A two-way ANOVA of the FST data revealed that the durations of immobility differed as a function of the significant interaction between CD4+CD25+ Treg cell depletion and the CIS (F1, 56 = 4.85, p = 0.0319) and a significant effect of the CIS (F1, 56 = 8.45, p = 0.0052) was observed, as the stressed mice exhibited a markedly depressed phenotype characterized by increased durations of immobility during the FST when compared with non-stressed mice. This evidence concerns the gene CD4 and in situ carcinoma.