To determine the contribution of TrkC to primary tumor formation, we injected MCF10A-Ras, MCF10A-Ras-TrkC, Hs578T control-shRNA or TrkC-shRNA cells into the mouse mammary fat pads of BALB/c Nu/Nu mice and examined the resulting primary tumors 29 days or 47 days later. This evidence concerns the gene NTRK3 and neoplasm.