ST-3 induced increase of tumour volume is dependent on the presence of growth factors in vivo. Tumour volume in relation to the day of surgery is shown from A) MDA-MB-231 cell clones delivered with complete matrigel, B) MDA-MB-231 cell clones applied in growth factor depleted matrigel, C) MCF-7 cell clones injected with complete matrigel and D) MCF-7 cells applied with growth factor depleted matrigel. A pool of equal parts of three cell clones (total number: 2 × 106) was injected in a volume of 50 μl of (depleted) matrigel into the mammary fatpad of nude mice. Tumour volume was monitored twice a week. One week prior to MCF-7 cell transplantation, animals received oestrogen pellets subcutanously. Groups included eight animals each. Stars indicate a p-value ≤ 0.05.