Production of β‐human chorionic gonadotrophin by human squamous carcinoma cell lines

Eight out of 9 human squamous carcinoma cell lines ectopically secrete the beta subunit of human chorionic gonadotrophin (beta-HCG) in amounts detectable by radioimmunoassay. In contrast, both normal and SV40-transformed keratinocytes show no such evidence of beta-HCG secretion. Ectopic beta-HCG is identical in its gel exclusion and high-performance liquid chromatographic properties to placental beta-HCG and, in radioimmunoassay, yields a dilution curve parallel to that of placental beta-HCG. Dibutyryl cyclic AMP, but not sodium butyrate, stimulates beta-HCG secretion by the one human cell line examined, LICR-LON-HN-5, suggesting that ectopic production by these cells is similar to trophoblastic beta-HCG secretion, and differs from most other non-trophoblastic cell lines previously examined.