Abstract
405 Background: The transmembrane protein MN (carbonic anhydrase IX)(CAIX) catalyzes the hydration of carbon dioxide to carbonic acid and decreases pH. In cancer, up-regulation of CAIX gene expression occurs under hypoxic conditions within tumors. Significant levels of CAIX protein have been detected in a variety of cancers including kidney, cervix, lung, bladder, colon, breast, liver, gall bladder, and pancreas. Methods: Pretreatment plasma CAIX and VEGF-A levels were determined from 52 metastatic renal cell cancer patients enrolled in a phase III first-line trial of sunitinib vs. interferon alpha (IF). The CAIX and VEGF-A ELISAs (WILEX/Oncogene Science, Cambridge MA) were used for determination of plasma biomarker levels. 51 of 52 patients had an MSKCC score of 0 or 1. Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method and Cox modeling with both continuous and dichotomous (median) plasma CAIX and VEGF levels. Results: Pretreatment plasma CAIX levels averaged 371 pg/ml, with a median of 194 pg/ml and 25th and 75th percentile values of 125 and 298 pg/ml, respectively. In the whole population, higher plasma CAIX was significant on a continuous basis for predicting reduced PFS (p < 0.007) and shorter OS (p <0.0001). When analyzed using the median as cutpoint, the elevated plasma CAIX cohort trended for reduced PFS (p = 0. 13) and had a significantly reduced OS (HR 2.77, p = 0.026) (median 94 vs. 115 weeks). In univariate analysis plasma VEGF-A did not predict for PFS or OS when analyzed as a continuous or dichotomous variable. In multivariate analysis for PFS (including treatment arm, CAIX, and MSKCC score), treatment with sunitinib (vs. IF) (p = 0.006) and lower plasma CAIX (p = 0.04) resulted in a significantly longer PFS. In multivariate analysis for OS, again treatment with sunitinib (vs. IF) (p=0.037), and lower plasma CAIX (p < 0.0001) resulted in a significantly longer OS. Conclusions: Elevated pretreatment plasma CAIX predicted for reduced PFS and overall survival in metastatic renal cancer patients. In addition, sunitinib was superior to interferon, regardless of plasma CAIX status.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
