CD4 and neoplasm: To determine whether the vaccine could induce the recruitment of immune cells at the site of carcinogenesis, we investigated by real-time PCR the expression of NKp46, CD8 and CD4 mRNAs in tumor-free mammary glands from 26-week-old vaccinated NeuT mice compared to that in preneoplastic mammary glands from untreated NeuT mice at 6 weeks of age, at the baseline of vaccination.