title: Interferon stimulated gene-ISG15 is a potential diagnostic biomarker in oral squamous cell carcinomas.
abstract: BACKGROUND
  Cancer diagnostic biomarkers have a wide range of applications that include early detection of oral precancerous lesions and oral squamous cell carcinomas, and assessing the metastatic status of lesions. The interferon stimulated ISG15 gene encodes an ubiquitin-like protein, which conjugates to stabilize activation status of associated proteins. Hence a deregulated expression of ISG15 may promote carcinogenesis. Indeed overexpression of ISG15 has been observed in several cancers and hence it has been proposed as a strong candidate cancer diagnostic biomarker. Given the emerging relationship between malignant transformation and ISG15, we sought to examine the expression pattern of this gene in tumor biopsies of oral squamous cell carcinoma (OSCC) tissues collected from Indian patients.
  
  
  METHODS
  Total RNA isolated from thirty oral squamous cell carcinoma tissue biopsy samples were subjected to semi-quantitative RT-PCR with ISG15 specific primers to elucidate the expression level.
  
  
  RESULTS
  Of the thirty oral squamous cell carcinomas that were analyzed, ISG15 expression was found in twenty four samples (80%). Twelve samples expressed low level of ISG15, six of them expressed moderately, while the rest of them expressed very high level of ISG15.
  
  
  CONCLUSIONS
  To the best of our knowledge, the results show for the first time an overexpression of ISG15 in up to 80% of oral squamous cell carcinoma tissues collected from Indian patients. Hence ISG15 may be explored for the possibility of use as a high confidence diagnostic biomarker in oral cancers.
authors.affiliation: Department of Prosthodontics and Implantology, Coorg Institute of Dental Sciences, Coorg, Karnataka, India. drarvindram@yahoo.co.in
authors.forename: Rupesh Puthenparambil
authors.initials: RP
authors.lastname: Laljee
authors.forename: Sunil
authors.initials: S
authors.lastname: Muddaiah
authors.forename: Basavaraj
authors.initials: B
authors.lastname: Salagundi
authors.forename: Ponappa Muckatira
authors.initials: PM
authors.lastname: Cariappa
authors.forename: Adarsh Surendran
authors.initials: AS
authors.lastname: Indra
authors.forename: Venkataram
authors.initials: V
authors.lastname: Sanjay
authors.forename: Arvind
authors.initials: A
authors.lastname: Ramanathan
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000235:genetics*; D016207:Cytokines / Q000235:genetics*; D055088:Early Detection of Cancer; D015870:Gene Expression / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D011230:Precancerous Conditions / Q000175:diagnosis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014452:Ubiquitins / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D016207:Cytokines; D014452:Ubiquitins; C074034:ISG15 protein, human