According to that, it has been recently hypothesized [67, 124] that the poorer survival associated with high stromal CA IX expression may be attributable, rather than hypoxia per se, to the acidification of the tumor microenvironment [125], which confers to cancer cells a survival advantage and contributes to the invasiveness and poor prognosis, activating proteases and disrupting cell adhesion molecule function [31, 43, 126]. This evidence concerns the gene CA9 and cancer.