LEP and breast cancer: To test this hypothesis inhibitors of leptin-induced kinases, RNA knockdown for transcription factors and luciferase reporter for IL-1 gene promoter were used in mouse mammary 4T1 cells, a model that closely resembles human invasive/metastasic stage IV breast cancer (Gonzalez et al, 2006; Gonzalez-Perez et al, 2010).