TNF and breast cancer: To identify a cell type that produced high level of sheddases suitable for the purpose of this experiment, seven cell lines were tested for their TNF-α and HB-EGF shedding ability, namely: A549 lung adenocarcinoma, human embryonic kidney cell-derivative AAV293, BHK21 fibroblast, cervical carcinoma HeLa, HT1080 fibrosarcoma, MCF7 breast cancer cell and the cervical cancer cell SiHa.