Differences between preneoplastic cells, neoplastic cells and their normal counterparts

Potential Biological Markers for the Staging of Tumor Progression in Oral Mucosa: A Multivariate Analysis

A recent trend in cancer control programmes is the development of early detection strategies and chemoprevention of premalignant lesions. The present study evaluates the potential of selected markers in the biological staging of tumor progression in oral mucosa for better management of the disease. The expression patterns of various cytokeratin protein types such as 10/11, 13 & 16, 19, 18, 14 and pancytokeratin, involucrin, ras p21, epidermal growth factor (EGF) and its receptor (EGFR) were assessed immunohistochemically in various stages of tumor progression in oral mucosa. Statistical analyses such as the Kruskal-Wallis one-way ANOVA, Spearman's rank correlation and multiple regression analysis were carried out to see which proteins have a significant association with tumor progression in oral mucosa. Statistical analysis showed that the expression patterns of cytokeratin types 10/11, 14 and 19, involucrin and epidermal growth factor were significantly correlated with tumor progression in oral mucosa in both univariate and multivariate analysis. Thus the biological stage of a lesion can be calculated from the multiple regression equation derived for these proteins, which could be more useful in assessing the stage of tumor progression in oral mucosa than histopathological grading.

Epigenome and DNA methylation in oral squamous cell carcinoma

Epigenetics studies and defines inherited changes in gene expression that are not encoded in the DNA sequence. The most studied epigenetic change in mammalian DNA is cytosine methylation in CpG dinucleotide areas. The other main group in epigenetic changes includes the posttranslational modifications of histones, mainly phosphorylation, deacetylation changes, and in the ubiquitinylation status. Oral squamous cell carcinoma is the most common malignancy of the oral cavity, and epigenetic changes are very common, as described in this chapter. Alterations in the DNA methylation status resulting from exposure to environmental stress agents have been documented even before birth. Although many epigenetic markers are potentially reversible, the mechanism still remains unclear and many epigenetic changes persist across cell lines and the life of the organism.

Predictive value of flow cytometric analysis in DNA contents in patients with locally advanced head and neck carcinoma

A retrospective study was performed on 61 eligible patients with stage III and IV (AJC/UICC Staging System) squamous carcinomas of the head and neck region who were treated with definitive radiotherapy with, or without, surgery. DNA contents were measured by flow cytometric analysis of archival paraffin blocks and were correlated with clinicopathological findings, tumour response and patient survival. Comparison of variables including treatment modality was performed for identification of significant prognostic factors. There were 28 diploid, 27 aneuploid tumours and the remaining six were questionable. All patients were followed-up for at least two years or until death. Aneuploid tumours had a significantly higher S-phase fraction (percentage S-phase) (p < 0.001). Neither ploidy nor percentage S-phase were found to have predictive value in tumour response or patient survival within the power of a sample size of 61. Twenty of the 27 (74 per cent) aneuploid tumours had a complete response (CR) whereas 19 out of 28 (68 per cent) diploid tumours achieved CR. Five-year survival by the Kaplan-Meier method was 33 per cent for both aneuploid and diploid tumours. However, nodal stage (N stage) was found to have significant predictive value in both tumour response and patient survival. The complete response for stage N0 patients was 96 per cent, N1 patients 61 per cent, N2 patients 60 per cent and 43 per cent for N3 patients (p < 0.002). Similarly, the five year survival for the N0 and N3 groups of patients was 53 per cent and 29 per cent respectively (p < 0.05).

Lectin histochemistry of oral premalignant and malignant lesions: correlation of JFL and PNA binding pattern with tumour progression

The expression of glycoconjugates specific to Jack fruit lectin (JFL) and peanut agglutinin (PNA) in various clinicopathological stages of tumour progression in the oral mucosa were studied. These included various clinical forms of dysplastic and non-dysplastic oral leucoplakias, carcinomas, normal keratinising (gingiva) and non-keratinising (buccal mucosa) epithelia. It was seen that the binding patterns of PNA and JFL in the epithelial cells of various types of oral lesions were more or less similar. Normal non-keratinising epithelium showed mild membrane staining only in the spinal layers, while normal keratinising epithelium showed a moderate membrane staining and mild cytoplasmic staining in all layers. Moderate membrane and mild cytoplasmic staining were observed in leucoplakias, irrespective of various clinical or histological types. In carcinomas, the intensity of lectin binding was high, particularly in the membrane of differentiated cells. Correlation analysis of the binding pattern of PNA and JFL showed significant correlation in the membrane and cytoplasm of all layers with histological stages of tumour progression. The present study thus showed that PNA and JFL may be used as cytochemical probes in differentiating malignancy from benign lesions of the oral mucosa.

Immunohistochemical characterization of nitric oxide synthase activity in squamous cell carcinoma of the head and neck

This study was designed to investigate the presence of nitric oxide in human squamous cell carcinoma of the head and neck. We localized the activity of nitric oxide synthase in these tumors through immunohistochemical analysis using antibodies to L-citrulline (a byproduct of nitric oxide synthase), to inducible nitric oxide synthase, and to constitutive nitric oxide synthase. We found presence of inducible enzyme in squamous cells throughout these tumors, with the highest intensity staining occurring directly around keratin pearls. Our findings suggest that inducible nitric oxide synthase activity is present in squamous cell carcinomas of the head and neck, leading us to conclude that inducible nitric oxide synthase may play a significant role in tumor growth.

Argyrophilic nucleolar organizer regions in the evaluation of tumour progression in the oral mucosa: correlation with tissue pathology

The present study has analysed the numbers of argyrophilic nucleolar organizer regions (AgNOR) in normal tissues and in premalignant and malignant lesions of the oral mucosa in order to assess their potential as a biological marker for tumour progression. On comparison of AgNOR numbers in different lesions, carcinomas showed the highest number (4.65 +/- 0.98) compared to leukoplakias (2.38 +/- 0.47) and normal tissues (1.53 +/- 0.39). Spindle cell carcinomas and poorly differentiated squamous cell carcinomas had higher AgNOR counts than well-differentiated carcinomas. In various clinically different types of oral leukoplakia, the lowest AgNOR counts were observed in homogenous leukoplakia and the highest in speckled leukoplakia. No significant difference in AgNOR number was observed between non-dysplastic and dysplastic leukoplakia, although a significant difference was evident between dysplastic leukoplakia and normal oral mucosa. Correlating the AgNOR count and tumour progression, a significantly high positive correlation coefficient (r = 0.7969, P = 0.0000) was observed.

Expression of galactoside-specific endogenous lectins and their ligands in human oral squamous cell carcinoma

Human endogenous lectins have a wide spectrum of biological functions. The present study analyses the expression of beta-galactoside specific and N-acetyl-D-galactosamine specific endogenous lectins in oral squamous cell carcinomas using biotinylated neoglycoproteins. The expression pattern of beta-galactosyl-containing glycoconjugates or ligands of beta-galactoside specific lectins in these tissues was also studied using an endogenous biotinylated lectin, the human 14-kDa lectin. For comparison a galactoside specific plant lectin from mistletoe, Viscum album was also employed. The results demonstrate that oral squamous cell carcinomas mainly express accessible binding sites for lactosylated neoglycoprotein (90%) while few carcinomas expressed mild amount of N-acetyl-D-galactosamine specific binding sites (40%). There was no difference in the binding patterns of these probes between well and less differentiated carcinomas. Expression of these neoglycoprotein binding sites were mostly concentrated in immature basaloid cells, indicating a possible association with cell proliferation. The binding pattern of D-galactosyl specific lectins (human 14-kDa and mistletoe lectins) showed conspicuous differences. This feature emphasizes the caution that needs to be exercised in interpreting the biological significance of results attained using plant lectins on human tissue.

Expression of lectin-specific cellular glycoconjugates during oral carcinogenesis

The binding pattern of two lectins, concanavalin A (ConA) and peanut agglutin (PNA), in various phases of tumour progression in the oral epithelium was studied. These included non-dysplastic, dysplastic and neoplastic lesions as well as normal tissue. ConA and PNA showed intense staining in the basement membrane of all types of lesions. Little difference was observed in the staining patterns between different stages of oral carcinogenesis, either with ConA or PNA. ConA showed mild cytoplasmic and membrane staining in all types of lesions while PNA showed moderate to intense staining in both the cytoplasm and membrane of lower-layer cells in all histological groups. The present study therefore shows that these lectins have limited value in the elucidation of oral carcinogenesis and are of insignificant diagnostic value.

Characterization of a novel monoclonal antibody, 3H-1, reactive with squamoproliferative lesions and squamous-cell cancers

Immunization of mice with membranes from a virus-transformed human keratinocyte cell line (KJD-I/SV40) yielded an IgM monoclonal antibody (MAb 3H-I) which reacted with the membrane and cytoplasm of KJD-I/SV40 cells and in the perinuclear region of a squamous-cell carcinoma line (Colo-16). Immunohistochemistry of formalin-fixed, paraffin-embedded sections using MAb 3H-I gave intense staining of proliferating squamous epithelium in several characteristic patterns. Acanthotic squamous epithelium and well-differentiated squamous-cell carcinomas (SCC) demonstrated a membranous staining pattern whereas psoriatic skin and undifferentiated SCC of the head and neck exhibited diffuse cytoplasmic, focal cytoplasmic or, in some tumours, no staining. Simple squamous epithelium was unreactive. Western blotting revealed an antigen of 55 kDa. The epitope recognized by MAb 3H-I may be a marker for particular stages of squamous proliferation and differentiation.

Prognostic importance of cellular DNA content in head-and-neck squamous-cell cancers. A comparison of retrospective and prospective series

Flow cytometric DNA-ploidy measurements were performed on formalin-fixed tumour specimens from 172 patients with squamous-cell cancers (SCCs) of the head and neck region. One hundred and two samples were chosen retrospectively and a further 70 consecutive patients were analysed prospectively in order to assess the prognostic significance of DNA ploidy and DNA index (DI). There were no statistically significant differences between retrospective and prospective groups in regard to age, sex, TNM stage, ploidy or DI. Sixty-seven percent of patients were aneuploid (65% retrospective; 71% prospective). The proportion of aneuploid tumours was significantly higher among poorly differentiated tumours. Survival analysis using Cox multivariate regression modelling revealed that DNA aneuploidy and increasing DI were significant independent prognostic factors for both relapse-free and overall survival. The relapse and death rates among aneuploid subjects were approximately 3 times as high as those for diploid subjects. Patients with a DI greater than 2.11 (hypertetraploidy) experienced a 6.6-fold higher death rate than diploid subjects. These results provide strong support for the incorporation of DNA ploidy profiles into the clinical management of patients with head and neck cancer.

Acetowhite staining and its significance in diagnosis of oral mucosal lesions in women with genital HPV infections

White staining of genital mucosa after acetic acid application (3-5%) (acetowhiteness) has been commonly regarded as a sign of HPV infection, and acetic acid application is widely used as a routine diagnostic means to screen the HPV infections. However, the sensitivity and specificity of acetowhite staining to detect HPV infections has not been properly studied. The usefulness of acetic acid application in detecting oral HPV infections is not established. In this communication, the oral mucosal changes after acetic acid application were systematically recorded in 315 women prospectively followed-up for genital HPV infections, with special reference to smoking, alcohol consumption, histology, cytology and presence of HPV DNA. Strong and weak acetowhite staining were found in 2% and 38% of the patients, respectively. The mean age of these patients was 30.8 yr in contrast to 37.3 yr of the patients without acetowhite lesions, the difference being significant. In most cases, the staining was widely distributed over the buccal mucosa. Acetowhiteness on oral mucosa was seen significantly more frequently in smokers, but the staining did not show any correlation with alcohol consumption, histologic and cytologic findings, presence of HPV DNA or with glycogen content. The specificity of acetowhite staining to detect HPV DNA was 50%. Vacuolized cells were found significantly more often in PAS-positive biopsies. The mean day of the menstrual cycle of the acetic acid--positive and -negative patients at examination was 14.9 and 11.9, respectively. The results suggest that positive acetic acid staining in oral cavity should not be regarded as a diagnostic criteria for HPV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Alteration of cell surface carbohydrates associated with ordered and disordered proliferation of oral epithelia: a lectin histochemical study in oral leukoplakias, papillomas and carcinomas

Cell surface carbohydrates in healthy oral mucosa (n = 15), leukoplakias without (n = 48) and with (n = 62) dysplasia, oral papillomas (n = 6) and squamous cell carcinomas (SCCs) (n = 40) were examined using the lectins peanut agglutinin (PNA), Ulex europaeus agglutinin I (UEA I), soybean agglutinin (SBA), Helix pomatia agglutinin (HPA), and Griffonia simplicifolia agglutinin I (GS I-B4). Binding of these lectins in formalin-fixed, paraffin-embedded tissues was demonstrated using either the peroxidase-anti-peroxidase (PAP) method or the avidin-biotin method. Healthy oral epithelia revealed binding sites for these lectins mostly in the suprabasal keratinocytes with occasional PNA binding also in their basal cells. Unlike healthy mucosa, a number of leukoplakias without and with dysplasia revealed receptor sites for UEA I also in their basal layer. Only those keratinocytes undergoing squamoidal differentiation exhibited SBA binding. Staining patterns of UEA I and SBA did not vary significantly between either leukoplakias without and with dysplasia or papillomas and SCCs. Conversely, a reduction or lack of binding sites for PNA (Gal beta 1-3GalNAc), HPA (D-GalNAc alpha) and GS I-B4 (alpha D-Gal) was observed more frequently in leukoplakias with dysplasia and SCCs contrasting their counterparts lacking epithelial dysplasia. Cell surface glycosyl residues play an important role in the regulation of cell proliferation and epithelial growth. Aberrant glycosylation in oral dysplastic leukoplakias and carcinomas leading to the lack of the relevant terminal sugar residues from their cell surface carbohydrates is probably a major reason for the hyper-/disordered proliferation.