Six cLys-Cox-2 x ApcMin/+ mouse tumours contained patchy epithelial cells that expressed Cox-2 protein (Fig. 4E,F), in contrast to non-transgenic ApcMin/+ mouse adenomas, which consisted only of Cox-2-negative epithelium, a finding similar to previous immunohistochemical studies of non-transgenic ApcMin/+ mouse tumours using the same rabbit polyclonal anti-Cox-2 antibody from Cayman Chemical Co.9. This evidence concerns the gene PTGS2 and neoplasm.