The HBE135-E6E7 cell line was derived from normal bronchial epithelium taken from a man undergoing lobectomy for squamous cell carcinoma. Cells from the primary explant in their first passage were infected with the recombinant retrovirus LXSN16E6E7 containing the human papilloma virus (HPV) E6E7 gene. Cells were selected in the presence of 0.4 mg/mL G418