Proliferation of human testicular tumours.

Whole tumour perfusion with radioactive DNA precursors reveals that proliferation of human testicular tumours differs widely depending on type and stage of development. In seminomas a homogeneous distribution of proliferating cells at early stages is followed by a shift of the growth fraction to the periphery at advanced stage. Embryonal carcinomas show a chessboard-like pattern of proliferating fractions with high 3H-thymidine labelling indices and short tpot. In mature teratomas proliferation is low. It increases in immature teratocarcinomas. Lack of proliferation is observed in beta-hCG-positive syncytiotrophoblastic cells of choriocarcinomas, the growth fraction being limited to the cytotrophoblastic compartment.