Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 May-Jun;30(3):278-84.
doi: 10.1016/j.urolonc.2010.05.009. Epub 2010 Sep 26.

Splicing variants of carbonic anhydrase IX in bladder cancer and urine sediments

Francesca Malentacchi  1 , Serena Vinci, Alessandro Della Melina, Jitka Kuncova, Donata Villari, Gianluca Giannarini, Gabriella Nesi, Cesare Selli, Claudio Orlando
Affiliations

Splicing variants of carbonic anhydrase IX in bladder cancer and urine sediments

Francesca Malentacchi et al. Urol Oncol. 2012 May-Jun.

Abstract

Objective: In human cancers, carbonic anhydrase IX (CAIX) influences cell proliferation and tumor progression, maintaining intracellular and extracellular pH under hypoxic conditions. An alternative CAIX isoform, lacking of exons 8-9 (AS) and independent from the levels of hypoxia, was recently demonstrated in cancer cells. AS-CAIX competes with the full-length (FL) isoform in the regulation of the extracellular pH, mainly in a mild hypoxic status. In the present study, we evaluated mRNA expression of the 2 CAIX isoforms and their clinical relevance in bladder cancers and urine sediments.

Materials and methods: We measured mRNA expression of FL- and AS-CAIX isoforms in tumor tissues and benign mucosa from 45 patients with bladder transitional cell carcinoma. The expression of the 2 isoforms was also measured in urine sediment of 81 bladder cancer patients and 93 control subjects.

Results: Expression of FL-CAIX mRNA was lower than AS-CAIX in benign mucosa (P = 0.006) whereas in paired bladder cancers FL-CAIX mRNA was higher (P = 0.007). Consequently, the percentage of FL-CAIX in bladder cancers [median: 62.6%] was significantly higher than in benign mucosa [15.0%] (P < 0.0001). In the urinary sediments of bladder cancer patients FL-CAIX mRNA was significantly higher in comparison with normal controls (P = 0.003). FL-CAIX percentage appeared dramatically higher in urine sediments of bladder cancer patients [64.5%] in comparison with controls [7.5%] (P < 0.0001). In addition, FL-CAIX% was significantly different in sediments from pTa-pT1 and ≥ pT2 patients [51.5% and 91.7%, respectively] (P = 0.016). Stratification according tumor grade indicated that FL-CAIX% was significantly lower in G1 bladder cancers [33.3%] in comparison with G2-G3 [88.6%] (P = 0.005) The clinical sensitivity for FL-CAIX% in urine sediments was 0.93, with a 0.76 specificity. Using the same cut-off positive predictive value (PPV) was 0.78, whereas negative predictive value (NPV) was 0.93.

Conclusions: Our results seem to indicate that in bladder cancers and related urine sediments, FL-CAIX is the prevalent and is the most accurate clinically relevant variant surrogate of hypoxic stress.

PubMed Disclaimer

MeSH terms