MKI67 and neoplasm: Among the tumours with low proliferative activity, using a cut-off value of 15% for Ki67-positive cells and 8% for cyclin A-positive cells (see further Materials and Methods and Ahlin et al, 2007), between 5 and 10% of all tumours had developed distant metastases during the 9-year follow-up time (Figure 3A and B).