[Tumor-degenerating factor (TDF)].

: A new human fibroblast-producing factor which degenerates human tumor cells in vitro was found and designated as tumor-degenerating factor (TDF). The characteristics of the TDF were as follows: 1) The molecular weight of the TDF was estimated to be 30k by SDS-PAGE. 2) It may be basic and glycosylated. 3) Its activity was inhibited by fibronectin and, vice versa, by binding TDF molecule with fibronectin molecule. 4) Its activity was enhanced by interferons. It is possible that the TDF is an important substance concerning the interaction between tumor cells and interstitial cells.