These data indicated that IGF-IR, one of the major receptor tyrosine kinases (RTKs) in ERα-positive MCF-7 breast cancer cells, may be a key regulator of the proteolytic potential of MCF-7 cells since IGF-IR activation down-regulated MMPs/TIMPs expression that may limit tumour cell aggressiveness. This evidence concerns the gene NTRK1 and neoplasm.