Normal mammary fibroblasts engineered to secrete HGF have been reported to increase invasiveness of c-met expressing human ductal carcinoma in situ (DCIS) cells in vitro and promote the in vivo transition of nude mice DCIS cell xenografts to invasive carcinomas (Jedeszko et al, 2009). The gene discussed is HGF; the disease is ductal breast carcinoma in situ.