Conditional gene knockouts using Cre-LOX technology and using mammary luminal specific (MMTV-LTR-Cre; Wap-Cre; Blg-Cre) or basal specific (K14- or K5-Cre) targeting are useful to focus on the molecular involvement in epithelial cells but may not reflect the importance of changes in the microenvironment during breast cancer progression. Here, LOX is linked to breast cancer.