title: Increased Expression of Phosphatidylinositol 3-Kinase p110α and Gene Amplification of PIK3CA in Nasopharyngeal Carcinoma.
abstract: Molecular alterations in PIK3CA oncogene that encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K p110α) are commonly found in human cancers. In this study, we examined the expression of PI3K p110α and PIK3CA gene amplification in 74 nasopharyngeal carcinoma (NPC) cases. Immunohistochemical staining demonstrated overexpression of PI3K p110α protein in 44.6% (33/74) of NPCs and 4.8% (2/42) of the adjacent normal nasopharyngeal mucosa. Copy number of PIK3CA gene was successfully analyzed in 51 of the total NPC cases and 19 non-malignant nasopharynx tissues by quantitative real-time PCR. Using mean + 2(standard deviation) of copy numbers in the non-malignant nasopharynx tissues as a cutoff value, PIK3CA copy number gain was found in 10 of 51 (19.6%) NPC cases. High PI3K p110α expression level was correlated with increased PIK3CA copy number (Spearman's rho =0.324, P = 0.02). PI3K p110α expression and PIK3CA copy number did not associate with Akt phosphorylation, and patient and tumor variables. This study suggests that PI3K p110α overexpression, which is attributed, at least in part, to PIK3CA gene amplification, may contribute to NPC pathogenesis. However, these molecular aberrations may not be responsible for activation of Akt signaling in NPC.
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Wai Kien
authors.initials: WK
authors.lastname: Yip
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.|Department of Gastroenterology, Affiliated Hospital of Chengde Medical University, Chengde, Hebei, China.
authors.forename: Pei Yuan
authors.initials: PY
authors.lastname: He
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Maizaton Atmadini
authors.initials: MA
authors.lastname: Abdullah
authors.affiliation: Department of Pathology, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia.
authors.forename: Suryati
authors.initials: S
authors.lastname: Yusoff
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. shf@upm.edu.my.|Institute of Bioscience, Universiti Putra Malaysia, Selangor, Malaysia. shf@upm.edu.my.
authors.forename: Heng Fong
authors.initials: HF
authors.lastname: Seow
mesh_terms: D014408:Biomarkers, Tumor; D002277:Carcinoma; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D009305:Nasopharynx / Q000378:metabolism; D009367:Neoplasm Staging; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000378:metabolism*; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: D014408:Biomarkers, Tumor; D019869:Phosphatidylinositol 3-Kinases
keywords: Akt; Immunohistochemistry; Nasopharyngeal carcinoma; PIK3CA