Loss of transcriptional repression contributes to the ectopic expression of the calcitonin/alpha-CGRP gene in a human lung carcinoma cell line.

The calcitonin/alpha-CGRP (CT/CGRP) gene is ectopically expressed in a wide variety of neoplasia. We have investigated the molecular mechanisms responsible for this ectopic expression in the human cell line BEN, which is derived from a poorly differentiated squamous cell lung carcinoma. We show that a trans-acting factor which represses expression of the CT/CGRP gene in HeLa cells is absent or inactive in BEN cells, and have localised the repressor binding site to a 53 bp fragment 1500 bp upstream of the transcription start site.