A tripeptide consisting of tyrosine, serine, and leucine with potential antineoplastic activity. Although the mechanism of its antitumor activity has yet to be fully elucidated, tyroserleutide appears to inhibit the expression of ICAM-1 (CD54), a cell adhesion factor of the immunoglobulin (Ig) superfamily that plays an important role in the invasion, adhesion, and metastasis of tumor cells. In addition, this agent may influence the Ca2+/calmodulin pathway, inhibiting phosphatidylinositol 3 kinase (PI3K); PI3K is upregulated in tumor cells and is involved in cellular proliferation.