PRIMARY ORGAN-CULTURE OF NONNEOPLASTIC AND NEOPLASTIC THYROID-TISSUE AS MULTICELLULAR SPHEROIDS

Biopsy specimens from 5 papillary thyroid carcinomas (PC), 2 lymph nod e metastases (LM) from PC, 3 colloid goitres (CG) and 7 normal (N) thy roid tissue were maintained as three-dimensional structures in agar ov erlay culture for up to 6 weeks. This organ culture method provides a system that maintains the cellular complexity present in the original tissue, including the stromal elements. Organotypic cultures with a we ll defined surface architecture were obtained. Follicles present in th e spheroids maintained a polarized epithelial cell layer. Immunohistoc hemical staining showed thyroglobulin expression in most spheroids aft er two weeks of culture. Proliferating cells were also observed after the same time period evaluated by proliferation cell nuclear antigen ( PCNA) immunostaining. The spheroids obtained from one of the papillary carcinomas and the corresponding lymph node metastasis increased in v olume size during the first three weeks of culture while in the other cases volume decreased. The proportion of connective tissue increased in most of the spheroids during the culture period and a partial colla pse of follicles was observed in parallel. Papillary structures were o bserved in spheroids from papillary carcinomas and lymph node metastas es. Our data indicate that viable organotypic spheroid cultures can be obtained and propagated in vitro from thyroid tissue. Such a system h as a potential use for studying normal biological functions of thyroid tissue in vitro and this method may be of special value in studying m echanisms of invasive growth as well as effects of therapy on normal a nd neoplastic tissue taken from individual patients.