PTGS2 and colorectal carcinoma: In fact, it is well known that CRC cells overexpress the COX-2 protein and this phenomenon depends on transcriptional (Yamamoto et al, 1995; Duque et al, 2005; Wu et al, 2005; Kaidi et al, 2006) and post-transcriptional regulation (Dixon et al, 2001; Strillacci et al, 2009).