Gastrointestinal stromal tumors:
size, metastasis and bcl2 expression as prognostic factors for survival
in a mathematical model
Kontogianni E.3, Demonakou
M.3, Dallas L.4,
Lariou K.2,
Vourlakou C.2, Kavatzas N.1,
Davaris P.1
1Department of Pathology,
Medical School University of Athens,
2Department of Pathology "Evagelismos"
General Hospital,
3Depatment of Pathology "Sismanoglion"
General Hospital and
4Universite' Libre de Bruxelles
Aim: We examined 102 gastrointestinal stromal tumors (GIST)
by conventional light microscopy, immunohistochemistry and image
analysis, [66 males, 36 females; their age at diagnosis ranged
from 22 to 99 years (mean 63.33; median 65)] to determine the
prognostic factors for survival. Complete clinical data were available
in 72 cases. The tumor's location and size, immunophenotype, histologic
grade, proliferative activity index by PCNA and Ki-67, apoptotic
markers BCL2 and BAX, were considered as prognostic factors and
were correlated with patient survival [0-82 months (mean 33 months;
median 32 months)].
Results: Multivariate analysis selected: a) Tumor size
>8 cm (p=0.17), b) PCNA >10% (p=0.09), c) mitoses >5/10HPF (p=0.16),
d) necrosis (p=0.02), e) metastasis (p=0.04), as negative prognostic
markers associated with poor survival prognosis. BCL-2 protein
expression >37.42% (p=0.16) was associated with better survival.
The Linear Regression Technique can predict lifetime expectation
for patients with GIST, if these tumors are considered as borderline
malignancies. The mathematic model for survival is: Y=c - 0.68
· X1 + 0.25 · X2 - 22.9 · I3, (Y=lifetime,
c=49.6 months, X1=size, X2=% BCL2, I3 = metastasis) (r2=0.67%,
Prob >F=0.0001).
Cïnclusions: Tumor size, necrosis, mitoses (>5/10HPF),
PCNA >10% are independent prognostic factors and are associated
with poor prognosis, whereas BCL-2 protein is associated with
better prognosis. The linear regression model can predict lifetime
expectation in the 70% of patients with GIST.
Key words: Gastrointestinal stromal tumor, immunohistochemistry,
prognosis, proliferation, apoptosis, BCL2.
Abbreviations: GIST: gastrointestinal stromal tumor, HPF:
high-power field, PCNA: proliferation cell nuclear antigen.
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