NEW CONTINUOUS CELL-LINE FROM HUMAN MEDULLARY-THYROID CARCINOMA - SINJ - PHENOTYPIC ANALYSIS AND INVIVO CARCINOGENESIS

SINJ is a new continuous human cell line derived from a lymph node met astasis of a probably sporadic medullary thyroid carcinoma. It is comp ared to MTC-SK, another medullary thyroid carcinoma cell line, establi shed earlier (1). SINJ has been continuously cultivated in vitro for t wo years. The cells grow as a suspension of single cells and cell clus ters. Repeated immunocytochemistry showed positive immunoreactivity wi th antibodies to CT, CGRP and GRP. The maintenance of NSE and chromogr anins were proved. Northern blot analysis confirmed endocrine activity at mRNA level. Flow cytometry of 27 SINJ - clones showed 25 diploid a nd two tetraploid subpopulations. Cytogenetic analyses strengthened th ese findings. According to DNA analysis the cells are free of SV40 seq uences. Tumorigenicity was proved in nude mice. The new cell line SINJ has potential use for in vitro studies of medullary thyroid carcinoma s in sporadic as well as hereditary forms - the MEN2A syndrome.