An overview of the prevention of oral cancer and diagnostic markers of malignant change: 2. Markers of value in tumour diagnosis

Identification of AgNORs and cytopathological changes in oral lichen planus lesions

OBJECTIVE

To evaluate cytopathological changes in epithelial cells of the oral mucosa of patients with oral lichen planus (OLP) compared with patients without OLP.

SUBJECTS AND METHODS

Swabs were collected from the oral mucosa of 20 patients with OLP (case group) and 20 patients without OLP (control group) using liquid-based cytology. After Papanicolaou staining, the smears were characterized based on Papanicolaou classification and degree of maturation. Nuclear area (NA) measurements, cytoplasmic area (CA) measurements, and the NA/CA ratio were determined from 50 epithelial cells per slide. For quantification of argyrophilic nucleolar organizer regions (AgNORs), the smears were stained with silver nitrate, and the number of AgNORs was counted in 100 cells.

RESULTS

In both groups, there was a predominance of Papanicolaou Class I nucleated cells in the superficial layer. The average values of NA (p>0.05) and CA (p=0.000) were greater in the case group (NA=521.6, CA=22,750.3) compared with the control group (NA=518.9, CA=18,348.0). The NA/CA ratio was 0.025 for the case group and 0.031 for the control group (p=0.004). There was no significant difference between the mean AgNORs values of both groups (p>0.05).

CONCLUSION

The oral mucosa of patients with OLP exhibited significant cytomorphometric changes. However, there was no evidence of malignancy.

Actinic lesions in fishermen's lower lip: clinical, cytopathological and histopathologic analysis

INTRODUCTION

Actinic cheilitis (AC) is considered to be a pre-malignant lesion or an incipient and superficial form of lip squamous cell carcinoma. It is commonly found in individuals whose occupational activities are related to chronic sun exposure and the definitive diagnosis is performed with biopsy. Although Exfoliative cytology has been used as a screening procedure to evaluate cancer of the oral cavity no studies have proposed the use of exfoliative cytologic analysis to evaluate and diagnose AC.

OBJECTIVE

The purpose of this study was to evaluate lower lip lesions on fishermen related to chronic solar exposure using clinical, cytologic and histopathologic analyses.

PATIENTS AND METHODS

Smears taken from the vermilion of the lower lips of 125 fishermen and 30 control individuals were subjected to cytologic analysis.

RESULTS

The harvested cells were sufficient for cytologic analysis in 83.2% of the samples. Sixteen fishermen exhibited prominent lower lip lesions that justified biopsy and histological studies. In total, 4 specimens were malignant (3.2%), and 12 displayed epithelial dysplasia, demonstrating that the prevalence of epithelial dysplasia and malignant lesions was high among the fishermen population. These conditions were strongly associated with infiltration and blurring of the vermilion margin of the lower lip.

CONCLUSION

The cytologic analysis was not useful for detecting epithelial dysplasia or malignant alterations.

Optical molecular imaging of epidermal growth factor receptor expression to improve detection of oral neoplasia

BACKGROUND

The development of noninvasive molecular imaging approaches has the potential to improve management of cancer.

METHODS

In this study, we demonstrate the potential of noninvasive topical delivery of an epidermal growth factor-Alexa 647 (EGF-Alexa 647) conjugate to image changes in epidermal growth factor receptor expression associated with oral neoplasia. We report a series of preclinical analyses to evaluate the optical contrast achieved after topical delivery of EGF-Alexa 647 in a variety of model systems, including cells, three-dimensional tissue cultures, and intact human tissue specimens using wide-field and high-resolution fluorescence imaging. Data were collected from 17 different oral cancer patients: eight pairs of normal and abnormal biopsies and nine resected tumors were examined.

RESULTS

The EGF-dye conjugate can be uniformly delivered throughout the oral epithelium with a penetration depth exceeding 500 microm and incubation time of less than 30 minutes. After EGF-Alexa 647 incubation, the presence of oral neoplasia is associated with a 1.5- to 6.9-fold increase in fluorescence contrast compared with grossly normal mucosa from the same patient with both wide-field and high-resolution fluorescence imaging.

CONCLUSIONS

Results illustrate the potential of EGF-targeted fluorescent agents for in vivo molecular imaging, a technique that may aid in the diagnosis and characterization of oral neoplasia and allow real-time detection of tumor margins.

Metal and Ceramic Bracket Effects on Human Buccal Mucosa Epithelial Cells

Objective: To test the null hypothesis that metal and ceramic brackets have no effect on the epithelial cells of the buccal mucosa.

Materials and Methods: Two metal and two ceramic brackets were bonded in 21 individuals of both sexes. With the use of liquid-based exfoliative cytology, morphometric and morphologic changes in buccal mucosa cells adjacent to these brackets were determined and were compared at three time points: baseline (T0), 60 days after placement (T1), and 30 days after removal of the brackets (T2).

Results: A decrease in nuclear area and an increase in cytoplasmic area occurred in the buccal mucosa cells adjacent to the brackets at T1 (P < .01). At T2, this altered morphometry persisted only in cells adjacent to the metal brackets, although to a lesser degree than at T1 (P < .01). A greater decrease in nuclear area was noted in cells adjacent to the metal brackets than in those next to the ceramic brackets (P < .01). At T0, the proportions of surface and subsurface cells were similar, but at T1, a predominance of surface cells was observed (P < .05). At all time points, smears of cells appeared normal or normal with some inflammatory changes.

Conclusion: The hypothesis is rejected. Placement of metal and ceramic brackets in the buccal cavity induces cellular alterations. These alterations do not suggest malignancy.

LHX6 is a sensitive methylation marker in head and neck carcinomas

Head and neck cancer remains a morbid and often fatal disease and at the present time few effective molecular markers have been identified. The purpose of the present work was to identify new molecular markers for head and neck squamous cell carcinoma (HNSCC). We applied methylation-sensitive arbitrarily primed PCR (MS/AP-PCR) to isolate sequences differentially methylated in HNSCC. The most frequently hypermethylated fragment we found maps close to a cytosine guanine dinucleotide (CpG) island on chromosome 9q33.2, and hypermethylation of this CpG island was associated with transcriptional silencing of an alternative transcript of the LHX6 gene. Using combined bisulfite restriction analysis (COBRA), hypermethylation of this fragment was detected in 13 of 14 (92.8%) HNSCC cell lines studied and 21 of 32 (65.6%) primary tumors, whereas little or no methylation was seen in 10 normal oral mucosa samples. We extended this investigation to other cancer cell lines and methylation was found in those derived from colon, breast, leukemia and lung, and methylation was also found in 12/14 primary colon tumors. These findings suggest that differentially methylated (DIME)-6 hypermethylation is a good cancer marker in HNSCC as well as in other kinds of neoplasias and confirm the importance of searching for markers of epigenetic dysregulation in cancer.

Micro-Raman spectroscopy for optical pathology of oral squamous cell carcinoma

Micro-Raman spectra of formalin-fixed oral squamous normal and carcinoma tissues, stored at room temperature for 2 months, have been recorded. Spectra were recorded both in the epithelial and subepithelial regions of the tissues. No noticeable spectral contamination due to formalin was observed. Very significant differences between spectra of normal epithelial and malignant epithelial samples were found. No such differences in spectra of subepithelial malignant and subepithelial normal samples could be observed. This study shows that spectra from the epithelial region changes drastically because of malignancy-induced biochemical changes in this region. Major differences between normal and malignant spectra seem to arise from the protein composition, conformational/structural changes, and possible increase in protein content in malignant epithelia. The differences between normal epithelial and subepithelial spectra, as expected, arise mainly from the collagen in subepithelial tissue. Principal component analysis of the combined sets of spectra-epithelial and subepithelial, normal and malignant- showed that very good discrimination can be achieved by Raman microspectroscopy. This study thus validates the suitability of formalin-fixed tissues for optical pathology in oral malignancy.