title: Loss of PTEN expression is associated with aggressive behavior and poor prognosis in Middle Eastern triple-negative breast cancer.
abstract: PTEN is a tumor suppressor that negatively regulates the PI3 K-AKT signaling pathway which is involved in the pathogenesis of many different tumor types and serves as a prognostic marker in breast cancer. However, the significance of the role of PTEN in Middle Eastern ethnic breast cancer has not been explored especially with the fact that breast cancer originating from this ethnic population tend to behave more aggressively than breast cancer in the west. In this study, we analyzed PTEN alteration in a tissue microarray format containing more than 1000 primary breast cancers with clinical follow-up data. Tissue Microarray sections were analyzed for protein expression and copy number change using immunohistochemistry and fluorescence in situ hybridization. Loss of PTEN immunostaining was observed in 77 % of the cases. PTEN loss was significantly associated with large tumor size (p = 0.0030), high grade (p = 0.0281), tumor recurrence (p = 0.0333), and triple-negative breast cancers (p = 0.0086). PTEN loss in triple-negative breast cancers was significantly associated with rapid tumor cell proliferation (p = 0.0396) and poor prognosis (p = 0.0408). PTEN deletion was found only in 60 cases (6.4 %). Loss of PTEN protein expression occurs at high frequency in Middle Eastern breast cancer. PTEN inactivation may potentially lead to an aggressive behavior of tumor cells through stimulation of tumor cell proliferation. Furthermore, PTEN signaling pathway might be used as potential therapeutic target in triple-negative breast cancers since loss of its expression is shown to be significantly associated with this aggressive subtype of breast cancer.
authors.affiliation: Human Cancer Genomic Research, Research Center, King Faisal Specialist Hospital and Research Center, MBC#98-16, P.O. Box 3354, Riyadh, 11211, Saudi Arabia, bshaham@kfshrc.edu.sa.
authors.forename: Shaham
authors.initials: S
authors.lastname: Beg
authors.forename: Abdul K
authors.initials: AK
authors.lastname: Siraj
authors.forename: Sarita
authors.initials: S
authors.lastname: Prabhakaran
authors.forename: Zeenath
authors.initials: Z
authors.lastname: Jehan
authors.forename: Dahish
authors.initials: D
authors.lastname: Ajarim
authors.forename: Fouad
authors.initials: F
authors.lastname: Al-Dayel
authors.forename: Asma
authors.initials: A
authors.lastname: Tulbah
authors.forename: Khawla S
authors.initials: KS
authors.lastname: Al-Kuraya
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D018450:Disease Progression; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D051059:PTEN Phosphohydrolase / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D011379:Prognosis; D016019:Survival Analysis; D064726:Triple Negative Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human