Evaluation of micronuclear frequencies in both circulating lymphocytes and buccal epithelial cells of patients with oral lichen planus and oral lichenoid contact reactions.

Objective: The aim of this study was to evaluate the frequency of micronuclei (MNs) in both circulating lymphocytes and buccal epithelial cells of patients with oral lichenoid contact reactions (OLCRs) or with oral lichen planus (OLP) and compare their MN scores with those of healthy controls (HCs).

Material And Methods: The study group included 21 patients (mean age 51.3 ± 12.4; 6 males, 15 females) with OLCRs and 22 patients (mean age 47.6 ± 14.4; 4 males, 18 females) with OLP who were clinically diagnosed and histopathologically confirmed according to WHO diagnostic criteria (WHO Collaborating Centre for Oral Precancerous Lesions, 1978). All patients with OLCR demonstrated contact allergy to tested dental materials when evaluated by skin patch testing according to International Contact Dermatitis Research Group (ICDRG), while all OLP patients tested negative to patch testing. Seventeen individuals with no oral mucosal disorders (mean age 51.7 ± 11.3; 8 males, 9 females) were recruited to constitute the healthy control group. [Correction added on 30 May 2014, after first online publication: the term, 'mean age' has been added to the text in parenthesis throughout the Material and Methods section.] Clinical features including type of OLP, location, disease severity, presence of skin lesions, presence of systemic disease including any allergies and dental (periodontal) status were recorded. MN analyses were performed on peripheral blood lymphocytes and on smears of buccal epithelial cells of all three study groups.

Results: Most OLP and OLCR lesions were of reticular type (83%), and OLP lesions were distributed bilaterally on the buccal mucosa (90.5%). The medians of MN frequencies in buccal epithelial cells in OLP and OLCR groups were significantly higher when compared with HC group (P < 0.001). [Correction added on 30 May 2014, after first online publication: in the results, 2nd sentence, the word 'lymphocytes' has been removed.] There was no significant difference between OLP group (14.5 range 3-95) and OLCR group (16.0 range 3-93) in terms of median MN frequencies in buccal epithelial cells (P = 0.724) nor in peripheral lymphocytes between OLP group (2.0 range 0-7) and OLCR group (1.0 range 0-6) (P = 0.92). [Correction added on 30 May 2014, after first online publication: (P = 0.92) was wrongly placed after 'peripheral lymphocytes' and has now been shifted to the end of the last sentence.]

Conclusions: Micronuclei scores do not distinguish OLP from OLCR when using buccal smears. OLP and OLCR both demonstrated significantly higher MN frequencies in buccal cells, compared with healthy controls. MN assessment in both buccal epithelial cells and circulating lymphocytes may serve as a potential biomarker tool for evaluating any cancer risk in OLP and OLCR. [Correction added on 30 May 2014, after first online publication: the first and second sentences in the conclusions have been slightly changed.].