LLC1-Luc-GFP cancer cells were transplanted into Col1a2;rtTATetO7-Prrx1Luc mice, and tumor growth and lung and liver metastases were found to be significantly enhanced in the fibroblast-specific Prrx1-expressing group [Dox (+)] (Fig. 2B, Supplementary Fig. 7A) compared with Dox (−) control group. This evidence concerns the gene PRRX1 and neoplasm.