The mice with conditional KO of Srsf3 in the mammary glands bearing the mutant rat c-neu and in the liver tissues with a peritoneal DEN injection (25 mg/kg at 15 days of age) were examined weekly by palpation for breast tumor development from a month of age and liver tumor development from 6 months of age, up to 18 months (a total of 78 weeks). The gene discussed is SRSF3; the disease is breast neoplasm.