Clinicopathological Study On Biologic Markers For Malignant Mesothelioma

ObjectiveIn order to search for new molecular markers as prognostic factors for malignant mesothelioma and to provide more information for clinical practice, guiding treatment and reducing recrudescence and metastasis,the following biologic markers as HER2,P27,CyclinD1,P53,PTEN and EGFR were investigated,furthermore,their relevance to the above markers and the various clinicopathological parameters of the relationship and survival of patients were analyzed.Materials and methodsOur study is a retrospective research.137 cases with malignant mesothelioma of the PLA General Hospital of China from July 1980 to July 2008 were collected and reviewed by surgical resection,formalin fixed,embedded in paraffin,four cases from the autopsy.Read HE staining slices and immunohistochemistry,include Calrentinin,CK5/6,D2-40,WT-1 Vimentin,CEA and EMA,and reviewed some of the cases with the Electron microscopic study.According to the WHO classification and TNM clinical staging of International Mesothelioma Interest Group(IMIG) in 1994.A total of malignant mesothelioma of 60 cases with complete clinical data and successfully followed up with inquisition were enrolled in the study.Under microscope,review pathological biopsy of 60 malignant mesothelioma cases and observe pathological classification,invasion of neural and necrosis.Immunohistochemistry:The seven biologic markers-HER,P27,CyclinD1,P53,PTEN and EGFR expression were detected in 60 cases of malignant mesothelioma by PV6000 immunohistochemical method.Their relationships to clinical pathology and prognosis were also analyzed.To detect gene amplification of HER-2 of 60 malignant mesothelioma based on fluorescence in situ hybridization(FISH) with HER2 probes and a centromeric probe of chromosome 17.And then analyze the correlation between HER2 gene amplification and HER-2 protein expression.To detect somatic mutations of EGFR gene by RQ-PCR:detect DNA extraction and PCR-sequences in 20 cases of paraffin-embedded malignant mesothelioma.All cases were for EGFR-positive by immunohistochemical staining.The related clinical information was reviewed and EGFR mutation status in 18,19 and 20 and 21 Exon was observed.ResultsThe positive expression rates of biologic markers were as follows:HER2 3.3%(2/60),P27 58.3%(35/60),CyclinD1 26.7%(16/60),P53 38.3%(23/60),PTEN 23.3%(14/60) and EGFR 45.0%(27/60).CyclinDl was related to WHO classification,furthermore,the expression of sarcomatoid and biphasic mesothelioma was higher than epithelial mesothelioma(P=0.012).P27 and P53 were related to metastasis,the positive expression ratios of P27 in patients without distant metastasis was higher than in those with distant metastasis(P=0.016) and presented a negative correlation with the distant metastasis,meanwhile,P53 was on the contrary(P=0.039).The expression of P53 showed a positive correlation with the TNM clinical staging,the expression of P53 was increased,positively corresponding to the TNM clinical staging(P=0.023).The expressions of EGFR,HER2 and PTEN were not correlation with patient gender,age,location, histological subtype,localized or diffused,TNM clinical staging,metastasis, necrosis,and the exposure to the asbestos.By univariant survival analysis,P27,PTEN,histological subtype,age,TNM clinical staging and metastasis all showed significant correlation to prognosis. Survival time after operation with positive expression was better than with negative expression(P=0.026),while the survival time after operation with PTEN was better than with negative expression(P=0.042).And the age less than 55, epithelial mesothelioma,â… -â…¡staging of TNM clinical staging and lack of metastasis suggested better prognosis.In Cox multivariant survival analysis, PNET,age,histological subtype and TNM clinical staging were independent prognostic indicators.The positive expression of PTEN,the age less than 55, epithelial mesothelioma andâ… -â…¡staging of TNM clinical staging indicated longer and better prognosis.To detect gene amplification of HER-2 of malignant mesothelioma two of which had + reactive to HER2 by immunohistochemistry based on fluorescence in situ hybridization(FISH) with HER-2 probes and a centromeric probe of chromosome 17.And then analyze the correlation between HER-2 gene amplification and HER-2 protein expression.Somatic EGFR mutations were identified by RQ-PCR and one of 20 malignant mesothelioma patients was detected 19 exon deletion.Conclusions:1.PTEN,age,histological subtype and TNM clinical staging were independent prognostic factors of malignant mesothelioma.2.P27,CyclinD1,P53,PTEN,HER2 and EGFR may play an important role in the development of the tumor.They may become new clinical diagnostic and prognostic markers for malignant mesothelioma.3.HER2 protein was lack of expression in malignant mesothelioma and the HER2 protein expression was 3.3%(2/60);and HER2 amplification was not detective in malignant mesothelioma.4.The ratio of EGFR protein expression was 45.0%(27/60),but the Somatic mutations on exons 18-21 of EGFR gene were rare in malignant mesothelioma and one of the 20 cases was detected the 19 exon deletion,which require substantial further explored and confirmed samples.