FIG. 6.

Mammary tumorigenesis and metastasis in transgenic mice expressing neu autophosphorylation mutants. (A) Mammary tumor kinetics in YB 2, YD 5, and NYPD 10 mice. Age indicated is that (days) at which a mammary tumor was first palpable in each transgenic strain. The number of female animals analyzed for each strain (n) and median age at which tumors are palpable (t₅₀) are also shown. The mean tumor latencies for YB and YD are statistically different (P = 0.002, Students t test). (B) Percentage of tumor-bearing animals with metastatic lesions in the lung. The percentage of all tumor-bearing mice harboring lung metastases is indicated for each genotype; the number of animals analyzed is indicated (n). While there are no statistically significant differences between occurrence of lung metastastes in NYPD and YD animals, Fisher exact tests demonstrate significant differences between occurrence of metastases in YB versus NYPD (∗, P = 0.012) and YD (∗∗, P = 0.0002) mice.