These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Hypomethylation of CCGG sites in the 3' region of H-ras protooncogene is frequent and is associated with H-ras allele loss in non-small cell lung cancer.
    Author: Vachtenheim J, Horáková I, Novotná H.
    Journal: Cancer Res; 1994 Mar 01; 54(5):1145-8. PubMed ID: 8118795.
    Abstract:
    The methylation of MspI/HpaII sites flanking a variable tandem repeat in the 3' region of the c-Ha-ras protooncogene was analyzed in 74 DNA samples of non-small cell lung carcinomas and control lung tissues. Of 39 informative samples, 7 allelic deletions (18%) were found at the c-Ha-ras locus and of these, five (71%) showed hypomethylation of the nondeleted allele. Heterozygous DNA samples without allele loss revealed hypomethylation in 37% (12 of 32). Among 35 homozygotes, 9 showed hypomethylation (26%). We also analyzed c-Ha-ras mutations at codons 12, 13, and 61 by polymerase chain reaction and designed restriction fragment length polymorphism and found no mutation. Thus, c-Ha-ras mutations are not associated with the development of the detected abnormalities. We conclude that hypomethylation at specific sites in the 3' region is associated with loss of heterozygosity for the c-Ha-ras gene in non-small cell lung cancer. The finding that, in informative samples, hypomethylation occurs 2-3 times more frequently than allelic loss suggests that it might be a change contributing or predisposing to a genetic instability that can ultimately lead to c-Ha-ras allelic deletions found in tumor DNA.
    [Abstract] [Full Text] [Related] [New Search]