Table 1.

Numerical Characteristics of Animals Presenting Bone Tumors (Age and Background in Each Studied Group).

Apc1638N/+;twist-null/+ Mice	Animal Number Presenting Bone Tumors	Animal Number Presenting Bone Tumors by Age			Animal Number Presenting Bone Tumors by Background
		5–9 mo	10–15 mo	16–22 mo	CD1	C57BL/6J	129Sv
73 skeletons	14	6	3	6	6	4	4
92 cephalic regions	30	6	12	12	9	13	8
22 living animal (in vivo imaging)	15	0	7	8	5	4	6