[Morphologic comparison of stroma rich and stroma poor tumors in the agar colony-forming test]

In the study reported here the morphologic relationship between the original tumor and a colony cultured in vitro was investigated in stroma-rich and stroma-poor tumors. The colonies, cultured in a double-layer agar system were marked with graphite and bedded in paraffin after centrifuging. Subsequent preparation of the microtome sections was in accordance with customary histologic methods. Taking an ovarian carcinoma as an example, far-reaching agreement between the original histologic findings and the section through the colony in the light-microscopic image was demonstrated. In contrast, the tumor cell colonies in mammary carcinomas, which are typically representative of stroma-rich tumors, generally showed less similarity to the histologic structure of the mother tumor, since the formation of connective tissue cannot be induced due to the lack of mesenchymal elements in the agar culture. However, under comparable in vivo and in vitro conditions, e.g., tumor manifestation in performed cavities, there was, also with mammary carcinomas, a similar morphologic analogy between the original tumor and the clone, as in cell-rich neoplasms. The possibility of identifying malignancy directly in colonies and knowledge of their morphologic relationship to the primary tumor increase the relevance of chemosensitivity testing in colonization tests.