Protein tyrosine kinase (PTK) inhibitors are potential antiproliferative agents for diseases caused by the hyperactivity of PTKs. Tyrphostins are a class of antiproliferative compounds that act as PTK blockers. PTK inhibitors that preferentially inhibit the epidermal growth factor (EGF) receptor kinase block EGF-dependent cell proliferation. Protein tyrosine kinase (PTK) inhibitors are potential antiproliferative agents for diseases caused by the hyperactivity of PTKs. Tyrphostins are a class of antiproliferative compounds that act as PTK blockers. PTK inhibitors that preferentially inhibit the epidermal growth factor (EGF) receptor kinase block EGF-dependent cell proliferation. RG-13022 is an inhibitor of epidermal growth factor (EGF) receptor kinase with an IC50 value of 1 μM in HT-22 cells.