Cancer research
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Studies were designed to determine whether salivary gland extract (SGE) from the leech Haementeria officinalis could inhibit enhancement of lung tumor colonization induced by pretreatment of mice with cyclophosphamide (CY) or local thoracic irradiation (LTI). Tumor nodules in the lung were generated by i.v. injections of T241 sarcoma and FSA fibrosarcoma cells into syngeneic C57BL/6 and C3Hf/Kam mice, respectively. CY (200 mg/kg) was given i.p. 1 or 4 days prior to i.v. injection of tumor cells. ⋯ Using [125I]iododeoxyuridine-labeled tumor cells, it was observed that SGE did not affect the initial lodgement of tumor cells in the lung, but it greatly facilitated their subsequent release from the lung. In normal mice, the SGE was active when given on the day or 1 day before but not when given 4 days before tumor cells. The antimetastatic effect of SGE was ascribed to its anti-platelet-aggregating, anticoagulant, and antiproteolytic enzyme activities.