Importance of Ki-67 Labeling in Oral Leukoplakia with Features of Dysplasia and Carcinomatous Transformation: An Observational Study over 4 Years.

 Early detection of dysplastic changes within oral potentially malignant disorders is the mainstay to prevent oral cancer. Ki-67 is one of the most useful antigens in this purpose.  The study aims were to recognize and mutually compare the proliferative status of idiopathic oral leukoplakia (OL) patches, which presented through different forms of dysplasia and carcinoma.  In 4 years of observation, cumulatively 140 OL lesions were included for examination. The wholesome Ki-67 labeling scores in each of the subgroups were calculated.  The World Health Organization recommended histopathological classification was used to categorize the dysplastic and malignant lesions. Paraffin-embedded tissue sections were processed for Ki-67 immunostaining. The labeling indices (LIs) were quantified semiquantitatively at the site of maximal reactive cells on tissue sections.  The statistical comparison was performed by means of the SPSS software (Version 16.0 SPSS Inc.). A value < 0.05 was considered as the benchmark for statistical significance.  A steady and significant increment in Ki-67 expression was discovered from dysplastic to malignant OL patches compared with normal mucosa. The labeling differences were significant between normal mucosa and mild dysplasia, as well as between mild, moderate, and severe dysplasia. However, the expression did not differ significantly with the severity of oral cancers.  Ki-67 is a useful molecular marker of carcinogenesis in OL. It also serves worthwhile in separating marginally dysplastic lesions, such as mild dysplasia or verrucous carcinoma from their benign epigones.