To compared with the World Health Organization (1991) ve Ljubljana classifications applied for the laryngeal preinvasive epithelial lesions by using immunohistochemical markers

Introduction and objective: Laryngeal epithelial hyperplastic-dysplastic lesions with progression to invasive carcinoma are seen most common in the vocal cord and interarytenoid field. These lesions most often occur on mid aged smoking males. Laryngeal epithelial hyperplastic-dysplastic lesions are graded according to different risk groups. As there is sometimes discordance between established histopathological criteria and the biological behavior of these lesions, some difficulties occur. So, more than 20 classifications have been proposed associated with laryngeal epithelial hyperplastic-dysplastic lesions in literature. Various investigators classified these lesions using different histomorphological criteria. While these lesions graded as mild, moderate, severe dysplasia and in situ carcinoma for WHO (1991) classification, according to new classification suggested in Ljubljana on 1997 these lesions graded as simple, abnormal, atypical hyperplasia and in situ carcinoma.The rate of malignant transformation of laryngeal dysplastic lesions ranges between 1.5% and 52.9%. Evaluations of dysplasia solely based on light microscopic examination may lead to false-positive or even to false-negative results. Therefore, new markers are required in order to provide more objective data when it comes to determining the neoplastic potential of these lesions. In this study, the comparison of the WHO and the Ljubljana classifications applying to laryngeal epithelial hyperplastic-dysplastic lesions was aimed. With this purpose, it was aimed to provide objective data about proliferative activity, genetic changes and angiogenesis by using Ki-67, p53 and CD34 immunohistochemical markers and to evaluate validity of histological criteria of these classifications with these objective data.Material and methods: Of 108 cases diagnosed laryngeal epithelial hyperplastic-dysplastic lesion from the archives of Dokuz Eylul University, School of Medicine, Department of Pathology between 1990-2000 years, 54 cases were included in this study. The histologic slides were re-examined, and each case was reclassified according to both the WHO and the Ljubljana classifications.58Then, sections from each paraffin block were stained for Ki-67, p53 and CD34 antibodies. For Ki-67 antigen, evaluation of immunostaining was based on the percentage of positively stained nuclei by counting 1000 cells. For p53 antigen, scoring was done based on the distribution of positively stained cells within the epithelium. For CD34 antigen, subepithelial CD34-positive vessels were counted in three high power fields for each case, and then the mean value was calculated.Statistical analysis: Ki-67 and CD34 expressions of cases graded according to the WHO and the Ljubljana classifications were compared by Kruskal Wallis test with increasing histological grades. Correlation between Ki-67, p53 and CD34 expressions and increasing histological grades according to the WHO and the Ljubljana classifications was investigated by Spearman corelation test. Also simple hyperplasia was taken as control group, immunohistochemical expressions of cases with hyperplasia were compared with immunohistochemical expressions of cases with mild dysplasia and moderate dysplasia at the WHO classification; also results of control group were compared with immunohistochemical expressions of cases with abnormal hyperplasia at the Ljubljana classification by using Mann-Whitney U and Chi-Square tests. Also immunohistochemical expressions of cases with mild dysplasia were compared with immunohistochemical expressions of cases with moderate dysplasia at the WHO classification by using same statistical tests.Results: Of 54 cases, 48 were men (88.8%) and six were women (11.1%). The mean age for all cases was 52±12 (27-76) years. According to the WHO classification, six cases were squamous cell hyperplasia, 22 cases were mild dysplasia, eight cases were moderate dysplasia, 12 cases were severe dysplasia and six cases were carcinoma in situ. According to the Ljubljana classification, six were simple hyperplasia, 26 cases were abnormal hyperplasia, 15 cases were atypical hyperplasia and seven cases were carcinoma in situ.There was a significant result between cases of increasing histological grades and Ki-67 and CD34 expressions of both the WHO and the Ljubljana classifications. As well as there was a positive correlation between Ki-67, p53 and CD3459expressions and histological grades. When simple hyperplasia was taken as control group, there was a significant difference between mild dysplasia and simple hyperplasia, moderate dysplasia and simple hyperplasia, and mild and moderate dysplasia graded according to the WHO classification compared with Ki-67 expressions. Similar results were obtained between abnormal hyperlasia and simple hyperplasia graded according to the Ljubljana classification. With regard to counts of vessels with stained CD34, a significant difference was obtained between mild dysplasia and simple hyperplasia and moderate dysplasia and simple hyperplasia, there was not a significant difference between mild and moderate dysplasia graded according to the WHO classification. A significant difference was also obtained between abnormal hyperlasia and simple hyperplasia graded according to the Ljubljana classification. For the p53 expression scores, there was a significant difference between moderate dysplasia and simple hyperplasia graded according to the WHO classification, there were not significant differences between mild dysplasia and simple hyperplasia, and mild dysplasia and moderate dysplasia. When compared with p53 expressions, a significant difference was obtained between abnormal hyperplasia and simple hyperplasia graded according to the Ljubljana classificationDiscussion and conclusion: There was a positive correlation between and Ki-67, p53 and CD34 expressions of both the WHO and the Ljubljana classifications. But results of p53 and CD34 expressions supported thesis that grades of the Ljubljana classification based on more objective criteria compared with the WHO classification. According to obtained results, it showed no correlation between mild and moderate dysplasia categories of the WHO classification with regard to p53 and CD34 expressions. These categories in the WHO classification was favored to collect under a single title as in the Ljubljana classification. Since our case series were not very large and limited markers were used in our study, there is necessity to studies done with more large series in terms of examining the sufficiency and objectivity of the WHO and the Ljubljana classifications.