Figure 5.

Strategies for selective culture of tumor cells under CR condition. Although early histological examination help distinguish between normal and tumor tissues, mixed CR culture of both normal and tumor cells is often seen in early passages. In some cases, normal primary cell outgrows tumor cells. To selectively maintain primary tumor cell culture, it is suggested to use human fibroblast instead of mouse fibroblast as feeder cells, which preferentially supports tumor cell proliferation. Moreover, short-term serum-free medium induces differentiation of CR normal cells, which is irreversible by re-using complete medium, but CR tumor cells can be recovered. 3D culture or xenografts also can mediate irreversible differentiation of normal cells. In addition, CR tumor cells can be selected and purified by tumor-specific markers or antibody.