The frequency of regressor cell lines is greater from tumors generated in RAG2^−/−x γc^−/− mice compared with WT and other immune deficient mice. A summary of two MCA-induction experiments performed in this manuscript is plotted in the context of previous MCA-induction experiments. Previously published experiments are included for comparison purposes and are from previous studies (Shankaran et al., 2001; Dunn et al., 2005; Koebel et al., 2007). Absolute numbers of regressors/total number of cell lines tested is shown next to the bar for each experiment.