Elevated tumor and serum levels of the hypoxia-associated protein osteopontin are associated with prognosis for soft tissue sarcoma patients.
BACKGROUND
Osteopontin (OPN) overexpression is correlated with a poor prognosis for tumor patients. However, only a few studies investigated the prognostic impact of expression of OPN in soft tissue sarcomas (STS) yet.


METHODS
This study is based on tumor and serum samples from 93 adult STS patients. We investigated OPN protein levels in serum (n = 86) and tumor tissue (n = 80) by ELISA and OPN mRNA levels in tumor tissue (n = 68) by quantitative real-time PCR.


RESULTS
No correlation was found between OPN levels in serum and tumor tissue. Moreover, an elevated OPN protein level in the serum was significantly associated with clinical parameters such as higher stage (p = 0.004), higher grade (p = 0.003), subtype (p = 0.002) and larger tumor size (p = 0.03). OPN protein levels in the tumor tissue were associated with higher stage (p = 0.06), higher grade (p = 0.003), subtype (p = 0.07) and an increased rate of relapse (p = 0.02). In addition, using a Cox's proportional hazards regression model, we found that an elevated OPN protein level in the serum and tumor tissue extracts is a significant negative prognostic factor for patients with STS. The relative risks of tumor-related death were 2.2 (p < 0.05) and 3.7 (p = 0.01), respectively.


CONCLUSIONS
Our data suggest OPN protein in serum as well as in tumor tissue extracts is an important prognostic factor for soft tissue sarcoma patients.
Bache
Matthias
M
Department of Radiotherapy, Martin-Luther-University Halle-Wittenberg, Halle, Germany. matthias.bache@medizin.uni-halle.de
Kappler
Matthias
M
Wichmann
Henri
H
Rot
Swetlana
S
Hahnel
Antje
A
Greither
Thomas
T
Said
Harun M
HM
Kotzsch
Matthias
M
Würl
Peter
P
Taubert
Helge
H
Vordermark
Dirk
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood / Q000378:metabolism*; D015687:Cell Hypoxia / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D053495:Osteopontin / Q000097:blood / Q000378:metabolism*; D012509:Sarcoma / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate; D055815:Young Adult
D014408:Biomarkers, Tumor; D053495:Osteopontin