Alterations of ROBO1/DUTT1 and ROBO2 loci in early dysplastic lesions of head and neck: clinical and prognostic implications

Hum Genet. 2009 Mar;125(2):189-98. doi: 10.1007/s00439-008-0610-9. Epub 2008 Dec 24.

Abstract

Deletion of chromosomal 3p12.3 was suggested to be associated with dysplastic lesions of head and neck. This region harbors two candidate tumor suppressors ROBO1/DUTT1, ROBO2 and two non-coding RNAs (ncRNAs) located at intron 2 of ROBO1/DUTT1. Aim of this study is to understand the role of these genes in development of head and neck squamous cell carcinoma. A collection of 72 dysplastic lesions and 116 HNSCC samples and two oral cancer cell lines were analyzed for ROBO1/DUTT1 and ROBO2 deletion and promoter methylation. ROBO1/DUTT1, ROBO2 and two ncRNAs mRNA expression were analyzed by Q-PCR. Immunohistochemical analysis of ROBO1/DUTT1 and ROBO2 was performed. Alterations of these genes were correlated with different clinicopathological parameters. High frequency of molecular alterations (deletion/methylation) was seen in ROBO1/DUTT1 than ROBO2. In mild dysplastic lesions both of these genes showed high molecular alterations and remained more or less constant in subsequent stages. Q-PCR analysis showed reduced expression of these genes and the two ncRNAs. In vitro demethylation experiment by 5-aza-dC showed upregulation of ROBO1/DUTT1 and ROBO2 while the expression of the ncRNAs remained unchanged. Immunohistochemical analysis of ROBO1/DUTT1 and ROBO2 showed concordance with their mRNA expression and molecular alterations. Poor patients' outcome was predicted in the cases with alteration of ROBO1/DUTT1 along with tobacco addiction and nodal involvement. Our data suggests (a) ROBO1/DUTT1 and the ncRNAs are transcribed from different promoters, and (b) inactivation of ROBO1/DUTT1 could be used as molecular signature for early detection and prognosis of the head and neck cancer.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / pathology
  • Cell Line, Tumor
  • Chromosomes, Human, Pair 3 / genetics*
  • DNA Methylation*
  • Female
  • Gene Deletion*
  • Head and Neck Neoplasms / genetics*
  • Head and Neck Neoplasms / pathology
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Nerve Tissue Proteins / genetics*
  • Polymerase Chain Reaction
  • Prognosis
  • RNA, Untranslated / genetics*
  • Receptors, Immunologic / genetics*
  • Survival Analysis

Substances

  • Nerve Tissue Proteins
  • RNA, Untranslated
  • ROBO2 protein, human
  • Receptors, Immunologic
  • roundabout protein