Purpose: To investigate the expression of Ki67 protein in papillary thyroid microcarcinoma(PTMC), and toanalyze its clinical significance. Materials and
Methods: Ki67 protein expression was evaluated in the tissues of108 human PTMC and 50 other benign papillary hyperplasia of thyroid specimens using immunohistochemistry.
Results: The expression intensity of Ki67 in PTMC and benign papillary hyperplasia of thyroid specimenswere 1.45±1.83% and 0.46±0.46%.The positive expression rates were 46.3% and 14%. There were significantdifferences between these two groups (p<0.01). There was no significant variation of the expression intensityand positive expression rates of Ki67 in PTMC with gender, age, position of the tumor and the level of TSHpre-operation (p>0.05), but these parameters varied with tumor size, invasion by membrane and cervical lymphnode metastasis (p<0.05 or p<0.01).
Conclusions: The expression of Ki67 in PTMC was related to tumor size,invasion by membrane and cervical lymph node metastasis, and could be the important indicator for judgingclinical progress and estimating prognosis.