Prognostic associations of activated mitogen-activated protein kinase and Akt pathways in glioblastoma.
OBJECTIVE
Activation of mitogen-activated protein kinase (MAPK) and members of the Akt pathway have been shown to promote cell proliferation, survival, and resistance to radiation. This study was conducted to determine whether any of these markers are associated with survival time and response to radiation in glioblastoma.


METHODS
The expression of phosphorylated (p-)Akt, mammalian target of rapamycin (p-mTOR), p-p70S6K, and p-MAPK were assessed by immunohistochemical staining in 268 cases of newly diagnosed glioblastoma. YKL-40, a prognostic marker previously examined in these tumors, was also included in the analysis. Expression data were tested for correlations with response to radiation therapy in 131 subtotally resected cases and overall survival (in all cases). Results were validated in an analysis of 60 patients enrolled in clinical trials at a second institution.


RESULTS
Elevated p-MAPK expression was most strongly associated with poor response to radiotherapy, a finding corroborated in the validation cohort. For survival, higher expressions of p-mTOR, p-p70S6K, and p-MAPK were associated with worse outcome (all P < 0.03). YKL-40 expression was associated with the expressions of p-MAPK, p-mTOR, and p-p70S6K (all P < 0.02), with a trend toward association with p-Akt expression (P = 0.095). When known clinical variables were added to a multivariate analysis, only age, Karnofsky performance score, and p-MAPK expression emerged as independent prognostic factors.


CONCLUSIONS
p-MAPK and activated members of the Akt pathway are markers of outcome in glioblastoma. Elevated expression of p-MAPK is associated with increased radiation resistance and represents an independent prognostic factor in these tumors.
Pelloski
Christopher E
CE
Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Lin
E
E
Zhang
Li
L
Yung
W K Alfred
WK
Colman
Howard
H
Liu
Juinn-Lin
JL
Woo
Shaio Y
SY
Heimberger
Amy B
AB
Suki
Dima
D
Prados
Michael
M
Chang
Susan
S
Barker
Fredrick G
FG
Fuller
Gregory N
GN
Aldape
Kenneth D
KD
D054392:Adipokines; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000071451:Chitinase-3-Like Protein 1; D015331:Cohort Studies; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000175:diagnosis* / Q000378:metabolism* / Q000628:therapy; D006023:Glycoproteins / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D037102:Lectins; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis / Q000378:metabolism*; D010766:Phosphorylation; D011237:Predictive Value of Tests; D011379:Prognosis; D011494:Protein Kinases / Q000096:biosynthesis; D051057:Proto-Oncogene Proteins c-akt / Q000096:biosynthesis / Q000378:metabolism*; D012189:Retrospective Studies; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000096:biosynthesis; D015398:Signal Transduction; D015996:Survival Rate; D058570:TOR Serine-Threonine Kinases; D016896:Treatment Outcome
D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins; D011494:Protein Kinases; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases