A study on the biological behavior of human brain tumors Part I. Arachidonic acid metabolism and DNA content

The study of proliferative characteristics and biochemical aspects seem to be of great importance in order to define brain neoplastic behavior. The purpose of this study is to verify the existence of any possible correlation between Arachidonic Acid (AA) metabolism and proliferative characteristics in 30 meningiomas and 30 neuroepithelial tumors. The most represented metabolite in neuroepithelial tumors is TxB₂, while 6-Keto-PGF_1α is the lowest represented product. Unimodal DNA distribution was observed in 66% of neuroepithelial tumors and in 87% of meningiomas. Aneuploidy was more frequent in glioblastomas and anaplastic meningiomas as previously reported; AA overall synthesis capacity and profile were similar between unimodal and bimodal cases of neuroepithelial tumors. Total AA metabolite, as well as TxB₂ and PGD₂, synthesis capacity are significantly higher in cases with S-phase cell percentage ≥ 3% than in cases with S-phase % <3%. Total production of AA metabolites via the cyclooxygenase pathway is significantly higher in meningiomas with bimodal DNA distribution than in cases with unimodal DNA content; when considering S-phase cell percentage, similarly to what observed in neuroepithelial tumors, meningiomas with S% > 3% shows a significantly higher overall synthesis capacity for AA. AA metabolism capacity well correlates with proliferative patterns in neuroepithelial tumors: the relationship depends preferentially on TxB₂ and PGD₂ synthesis capacity. In cases of meningiomas, the amount of AA metabolites seem to be related to DNA content and proliferative activity when anaplastic features are histologically demonstrated.