TUMOR-GROWTH FRACTION AND APOPTOSIS IN SALIVARY-GLAND ACINIC CELL CARCINOMAS - PROGNOSTIC IMPLICATIONS OF KI-67 AND BCL-2 EXPRESSION AND OFIN-SITU END LABELING (TUNEL)

bcl-2 protein and Ki-67 (MIB-1) were studied in 32 acinic cell carcino mas (ACCs), all with a minimum of 5 years' clinical follow-up. Tumour apoptosis was evaluated by TdT dUTP nick end labelling (TUNEL) and by morphological criteria. Five patients died of their disease. Patients with stage I tumours had significantly better survival compared with o ther stages (P<0.05). Patients with MIB-1-negative rumours had signifi cantly better survival than patients with MIB-1-positive tumours (P=0. 05). This study confirms a previous report that MIB-1 is an independen t prognostic factor for survival in patients with ACC. Stage I tumours had high expression of bcl-2 protein, but there was no difference whe n compared with other stages. TUNEL positivity was most prevalent in s tage I tumours, compared with stages II, III, and IV (P<0.05), probabl y indicating more apoptosis. This could imply a capacity of stage I tu mours ('early tumours') for early selection of tumour cells for elimin ation by apoptosis. There was no significant difference between expres sion of bcl-2 and TUNEL, between these parameters and clinical outcome , or between any parameter and morphological subclassification. We con clude that MIB-1 has prognostic value in ACC. Clinical staging, bcl-2, and TUNEL are also potentially useful as prognostic markers. (C) 1997 by John Wiley & Sons, Ltd.