[Significance of MIB-1 labeling index and TUNEL labeling index in papillary carcinoma].
Papillary carcinomas, which comprise more than 80% of all thyroid gland cancers, are generally regarded as slow-growing tumors with relatively good prognosis. Histologically and pathologically, there is a close relationship in papillary carcinoma between differentiation and the clinical picture, particularly progress and prognosis, However, tumors with the same degree of differentiation may have very different growth rates. Therefore, it is important that we have some clinical indicator, in addition to differentiation, for projecting clinical prognosis, including the likelihood of postoperative recurrence, and for planning follow-up care. In this study, we used paraffin embedded specimens obtained from 40 cases of papillary carcinoma and assessed the proliferative ability of the tumor with MIB-1 staining. Moreover, in 28 of the 40 cases we used TUNEL staining to study apoptosis in cancer cells, then correlated these two indicators with known information about the clinical pathology and prognosis. The degree of differentiation and intensity of the MIB-1 labeling index correlated almost exactly. Some well-differentiated papillary carcinomas stained heavily with MIB-1. In fact, in all cases of postoperative recurrence the carcinomas were well differentiated, and over half of those showed strong MIB-1 staining. The difference between the MIB-1 labeling index for recurring cancers and non-recurring cancers was statistically significant. In contrast, there was no correlation between the TUNEL labeling index and clinical pathology or postoperative recurrence. However, in cases of well-differentiated papillary carcinoma with anaplastic reversion in the recurrence, the TUNEL labeling index was particularly low at the time of the first operation. This indicates that for the purpose of patient follow-up, an extremely low TUNEL labeling index may be an important piece of information. We also believe that the MIB-1 labeling index is another indicator of potential postoperative recurrence.