Cancer Res Treat.  2006 Jun;38(3):139-143.

Occludin Expression in Brain Tumors and its Relevance to Peritumoral Edema and Survival

• Park MW
• Kim CH
• Cheong JH
• Bak KH
• Kim JM
• Oh SJ

Abstract

PURPOSE: Peritumoral brain edema (PTBE) is a serious causative factor that contributes the morbidity or mortality of brain tumors. The development of PTBE is influenced by many factors, including such tight junction proteins as occludin. We evaluated the PTBE volume and survival time with respect to the occludin expression in various pathological types of brain tumors.
MATERIALS AND METHODS
Fresh-frozen specimens from sixty patients who had brain tumors were obtained during surgery and the tumors were confirmed pathologically. The occludin expression was investigated by Western blot analysis. The PTBE volume was measured by using preoperative magnetic resonance (MR) imaging, and the survival time in each patient was estimated retrospectively.
RESULTS
Occludin was detected in 41 (68.3%) of the cases with brain tumors and it was not expressed in the other 19 (31.7%) cases. Although the lowest expression was revealed in high-grade gliomas, its expression was variable according to the pathology of the brain tumors (p>0.05). The difference of PTBE volume between occludin-positive and negative brain tumors was statistically significant (2072.46+/-328.73 mm3 vs. 7452.42+/-1504.19 mm3, respectively, p=0.002). The mean survival time was longer in the occludin-positive tumor group than in the occludin-negative group (38.63+/-1.57 months vs. 26.16+/-3.83 months, respectively; p=0.016).
CONCLUSIONS
This study suggests that the occludin expression is highly correlated to the development of PTBE in brain tumors and it might be a prognostic indicator for patient survival.

Keyword

Occludin; Peritumoral brain edema; Brain neoplasms; Survival rate

MeSH Terms

Blotting, Western
Brain Edema
Brain Neoplasms*
Brain*
Edema*
Glioma
Humans
Mortality
Occludin*
Pathology
Retrospective Studies
Survival Rate
Tight Junction Proteins
Occludin
Tight Junction Proteins

Figure

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  Fig. 1 Western blot analysis for the detection of occludin expression immunoblotting by using 1:1,000 mouse monoclonal anti-occludin (Zymed, San Francisco, CA). Note the presence of the 55 kDa bands of occludin in lanes 1, 4~6, 8, 31~33, 36 and 39.

• 

  Fig. 2 Bar graph demonstrating the expression rate of occludin according to pathological types of different brain tumors. The high expression rate of occludin is noted in hemangioblastoma and pituitary adenoma; however, its difference was not significant among the pathological types of brain tumor (p>0.05).

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  Fig. 3 Graphs showing the peritumoral brain edema (PTBE) volume according to the occludin expression in brain tumors. A lower PTBE volume is noted in the positive group while a higher PTBE volume is evident in the negative group (p=0.002). *number of cases.

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  Fig. 4 Graph demonstrating the PTBE volume according to the pathology of the various brain tumors. There are high PTBE volumes in the malignant brain tumors such as metastatic tumors and high grade gliomas. However, the differences among pathological types of brain tumor (p>0.05) are not significant. *number of cases.

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  Fig. 5 Graph demonstrating the result of comparison of the survival time of positive occludin expression vs. negative occludin expression groups of brain tumors. The positive-occludin expression group shows significantly longer survival time in contrast to the negative-occludin expression group (p=0.016). *number of cases.

• 

  Fig. 6 Scatterplot demonstrating the correlation between survival time and PTBE volume. There is an inverse relationship between survival time and the PTBE volume (R-square=0.40, p=0.001).

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