Difference in expression of EGFR, pAkt, and PTEN between oropharyngeal and oral cavity squamous cell carcinoma.
OBJECTIVE
The aims of this study were to evaluate the expression of EGFR, PI3K, Akt, mTOR, and PTEN in the oral cavity and oropharyngeal cancers, and to investigate their clinical significance as prognostic markers.


METHODS
One hundred twenty-one patients who underwent curative surgery for oral cavity or oropharyngeal squamous cell carcinoma in Seoul St. Mary's Hospital between January 1995 and September 2009 were evaluated. The level of protein expression of EGFR, PIK3CA, pAkt, mTOR, and PTEN was assessed by immunohistochemistry. In situ hybridization was used to detect the existence of human papillomavirus (HPV).


RESULTS
Nineteen of 61 patients with oropharyngeal cancer showed HPV-positive tumors, and two of 60 patients with oral cavity cancer showed HPV-positive tumors. EGFR and pAkt expression was significantly higher in oral cavity cancers than in oropharyngeal cancers. Loss of PTEN occurred significantly more frequently in oral cavity cancers than in oropharyngeal cancers. The expression levels of PIK3CA, mTOR, and p53 did not differ significantly between the two cancers. Overexpression of EGFR and pAkt and loss of PTEN were observed more frequently in HPV-negative tumors. Multivariate Cox regression analysis showed that pAkt expression had a significantly unfavorable impact on relapse-free survival in oropharyngeal cancer.


CONCLUSIONS
We conclude that the expression levels of EGFR, pAkt, and PTEN differ between oropharyngeal and oral cavity cancer and it may be attributed to HPV-related molecular pathogenesis. The expression of pAkt might be an unfavorable prognostic marker for relapse-free survival in oropharyngeal cancer.
Division of Medical Oncology, Department of Internal Medicine, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Hye Sung
HS
Won
Department of Hospital Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Chan-Kwon
CK
Jung
Division of Medical Oncology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Sang Hoon
SH
Chun
Division of Medical Oncology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea. Electronic address: jinkang@catholic.ac.kr.
Jin-Hyoung
JH
Kang
Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Yeon-Sil
YS
Kim
Department of Otorhinolaryngology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Dong-Il
DI
Sun
Department of Otorhinolaryngology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
Min-Sik
MS
Kim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D058534:Class I Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism*; D009959:Oropharyngeal Neoplasms / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011379:Prognosis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
D014408:Biomarkers, Tumor; D058534:Class I Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C546842:MTOR protein, human; C484760:PIK3CA protein, human; C494929:PTEN protein, human