TumorCOX-2-dependent production of PGE(2) triggers the synthesis of lymphocyte and macrophage interleukin (IL)-10 that, in turn, is known to potently suppress COX-2 in normal cells.
Tumors with methylated COX-2 and HMLH1 genes were associated with H. pylori vacA s1 (p = 0.025 and 0.047, respectively), and the nonmethylated tumors were associated with the presence of the gene flaA.
Tumor-infiltrating PD-L1<sup>+</sup> cells isolated from tumor-bearing mice also exerted morphology of tumor-associated macrophages and expressed high levels of prostaglandin E<sub>2</sub> (PGE<sub>2</sub>)-forming enzymes microsomal PGE<sub>2</sub> synthase 1 (mPGES1) and COX2.
COX-2 expression was detected in 48/58 (82.8%) tumors by immunohistochemistry and in an additional 52/59 (88.1%) tumors tested by microarray gene analysis.
COX-2 is expressed in a high percentage of a large series of primary endometrial tumors and its expression may be associated closely with parameters of tumor aggressiveness The possible prognostic role of COX-2 in endometrial carcinoma deserves further study.
COX-2 expression in stromal cells appears to have a role in tumor angiogenesis because tumor growth is attenuated when colon cancer cells are implanted in COX-2 knockout mice due to a decreased vascular supply to the tumors.
COX-2-positive tumor specimens were also evaluated with CD68 (macrophage/microglial cell marker) by coimmunolabeling to confirm that the observed COX-2 immunostaining was not due to immunoreactive macrophages or microglial cells.
COX-2 expression is strongly correlated with increased tumor microvasculature density and plays an important role in inhibiting apoptosis, stimulating angiogenesis and promoting tumor cell metastasis and invasion.
COX-2 may be associated with endometrial cancer carcinogenesis during the postmenopausal period but not with tumor aggressiveness and p53 overexpression.
COX-2 expression in the undifferentiated carcinoma deserves special consideration due to its prognosis and to the fact that selective COX-2 inhibitors were found to enhance tumour response to radiation in some studies.
COX-2 was not detected in MCF-7 cells, but its expression in RMTCs was inhibited by SA treatment, which also significantly reduced BCC growth, but failed to cause cell death by necrosis or apoptosis.