Analysis of PTCH/SMO/SHH pathway genes in medulloblastoma

Inactivation of the PTCH tumor suppressor gene occurs in a subset of sporadic medulloblastomas, suggesting that alterations in the PTCH pathway may be important in the development of this tumor. In order to address the frequency of genetic alterations affecting genes in this pathway, we used a combination of loss of heterozygosity (LOH) analysis, single‐stranded conformational polymorphism (SSCP) analysis, and direct sequencing of DNA samples from sporadic primitive neuroectodermal tumors (PNETs). To identify alterations in the PTCH gene, we performed LOH analysis on 37 tumor DNA samples. Of those with matched constitutional DNA samples, one demonstrated LOH. Of those without matched constitutional DNA, six were homozygous with all markers. All exons of the PTCH gene were sequenced in these seven tumors, and three mutations were found. To identify alterations in the SHH and SMO genes, we analyzed all exons of both genes in 24 tumors with SSCP and sequenced any exons that showed aberrant band patterns. No mutations were found in either SHH or SMO in any tumor. We also identified the following genes as candidate tumor suppressors based on their roles in controlling hh/ptc signaling in Drosophila: EN‐1 and EN‐2, deletion of which results in a lack of cerebellar development in mice; SMAD family members 1–7, and protein kinase A subunits RIα, RIβ, RIIβ, Cα, and Cβ. Each of these genes was investigated in a panel of 24 matched constitutional and tumor DNA samples. Our search revealed no mutations in any of these genes. Thus, PTCH is the only gene in this complex pathway that is mutated with notable frequency in PNET. Genes Chromosomes Cancer 27:44–51, 2000. © 2000 Wiley‐Liss, Inc.

[1]  P. Ingham,et al.  Transcriptional activation of hedgehog target genes in Drosophila is mediated directly by the cubitus interruptus protein, a member of the GLI family of zinc finger DNA-binding proteins. , 1996, Genes & development.

[2]  Susan M. Parkhurst,et al.  Signal transduction by cAMP-dependent protein kinase A in Drosophila limb patterning , 1995, Nature.

[3]  M. Scott,et al.  Basal cell carcinomas in mice overexpressing sonic hedgehog. , 1997, Science.

[4]  G. Struhl,et al.  In vivo evidence that Patched and Smoothened constitute distinct binding and transducing components of a Hedgehog receptor complex. , 1998, Development.

[5]  M. Scott,et al.  Control of Neuronal Precursor Proliferation in the Cerebellum by Sonic Hedgehog , 1999, Neuron.

[6]  K. Kinzler,et al.  Inactivation of the type II TGF-beta receptor in colon cancer cells with microsatellite instability. , 1995, Science.

[7]  A. Joyner,et al.  Abnormal embryonic cerebellar development and patterning of postnatal foliation in two mouse Engrailed-2 mutants. , 1994, Development.

[8]  R. Myers,et al.  Human Homolog of patched, a Candidate Gene for the Basal Cell Nevus Syndrome , 1996, Science.

[9]  C. James,et al.  Sporadic medulloblastomas contain PTCH mutations. , 1997, Cancer research.

[10]  C. Helms,et al.  Identification of Sonic hedgehog as a candidate gene responsible for holoprosencephaly , 1996, Nature Genetics.

[11]  D. Lacombe,et al.  Medulloblastoma in the nevoid basal-cell carcinoma syndrome: case reports and review of the literature. , 1990, Genetic counseling.

[12]  R. Derynck,et al.  Smad3 and Smad4 cooperate with c-Jun/c-Fos to mediate TGF-β-induced transcription , 1998, Nature.

[13]  R. Goodman,et al.  Protein kinase A directly regulates the activity and proteolysis of cubitus interruptus. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[14]  L. Becker,et al.  Medulloblastoma: clinical presentation and management. Experience at the hospital for sick children, toronto, 1950-1980. , 1983, Journal of neurosurgery.

[15]  C. Tabin,et al.  Biochemical evidence that Patched is the Hedgehog receptor , 1996, Nature.

[16]  Michael Dean,et al.  Mutations of the Human Homolog of Drosophila patched in the Nevoid Basal Cell Carcinoma Syndrome , 1996, Cell.

[17]  S. Scherer,et al.  Mutations in the human Sonic Hedgehog gene cause holoprosencephaly , 1996, Nature Genetics.

[18]  M. Scott,et al.  The tumour-suppressor gene patched encodes a candidate receptor for Sonic hedgehog , 1996, Nature.

[19]  Robert J. Gorlin,et al.  Nevoid Basal‐Cell Carcinoma Syndrome , 1987, Medicine.

[20]  M. Scott,et al.  Antagonizing cAMP-dependent protein kinase A in the dorsal CNS activates a conserved Sonic hedgehog signaling pathway. , 1996, Development.

[21]  V. P. Collins,et al.  Somatic mutations in the human homologue of Drosophila patched in primitive neuroectodermal tumours , 1997, Oncogene.

[22]  D. Evans,et al.  The incidence of Gorlin syndrome in 173 consecutive cases of medulloblastoma. , 1991, British Journal of Cancer.

[23]  Yigong Shi,et al.  A structural basis for mutational inactivation of the tumour suppressor Smad4 , 1997, Nature.

[24]  M. Scott,et al.  Mutations of the PATCHED gene in several types of sporadic extracutaneous tumors. , 1997, Cancer research.

[25]  P. Ingham.  Signalling by hedgehog family proteins in Drosophila and vertebrate development. , 1995, Current opinion in genetics & development.

[26]  K. Kinzler,et al.  Microsatellite instability and mutations of the transforming growth factor beta type II receptor gene in colorectal cancer. , 1995, Cancer research.

[27]  M. Wolter,et al.  Missense mutations in SMOH in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system. , 1998, Cancer research.

[28]  N. Hayward,et al.  No evidence for the H133Y mutation in SONIC HEDGEHOG in a collection of common tumour types , 1998, Oncogene.

[29]  Wei-Jen Tang,et al.  Two Cytoplasmic Domains of Mammalian Adenylyl Cyclase Form a G- and Forskolin-activated Enzyme in Vitro(*) , 1996, The Journal of Biological Chemistry.

[30]  D. Stevanović.  Nevoid basal cell carcinoma syndrome. , 1967, Archives of dermatology.

[31]  G. Struhl,et al.  Dual Roles for Patched in Sequestering and Transducing Hedgehog , 1996, Cell.

[32]  C. Raffel,et al.  Sporadic Medulloblastomas Contain Oncogenic β-Catenin Mutations , 1998 .

[33]  Bert Vogelstein,et al.  Mutational Analysis of the APC/β-Catenin/Tcf Pathway in Colorectal Cancer , 1998 .

[34]  T Pietsch,et al.  Medulloblastomas of the desmoplastic variant carry mutations of the human homologue of Drosophila patched. , 1997, Cancer research.

[35]  K. Kinzler,et al.  Frequency of Smad gene mutations in human cancers. , 1997, Cancer research.

[36]  A. Joyner,et al.  Subtle cerebellar phenotype in mice homozygous for a targeted deletion of the En-2 homeobox. , 1991, Science.

[37]  M. Wolter,et al.  Mutations in the human homologue of the Drosophila segment polarity gene patched (PTCH) in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system. , 1997, Cancer research.

[38]  Q. Gu,et al.  Activating Smoothened mutations in sporadic basal-cell carcinoma , 1998, Nature.

[39]  G. Struhl,et al.  Sequential organizing activities of engrailed, hedgehog and decapentaplegic in the Drosophila wing. , 1995, Development.

[40]  I. Vořechovský,et al.  A Mammalian patched Homolog Is Expressed in Target Tissues of sonic hedgehog and Maps to a Region Associated with Developmental Abnormalities (*) , 1996, The Journal of Biological Chemistry.

[41]  K. Weinberg,et al.  Reduction to homozygosity and gene amplification in central nervous system primitive neuroectodermal tumors of childhood. , 1990, Cancer research.