Second, even if data in AVICs from diseased valve show that COX-2 inhibition promotes calcification, and we found a strong decrease of COX-2 expression in CAVD samples, it remains to be established whether the reduction of COX-2 expression is a cause or a consequence of CAVD. This evidence concerns the gene PTGS2 and congenital bilateral aplasia of vas deferens from CFTR mutation.