Table 2. Malignancy incidence in secondary recipient mice in Exp. 1 (donor: γ_C ^−/−, recipient: γ_C ^−/− Rag2^−/− ).

Vector	# Primary donor mice for secondary transplant	# Secondary recipients	# Vector+ Hematological Malignancies	# Other death*	# tumor free at autopsy(6–7 months)
Mock	11	23	0	1	22
MSCV	14	36	0	13	23
EF1α	15	39	3 **	3	33

^*Other death: Mice died or sacrificed before reaching end points, but not due to hematological malignancies that have transgene insertion (for examples, recipient derived tumor).

^**All three mice are from the same donor.

VCN: Vector copy number in peripheral blood mononuclear cells at 30 weeks.