READ BY TITLE The extent of mitotic and amitotic indices in oral cancers and their significance vis-a-vis tumour development and chemoprevention

VN Bhattathiri

Clinical Cancer Center, Trivandrum, India

Aim: To analyse the relative extent and significance of amitotic and mitotic indices in oral cancers. Materials and methods: Pretreatment scrape smears were collected from the tumours of 180 patients with epidermoid cancers of the mouth, stained with Giemsa’s and the frequency of binucleated, micronucleated, nuclear budded and multinucleated cells counted, their sum being taken as the total number of dividing cells. The relative frequency of binucleated cells was taken as the mitotic index (MIrel), multinucleated cells as acytokinesis index (ACIrel), micronucleated and nuclear budded as akaryokinesis index (AKIrel) and ACIrel+AKIrel as amitotic index (AMIrel). Their correlation with serum iron (SFe) was evaluated in 50 of these patients and correlation with tumour size in 106. Results: The AKIrel was lowest (1.3%) in the hard palate and highest (32.1%) in the floor of mouth tumours, whereas the reverse was true for ACIrel (30.2% and 8.7% respectively). The AMIrel and ACIrel showed significant correlation with serum iron (r=0.43 and 0.38; p value = 0.03 and 0.01 respectively). As regards tumour size, the AMIrel and AKIrel were significantly higher in larger tumours. Conclusions: The study shows that amitosis is common in oral cancers and is related to their growth. This being so, it is possible that all these amitosis may occur in leukoplakias and other premalignancies and that evaluating micronucleation alone is redundant from the point of view of chemoprophylaxis. It is hypothesized that amitosis contribute to spontaneous regression of tumours or leukoplakias, and that reduction in amitosis with retinoids may explain their failure in chemoprevention.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Carcinogenesis.