TK1 and breast cancer: In healthy, TK1 activity values ranged from 0.6 to 3.1 pmol/min/ml (mean ± SD = 1.6 ± 0.6) and in breast cancer patients, the STK1 activity levels were significantly higher compared to the healthy group (Fig. 1a), in the range of 0.9 to 48 pmol/min/ml (mean ± SD = 4.5 ± 8.3) with a median value of 2.5 pmol/min/ml.