Table 1.

Activity of Met mutants

Met construct*	Met phos-phorylation†	Focus formation‡ #foci/μg DNA	Tumor formation§
			# mice with tumors/# mice injected	Mean tumor size, mm2
Wild type	−	0	0/14¶	0¶
M1268T(s)	+++	>300	8/8	216  ±  77
Y1248H(s)	++	156  ± 16	8/8	100  ±  40
D1246H(s)	++	119  ± 16	8/8	60  ±  52
D1246N(g)	++	147  ± 5	9/9	50  ±  25
Y1248C(g)	++	115  ± 11	7/8	77  ±  89
V1238l(g)	++	0	5/8	13  ±  15
V1206L(g)	+	0	6/6	50  ±  32
M1149T(g)	+	0	4/8	46  ±  56

^*See legend to Fig. 1.

^†Data from Fig. 1A (and data not shown).

^‡NIH 3T3 cells transfected with the indicated constructs were scored for focus formation after 2 weeks. Results represent the mean of two independent experiments. Also see Fig. 2.

^§NIH 3T3 cells transfected with the indicated constructs were inoculated subcutaneously into nude mice, and tumors were measured after 2 weeks. Results represent the mean of two independent experiments.

^¶Cells transfected with wild-type Met do eventually form tumors, probably due to the generation of an autocrine Met-HGF/SF stimulatory loop, as we previously described (29). However, tumors derived from cells expressing wild-type Met do not appear until ∼4 weeks after inoculation, by which time most mice inoculated with cells expressing mutant Met molecules have had to be sacrificed due to tumor burden.