Study On Expression And Correlation Of Survivin, P53 And PCNA In Meningiomas

Objective:Tumours are thought to arise from an imbalance between cellular proliferation and cellular apoptosis and both processes are controlled by the coordinate regulation of a number of genes. Cellular apoptosis is known to be controlled by the action of both apoptosis promoting genes (such as bax) and apoptosis inhibiting genes (such as bcl-2). Survivin gene is a new member of the inhibitor of apoptosis proteins gene family that blocks apoptosis pathways by inhibiting effector caspase molecules. High expression of survivin protein was reported in the majority of human malignant tumors arising from the lymphocyte, the lung, the pancreas, the breast, the stomach, the colon, and the prostate. And there are also cumulative evidences that spontaneous immune response against survivin may occur. p53 is a definite tumour suppressor gene. PCNA (proliferating cell nuclear antigen) is a marker which can reflect the proliferative activity of the tumour cells. Meningioma is one of the most common tumors of central nervous system. The correlation among survivin, p53 and PCNA expression in meningiomas and whether the survivin may serve as an immunotherapeutical target gene for meningiomas have not been reported yet. So in this report, the expression of survivin, p53 and PCNA proteins in meningiomas was detected. Using statistical analysis, the correlation between survivin, p53 and PCNA and different histologic types of meningioma and the correlation among survivin, p53 and PCNA expression have been studied in order to further explore the function of these genes in the oncogenesis, proliferation, malignancy and recurrence of meningioma. In addition, we try to offer a theoretical basis that survivin may serve as a new and better diagnostic marker and be an ideal and promising immunotherapeutical target gene designed for meningiomas.Methods: 97 specimens and archived paraffin-blocks of meningiomas were collected from patients who underwent surgery at the Second Affiliated Hospital, Hebei Medical University from January 2000 to May 2006. There were 45 males and 52 females with a mean age of 50.7±10.9 years (range: 15 to 76 years). And the range of disease course was from 3 to 26 months. Among 97 meningioma cases, 86 were initial and 11 were recurrencent, including 21 flax meningiomas, 22 convexity, 12 sphenoid, 3 parasellar, 3 tentorial, 13 anterior fossa, 15 posterior fossa and 8 others. Their medical historical data, radiological image data before or after operation and pathological data were full. None of the patients were treated by chemiotherapy, radiotherapy or immunotherapy before operation. 18 normal brain meninges used as the control group were obtained from patients with acute craniocerebral injury who underwent subtemporal decompression within the corresponding period. All tissues were routinely fixed in 10% formalin, dehydrated conventionally, embedded in paraffin wax, and then archived to prepare for using. Serial sections of 4μm were cut from the blocks. Then representative sections were stained with hematoxylin and eosin (H&E) in order to confirm the histopathological type. A SP (streptavidinbiotin peroxidase) immunohistochemical method has been used to perform survivin, p53 and PCNA monoclonal antibodies to the selected sections of the 97 meningiomas and the 18 normal brain meninges. Immunohistochemistry has been strictly performed according to reagent box directions. The positive expression frequencies of survivin, p53 and PCNA were calculated as a percent of their positive cells to the total number of 1000 tumor cells in five randomly selected HPFs (high-power microscopic field,×400) of the positive pathological section. They were expressed as following: - was assigned to specimens with 0 staining positive cells; +, approximately less than 30% positive; ++, approximately 31-50% positive; +++, more than 50% positive. For evaluation of PCNA LI, tumor areas with a high density of labeling were chosen. PCNA LI was calculated as PCNA positive staining cells to the total number of 1000 tumor cells in ten HPFs (100 tumor cells calculated in each field). Data have been analysed using the SPSS 11.0 sofeware package for Windows. For the comparsion of the findings, Chi-square test, Mann-Whitney U-test, ANOVA-q test and Spearman correlation rank test were performed in this report. For all tests, results at P value less than 0.05 were considered statistically significant.Results: According to the WHO grading system, 60 cases were grade I, 21 cases were grade II, and 16 cases were grade III. In all cases, immunoreactivity for survivin was located in the cytoplasm; p53 and PCNA immunoreactivity was confined to nuclei. Immunohistochemistry for survivin, p53 and PCNA revealed yellow, buffy or brown granular stainings in the positive tumor cells.There was no correlation between the expression of survivin, p53, PCNA and the patient age, gender, tumor size or tumor location (P﹥0.05).The positive expression rates of survivin, p53, PCNA in initial meningiomas and recurrent meningiomas were found to be 61.6%, 100%; 20.9%, 81.8%; 51.2%, 90.9% respectively. The expression of survivin, p53, PCNA in the recurrent group was much higher than the initial group (P﹤0.05).The positive expression rate of survivin in meningiomas and normal brain meninges were 65.9% (64/97) and 0% (P﹤0.001). The positive survivin expression rates were 51.7% (31/60), 85.7% (18/21) and 93.8% (15/16) in meningiomas of grade I, grade II, grade III respectively, which were closely correlated and increased with histological grade(sP﹤0.01). The positive expression rate in grade II was much significantly higher than in grade I (P﹤0.001); and in grade III than in grade I (P﹤0.001). But no significant difference between grade II and grade III (P﹥0.05) had been found. The positive expression rate of p53 in meningiomas and normal brain meninges were 27.8% (27/97) and 0% (P﹤0.05). The positive p53 expression rates were 13.3% (8/60), 38.1% (8/21) and 68.8% (11/16) in meningiomas of grade I, grade II, grade III respectively, which were closely correlated and increased with histological grades of meningioma (P﹤0.01). The expression of p53 was significantly different between different degrees of pathological differentiation (grade I, gradeII, grade III) (P﹤0.001).The positive expression rate of PCNA in meningiomas (55.7%) was much higher than in normal brain meninges (0%) (P﹤0.001). The PCNA expression rates were 41.7% (25/60), 71.4% (15/21) and 87.5% (14/16) in grade I, grade II, grade III meningiomas respectively, which were closely correlated and increased with histological grades of meningiomas(P﹤0.01). The positive rate in grade II was much significantly higher than in grade I (P﹤0.01); grade III than grade I (P﹤0.01). But there was no significant difference between grade II and grade III (P > 0.05). The mean PCNA LI values (%) were 15.48±1.13, 38.14±27.78, 57.69±35.07 in grade I, grade II, and grade III meningiomas respectively, which were increased with histological grades of meningioma. There were significant differences among these three groups (P﹤0.001) .Positive correlations in meningiomas had been found between survivin expression and p53 expression (rs=0.451,P﹤0.01); survivin and PCNA (rs=0.640,P﹤0.01); p53 and PCNA (rs=0.625,P﹤0.01).Conclusion:①Survivin, p53 and PCNA proteins were widely expressed in meningiomas and were closely correlative with the histological grade of meningiomas.②The positive correlation can be found among survivin, p53 and PCNA expression in meningiomas, which influences and promotes the oncogenesis, proliferation, malignancy and recurrence of meningiomas.③Survivin over-expression represents an early or even initiating event in meningioma genesis and may function as an early diagnostic index to judge occurrence and recurrence of meningiomas.④Survivin may serve as an ideal immunotherapeutical target gene and provide a new idea and an effective approach for meningiomas(including residual or recurrent meningiomas after operation).