Expression Of MMP-2 And Rb Genes In Osteosarcoma And Clinical Significance

Osteosarcoma is the commonest primary malignant bone tumor which is highly malignant and Patients often have invasion,metastasis and poor prognosis.The initiation,formation and development of Osteosarcoma is a complex multi-stage process which many genes are involved.Its molecular mechanism is not still clear.Invasion and metastasis,as two important biological features of osteosarcoma whose process is affected by factors as cellular adhesion,degradation of extracellular matrix(ECM) and migration of the tumor cells.In this research,Immunohistochemical Streptavidin Peroxidase(S-P) method is applied to detect the expression of MMP-2 and Rb at the protein level and we analyze the relationship between their expression and biological behavior of osteosarcoma,approach the possibility of using MMP-2 and Rb as molecular tumor marker to appraise the latent energy of invasion and metastasis of osteosarcoma.Objective:To study the expression of Matrix metalloproteinase-2(MMP-2) and Rb in osteosarcoma and their clinical significance as well as their correlation.Methods:Immunohistochemistry(S-P method) was applied to study the expressions of MMP-2 and Rb in tissues of osteosarcoma(n=67) and osteochondroma (n=10).The 67speciments of osteosarcoma were from the Department of Orthopaedics in the Affiliated Hospital of Chengde Medical College from January 2000 to May 2008.There were 36 speciments from male and 31 speciments from female.The age of the patients was from 5 to 63 years old and the medium age was 20.1 years old.Tumors were located in the femur in 34 patients,the tibia and fibula in 24 and the others in 9.In Enneking surgery stages,the number of gradeⅠis 16,gradeⅡis 38 and gradeⅢis 13.The number of Osteoblastic osteosarcoma is 30,chondroblastic 16,fibroblastic 13 and the others 8.Routine slice is done for 3 serial sections in 5μm thickness and 1 section is made for H.E staining and observed by conventional pathological diagnosis while the other two sections are detected for the expression of MMP-2 and Rb.We have analyzed the relationship between the expression of MMP-2 and Rb and the clinical biological characteristics, including sex,tumor location,histological type,Enneking surgery stages and metastasis and so on.The expressions of MMP-2 and Rb were detected by immunohistochemical method(S-P) which described them only by qualitative analysis.The positive judgement criteria:MMP-2 and Rb were described by half-quantitative integration analysis.Every slice was chosed 10 highpower field at random and the dyeing positive cells were counted.Then we chosed the mean value and counted the percentage of positive cells.The criteria of score:(1) Colouration shade:0 score means colorless,1 score means tint,2 score means midrange colour,3 score means powerful colour.(2) Percentage of positive cells:0 score means positive cells≤5%,1 score means 6%～25%,2 score means 26%～75%,3 score means＞75%.The result of evaluation is the two above items addition.(-) means 0～1 score,(+) means 2～3 score,(++) means 4～5 score, (+++) means＞5 score.The breast cancer was used for positive control of MMP-2 and Rb.The data are statistically analyzed with Chi square test,Kruskal-Wallis test and Spearman rank correlation using SPSS 11.5 for windows.Results:1 MMP-2The MMP-2 positive cancer cells show buffy particles which are mainly in cytoplasm.The positive cells often clustered together or localized at the margin of the tumor.The positive ratio of MMP-2 expression is 79.1%in osteosarcoma group and 0%in osteochondroma group.There was prominent difference between them(P＜0.01).No obvious correlations were found between the expression of MMP-2 and sex,tumor location and histological type.However,the statistically significant correlations were found between the positive expression of MMP-2 and the tumor surgery staging and metastasis.2 RbThe Rb positive cancer cells show buffy or brown particles which are mainly in cytoblast.The positive ratio of Rb expression is 50.7%in osteosarcoma group and 90%in osteochondroma group.There was statistically significant between them(P＜0.05).No obvious correlations were found between the expression of Rb and the sex,tumor location and histological type.However,the statistically significant correlations were found between the positive expression of MMP-2 and the tumor surgery staging and metastasis.3 MMP-2 and RbThere are no prominent correlations between the expression of MMP-2 and the expression of Rb in tumor cells.Conclusions:1 The expression of MMP-2 is high and Rb low in osteosarcoma.They may play important roles in the initiation,formation and development.2 There are no prominent correlations between the expression of MMP-2 and the expression of Rb in osteosarcoma.3 The expression of MMP-2 and Rb genes can be used as molecular tumor markers to appraise the latent energy of invasion and metastasis of osteosarcoma.