Aberrant promoter methylation and silencing of the RASSF1A gene in pediatric tumors and cell lines

Kenichi Harada, Shinichi Toyooka, Anirban Maitra, Riichiroh Maruyama, Kiyomi O. Toyooka, Charles F. Timmons, Gail E. Tomlinson, Domenico Mastrangelo, Robert J. Hay, John D. Minna, Adi F. Gazdar

Research output: Contribution to journalArticlepeer-review

190 Scopus citations


Aberrant promoter methylation of tumor suppressor genes has not been fully investigated in pediatric tumors. Therefore, we examined the methylation status of nine genes (p16INK4A, MGMT, GSTP1, RASSF1A, APC, DAPK, RARβ, CDH1 and CDH13) in 175 primary pediatric tumors and 23 tumor cell lines using methylation-specific PCR. We studied the major forms of pediatric tumors - Wilms' tumor, neuroblastoma, hepatoblastoma, medulloblastoma, rhabdomyosarcoma, osteosarcoma, Ewing's sarcoma, retinoblastoma and acute leukemia. The most frequently methylated gene in both primary tumors and cell lines was RASSF1A (40, 86%, respectively). However, the rates of RASSF1A methylation in individual tumor types varied from 0 to 88%. RASSF1A methylation was tumor specific and was absent in adjacent non-malignant tissues. Methylation of the other genes was relatively rare in tumors and non-malignant tissues (less than 5%). Neuroblastoma patients with methylation of RASSF1A were significantly older than patients without methylation (P = 0.008). There was no relationship between methylation status and other clinico-pathologic parameters. We treated six cell lines lacking RASSF1A mRNA with 5-aza-2′deoxycytidine to examine the relationship between methylation and transcriptional silencing. In five of six cell lines, restoration of RASSF1A mRNA was confirmed by RT-PCR. Our findings indicate that aberrant promoter methylation of RASSF1A may contribute to the pathogenesis of many different forms of pediatric tumors.

Original languageEnglish (US)
Pages (from-to)4345-4349
Number of pages5
Issue number27
StatePublished - Jun 20 2002
Externally publishedYes


  • Epigenetic
  • Pediatric tumor
  • Tumor suppressor gene

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Cancer Research


Dive into the research topics of 'Aberrant promoter methylation and silencing of the RASSF1A gene in pediatric tumors and cell lines'. Together they form a unique fingerprint.

Cite this