title: Quantification of insulin receptor mRNA splice variants as a diagnostic tumor marker in breast cancer.
abstract: BACKGROUND
  The mature human insulin receptor (INSR) has two isoforms: The A isoform and the B isoform. INSR upregulation has been suggested to play a role in cancer.
  
  
  OBJECTIVE
  To establish quantitative PCR method for INSR transcript variants and examine their differential expression as a diagnostic tumor marker in breast cancer.
  
  
  METHODS
  The differential expression of IR-A and IR-B were evaluated by TaqMan qRT-PCR assay in the commercially available Breast Cancer Disease cDNA and Cancer Survey cDNA arrays.
  
  
  RESULTS
  The mRNA expression levels of IR-A was statistically significantly higher in breast cancer when compared to normal breast tissue while IR-B mRNA expression was down regulated significantly in breast cancer. Stratification of patients into groups according to metastatic stages indicated statistically significantly higher levels of IR-A mRNA in clinical stage (CS)-IV, and lower IR-B levels in CS-IIA, CS-IIIB and CS-IIIC. However, IR-A:IR-B ratio showed a statistically significant increase in all stages. Cancer Survey cDNA array demonstrated lower levels of IR-B mRNA in breast adenocarcinoma, liver carcinoma and lung carcinoma only while IR-A expression was significantly altered in kidney carcinoma without any significant differences in IR-A:IR-B ratios.
  
  
  CONCLUSIONS
  The results demonstrate an increased IR-A:IR-B ratio in all clinical stages of breast cancer. Thus, IR-A:IR-B ratio may have a diagnostic biomarker utility in breast cancer.
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.|King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Aljada
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.|King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Ayman M
authors.initials: AM
authors.lastname: Saleh
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.
authors.forename: Suliaman M
authors.initials: SM
authors.lastname: Al-Aqeel
authors.affiliation: King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Heba Bani
authors.initials: HB
authors.lastname: Shamsa
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Al-Bawab
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Al Dubayee
authors.affiliation: Department of Basic Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Kingdom of Saudi Arabia.
authors.forename: Altayeb Abdalla
authors.initials: AA
authors.lastname: Ahmed
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009367:Neoplasm Staging; D020033:Protein Isoforms / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger; D011972:Receptor, Insulin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; D020033:Protein Isoforms; D012333:RNA, Messenger; C435941:INSR protein, human; D011972:Receptor, Insulin
keywords: IR-A; IR-B; Insulin receptor (INSR); breast cancer; cDNA arrays; metastasis