Collectively, our experiments indicate that the MAFP-resistant TAMRA-FP signal in the tumor is principally due to neutrophil serine proteases migrating in the ~ 25 kDa band, while the bulk of MAFP-sensitive activity in glioma is likely due to PAFAH1b3 and PAFAH1b2. Here, PAFAH1B3 is linked to central nervous system cancer.