific antiserum. A detailed examination of protein extracts from the nude mouse-passaged nasopharyngeal carcinoma cell line C-15 failed to detect any antigenic or biochemical evidence for the presence of the DNase. Immunostaining of biopsies of oral 'hairy' leukoplakia with the antisera against EBV DNase revealed high level expression in the more differentiated spinous layers of the epithelium, a pattern of reactivity identical to that observed for other lytic cycle antigens.

[The effect of antioxidants on the activity of acid hydrolases in blood leukocytes from patients with leukoplakia of mouth mucosa]

Activity of acid hydrolases, alkaline phosphatase and leucine aminopeptidase was studied in leukocytes of patients with leukoplakia of mouth mucosa before and after the treatment involving antioxidant drugs. The enzymatic activity studied was increased in leukoplakia. Cryotherapy combined with antioxidants and the treatment with antioxidants only contributed to a decrease in these enzymes activity.

Histoenzymological features of epithelial cells in lesions of oral mucosa in cysts and ameloblastomas of jaws

A histoenzymological study was carried out on 41 tissue specimens removed at biopsy and for surgical operations of the following lesions: benign hyperkeratosis, lichen planus, severe epithelial dysplasia, carcinoma in situ, epidermoid carcinoma, radicular cyst, odontogenic keratocyst and ameloblastoma. The purpose of this study was to study some possibly significant variations in levels of activities of oxidative enzymes, diaphorases, acid phosphatases and Naphthol esterases in such lesions (normal oral mucosa and epidermis serving as controls). In the lesions of the oral mucosa, these histoenzymological variations were not sufficiently characteristic to contribute to histological diagnosis. In lichen planus, some vacuolated or necrotic basal cells lacked enzyme activities, whereas in the upper layers, enzyme activities were irregularly present. Benign hyperkeratosis showed enzymatic activities similar to those of the normal epidermis, namely high oxidative activities particularly prominent in basal cells and in granular layer, and esterase activity beneath the keratinized layer. In severe epithelial dysplasia, carcinoma in situ and epidermoid carcinoma, numerous variations of activities of oxidative enzymes, esterases and acid phosphatase were seen from one cell to the other. In cystic diseases of jaws, enzymatic activities were equally nonspecific in the epithelial lining of the radicular cyst and the odontogenic keratocyst (activities similar to those of normal oral epithelium and epidermis, respectively). But in common ameloblastoma, there was diffuse uniformly low oxidative enzymatic activities in the epithelium and high widespread activity of alkaline phosphatase in the stroma. The latter may be useful in differentiating the cystic acanthomatous variety of ameloblastoma from odontogenic keratocysts of the jaws.

[Histoenzymological characteristics of epithelial cells in oral mucosal lesions and jaw cysts. Diagnostic significance]

An histoenzymological study (including oxidative enzymes, diaphorases, acid and alkaline phosphatases and naphtolesterases) of 41 biopsy and operation specimens revealed interesting factors in the diagnosis of some lesions of the buccal mucosa, and also of cysts and ameloblastomas of the jaw. When compared with normal buccal mucosa and epidermis, the enzymatic activities found in the oral lesions, fell into three different types. In non dysplasic leukoplakia, enzymatic activities were found that were similar to those of the epidermis (high oxidative activities, particularly prominent in basal cells and in the granular layer and esterasic activity beneath the keratinised layer). In lichen planus, some vacuolized or necrotic basal cells occurred which lacked enzymatic activity. In the upper layers, the distribution of the enzymes was irregular. In severe dysplasia and epidermoid carcinoma, numerous variations of oxidative, esterasic and acid phosphatase activities were seen from one cell to another. Among the lesions of the jaws, radicular cysts as well as dentigerous cysts, had low enzymatic activities, similar to those of normal buccal epithelium. The epidermoid cysts (keratocysts), because of their highly differentiated keratinization, like leukoplakia, had the same enzymatic activities as epidermis. The enzymatic activities of common ameloblastoma differed from those of malpighian tissues (low oxidative activities without decreasing gradient). Besides round epithelial nests, the stroma showed a high and widespread alkaline phosphatase activity, which indicated a low degree of odontogenic induction. Thus, this peculiar stromal activity may be useful in differentiating between cystic epidermoid varieties of ameloblastoma and the other epidermoid cysts of the jaws.

Serum alkaline deoxyribonuclease in oral cancer and premalignant lesions

Serum activities of alkaline deoxyribonuclease were assayed in 61 patients with oral squamous cell carcinoma, 23 with oral keratosis (a possible premalignant lesion), and 48 matched controls. The activity of alkaline deoxyribonuclease was significantly greater in patients with oral cancer than in either those with oral keratosis, or controls. The activities of deoxyribonucleases in keratosis were greater than in controls but not at a significant difference.