One of the two mutations detected in this study had been missed by SSCP, suggesting that the true rate of PTCH mutations in sporadic medulloblastomas may be underestimated by SSCP screening.
In keeping with the role of PTCH as a tumor-suppressor gene, somatic mutations of this gene occur in sporadic basal-cell carcinomas and medulloblastomas.
Further, the expression of murine homolog of miR-206 was also found to be downregulated in SHH subgroup medulloblastomas from the Smo (+/+) transgenic mice and the Ptch1 (+/-) knockout mice.
Nevoid basal cell carcinoma syndrome (NBCCS), caused by a PTCH1 mutation in the hedgehog signaling pathway, occasionally exhibits macrocephaly and medulloblastoma.
In several of these cases, activation of HH-GLI signaling is mediated by overproduction of HH ligands (e.g., prostate cancer), loss-of-function mutations in <i>PTCH1</i> or gain-of-function mutations in <i>SMO</i>, which occur in the majority of basal cell carcinoma (BCC), SHH-subtype medulloblastoma and rhabdomyosarcoma.
Together, our results indicate that DNA damage promoted by Boc leads to the demise of its own coreceptor, Ptch1, and consequently medulloblastoma progression.
The IGF-I transgene produced a marked brain overgrowth, and significantly accelerated tumor development, increasing the frequency of pre-neoplastic lesions as well as full medulloblastomas in Ptc1+/-/IGF-I Tg mice.
Most human MB cell lines tested (five of seven = 71.4%), two MB cell lines derived from spontaneously arising tumors in Patched-1(+/-) mice (two of two = 100%) and three MB primary cultures derived from surgical specimens, were susceptible to reovirus infection.
The PTCH gene was found to contain somatic mutations also in sporadic basal cell carcinomas and medulloblastomas, tumors seen in NBCCS, consistent with PTCH acting as a tumor suppressor.
Mice heterozygous for patched homolog 1 mutations, like heterozygous patched 1 humans, have a higher incidence of Shh subgroup medulloblastoma (MB) and other tumors.
Whereas genetic mutations in PTCH1 have previously been shown to lead to medulloblastoma, our study indicates that epigenetic silencing of PTCH1, and other critical developmental loci, by DNA methylation is a fundamental process of pediatric medulloblastoma formation.
The PTC gene is mutated in a subgroup of medulloblastomas, and may lead to increased proliferation in granule cells that normally express this receptor.
Patched1 heterozygous (Ptch1 <sup>+/-</sup>) mice, carrying a germ-line heterozygous inactivating mutation in the Ptch1 gene, the Shh receptor and negative regulator of the pathway, are uniquely susceptible to MB development after radiation damage in neonatal cerebellum.
We have identified the known c.1022 + 1G>A SUFU germ line splicing mutation in a family that was PTCH1-negative and who had signs and symptoms of GS, including medulloblastoma.
Gorlin syndrome is associated with germline mutations in components of the Sonic Hedgehog pathway, including Patched1 (<i>PTCH1)</i> and Suppressor of fused (<i>SUFU)</i><i>SUFU</i> mutation carriers appear to have an especially high risk of early-onset medulloblastoma.
Although medulloblastomas occurring in Ptc1+/- mice were histopathologically heterogeneous and contained intermixed regions of both rapidly proliferating and nondividing more differentiated cells, tumors that also lacked Kip1 were uniformly less differentiated, more highly proliferative, and invasive.
It now appears that constitutive activation of Hedgehog signalling, by inactivating mutations in PTCH1 or activating mutations in the coreceptor SMOH, is required and possibly sufficient for basal cell carcinoma development and also contributes to the formation of a variety of other tumour types, including medulloblastoma and rhabdomyosarcoma.
We firstly isolated CSCs from Sonic Hedgehog (SHH) MB derived from Ptch1 heterozygous mice and compared their expression level of EMT-related transcripts and microRNAs with cerebellar NSCs.
We also briefly review two important advances in this area: the treatment of medulloblastomas in patients with mutations in the PTCH1 gene, and the discovery of deregulated mammalian target of rapamycin as a major oncogenic driver molecule in patients with TSC mutations and subependymal giant cell astrocytoma.
The human Patched (PTCH) gene is a classical tumour suppressor gene for basal cell carcinomas and medulloblastomas, the loss of which causes increased signalling through the Sonic Hedgehog (SHH) pathway.