Her2 diagnostic methods
In certain aspects, the present invention provides methods for determining whether a Her-2 positive cancer is likely to respond to treatment with a Her2-acting agent and/or whether a patient with a Her-2 positive cancer is likely to have a slow disease progression. In other aspects, the present invention is drawn to methods for determining whether a subject with a Her-2 positive cancer is unlikely to respond to treatment with at least one chemotherapeutic agent in addition to a Her2-acting agent and/or whether a patient with a Her-2 positive cancer is likely to have a fast disease progression.
1. A method of quantitating an amount of HER-2 protein in a sample of a cancer from a subject, the method comprising:
(a) measuring the amount of HER-2 protein in a sample of cancer from a subject, wherein the sample is deposited on a solid support, wherein the sample on the solid support comprises viable tumor tissue, necrotic tumor tissue and non-tumor tissue, and wherein the measuring is performed using an immunoassay comprising the steps of:
(i) contacting the sample with a first antibody that binds specifically to HER-2 and comprises a molecular tag attached thereto via a cleavable linkage,
(ii) cleaving the cleavable linkage thereby releasing the molecular tag in a buffer volume, and
(iii) quantifying the amount of released molecular tag in the buffer volume;
(b) after step (a), performing immunohistochemistry staining on the sample to distinguish viable tissue from non-viable tissue;
(c) defining a total tumor surface area on the sample on the solid support based on imaging of the immunohistochemistry staining of step (b), wherein the total tumor surface area includes all areas of viable tumor and excludes necrotic tissue and non-tumor tissue in the sample on the solid support;
(d) quantifying the size of the total tumor surface area; and
(e) determining the amount of HER-2 protein in the sample based on the amount of released molecular tag in the buffer volume normalized to the size of the total tumor surface area.
2. The method of claim 1 , wherein the amount of HER-2 protein is total HER-2 or HER-2 homodimer.
3. The method of claim 1 , wherein the cancer from the subject is a HER-2 positive cancer.
4. The method of claim 1 , wherein the cancer from the subject is breast cancer.
5. The method of claim 1 , wherein the solid support is a histology slide.
6. The method of claim 1 , wherein the sample is histologically stained before defining the total tumor surface area.
7. The method of claim 1 , wherein the total tumor surface area of interest is defined by a pathologist.
8. The method of claim 1 , wherein the size of the total tumor surface area is quantified using software.
9. The method of claim 1 , wherein the released molecular tag is analyzed by electrophoretic separation to generate an electropherogram.
10. The method of claim 9 , wherein an internal reference control molecule having a known concentration is co-analyzed with the released molecular tag by electrophoretic separation.
11. The method of claim 10 , wherein the released molecular tag and the internal reference control molecule are quantified by measuring relative fluorescence units (RFU) of an electropherogram peak area of the released molecular tag and RFU of an electropherogram peak area of the internal reference control molecule, and wherein a relative peak area (RPA) representing the amount of the released molecular tag is calculated as a ratio of the RFU of the electropherogram peak area of the released molecular tag to the RFU of the electropherogram peak area of the internal reference control molecule.
12. The method of claim 1 , wherein cleaving the cleavable linkage comprises contacting the sample with a second antibody that binds specifically to HER-2 and comprises a cleaving agent attached thereto.
13. The method of claim 12 , wherein the first antibody and the second antibody are each specific for a first epitope of HER-2 when quantitating the amount of HER-2 homodimer in the sample.
14. The method of claim 12 , wherein the first antibody binds a first epitope of HER-2 and the second antibody binds a second epitope of HER-2 when quantitating the total amount of HER-2 protein in the sample.
15. The method of claim 12 , wherein the cleaving agent produces an active species that cleaves the cleavable linkage.
16. The method of claim 15 , wherein the cleaving agent has an effective proximity that is the distance within which the cleaving agent can effectively cleave the cleavable linkage.
17. The method of claim 15 , wherein at least one of the first antibody and the second antibody comprise a sensitizer attached thereto, wherein the sensitizer induces the cleaving agent to produce the active species.
18. The method of claim 1 , wherein the method quantitates the amount of HER-2 in the sample over a dynamic range greater than 2 logs.
19. The method of claim 1 , wherein the step of quantifying the size of the total tumor surface area comprises: (i) scanning the total tumor surface area, (ii) obtaining the total pixels of the total tumor surface area scanned area, and (iii) converting the total pixels into the size of the total tumor surface area.
20. The method of claim 1 , wherein the step of determining the amount of HER-2 protein is based on the amount of released molecular tag multiplied by the buffer volume and divided by the total tumor surface area, wherein the calculated amount of HER-2 protein is expressed in pmol per mm2.
21. The method of claim 1 , wherein the immunohistochemistry staining in step (b) is an hematoxylin and eosin (H&E) staining.