Methods for determining signal transduction activity in tumors
The method of the invention pertains to determining signal transduction activity in a tissue section by immunohistochemistry techniques. The expression level of the receptor of interest is determined as well as the expression levels of one or more effector molecules of the receptor signal transduction pathway. Furthermore a combined ratio of expression levels of effector molecules in subcellular compartments with the receptor expression was found to have prognostic significance.
1. A method for determining an EGFR signaling profile of a tissue section, comprising the steps of:
(a) staining the tissue section with:
(i) a reagent which detects EGFR;
(ii) a second reagent which detects an EGFR effector molecule; and
(iii) a third reagent which detects a subcellular compartment;
(b) obtaining a high resolution digital image of:
(i) the EGFR;
(ii) the EGFR effector molecule; and
(iii) the subcellular compartment; and
(c) analyzing the digital image so obtained to obtain an amount of:
(i) the EGFR;
(ii) the EGFR effector molecule present in the subcellular compartment; and
(iii) the EGFR effector molecule present outside the subcellular compartment;
(d) determining a ratio of the amount obtained in step c(ii) to the amount obtained in step c(iii);
(e) comparing the EGFR amount obtained in step c(i) to an expression level of EGFR in a control specimen;
(f) comparing the ratio determined in step (d) to a corresponding ratio obtained for the control specimen;
thereby determining the EGFR signaling profile.
2. The method of claim 1 wherein the subcellular compartment is the nucleus and the area present outside the subcellular compartment comprises the cytoplasm.
3. The method of claim 2 , wherein the EGFR effector molecule is selected from the group consisting of: Akt1, Erk and Stat3.
4. A method of determining the prognostic status of an EGFR expressing tumor comprising
(a) staining the tissue section with:
(i) a reagent which detects EGFR;
(ii) a second reagent which detects an EGFR effector molecule; and
(iii) a third reagent which detects a subcellular compartment;
(b) obtaining a high resolution digital image of:
(i) the EGFR;
(ii) the EGFR effector molecule; and
(iii) the subcellular compartment; and
(c) analyzing the digital image so obtained to obtain an amount of:
(i) the EGFR;
(ii) the EGFR effector molecule present in the subcellular compartment; and
(iii) the EGFR effector molecule present outside the subcellular compartment;
(d) determining a ratio of the amount obtained in step c(ii) to the amount obtained in step c(iii);
(e) comparing the EGFR amount obtained in step c(i) to an expression level of EGFR in a control specimen;
(f) comparing the ratio determined in step (d) to a corresponding ratio obtained for the control specimen;
wherein (i) a tumor with an elevated level of EGFR and a lower than control effector ratio indicates a poor prognosis; (ii) a tumor with an elevated level of EGFR and a higher than control effector ratio indicates a better prognosis; (iii) a tumor with a decreased level of EGFR and a lower than control effector ratio indicates a good prognosis.
5. The method of claim 1 , wherein the effector molecule is an end effector.
6. The method of claim 1 , wherein the staining in step a) is by a immunohistochemical method.
7. The method of claim 1 , wherein the high resolution digital image in step b) is obtained with a microscope.
8. The method of claim 7 , wherein the microscope is an optical microscope.
9. The method of claim 1 , wherein the effector molecule is selected from the group consisting of Grb2, Ras, ERK1, ERK2, RAF1, MEK1, MEK2, AKT, pAKT, GSK3, pGSK3, Mt0R, 70s6k, eIF4B, 4E-BPI, eIF2B, NFkB, CREB, JAK, and STAT.
10. The method of claim 1 , wherein the second reagent is used to determine a total effector molecule expression amount.
11. The method of claim 1 , wherein the second reagent is used to determine a phosphorylated effector molecule expression amount.
12. The method of claim 1 , wherein the tissue section is fixed.