LiCl reduces tumour growth in syngeneic rats. (A) Wistar rats were injected with 50 mg/kg of LiCl dissolved in PBS or received the same amount of PBS without LiCl for control. 14 days after the first drug dose, 1 × 105 MT450 cells were inoculated subcutaneously. Tumour sizes and lithium concentrations in the blood were determined once a week. The graphs show mean values for 6-8 individuals (A.I) and corresponding blood serum concentrations of lithium (A.II). (B) Tumours were fixed and sections were stained for PCNA expression. PCNA-positive cells of an area of 25 mm2 were counted. The graph shows the mean values and standard deviations of PCNA-positive cells (in%). (C) Tumour sections were stained for apoptotic cells. TUNEL-positive cells in an area of 25 mm2 were counted. The graph shows the mean values and standard deviations of TUNEL-positive cells.