Growth of Human Urological Tumors on Extracellular Matrix as a Model for the in Vitro Cultivation of Primary Human Tumor Explants1

The goal of this study was to establish an optimal in vitro growth assay system for human urologica! tumor expiants. Bovine corneal endotelial cell extracellular matrix (ECM) coated dishes were evaluated as a growth substrate for tumor cultures. Growth success for different urologica! carcinomas (prostatic, bladder, kidney, and testicular) was compared after seeding fresh surgical expiants onto bovine corneal endothelial cell ECM and plastic culture flasks. Tumor samples were disaggregated enzymatically, and 1 x IO4 cells were seeded onto the different substrates using RPMI 1640 medium containing 10% fetal calf serum and/or different growth factors, nutrients, and hormones. Cell growth on ECM was quantitated on days 7-15 by pHJthymidine uptake, cell counting, and total protein. Tumor cells were characterized by flow cytometry and cytology. It was observed that ECM provides superior culture conditions for urologica! carcinomas. By increasing the initial number of cells plated on ECM and by adding different growth factors or hormones, the growth rate for specific tumor types was increased significantly. Several tumors (11 cases) grown on ECM were examined under the light microscope, and in all cases preand post-cytology confirmed malignancy. Tumor cells maintained on ECM and transplanted into nude mide retained their tumorigenic and morphological character istics. Clinically aggressive tumors were associated with extensive ECM degradation. In addition, the growth of fresh human tumors on ECM provides a biologically relevant model system (for assessing the invasiveness of tumors in vitro) and should also be useful for drug evaluation studies.