title: Expression of PTEN and its correlation with proliferation marker Ki-67 in head and neck cancer.
abstract: BACKGROUND
  PTEN is part of large family of tyrosine phosphatases and has been found inactivated in a wide variety of human cancers.
  
  
  OBJECTIVE
  In the present study we have tried to determine the association of the expression patterns of this gene with carcinogenesis.
  
  
  METHODS
  First, a systematic review was carried out to ascertain the importance of the PTEN gene and its role in carcinogenesis. In the second phase, a case-control study was designed using different expression analysis techniques. Expression of PTEN mRNA was analyzed using reverse transcriptase polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  Significantly downregulated expression of PTEN was observed in patients with head and neck cancer (HNC) compared to adjacent normal-tissue controls. These results were confirmed with quantitative polymerase chain reaction (qPCR). Significant downregulation of the gene was observed in HNC patients compared to adjacent normal-tissue controls. PTEN expression was correlated with different histopathological parameters of the study cohort by Spearman's correlation coefficient and a significant negative correlation was observed with pT stage (r = -0.271*; p&lt;0.02) and grade (r = -0.228*; p&lt;0.02) of HNC tissues. Furthermore, the expression variations of PTEN were correlated with the expression pattern of the proliferation marker Ki-67. Significantly (p&lt;0.008) upregulated expression of Ki-67 was observed in HNC patients compared with adjacent normal-tissue controls This upregulation of Ki-67 was confirmed at the protein level by immunohistochemistry in HNC patients. When Spearman's correlation was carried out a significant negative correlation was observed between PTEN and Ki-67 (r = -0.230*; p&lt;0.03).
  
  
  CONCLUSIONS
  Our data suggest that downregulation of PTEN and overexpression of Ki-67 may contribute to the initiation and progression of HNC.
authors.affiliation: Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information Technology, Islamabad - Pakistan.
authors.forename: Malik W
authors.initials: MW
authors.lastname: Ahmed
authors.affiliation: Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information Technology, Islamabad - Pakistan.
authors.forename: Mahmood A
authors.initials: MA
authors.lastname: Kayani
authors.affiliation: Department of Plastic and Reconstructive Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad - Pakistan.
authors.forename: Ghulam
authors.initials: G
authors.lastname: Shabbir
authors.affiliation: Department of ENT, Pakistan Institute of Medical Sciences (PIMS), Islamabad - Pakistan.
authors.forename: Syed M
authors.initials: SM
authors.lastname: Ali
authors.affiliation: Department of ENT, Pakistan Institute of Medical Sciences (PIMS), Islamabad - Pakistan.
authors.forename: Wajih-Ud-Din
authors.initials: WU
authors.lastname: Shinwari
authors.affiliation: Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information Technology, Islamabad - Pakistan.
authors.forename: Ishrat
authors.initials: I
authors.lastname: Mahjabeen
mesh_terms: D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D063646:Carcinogenesis / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000502:physiology; D005260:Female; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human