Correlation analysis between the expression of P21WAF1/CIP1, P16 proteins and human glioma.
OBJECTIVE
Glioma is the most common neoplasm of the brain. Unfortunately, surgical cure of it is practically impossible and clinical course is primarily determined by the biological behaviour of the tumour cells. The purpose of this study was to investigate the correlation between the expression levels of P21WAF1/CIP1, P16 proteins and the grading of glioma.


METHODS
T98G human glioma cell line, normal human astrocyte (HA) cell line, tumour tissue samples from 70 patients suffering from glioma and normal brain tissues from 20 cases with brain contusion were investigated. The expression levels of P21WAF1/CIP1 and P16 proteins were detected using SABC immunohistochemical staining and semi-quantitive reverse transcriptase polymerase chain reaction (RT-PCR) assay. Then, the correlation of the two markers' expression with glioma grading of patients was analysed.


RESULTS
The expression levels of P21WAF1/CIP1 and P16 proteins in the T98G cell line were much lower than that in the HA cell line. Their positive expression rates in glioma tissues were 55.71% and 42.86% respectively, and a significant increase was observed in normal brain tissues (p = 0.012, 0.008). Combined with the result of semi-quantitive RT-PCR, we could demonstrate that the expression intensity of P21WAF1/CIP1 and P16 decreased with the glioma grade increase. Co-expression of them was also found in glioma and normal brain tissues. Furthermore, there was a negative correlation between the two markers' expression and glioma grading of patients (rs = -0.68, -0.56).


CONCLUSIONS
The positive expression rate and co-expression rate of P21WAF1/CIP1 and P16 proteins could reflect the malignant grade of glioma to some extent, and they can be considered as a sensitive index for glioma grading.
Song
Tao
T
Neurosurgery Department, Xiangya Hospital of Central South University, Changsha, Hunan, P.R. China.
Wu
Jun
J
Fang
Fang
F
Chen
Fanghua
F
Huo
Lei
L
Zhang
Mingyu
M
Wu
Lei
L
Zhai
Zhiyong
Z
Yang
Liang
L
Fang
Jiesheng
J
D001483:Base Sequence; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D017931:DNA Primers; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D009363:Neoplasm Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C493956:CDKN1A protein, human; C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D017931:DNA Primers; D009363:Neoplasm Proteins
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