RESUMEN
<p><b>OBJECTIVE</b>To explore the relationship between abnormal expressions of positive cell cycle control factors and thyroid carcinoma occurrence and progression, and assess the value of these factors in evaluating tumor cell proliferation activity and the prognosis of the patients.</p><p><b>METHODS</b>Immunohistochemical SP method was used to detect the expressions of MCM7, CDK2 and Ki-67 proteins in 50 cases of thyroid carcinoma, 30 cases of thyroid adenoma, 30 cases of nodular goiter and 20 cases of normal thyroid gland tissues.</p><p><b>RESULTS</b>The positive rates of MCM7, CDK2 and Ki-67 expressions in thyroid carcinoma were 100% (50/50), 80.00% (40/50) and 84.00% (42/50), significantly higher than the rates in thyroid adenoma, nodular goiter and normal thyroid tissue (P<0.01). In thyroid carcinoma tissues, positive correlations were observed between the expressions of MCM7 and CDK2 proteins (r=0.637, P<0.01), MCM7 and Ki-67 proteins (r=0.633, P<0.01), and CDK2 and Ki-67 proteins (r=0.862, P<0.01).</p><p><b>CONCLUSION</b>The high expressions of MCM7, CDK2 and Ki-67 protein may contribute to the development of thyroid carcinoma, and their combined examination may serve as useful index for early diagnosis and prognostic evaluation of thyroid carcinoma. MCM7 is superior to Ki-67 in the evaluation of the thyroid tumor cell proliferation activity.</p>