PTGS2 and colorectal adenoma: These results are in agreement with earlier studies, that found both stromal and epithelial colorectal cells expressing COX-2 in colorectal adenomas (Arnoletti et al, 2005; Pisano et al, 2005; Tatsu et al, 2005) and carcinomas (Battu et al, 1998; Yamashita et al, 2003; Ohta et al, 2006).