title: Cyclin d1 gene expression in oral mucosa of tobacco chewers"-an immunohistochemical study.
abstract: OBJECTIVE
  The objective of the present study was to evaluate the expression of cyclin D1 in normal oral mucosa of both non tobacco habituated and tobacco habituated individuals histologically and also compare and correlate cyclin D1 expression with histopathologically confirmed cases of oral squamous cell carcinomas.
  
  
  METHODS
  The present study involved 20 cases of tobacco habituated individuals with normal oral mucosal tissue and 20 histopathologically confirmed cases of squamous cells carcinomas. Twelve cases of non tobacco habituated individuals served as control group. Chi-square analysis was used to determine statistical significance.
  
  
  RESULTS
  Fifty percent of control cases, 70% of squamous cell carcinoma cases and 80% of tobacco habituated individuals of clinically normal mucosa showed cyclin D1 positivity. Thirteen cases with tobacco chewing habit, with clinically normal mucosa, showed dysplasia, out of which seven were mildly dysplastic and six were moderately dysplastic. A larger percentage of cyclin D1 expression was observed in lower grade dysplasias (53.8%) than higher grade dysplasias (46.1%). However statistical analysis showed no significant association between groups. Chi-square value was < 7.82 for p=0.05.
  
  
  CONCLUSIONS
  The finding of cyclin D1 expression in 80% of tobacco users with clinically normal mucosa indicates that the mutation of cyclin D1 occurs early, even before clinical changes are apparent. This finding appears to be previously unreported. The presence of dysplasia in the same group and cyclin D1 expression in 84.6% of dysplastic cases show that the patients are susceptible for further changes, including progression to higher grades of dysplasia and development of carcinoma. Relatively lower expression of cyclin D1 positivity (70%), in oral cancer patients, when compared with tobacco users with clinically normal mucosa (80%) is indicative of increased traverse of the cell through the cell cycle, which may occur early in tumor progression. Cyclin D1 immunoreactivity was detected in all the three study groups.
authors.affiliation: Professor and Head of Department, Department of Oral Pathology & Microbiology, H.K.E.'s S. Nijalingappa Institute of Dental sciences & Research Center , Gulbarga .
authors.forename: Maharudrappa
authors.initials: M
authors.lastname: Basnaker
authors.affiliation: Post Graduate Student, Department of Oral Pathology & Microbiology, H.K.E.'s S. Nijalingappa Institute of Dental sciences & Research Center , Gulbarga .
authors.forename: Srikala
authors.initials: S
authors.lastname: Sp
authors.affiliation: Professor, Department of Oral Pathology & Microbiology, H.K.E.'s S. Nijalingappa Institute of Dental sciences & Research Center , Gulbarga .
authors.forename: Satish
authors.initials: S
authors.lastname: Bnvs
keywords: Cyclin D1; Epithelial dysplasia; Immunohistochemistry; Oral cancer; Tobacco chewers; normal oral mucosa