RESUMEN
To determine frequency of Ki-67-antigen over-expression in thyroid tumours. A retrospective study of 50 patients suffering form thyroid tumours. Was carried out in BMSI, Jinnah Postgraduate Medical Center, Karachi frornl993-2001. Maximum numbers of tumour among total cases were is age group ranging from 20-39 years. This age group 18 [72%] papillary Carcinoma, 04 [80%] medullary carcinoma, 03 [30%] follicular carcinoma, 04 [57%] follicular adenoma. The mean+ SD of follicular adenoma, follicular carcinoma, papillary carcinoma, medullary carcinoma and anaplastic carcinoma are 12.96 + 54.44, 49 + 8.90, 45.5 + 7.3, 44.62 + 4.7 and 5 1.7 + 2.2 respectively. The p value between benign and malignancy condition is 0.001 which is highly significant. The result and observation of study show that immunohistochemical study using Ki-67 antibody suggest that positive reaction for Ki-67 antigen could be used as a tool for distinguishing malignant tumour from benign tumors. Ki-67 proliferative activity has been shown to have a diagnostic value, further evaluation as prognostic indicator in the study of tumour pathology is warranted in hope that this parameter will allow clinicians to provide more appropriate treatment