Micronuclei have been used since 1937 as an indicator of genetic toxic exposure due to their association with chromosomal alterations. They can be detected in exfoliated cells and used as an indicator of recent DNA injury within oral mucosa. The buccal epithelial cells are first to be interacted with the cancer compounds such as tobacco (nicotine), which in turn induces the frequency of micronuclei under the influence of saliva. The exfoliated cell micronuclei assay involves microscopic analysis of oral smears to determine the prevalence of micro-nucleation. The assay is reliable and technically easy to perform, noninvasive and sensitive with limited cost.

The study will be held at the Faculty of Dentistry Cairo University and the NCI All the participants will be administrated a standardized questionnaire to obtain demographic data, medical records and any history of relevant risk factors. The detailed clinical examination will be performed on each patient to assess the site, size, and the clinical characteristics of the lesion as well as the extent of local infiltration (if any) and cervical lymph node metastases (if any).

The entire procedure will be explained to the patients and an informed consent will be obtained. The participants were asked to rinse their mouth thoroughly with tap water 2-3 times immediately before the sampling procedure to reduce the oral bacterial load. Pre-moistened separate wooden spatula was used to scrape the oral buccal mucosa cells (right and left buccal mucosal cells). The cells were then smeared over clean, coded glass slides. The slides were then air dried and fixed in fixative for 20 minutes and stained. Afterwards the glass slide was rinsed with aqua dest and dried in the air. The slides will be prepared for microscopic analysis The criteria parameters for identifying micronucleus:

• Rounded smooth perimeter suggestive of a membrane.
• Less than one-third the diameter of the associated nucleus, but large enough to discern shape and color.
• Staining intensity similar to the nucleus.
• Texture similar to the nucleus.
• Same focal plane as the nucleus.
• Absence of overlap with or bridge to the nucleus.

Dead or degenerating cells (karyolysis, karyorrhexis, nuclear fragmentation) were excluded from the evaluation. Incisional or excisional biopsy will be obtained from subjects diagnosed with premalignant lesions and histo-pathological examination will be performed as an additional supportive test .

Inclusion Criteria:

• Control group I: Participants with clinically normal oral mucosa and no evidence of any cancer risk factor as smoking and alcohol consumption.
• Control group II: Participants with clinically normal oral mucosa and with evidence of any cancer risk factor as smoking and alcohol consumption.
• Compare group III: Participants with potentially malignant lesions
• Compare group IV: Participants diagnosed with malignant disorders.
• All age range will be included irrespective of their sex.

Exclusion Criteria:

• • Individuals who had a recent viral infection or had undergone radiation therapy.

  • Those patients were excluded from the control group who had any history of tobacco intake or alcohol consumption and under medications.

Participants with clinically normal oral mucosa and no evidence of any cancer risk factor as smoking and alcohol consumption.Participants with clinically normal oral mucosa and with evidence of any cancer risk factor as smoking and alcohol consumption. Participants with potentially malignant (leukoplakia, oral lichen planus, smoker keratosis and erythroplakia) Participants diagnosed with malignant disorders.

• All age range will be included irrespective of their sex.