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

• Published in: Human genetics 2009-03, Vol.125 (2), p.189-198
• Main Authors: Ghosh, Susmita, Ghosh, Amlan, Maiti, Guru Prasad, Alam, Neyaz, Roy, Anup, Roychoudhury, Susanta, Panda, Chinmay Kumar
• Format: Article
• Language: English
• Subjects: Adult; Biomedical and Life Sciences; Biomedicine; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - pathology; Cell Line, Tumor; Chromosomes, Human, Pair 3 - genetics; DNA Methylation; Female; Gene Deletion; Gene Function; Genes; Head and Neck Neoplasms - genetics; Head and Neck Neoplasms - pathology; Human Genetics; Humans; Immunohistochemistry; Male; Medical research; Medicine, Experimental; Metabolic Diseases; Methylation; Middle Aged; Molecular Medicine; Nerve Tissue Proteins - genetics; Original Investigation; Polymerase Chain Reaction; Prognosis; Receptors, Immunologic - genetics; RNA; RNA, Untranslated - genetics; Roundabout Proteins; Squamous cell carcinoma; Survival Analysis
• ISSN: 0340-6717; 1432-1203
• DOI: 10.1007/s00439-008-0610-9

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.