In a recent study conducted by Mezencev et al (2011), they have demonstrated growth characteristics and histology of tumor masses developed following subcutaneous implantation of Jurkat cells into nude mice. Tumor develops in about 86.4% of the mice at a median time of 39 days post-implantation. This study indicates that Zurkat cells are tumorigenic in immune-compromised model system, similarly you can test your line for tumorigenicity in these mice.