Increased thromboxane A2 production at primary tumor site in metastasizing squamous cell carcinoma of the larynx.

In order to evaluate the possible role of prostaglandins (PG) in invasion and metastasis of malignant cells in larynx carcinoma, arachidonic acid (AA) metabolite production by tumor tissue, peritumor tissue and node metastasis was investigated in comparison to that by healthy mucosa and unaffected lymph nodes. The study was performed by evaluating PGE2, 6ketoPGF1 alpha and thromboxane B2 (TXB2) production by radioimmunoassay in specimens from eight patients who underwent surgical treatment. The highest rate of AA metabolism was observed in peritumor tissue. PGE2 was the main metabolite produced in all tissues and its levels were significantly higher than those of 6ketoPGF1 alpha and TXB2 (p < 0.05). 6ketoPGF1 alpha production was higher (p < 0.01) than that of TXB2 and did not significantly change among the different tissues. TXB2 production was significantly increased (p < 0.05) by peritumor tissue as compared to healthy mucosa. The ratio between TXB2 and 6ketoPGF1 alpha production was found to be almost twofold higher in tumor tissue, peritumor tissue, metastatic and non-metastatic lymph nodes as compared to control tissue. The lowest AA metabolism was found in affected lymph nodes. These findings demonstrate a different AA metabolism at primary tumor sites in comparison to healthy mucosa suggesting a prometastatic role of TXB2 and supporting the hypothesis of the occurrence of an imbalance between TXB2 and 6ketoPGF1 alpha production in favouring metastatic spread.