Expression of cadherin and NCAM in human small cell lung cancer cell lines and xenografts.

Tumour cell adhesion, detachment and aggregation seem to play an important part in tumour invasion and metastasis, and numerous cell adhesion molecules are expressed by tumour cells. Several families of cell-cell adhesion molecules have been described, of which two groups are particularly well characterised, the cadherin family and the Ig superfamily member, neural cell adhesion molecule (NCAM). We investigated expression of these two adhesion molecule families in small cell lung cancer (SCLC) cell lines and xenografts by immunoblotting. Nineteen tumours established from 15 patients with SCLC were examined. All tumours but one expressed both cadherin and NCAM. The tumours expressed one, two or rarely three cadherin bands, and different combinations of two major isoforms of NCAM with M(r)'s of approximately 190,000 and 135,000. Polysialylation of NCAM, a feature characteristic of NCAM during embryonic development, which may play a role in connection with tumour invasion and metastasis, was found in 14/18 NCAM expressing SCLC tumours. Individual tumours grown as cell lines and as nude mouse xenografts showed no qualitative differences in cadherin or NCAM expression.