Figure 6.
Mammary tumor development in mice harboring the PtenFVmutation. (A) The incidence of neoplastic lesions in mammary glands of Pten+/+ and PtenFV/+ female mice analyzed at the various ages indicated (in months). Histopathological grades are described in detail in the Materials and Methods. (Carcino) Carcinoma; (LG) low grade; (HG) high grade; (NSL) no significant gross or microscopic neoplastic lesions. Two sample tests were used to compare proportions of groups into two categories (carcinoma and/or high-grade Min vs. low-grade Min and/or NSL) within each age group. (*) P < 0.01. No test was performed for the 6- to 11-mo age group, since carcinoma or high-grade Min was not observed. (B,C) Kaplan-Meier curves for tumor-free survival of mice with the indicated Pten genotypes in either the absence (B) or presence (C) of the MMTV-ErbB2 oncogene. Tumors were detected and measured weekly by palpation; tumors were recorded if ≥0.5 cm2. (n) Number of mice. Log-rank test was used to compare Kaplan-Meier curves for each mutant genotype with wild type (B) or between the indicated genotypes (C).