Salivary gland extract from the South American leech Haementeria ghilianii, administered i.v. on the same day as the i.v. inoculation of T241 sarcoma cells, completely suppresses colonization of the mediastinal lymph nodes and markedly reduces the number and size of lung tumor colonies produced by this tumor. Additional studies indicate that the extract contains various types of proteinase inhibitors and has the capacity to inhibit clotting and platelet aggregation by tumor material and collagen. Although not yet proved by direct evidence, these activities may be involved in the inhibitory effect of lung tumor colonization by the leech extract.
↵1 Supported by Grant HL-18827 (Subproject A3) from the National Heart, Lung, and Blood Institute, by a gift from Mary L. Smith to the Section of Hematology-Oncology of Pennsylvania Hospital, and by Biomedical Research Support Funds from Pennsylvania Hospital.
↵2 To whom requests for reprints should be addressed.
- Received June 16, 1982.
- Accepted January 4, 1983.
- ©1983 American Association for Cancer Research.