With 3 mice for each time point, the distribution of tissues for the various tests was as follows: 3 matrigel controls and 6 tumor cell injected mammary glands for whole mount, 3 controls and 6 tests each for H and E staining and HER2 IHC accounting for a total of 27 measurements at each time point. The gene discussed is ERBB2; the disease is neoplasm.