Activation of the PI3K/mTOR/AKT pathway and survival in solid tumors: systematic review and meta-analysis.
BACKGROUND
Aberrations in the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)/AKT pathway are common in solid tumors. Numerous drugs have been developed to target different components of this pathway. However the prognostic value of these aberrations is unclear.


METHODS
PubMed was searched for studies evaluating the association between activation of the PI3K/mTOR/AKT pathway (defined as PI3K mutation [PIK3CA], lack of phosphatase and tensin homolog [PTEN] expression by immunohistochemistry or western-blot or increased expression/activation of downstream components of the pathway by immunohistochemistry) with overall survival (OS) in solid tumors. Published data were extracted and computed into odds ratios (OR) for death at 5 years. Data were pooled using the Mantel-Haenszel random-effect model.


RESULTS
Analysis included 17 studies. Activation of the PI3K/mTOR/AKT pathway was associated with significantly worse 5-year survival (OR:2.12, 95% confidence intervals 1.42-3.16, p<0.001). Loss of PTEN expression and increased expression/activation of downstream components were associated with worse survival. No association between PIK3CA mutations and survival was observed. Differences between methods for assessing activation of the PI3K/mTOR/AKT pathway were statistically significant (p = 0.04). There was no difference in the effect of up-regulation of the pathway on survival between different cancer sites (p = 0.13).


CONCLUSIONS
Activation of the PI3K/AKT/mTOR pathway, especially if measured by loss of PTEN expression or increased expression/activation of downstream components is associated with poor survival. PIK3CA mutational status is not associated with adverse outcome, challenging its value as a biomarker of patient outcome or as a stratification factor for patients treated with agents acting on the PI3K/AKT/mTOR pathway.
Translational Research Unit, Albacete University Hospital, Albacete, Spain.
Alberto
A
Ocana
Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre and University of Toronto, Toronto, Canada.
Francisco
F
Vera-Badillo
Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre and University of Toronto, Toronto, Canada.
Mustafa
M
Al-Mubarak
Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre and University of Toronto, Toronto, Canada.
Arnoud J
AJ
Templeton
Translational Research Unit, Albacete University Hospital, Albacete, Spain.
Verónica
V
Corrales-Sanchez
Translational Research Unit, Albacete University Hospital, Albacete, Spain.
Laura
L
Diez-Gonzalez
Translational Research Unit, Albacete University Hospital, Albacete, Spain.
María D
MD
Cuenca-Lopez
Sector of medical Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
Bostjan
B
Seruga
Centro de Investigación del Cáncer, CSIC-University of Salamanca, Salamanca, Spain.
Atanasio
A
Pandiella
Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre and University of Toronto, Toronto, Canada.
Eitan
E
Amir
D006801:Humans; D009369:Neoplasms / Q000473:pathology*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction; D016019:Survival Analysis; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
C546842:MTOR protein, human; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases