6-ketoprostaglandin-f1-alpha and Head-and-Neck-Neoplasms

Circulating prostaglandins, including thromboxane A2 and prostacyclin, have been implicated as possible facilitative agents in the growth and dissemination of squamous cell carcinomas of the head and neck. The purpose of this study was to evaluate the relationship of plasma concentrations of these compounds to tumor stage and the effect of surgical resection on plasma prostaglandin levels. Blood samples were obtained from 40 patients with head and neck cancer. Ten treated patients were clinically disease-free (NED), and 30 patients with active disease were previously untreated at the time of this study. Plasma concentrations of thromboxane A2 and prostacyclin were measured by radioimmunoassay of their stable metabolites thromboxane B2 (TxB) and prostaglandin 6-keto-F1 (PGI). Platelet aggregation was performed with normal donor platelets (PRP) and normal control or patient plasma (PPP). TxB and TxB/PGI ratios were increased in T1N0M0 patients, compared with NED and with T4N0M0 primary lesions versus all other groups. With lymphatic and hematogenous metastases, TxB and TxB/PGI ratios fell to NED levels. ADP-induced platelet aggregation was significantly increased in head and neck cancer patients, compared with normal controls, and with T4N0M0 lesions, compared with NED. There were no significant differences in PGI levels. TxB, PGI, TxB/PGI, and platelet aggregometry did not change significantly with curative surgery. TxB and TxB/PGI interactions are involved in head and neck cancer. Changes in TxB and TxB/PGI may be related to increased platelet aggregation.

Topics: 6-Ketoprostaglandin F1 alpha; Aged; Aged, 80 and over; Carcinoma, Squamous Cell; Epoprostenol; Female; Head and Neck Neoplasms; Humans; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Staging; Platelet Aggregation; Thromboxane A2; Thromboxane B2

Abnormalities of 5 cyclooxygenase products were studied in tumours from patients with head and neck cancer. The studies were designed to measure tissue prostaglandin content (ng/g wet tissue) as well as production in vitro by tumour microsomes (ng/mg protein/10 min). Head and neck tumours contained large amounts of 5 eicosanoids in the order. PGE2 greater than PGE1 greater than 6-keto-PGF1 alpha greater than PGF2 alpha greater than TXB2. When tumours less than or equal to 2 cm were compared with tumours equal to or more than 3 cm in size, amounts of all but PGF2 alpha were higher in the larger tumours. However, the capacity of tumour microsomes to synthesize PGs in vitro was inversely related to tumour size. These results suggest a defect in removal of eicosanoids from large tumours. The physiological significance of this increase in local levels of eicosanoids remains to be determined in head and neck cancer.

Topics: 6-Ketoprostaglandin F1 alpha; Alprostadil; Dinoprost; Dinoprostone; Head and Neck Neoplasms; Humans; Microsomes; Prostaglandins; Prostaglandins E; Prostaglandins F