The pregnant mice and their offspring were fed with tetracycline analog, Dox (0.5 mg/ml, 10 ml/day), in drinking water to inhibit the expression of ErbB2V664E in Mlc1-ErbB2V664E mice from embryonic to indicated postnatal days. Water bottles were wrapped with foil to protect Dox from light. Mlc1-dnEGFR mice and their littermate controls were not treated with Dox for they did not exhibit developmental difference. Withdrawal from Dox induces the expression of ErbB2V664E and dnEGFR in astrocytes of Mlc1-ErbB2V664E and Mlc1-dnEGFR mice. All used littermate control mice were treated the same.