An in vitro approach explored the SERPINB3 gene (highly active in oral squamous cell carcinoma): SERPINB3 promoter-mediated PE38KDEL expression vector transfected with PEI (C202H505N101) was tested in different cell lines TCA8113 (tongue squamous cell carcinoma), MG63 (osteosarcoma), Eca-109 (esophageal cancer), HeLa (endocervical adenocarcinoma) and MCF-7 (breast cancer). This evidence concerns the gene SERPINB3 and breast cancer.