[Effect of DL-tryptophan on blastomogenesis induced by acrylic plastic]

Plastic plates implanted subcutaneously to rats induced sarcoma in 11 of 27 animals (40.7%) which survived up to the time of the first tumour appearance (12.3 months). No tumours were revealed at the sites of the plastic powder implantation. Following long-term administration of DL-tryptophan tumours developed around the plates in 6 to 19 rats (31.5%) in 13.8 months, and around the powder in 2 of 5 rats which survived for 18.7 months. Some animals of this group displayed preneoplastic changes around the powder clumps.