RESUMO
OBJECTIVE: Carbonic anhydrase IX (CA IX) is one indicator of hypoxia in the tumor and its expression is associated with more aggressive forms of breast cancer. The aim of this study is to point out its own set of correlation between CA IX expression and selected morphological and biological indicators. TYPE OF STUDY: Cohort prospective study. SETTING: Department of Pathology of Slovak Medical University and St. Elisabeth Cancer Institute, Bratislava, Slovak Republic. METHODS: These were 145 cases of breast cancer aged 25 to 85 years (median 59 years) from the Register of the Institute of Pathology and Slovak Medical University and St. Elisabeth Cancer Institute in Bratislava for the period 1. 9. 2012 to 28. 2. 2013. In all cases were examined CA IX, estrogen receptor (ER), progesterone receptor (PR), HER2, p53 and Ki67 by immunohistochemistry. Typing, grading and staging of the disease were evaluated according to the classification systems currently in place. RESULTS: CA IX expression was demonstrated in 51 cases (35.2%). CA IX positivity correlated with the degree of differentiation (p = 0.0001), with ER status (p <0.0001) and PR (p <0.01) and HER2 (p <0.01) and proliferative activity as measured by Ki67 (p <0.001). HER2-positive cancers and triple-negative cancers were more frequently associated with the expression of CA IX compared with luminal subtypes (p <0.0001). The state of CA IX and age range of the tumor - pT and lymph node status - pN and p53 have not been shown statistically significant correlations. CONCLUSION: CA IX examination in breast cancer provides valuable information on the state of hypoxia in the tumor, thereby supplementing view of prognosis of the disease.