The human p73 protein is essential for normal morphogenesis and maintenance of 
neural tissue. Recently, several TP73 transcripts have been revealed in 
medulloblastoma (MB), the most common malignant brain tumor in children. Here, 
we performed immunohistochemical analysis on 29 MB specimens using anti-p73alpha 
and anti-DeltaNp73 antibodies. Real-time PCR quantification was performed to 
assess TAp73 and DeltaNp73 transcripts in a subset of 13 MB samples. Normal 
cerebellar tissues and RNA were used for comparison. Pilot clinical-pathological 
correlations were also provided. We report significant differences for TAp73 and 
DeltaNp73 mRNA expression between tumor tissues and reference (P = 0.013, P = 
0.028). Immunohistochemically, 52 and 29% MB samples were positive for p73alpha 
and DeltaNp73, respectively. p73alpha expression was found to be in both the 
nucleus and cytoplasm, whereas DeltaNp73 was localized predominantly in the 
cytoplasm. In normal cerebellum, positive staining for p73alpha and DeltaNp73 
was observed in the Purkinje cells of newborns, not adult samples, which 
supports the developmental role of TP73 during organogenesis of the human 
cerebellum. Survival analysis has shown negative relationship of 
DeltaNp73-immunoreactivity with overall survival (OS) and event free survival 
(EFS) (P = 0.026 and P = 0.127, respectively). For p73alpha-positive cases, the 
negative trend in OS (P = 0.149) and EFS (P = 0.216) was also apparent. Our 
results indicate the involvement of p73 protein in MB tumorigenesis and define 
TP73 as a potential prognostic and therapeutic target for medulloblastoma.