Clinical praxis and laboratory procedures in subrenal capsule assay (SRCA)

Subrenal capsule assay (SRCA) is a promising method in cancer research and in the selection of individual chemotherapy for cancer patients. The laboratory procedures of SRCA are as follows: on day zero 1 X 1 X 1 mm pieces of fresh human tumour are carefully prepared. The pieces are transferred by a trocar under the outer capsule of normal immunocompetent mice, one piece to each. The mice (about 30-40/test) are divided randomly into groups of at least five. The size of each piece (initial size) is measured in situ by a stereomicroscope fitted with an ocular micrometer. On days 1-5 cytostatics are administered to the animals. On day 6 the animals are killed and the final tumour size is measured. The difference between the final and initial tumour size describes the response of the tumour to the treatments. The critical point of the assay is the selection of the tumour fragment which has to be representative, as homogeneous as possible and contain living tumour cells. When the sample is in pieces of about 3 X 3 mm (4-5 tumour fragments are sufficient for the assay) in the culture medium, it may be stored in an ice bath or at room temperature for one day. During this time, though as rapidly as possible, the sample has to be delivered to a research laboratory where the SRCA is carried out.