Chromosomal damage and apoptosis in exfoliated buccal cells from individuals with oral cancer

State of Art of Micronuclei Assay in Exfoliative Cytology as a Clinical Biomarker of Genetic Damage in Oral Carcinogenesis: A Systematic Review and Meta-Analysis

Oral squamous cell carcinoma (OSCC) is the most common oral malignancy, often preceded by oral potentially malignant disorders (OPMDs). Currently, no clinical biomarkers exist to predict malignancy, necessitating OPMD follow-up. Habits and environmental factors, such as smoking, and alcohol consumption, influence OSCC onset. Micronuclei (MNs) formation has been linked to normal mucosa to OSCC progression. Non-invasive diagnostic tests like exfoliative cytology offer painless and regular monitoring options. This study evaluates the impact of tobacco, alcohol, and pesticide exposure on MNs occurrence in exfoliative cytology-collected oral mucosal cells, assessing their potential as non-invasive biomarkers for OSCC development prediction and monitoring in high-risk patients. Despite results from this meta-analysis supporting the existence of a stepwise increase from controls to patients with OPMD to OSCC, the translation of these findings into clinical practice is limited due to intra- and inter-individual heterogeneity, as well as methodological variability in MNs quantification. Various factors contribute to this heterogeneity, including demographic variables, methodological variables in different laboratories, staining techniques, sample collection location, and patient characteristics. All these points were discussed to provide further insights and improve standardization for future studies.

Cytogenetic analysis (buccal micronucleus cytome assay) of radioactive waste management workers

The Russian Federation is implementing a program for dismantling nuclear-powered submarines and nuclear service vessels decommissioned from the Navy. Program personnel may be exposed to mutagenic and carcinogenic factors, including ionizing radiation. Improved preclinical health diagnostics are desirable, for timely identification of health effects, optimization of preventive measures, and medical interventions. We used an improved version of the buccal micronucleus cytome assay (BMCyt) to conduct cytogenetic status assessment of 59 employees of the Far Eastern Center for Radioactive Waste Management (DalRAO). We observed a statistically significant increase in the frequency of buccal epithelial cells with cytogenetic abnormalities (2.31‰ versus 1.15‰) and a small decrease in the apoptotic index (42 % versus 44 %) in the exposure group vs. controls. An accumulation index of cytogenetic disorders (the ratio of cells with nuclear abnormalities to cells in apoptosis) was determined and significant differences were found between the exposure and control groups. The proposed approach is simple, non-invasive, and highly informative for monitoring the health status of personnel exposed to complex factors in the working environment.

Cytogenotoxicity Evaluation of Young Adults Exposed to High Levels of Air Pollution in a Mexican Metropolitan Zone Using Buccal Micronucleus Cytome Assay

Air pollution has become a serious public health problem globally. Recent studies support the harmful effect of air pollution on human health, in addition to scientific evidence that recognizes it as a human carcinogen. The buccal micronucleus cytome (BMC) assay is employed extensively to measure cytotoxic and genotoxic damage in a population exposed to environmental contamination. The objective of this study was to evaluate the cytotoxic and genotoxic effects in healthy young adults exposed to different levels of air pollution and to identify areas with air pollution rates above the regulatory limits. This study was performed through the BMC assay in oral mucosa samples from 80 healthy young adults from the Guadalajara metropolitan zone. Three highly contaminated areas were taken into account: Tlaquepaque, Miravalle, and Las Pintas. Las Aguilas, a less contaminated area, was used as a reference. The frequencies of nuclear abnormalities in the areas with the highest and lowest levels of air pollution were compared with the Mann–Whitney U test. In addition, an analysis of the concentration of environmental pollutants, particulate matter ≤ 10 μm (PM10), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO), were carried out in the mentioned areas, in order to identify the events above the regulatory limits in a year period. The results showed that young adults exposed to a higher concentration of pollutants showed higher frequencies of nuclear abnormalities. The individuals from the areas of Tlaquepaque, Miravalle, and Las Pintas showed cytotoxic damage since statistically significant differences were found in the abnormalities of pyknotic nuclei (PNs), condensed chromatin (CC), karyorrhexis (KX), and karyolysis (KL). The individuals who showed the most cytotoxic damage were from the Las Pintas area with higher frequencies in nuclear abnormalities (PNs, CC, KX, and KL) (p < 0.0001). Genotoxic damage was found in individuals from two zones, Miravalle and Las Pintas, with statistically significant differences in the abnormality of nuclear buds (NBUDs) (p < 0.0001). Our results suggest that exposure to high levels of air pollution in healthy young adults has an effect on cellular and nuclear integrity and thus in human health, since areas with higher air pollution showed an increase in cytotoxicity, specifically in early and late markers of cell death (CC, KX, PN, and KL) and genotoxic damage (BUDs).

DBD-FISH, an effective marker for detecting genotoxicity in buccal mucosa exfoliated cells of patients with oral cancer

Oral squamous cell carcinoma (OSCC) is characterized by increased genetic instability as an essential variable of event of neoplastic transformation. The aim of this study was to evaluate genomic instability in exfoliated cells from the buccal mucosa of patients with OSCC vs. the control group, using DNA Breakage Detection/Fluorescence In Situ hybridization (DBD-FISH). Exfoliated cells from the buccal mucosa were obtained from 38 patients with oral cancer (case group) and from 10 individuals without oral lesions (control group). DNA damage was evaluated by DBD-FISH using the whole-genome DNA probe and digital imaging analysis. Collaterally, HPV infection was determined utilizing the INNO-LiPA HPV kit. Patients with OSCC showed an increase in the hybridization signal five times more intense than that of the baseline level of DNA damage detected in control individuals. The best cutoff value for predicting oral squamous cell carcinoma was 67.46, and an Odds Ratio (OR) value of 87. HPV detection analysis revealed than one patient with OSCC (2.6%) was positive for HPV. All controls were negative HPV. In conclusion, DBD-FISH permitted the clear visualization of level high of DNA damage in the buccal epithelial cells of patients with OSSC respect to control group. Chromosome instability in oral mucosa may be an individual marker of malignant transformation in OSCC.

Micronuclei and upper body cancers (head, neck, breast cancers) a systematic review and meta-analysis

A systematic review and a meta-analysis were performed on 19 studies on head and neck cancer (HNC) and 21 studies on breast cancer (BC) to evaluate the application of micronucleus (MN) assay as a predictive and prognostic test for cancer risk. In these studies the MN test was applied in peripheral lymphocytes and buccal cells of patients and healthy subjects with family history of cancer. The meta-analysis on MN applied in buccal cells of HNC patients was performed on two subgroups of studies. A significant increase of MN frequency in patients compared to healthy controls was observed for the subgroup on oral cancer (243 cases/370 controls, meta-MR = 4.71 95 %CI:2.75-8.06) and HNC (204 patients/163 controls metaMR=2.28 95 %CI:2.02-2.58). A metaMR = 3.27 (95 %CI:1.41-7.59) was obtained for MN applied in peripheral lymphocytes on HNC (160 cases/160 controls). For BC, the analysis of MN in peripheral lymphocytes showed significantly higher values in patients (n = 761) than in controls (n = 788) (meta-MR1.90 95 % CI:1.44-2.49). No statistically significant increase of baseline MN was detected in studies on groups of healthy subjects with BC family history (n = 224) or with BRCA1/2 mutations (n = 101) with respect to the controls. After ex-vivo challenge with ionizing radiation, the meta-analysis revealed a slightly statistically significant increase in MN only in BC patients (n = 614) compared to controls (n = 622)(meta-MR = 1.11 95 %CI:1.02-1.21); no increase was observed in healthy subjects with BC family history carrying or not BRCA1/2 mutations. Significant difference between BC patients (n = 183) and controls (n = 165) was observed by the meta-analysis of data on MN in buccal cells (MR = 3.89 95 %CI:1.54-9.78). The MN assay in buccal cells has some perspective of clinical application in HNC.

Cytogenetic and micronuclei study of human papillomavirus-related oral squamous cell carcinoma

BACKGROUND

The association of human papilloma viral infection in oral squamous cell carcinoma is well studied in the Western countries, but its correlation with DNA damage in the form of micronuclei (MN) formation, ceased apoptosis or presence of chromosomal abnormalities has not yet been studied.

AIM

The aim of this study is to find any possible correlation between human papillomavirus (HPV) infection and cytogenetic damage in the oral malignant and premalignant population of West Bengal.

SETTINGS AND DESIGN

A total of 104 malignant and 103 premalignant cases were selected along with 200 controls.

METHODS

The buccal smear samples were Pap stained for the detection of MN, apoptosis frequency and koilocytes. The buccal swab samples were processed for DNA extraction followed by polymerase chain reaction for the detection of HPV DNA. The peripheral venous blood samples were processed for the detection of any chromosomal abnormality, by the method of human leukocyte culture followed by Giemsa staining.

STATISTICAL ANALYSIS USED

Correlation analysis using GraphPad Prism software was used in this study.

RESULTS

About 34.6%, 42.3% and 6.73% of malignant and 6.79%, 3.88% and 20.38% of premalignant cases showed the presence of HPV DNA, koilocytes and apoptosis, respectively. The difference between the MN frequencies of premalignant and malignant oral lesions with the control group is significant with respect to various risk factors (P < 0.05). One percentage of malignant cases showed the presence of chromosomal break.

CONCLUSION

A considerable percentage of malignant cases showing the presence of koilocytes and viral DNA may indicate the effect of HPV infection leading to the malignancy, which can be correlated with the MN and apoptosis frequency.

Micronucleus Study on Breast Cytology Aspirate Smears and its Diagnostic Utility

Background:

Micronucleus is a small fragment of nucleus present in the cells which have undergone chromosomal damage. It is used as a biomarker of genomic damage.

Aims:

We aim to study the presence of micronucleus on breast cytology smears and the use of scoring the micronucleus as an additional criteria for the classification of breast lesions with emphasis on borderline gray zone categories.

Settings and Design:

This is a cross-sectional retrospective descriptive study.

Materials and Methods:

Retrospective analysis of breast cytology smears received over a period of 2 years formed the basis of the study. Micronucleus scoring was done by counting the number of micronuclei in 1000 epithelial cells under oil immersion and compared in the benign, adenosis, usual/atypical ductal hyperplasia, and the three grades of infiltrating ductal carcinomas.

Statistical Analysis:

Descriptive analyses and one-way analysis of variance was used for statistical analysis.

Results:

Of the 243 cases, the average statistically significant (P < 0.05) micronuclei scores of the benign (190), adenosis (7), usual (11)/atypical (5) hyperplasia, grade 1, 2, and 3 carcinomas (30) were 0.5, 2, 2.9, 6.6, 13.2, 20.6, and 27.5, respectively (the corresponding median scores were 0.5, 2, 3, 6, and 20, respectively). Micronucleus score of ≤1 had a high sensitivity (100%) and specificity (99%) in confirmation of benign cases. Micronucleus score of ≥5 and <10 had a moderate sensitivity (60%) but a high specificity of 99% in detecting atypical ductal hyperplasia. Micronucleus score of ≥10 had a high sensitivity (96%) and specificity (99%) of detecting carcinomas.

Conclusion:

Micronucleus scores showed a gradual increase across the categories proving the gradual occurrence of genomic damage. Micronucleus scoring serves as an additional criterion for the diagnosis of breast lesions.

Assessment of cytotoxic and genotoxic effects of conventional and whitening kinds of toothpaste on oral mucosa cells

OBJECTIVE

This study aimed to evaluate possible DNA damages to oral epithelial cells exposed to whitening kinds of toothpaste considering the effect of conventional non-whitening toothpaste.

MATERIALS AND METHODS

Sixty volunteers were assigned into three experimental groups, each of them using a different regular toothpaste for the initial 2 months, followed by the use of whitening kind of toothpaste of the same brand for next 2 months. The oral epithelial cells were sampled prior and 30, 60, 90 and 120 days after the beginning of the use of tested kinds of toothpaste. Chromosomal damages were analyzed by micronucleus assay.

RESULTS

For just one kind of tested whitening toothpaste was observed the significant increase in the number of micronucleated cells after 60 days of use compared values obtained 60 days of usage of conventional non-whitening toothpaste (6.35 ± 3.67 and 2.8 ± 1.91; p < .05). There was no statistically significant difference in other micronucleus assay endpoints between tested types of toothpaste at either of the sampling times during the period of toothpaste application.

CONCLUSIONS

Based on the results, it can be concluded that the use of certain whitening kinds of toothpaste may cause a limited biologically insignificant genotoxic effect on buccal epithelial cells.

Evaluation of Various Nuclear Cytological Changes in Normal Buccal Mucosa and Peritumoural Area in Patients with Oral Squamous Cell Carcinoma Receiving Concomitant Chemoradiotherapy

Objectives. To evaluate the role of serial cytological assay in calculating the nuclear response of contralateral normal buccal mucosa and peritumoural area of squamous cell carcinoma of oral cavity in patients receiving fractionated radiotherapy (RT) and chemotherapy. Materials and Methods. This prospective, nonrandomized study was comprised of 76 histologically confirmed cases of oral squamous cell carcinoma on cyclical chemoradiation treatment. Chemoradiosensitivity was evaluated using serial scrape smears taken before and after immediate exposure to CCRT, at 17th day of CCRT (mid of treatment), and at the end of treatment. The nuclear changes, such as multinucleation, micronucleation, karyorrhexis, karyolysis, nuclear budding, prominent nucleoli, and binucleation occurring in both irradiated cancer cells and contralateral normal buccal mucosa, had a statistically significant dose related increase with concomitant chemoradiotherapy (p < 0.05). Conclusion. We recommend regular use of serial cytological assay during CCRT as it may prove to be a valuable tool for assessment of chemoradiosensitivity and persistence of tumour/dysplastic cells after radiotherapy.

Role of micronucleus in oral exfoliative cytology

In the last few years, the interest for oral cytology as a diagnostic and prognostic methodology, for monitoring patients in oral potentially malignant disorders and oral cancer has re-emerged substantially. In 1983, buccal mucosal micronuclei assay was first proposed to evaluate genetic instability. There are biomarkers that predict if a potentially malignant disorder is likely to develop into an aggressive tumor. These genotoxic and carcinogenic chemicals have been reported to be potent clastogenic and mutagenic agents which are thought to be responsible for the induction of chromatid/chromosomal aberrations resulting in the production of micronuclei. Various studies have concluded that the gradual increase in micronucleus (MN) counts from normal oral mucosa to potentially malignant disorders to oral carcinoma suggested a link of this biomarker with neoplastic progression. MN scoring can be used as a biomarker to identify different preneoplastic conditions much earlier than the manifestations of clinical features and might specifically be exploited in the screening of high-risk population for a specific cancer. Hence, it can be used as a screening prognostic and educational tool in community centers of oral cancer.

Changes in Exfoliative Cell of Oral Mucosa in Kidney Transplant Patients

OBJECTIVES

The aim of this study was to investigate quantitative cytologic changes in oral mucosal smears collected from kidney transplant patients by modern stereologic methods.

METHODS

We enrolled 32 kidney transplant patients. Smears were obtained from the buccal mucosa transplant patients before and 12 months after kidney transplantation. Smears from each individual were stained using the Papanicolaou method and were analyzed using a stereological method.

RESULTS

Statistically, the nuclear volumes and cytoplasmic volumes in the cells of buccal mucosa were markedly higher after kidney transplantation (P < .05). There was a decreased positive cell density in the oral epithelial cells after kidney transplantation compared with before renal transplantation (P < .05).

CONCLUSIONS

These findings suggest that there are alterations in the oral epithelial cells after kidney transplantation, which are detectable by microscopy and cytomorphometry.

Cytogenetic abnormality in exfoliated cells of buccal mucosa in head and neck cancer patients in the Tunisian population: impact of different exposure sources

Chromosome/DNA instability could be one of the primary causes of malignant cell transformation. The objective of the present study was to evaluate the spontaneous genetic damages in exfoliated cells of buccal mucosa of head and neck cancer (HNC) by counting micronucleus (MN) and binucleated (BN) cells frequencies. MN and BN frequencies were significantly increased in HNC patients compared with controls (5.53 ± 3.09/1000 cells, 5.63 ± 2.99/1000 cells versus 2.36 ± 2.11/1000 cells, 3.09 ± 1.82/1000 cells, P < 0.001). Regarding the gender and the age, the frequencies of the MN and BN were significantly higher than those of controls (P < 0.01). The evaluation of the MN and BN frequencies revealed a significant increase (P < 0.001) in the cases in relation to the control group after controlling the risk factors (tobacco smoking and chewing and occupational exposure) of HNC. Moreover, MN and BN frequencies were significantly increased in smokers and chewers compared with nonsmokers and nonchewers among patients (P < 0.05). MN frequency was significantly (P = 0.014) different between patients occupationally exposed (6.99 ± 3.40/1000 cells) and nonexposed (4.70 ± 2.48/1000 cells) among HNC group. The logistic regression model illustrated that HNC was significantly associated with frequencies of MN (OR = 8.63, P < 0.0001) and BN (OR = 5.62, P = 0.001). Our results suggest that increased chromosome/DNA instabilities may be associated with HNC.

Periodontal disease and mouthwash use are risk factors for head and neck squamous cell carcinoma

PURPOSE

The purpose of this study was to examine associations between oral hygiene, including history of periodontal disease and mouthwash use, and risk of head and neck squamous cell carcinoma (HNSCC).

METHODS

We measured history of oral hygiene and dental care on 513 HNSCC cases and 567 controls from a population-based study of HNSCC. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI).

RESULTS

Periodontal disease was associated with a slightly elevated risk of HNSCC (OR = 1.09, 95% CI: 1.02, 1.16). Using any type of mouthwash at least once per day was associated with increased risk compared to never using mouthwash (OR = 1.11, 95% CI: 1.02, 1.20). HNSCC was associated with frequent use of non-alcoholic mouthwash compared to using any kind of mouthwash rarely or never (OR = 1.24, 95% CI: 1.05, 1.47).

CONCLUSIONS

Our results support an association between periodontal disease and HNSCC. Our data suggest that mouthwash use is associated with HNSCC, but we noted no difference between the effects of alcohol-containing and non-alcoholic mouthwashes.

Novel evolutionary models and periodic charts in p- and q-individual chromosomes of auxiliary lymph node and buccal cells

Signal copy number (SCN) and signal intensity (SI) of subtelomeres (ST) are investigated in auxiliary lymph node (ALN) and buccal (BUC) cells by fluorescence in situ hybridization. The extracted total cell of 38256 and 2309 was, respectively, analyzed from the benign ALN- and BUC-cells of an affected breast cancer patient. The Periodic model was based on ST behavior including normal-, down-, and upregulated clones with diverse SCN. The arm-p/q ratio based signature, as a subtelomeric array, reflects discordance and concordance of ST-behavior within individual chromosomes as a concept of "Individualization of Cells" rather than "Global Insight of Cells". The Periodic charts could be considered as a reliable and refreshable platform through which the cellular evolution could be patterned and characterized. Signature of ST-profile in the BUC and ALN cells and the nature of diverse SCN and SI as quantitative and qualitative value led to modeling the real personalized perspective of cellular evolution. Protein expression of Ki67, Cyclin D1, and Cyclin E was assayed, as a complementary panel. These targets could be applied as the predictive and preventive markers for an early detection at BUC and ALN levels to plan the required managements in the breast cancer patients.

Cytological changes in the oral mucosa after use of a mouth rinse with alcohol. A prospective double blind control study

AIM

The aim of this preliminary study was to detect cytological changes in the oral mucosa after using a mouth wash with alcohol.

MATERIAL AND METHODS

A prospective double-blind, controlled study was performed, for 6 months. Group 1 consisted of 30 subjects who used a mouth rinse with 26.9% of alcohol [Listerine] and Group 2 consisted of 30 subjects who used a mouth rinse with the same ingredients but with no alcohol. We obtained three cytological samples from the oral mucosa. The presence of cytological atypia, binucleation and karyorrhesis, and type of cells were studied. We also used a fluorescent in situ hybridization technique (FISH) in 15 samples in each group, for the micronucleus.

RESULTS

We found no clinical mucosal alteration after using the mouth wash at the end of the study in either group. We observed no cytological differences between the groups at the end of the study (p>0.05). Regarding the study of the micronucleus by FISH, we observed no significant difference between the groups (p>0.05).

CONCLUSIONS

Our results showed no cytological alteration in patients using a mouth rinse with alcohol, but these findings should be considered preliminary results, to be confirmed in a greater sample of patients.