The TGA stop codon was replaced with the "P2A-CreERT2-WPRE-BGH pA" cassette. CreERT2 recombinase is expressed under the regulatory control of S100a4 gene elements. This model is a Tamoxifen-inducible Cre mouse, and when crossed with mice containing loxP sites, the offspring mice are expected to undergo sequence recombination between loxP sites mediated by Cre recombinase in the mesenchymal fibroblasts of tissues such as the prostate, antral stomach, and mammary gland following Tamoxifen induction.