Lack of Plg increases the survival of mice with Lewis lung carcinoma after surgical resection of the primary tumor. Plot of the percentage of surviving mice versus time after resection of primary tumors. Tumor cells were injected into 15 control mice and 14 Plg^−/− mice, and the primary tumor was surgically resected at day 10. The P value was determined by the log-rank test. One control mouse did not die within the observation period and was alive and healthy more than 5 months after tumor cell inoculation, indicating that the tumor had spontaneously regressed. This mouse was included in the determination of the P value.