Gene expression profiling of FGFR1 KO mice

A novel RCAS-Cre-IRES-PyMT (RCI-PyMT) virus was designed to specifically knockout genes of interest in tumors generated in appropriate mutant mouse hosts. We used this tumor knockout, or TuKO, strategy to concisely ablate fgfr1 in PyMT induced mammary tumors in K19-tva/fgfr1loxP/loxP mice. The similarly injected control K19-tva mice developed mammary tumors exhibiting high metastasis penetration to lung, making this an ideal model for breast cancer metastasis. The fgfr1 TuKO tumors showed significantly decreased primary tumor growth, and most importantly, greatly reduced metastasis to lung. Our study suggests that FGFR1 signaling is a key pathway driving breast cancer lung metastasis and that targeting FGFR1 in breast cancer is an exciting approach to inhibit metastasis. Gene expression microarray analyses were performed on FGFR1 KO K19-tva/fgfr1loxP/loxP mice and control K19-tva mice.