. 2003 Feb 15;17(4):488–501. doi: 10.1101/gad.1051603

Table 1.

Tumor regression post-doxycycline withdrawal: p53(+/+) vs. p53(+/−) mice

Genotype	Tumor regression
Genotype	Complete	Incomplete
MTB/TWNT/p53(+/+)	33 (94%)	2 (6%)
MTB/TWNT/p53(+/−)	18 (60%)	12 (40%)
Tumors with p53 LOH	5 (71%)	2 (29%)
Tumors without p53 LOH	13 (57%)	10 (43%)

Mammary tumors arising in MTB/TWNT/p53(+/+) and MTB/TWNT/p53(+/−) mice were biopsied, and tumor size was monitored following doxycycline withdrawal. Tumors occurring in p53(+/−) mice were significantly less likely to regress completely following doxycycline withdrawal than tumors occurring in p53(+/+) mice (p < 0.005, chi-square). In addition, tumors that failed to fully regress promptly resumed growth.