Histochemical Assay for Activated Protein Kinases

Increased phosphorylation of receptor protein-tyrosine kinases has been implicated in different carcinomas. In these cancers the degree of amplification appears to correlate with the prognosis: the greater the amplification the worse the prognosis. It is unclear whether overall kinase amplification or the levels of activated kinase provides the better prognostic indicator. The major difficulty is the ability to specifically measure activated kinases. In this Phase I study, we will develop a histochemical assay to specifically measure the activated receptor kinase in frozen and formalin-fixed, paraffin embedded tissues. SH2 domain fusion proteins from specific signal transduction proteins will be directly conjugated with either biotin, alkaline phosphatase or horseradish peroxidase and used to specifically detect the activated kinase in tissue sections. In Phase II, the prognostic value of such a measurement will be evaluated by expanding the screening to different primary human tumors and correlating the data with other, independent prognostic indicators and modifying the assay to be compatible with automated image analysis. The ultimate goal of these studies will be to provide a tool to allow earlier diagnosis and better management of the cancer patient.