It is also noteworthy that the loss-of-function mutations affecting pathways known to contribute to cellular vesiculation, such as TSAP6 (Yu et al., 2006; Lespagnol et al., 2008) and acidic sphingomyelinase (Asmase; Garcia-Barros et al., 2003; Bianco et al., 2009), do not prevent formation of spontaneous brain tumors in mice injected with oncogenic vectors (Meehan and Rak, unpublished observation). The gene discussed is SMPD1; the disease is brain neoplasm.