Grace Zhou
Quantification of Carbonic Anhydrase IX
(CA9 )Expression in Tissue and Serum of
Renal Cell Carcinoma Patients

SchoolSolon High School • Solon, Ohio

ProgramScience Internship

MentorJames Finke, Ph.D.

DepartmentImmunology, Cleveland Clinic

mRI™: myRESEARCH illuminated

Research: Quantification of Carbonic Anhydrase IX (CA9 )Expression in Tissue and Serum of Renal Cell Carcinoma Patients

Hypothesis: The purpose of this study was (1) to validate ELISA as an accurate and quantitative method to measure CAIX (CA9) expression in renal cell carcinoma (RCC), including clear cell renal cell carcinoma (CRCC), (2) to investigate whether serum CAIX levels can be used to distinguish CRCC from other types of renal tumors, and (3) to correlate serum CAIX levels with tissue CAIX levels.

Methodology: These tissues and serum were analyzed from 40 RCC patients who underwent radical or partial nephrectomies at the Cleveland Clinic during 2006-2008. CAIX high-score was calculated by multiplying the highest CAIX intensity (0-3) by the % of cells exhibiting the highest CAIX intensity. The CAIX total-score was calculated by adding together the products of each of the CAIX intensities (0-3) and the % of cells exhibiting that respective staining intensity.

Outcomes: Tissue CAIX levels detected by ELISA highly correlated with the CAIX levels detected by immunohistochemical stains. The CRCC tumor tissue had significantly higher CAIX levels as detected by ELISA than non-CRCC tissue. Serum CAIX levels correlate with the tumor size and volume in patients with clear cell RCC. Serum CAIX levels do not correlate with tissue CAIX levels—therefore further study is needed to assess whether serum CAIX has prognostic significance.