title: Alterations of ROBO1/DUTT1 and ROBO2 loci in early dysplastic lesions of head and neck: clinical and prognostic implications.
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.
authors.affiliation: Department of Oncogene Regulation, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata, 700026, India.
authors.forename: Susmita
authors.initials: S
authors.lastname: Ghosh
authors.forename: Amlan
authors.initials: A
authors.lastname: Ghosh
authors.forename: Guru Prasad
authors.initials: GP
authors.lastname: Maiti
authors.forename: Neyaz
authors.initials: N
authors.lastname: Alam
authors.forename: Anup
authors.initials: A
authors.lastname: Roy
authors.forename: Susanta
authors.initials: S
authors.lastname: Roychoudhury
authors.forename: Chinmay Kumar
authors.initials: CK
authors.lastname: Panda
mesh_terms: D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D017353:Gene Deletion; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011379:Prognosis; D022661:RNA, Untranslated / Q000235:genetics*; D011971:Receptors, Immunologic / Q000235:genetics*; D016019:Survival Analysis; D000097905:Roundabout Proteins
chemical_list: D009419:Nerve Tissue Proteins; D022661:RNA, Untranslated; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C498890:ROBO2 protein, human