A431 cells are a model cell line (epidermoid carcinoma) used in biomedical research. More specifically, they are used in studies of the cell cycle and cancer-associated cell signalling pathways since they express abnormally high levels of the Epidermal growth factor receptor (EGFR). As such they are often used as a positive control for EGFR expression. They contain no functional p53, a potent tumor suppressor gene, and so are highly sensitive to mitogenic stimuli. A431 cells were established from an epidermoid carcinoma in the vulva of an 85 year old female patient...