Heterogeneity of apoptotic pathways and c.Jun/JNK expression in malignant gliomas

In brain tumors, the prognostic value of apoptosis is still debated, even t hough recent observations are rather negative. In 50 astrocytic gliomas, ap optotic nuclei were recognized by TUNEL technique and morphology and apopto tic index (AI), mitotic index (MI) and the MI/AI ratio were calculated in p roliferative areas and in areas containing perinecrotic palisadings and hyp ercellular centres. In proliferative areas, a positive linear correlation b etween MI and AI and a MI/AI ratio > I were found. The latter was < I in pe rinecrotic palisadings and hypercellular centres. This suggests the possibi lity that apoptosis is triggered respectively by cell proliferation and hyp oxia. A small number of apoptotic nuclei was positive for c-Jun and JNKl, s uggesting the involvement of this pathway in apoptosis as well as that of s phingomyelinase/ceramide. No relationship was found between AI and labeling indices of Bc1-2, Bcl-x, Bax, p53, APO.I/Fas. The rationale for a prognost ic value of apoptosis in gliomas is thus poor.