Another relevant study by Wen et al showed that immunity in mice against a methylcholanthrene induced fibrosarcoma was induced in both CD4−/− and CD8−/− single knock-out mice, but not in CD4−/−CD8−/− double knock-out mice [45], which is then in line with our results in BALB/c mice. This evidence concerns the gene CD8A and fibrosarcoma.