ABSTRACT
Long-term culture of normal tissue exhibiting differentiated properties of the tissue of origin has been a major field in medical and biological research. This chapter reviews the various techniques for three-dimensional culture of normal tissue and emphasizes their merits and limitations. It describes the most common methods for cell and spheroid characterization and discusses the applications of normal spheroids in cancer research. Spheroids of normal tissue have been used in studies of growth and differentiation in vivo, and also in studies of the interactions between normal and malignant tissues. Tissues are exposed to enzymes, such as trypsin and pronase, or to mechanical forces, which break the intercellular bonds between the cells. Normal tissues can be grown in culture as adherent or nonadherent tissue fragments or as multicellular spheroids formed by self-aggregation or rotation-mediated histogenesis. Spheroids of normal tissue have also been valuable in confrontation cultures between normal and malignant tissues.
