COX-2 expression induces carcinogenesis and is thought to be an adverse prognostic factor in gastric carcinomas while the prognostic value of DNA mismatch repair (MMR) is still controversial.
COX-2 was expressed in DCAMKL1-positive tuft cells in Cdx2- and DCAMKL1-transgenic mouse stomachs, whereas the Sox9 transcription factor was ubiquitously expressed in gastric carcinomas, including COX-2-positive cells.
Active caspase-3, ssDNA, p53, Bax and COX-2 were more frequently observed among high grade and higher stage (> or =T2) carcinomas compared with low grade and lower stage (T1) tumours.
HuR and COX-2 protein expression were studied by immunohistochemistry of normal colon mucosa (N=20), adenomas (N=112), carcinomas (N=9) from patients with FAP, and 141 sporadic colorectal adenocarcinomas (Dukes B and C).
By immunohistochemistry, we assessed COX-2 expression in 24 hyperplastic polyps, 7 sessile serrated polyp/adenomas (SSA), 5 mixed polyps with SSA and adenoma, 27 traditional serrated adenomas, 515 non-serrated adenomas (tubular adenoma, tubulovillous adenoma and villous adenoma), 33 adenomas with intramucosal carcinomas, 96 adenocarcinomas with serration (corkscrew gland) and 111 adenocarcinomas without serration.
We observed a positivity for COX-2 in 72.1% of PIN and in 44.7% of prostate carcinomas with an overexpression of COX-2 in prostate cancer and PIN compared to benign prostatic tissue (P < 0.0005).
This suggests that COX-2 over-expression may be an early event in breast cancer aetiology permitting clones within the normal epithelium to evade apoptosis, to increase their numbers and perhaps acquire further changes that promote the formation of hyperplasias, and eventually carcinomas.
COX-2 expression was evaluated through immunohistochemical and mRNA analysis in carcinomas, adenomas, and healthy mucosa from six patients carrying germ line biallelic MYH mutations.
In addition, PPARgamma protein was not detected in all of the eight carcinomas in which COX-2 protein was detected, suggesting that expression of PPARgamma and COX-2 was in a reciprocal relationship.
COX-2 gene product was evaluated immunohistochemically in 30 healthy persons, in 22 patients with dysplastic lesions without previous or concomitant carcinomas, and in 29 patients with oral carcinomas.
COX-2 expression was comparable in gastric stump carcinomas and conventional gastric carcinomas and localized primarily to the cytoplasm of the neoplastic cells.