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.
Recent studies have shown overexpression of cyclooxygenase 2 (COX 2) and 5-lipoxygenase (5-lipox) in exocrine pancreatic carcinomas, suggesting a potential role of the arachidonic acid (AA) cascade in the regulation of this cancer type.
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.
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 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.
These results indicate that Cox-2 is widely expressed in human bladder carcinomas and that the role of Cox-2 inhibition in bladder cancer should be further studied.
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 expression was evaluated through immunohistochemical and mRNA analysis in carcinomas, adenomas, and healthy mucosa from six patients carrying germ line biallelic MYH mutations.
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).
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.
The ratio of tumor:paired normal mucosa of mRNA expression of ldlr and of cox-2 was measured in specimens taken during colonoscopy. ldlr and cox-2 transcripts were apparent in 11 of 11 carcinomas.