The purpose of the present work was to analyze the role of PgE2 and indomethacin in the regulation of immune response. 18 patients with laryngeal cancer were chosen for the study. Three cultures on peripheral venous blood were taken from each subject in order to evaluate the variation in the different lymphocyte groups after the addition of PgE2 and its inhibiting factor: indomethacin. In the cultures with PgE2, an increase in T suppressor lymphocytes was observed while the T helper group showed a significant reduction (cultures with indomethacin produced the opposite effect). This result bears witness to the inhibiting effect PgE2 has on the immune system in subjects with laryngeal cancer. On the basis of these results, while awaiting further data, it can be suggested that future therapy be based on the administration of indomethacin in patients suffering from this disease.