Liquid-based versus conventional cytology of oral brush biopsies: a split-sample pilot study.

OBJECTIVE: The aim of this prospective split sample study was to evaluate the applicability of liquid-based cytology (LBC) of oral brush biopsies for detection of oral cancer. METHODS: Two different preparation techniques were investigated: the conventional transfer procedure to glass slides and the LBC preparation method. The obtainments of epithelial cells were performed five times with a nylon brush and transferred onto five glass slides. Additionally, the brushes, which were normally discarded, were stored in a fixative solution. Conventional slides and respective thin layers from a total of 113 cases were reviewed with both techniques. RESULTS: Thin layers showed excellent morphology on a clear background, which allowed an accurate diagnosis. In contrast, the conventional glass slides showed significantly more blood contamination and cell overlapping. The sensitivity of conventional cytological diagnosis was 96.3%, the specificity archived 90.6%, the positive predictive value was 96.3% and the negative predictive value scored 90.6%. The sensitivity of the cytological diagnosis using thin layers archived 97.5%, the specificity was 68.8%, the positive predictive value revealed 88.76% and negative predictive value was 91.7%. CONCLUSION: Our findings indicate that in oral cytology, LBC may replace other types of wet-fixed preparations using the full amount of collected cells, resulting in enhanced specimen quality archiving comparable values of diagnostic accuracy. CLINICAL RELEVANCE: LBC facilitates the cell collection due to simpler handling and less transfer errors by dentists and may improve the overall diagnostic accuracy of oral brush biopsies in future.

Clinical and cytological study of the oral mucosa of smoking and non-smoking qat chewers in Yemen.

OBJECTIVE: The study was conducted to investigate the role of qat and smoking habits on the prevalence of visible and cytological abnormalities in the oral mucosa among Yemenites. METHODS: We recruited 30 non-smoking and 30 smoking Yemenites chewing qat unilaterally for at least 5 years. We inspected oral cavities for the presence of lesions and took brush biopsies from the buccal mucosa/gingiva of the chewing/non-chewing region. RESULTS: All visible oral lesions were flat and homogeneous, and cytological changes were detected frequently. Among both non-smokers and smokers, white lesions and cytological changes were detected in 77% of all cases. On the chewing area, the proportion with white lesions ranged--depending on anatomical area and smoking status--between 47 and 93% and was significantly more frequent than on the non-chewing side (range 3-47%). The proportion of regions with changes was similar in non-smokers and smokers. Kappa statistics for "interobserver" agreement between visual inspection and cytological specimens of brush biopsies was at best fair (≤0.25). CONCLUSIONS: The high prevalence of visible lesions and cytological abnormalities among qat chewers was independent of smoking status. CLINICAL RELEVANCE: The moderate level of agreement between visual inspection and exfoliative cytology demonstrates the still challenging clinical management of chronic qat chewers, though brush biopsies including adjuvant techniques like DNA cytometry may support the clinical decision-making process in future.

Evaluation of single-cell biomechanics as potential marker for oral squamous cell carcinomas: a pilot study.

OBJECTIVES: Early detection of oral cancer is a major health issue. The objective of this pilot study was to analyze the deformability of healthy and cancer cells using a microfluidic optical stretcher (OS). MATERIAL AND METHODS: Different cancer cell lines, primary oral cancer cells, and their healthy counterparts were cultivated and characterized, respectively. A measurable deformation of the cells along the optical axis was detected, caused by surface stress, which is optically induced by the laser power. RESULTS: All cells revealed a viscoelastic extension behavior and showed a characteristic deformation response under laser light exposure. The CAL-27/-33 cells exhibited the highest relative deformation. All other cells achieved similar values, but on a lower level. The cytoskeleton reacts sensitively of changing environmental conditions, which may be influenced by growth behavior of the cancer specimens. Nevertheless, the statistical analysis showed significant differences between healthy and cancer cells. CONCLUSION: Generally, malignant and benign cells showed significantly different mechanical behavior. Cancer-related changes influence the composition of the cytoskeleton and thus affect the deformability, but this effect may be superimposed by cell cultivation conditions or cell doubling time. These influences had to be substituted by brush biopsies to minimize confounders in pursuing investigations.

Phenotypic heterogeneity of Streptococcus mutans in dentin.

Information concerning phenotypic heterogeneity of Streptococcus mutans in carious dentin is sparse. Matrix-assisted laser-desorption/ionization-time-of-flight mass-spectrometry (MALDI-TOF-MS) facilitates the phenotypic differentiation of bacteria to the subspecies level. To verify a supposed influence of restorative treatment on the phenotypic heterogeneity of S. mutans, we isolated and compared a total of 222 S. mutans strains from dentin samples of 21 human deciduous molars during caries excavation (T(1)) and 8 wks (T(2)) after removal of the temporary restoration. Phenotypic heterogeneity was determined by MALDI-TOF-MS and hierarchical clustering. Thirty-six distinct S. mutans phenotypes could be identified. Although indistinguishable phenotypes were found in the same teeth at T(1) and T(2), as well as in different teeth of individual participants, the phenotypic heterogeneity increased significantly, from 1.4 phenotypes per S. mutans-positive dentin sample at T(1) to 2.2 phenotypes at T(2). We attribute this to an adaptation of S. mutans to the modified environment under the restoration following caries excavation.

[Noninvasive brush biopsy as an innovative tool for early detection of oral carcinomas]. / Nichtinvasive Bürstenbiopsie als innovative Methode in der Früherkennung des Mundhöhlenkarzinoms.

PURPOSE: The aim of this prospective study was to investigate the diagnostic accuracy of DNA image cytometry in combination with non-invasive brush biopsies taken from suspicious oral lesions. MATERIAL AND METHODS: Cytological diagnoses obtained from 1328 exfoliative smears of 332 different lesions were compared with histology and/or clinical follow-ups of the respective patients. Additionally, nuclear DNA contents were measured after Feulgen restaining using a TV image analysis system. DNA aneuploidy was assumed if abnormal DNA stemlines or cells with DNA content greater than 9c were observed. RESULTS; The sensitivity of our cytological diagnosis in addition to DNA image cytometry on oral smears for the detection of cancer cells was 97.8%, specificity 100%, positive predictive value 100%, and negative predictive value 98.1%. CONCLUSION: The application of DNA image cytometry with DNA aneuploidy as a marker for neoplastic transformation in oral smears secures cytologic diagnosis of carcinomas. Smears from brushings of all visible oral lesions are an easily practicable, cheap, noninvasive, painless, and safe screening method for detection of oral precancerous lesions and squamous cell carcinoma in all stages. We conclude that DNA image cytometry is a very sensitive and highly specific, objective, and reproducible adjuvant tool for identification of neoplastic cells in oral smears.

Cytologic and DNA-cytometric early diagnosis of oral cancer.

OBJECTIVE: The aim of this prospective study was to report on the diagnostic accuracy of conventional oral exfoliative cytology taken from white-spotted, ulcerated or other suspicious oral lesions in our clinic. In addition we checked DNA-image cytometry as an adjuvant diagnostic tool. Our hypothesis is that DNA-aneuploidy is a sensitive and specific marker for the early identification of tumor cells in oral brushings. STUDY DESIGN: 251 cytological diagnoses obtained from exfoliative smears of 181 patients from macroscopically suspicious lesions of the oral mucosa and from clinically seemingly benign oral lesions which were excised for establishing histological diagnoses were compared with histological and/or clinical follow-ups of the respective patients. Additionally nuclear DNA-contents were measured after Feulgen restaining using a TV image analysis system. RESULTS: Sensitivity of our cytological diagnosis on oral smears for the detection of cancer cells was 94.6%, specificity 99.5%, positive predictive value 98.1% and negative predictive value 98.5%. DNA-aneuploidy was assumed if abnormal DNA-stemlines or cells with DNA-content greater 9c were observed. On this basis the prevalence of DNA-aneuploidy in smears of oral squamous cell carcinomas in situ or invasive carcinomas was 96.4%. Sensitivity of DNA-aneuploidy in oral smears for the detection of cancer cells was 96.4%, specificity 100%, positive predictive value 100% and negative 99.0%. The combination of both techniques increased the sensitivity to 98.2%, specificity to 100%, positive predictive value to 100% and negative to 99.5%. CONCLUSIONS: Brush cytology of all visible oral lesions, if they are clinically considered as suspicious for cancer, are an easily practicable, cheap, non-invasive, painless, safe and accurate screening method for detection of oral precancerous lesions, carcinoma in situ or invasive squamous cell carcinoma in all stages. We conclude that DNA-image cytometry is a very sensitive, highly specific and objective adjuvant tool for the early identification of neoplastic epithelial cells in oral smears.

Static DNA cytometry as a diagnostic aid in effusion cytology: II. DNA aneuploidy for identification of neoplastic cells in equivocal effusions.

OBJECTIVE: The sensitivity of conventional cytology for identification of neoplastic cells in effusions is unsatisfactory, about 58%. The rate of diagnostically equivocal effusions in routine cytology is about 6%. DNA aneuploidy has previously been proven to be a sensitive and specific marker for the identification of tumor cells in effusions. In the present study we determined if malignancy can be identified in cytologically equivocal cells in effusions using DNA aneuploidy as a marker, thus decreasing the rate of cytologically equivocal diagnoses in effusions. STUDY DESIGN: One hundred cytologically equivocal effusions of the serous cavities were obtained from routine diagnostic material. Nuclear DNA content was measured after Feulgen staining using a TV image analysis system. Data were correlated with patient follow-up. RESULTS: DNA aneuploidy was assumed if abnormal DNA stemlines, a coefficient of variation of the first DNA stemline > or = 10% or cells > 9c were observed. The sensitivity of DNA aneuploidy for the identification of malignancy was 55.9%. Specificity of DNA nonaneuploidy for benignity was 94.1%. The positive predictive value of the marker DNA aneuploidy for the occurrence of malignant cells was 97.9% since all but one DNA aneuploid case showed malignancy in follow-up. CONCLUSION: Image cytometry applying DNA aneuploidy as a parameter is able to detect the occurrence of malignant cells in cytologically equivocal effusions in about every second case. Thus, this method is able to increase diagnostic accuracy of conventional effusion cytology by decreasing the rate of diagnostically equivocal effusions.