Table 1. Experimental groups.

Group	Genotype	Constructs injected	No. harboring tumors (tumor multiplicity)
1	Arf –/–	pT/Caggs-V12Nras + pPGK-SB13	8/8 (TNTC)
2	Arf –/–	pT/Caggs-V12Nras + pPGK	4/7 (0–1)
3	Arf –/–	pT/Caggs-V12A38Nras + pPGK-SB13	1/7* (NA)
4	Arf –/–	pT2/Caggs-Luciferase + pPGK-SB13	0/5 (NA)
5	Arf +/–	pT/Caggs-V12Nras + pPGK-SB13	7/8 (2–10)
6	Arf –/–	pT/Caggs-V12S35Nras + pPGK-SB13	2/3† (1)
7	Arf –/–	pT/Caggs-V12G37Nras + pPGK-SB13	0/3 (NA)

Each group received a different combination of transposon and transposase and was monitored for sickness. When moribund, liver tumor burden was assessed, and approximate numbers are indicated. TNTC, too numerous to count; NA, not applicable.

^*This mouse developed a different tumor type than the others

^†The third mouse died during the study and was not recovered