Study On EGFR Mutations And Protein Expression In Phyllode Tumor Of The Breast

Phyllode tumor of the breast(PTB)is a biphasic fibroepithelial tumor composed of benign glandular epithelial and mesenchymal components.This tumor is rare,its incidence accounts for 0.3-1%of all primary breast tumors.In the classification of breast tumors by WHO 2012,phyllodes of breast tumors are classified into benign,borderline and malignant according to their biological behaviors.The classification indicators mainly include tumor margins,interstitial cell abundance,interstitial cell atypia,interstitial mitotic count,interstitial overgrowth and malignant heterogenous components.Currently,the diagnosis of the tumor is mainly based on its morphology.Since the molecular genetic changes of phyllodes tumors are complex and the role of immunohistochemical expression and gene changes in the diagnosis of Phyllode tumors has not been confirmed.When it mutation is related to the development of many kinds of tumors.Epidermal growth factor receptor(EGFR)is a transmembrane tyrosine kinase receptor,which mainly regulates the growth,proliferation and differentiation of normal cells in human and biological bodies.When it mutations and abnormal expression are associated with the development of various tum ors.Several studies have shown that EGFR gene and protein changes may be involved in the development and progression of phyllode tumors.In this study,the Sanger sequencing method was used to detect the mutations of EGFR in benign,borderline and malignant phyllode tumors.Meanwhile,immunohistochemical method was used to detect the expression of EGFR protein,so as to analyze the relation between EGFR gene and protein,explain the relation between the occurrence and development of phyllode tumor and provide useful indicators for molecular genetic study and pathological diagnosis of breast phyllodes.ObjectiveTo investigate the expression of EGFR in genes and proteins in benig,borderline and malignant phyllodes tumors,and to elucidate the relationship of EGFR expression in the occurrence and development of breast phyllodes from the perspective of molecular geneticsMethods1.The first generation sequencing method was used to detect the mutations of exon 18-21 of the EGFR gene in 22 cases of PTB,including 10 benign,6 borderline and 6 malignant cases.2.The immunohistochemical method was applied to detect the expression of EGFR protein in 22 cases of PTB,including 10 benign,6 borderline and 6 malignant cases.3.The Software SPSS19.0 was used for statistical analysis,and the counting data were tested with ?2 testResults1.The mutation rate of EGFR gene was statistically significant in different levels of phyllodes tumors:benign(10%),borderline(50%)and malignant(83.3%)(P<0.05).2.Exon 18-21 of EGFR gene was detected,and the mutation rate of exon 18 was 4.5%.No exon19 mutation was found,and the mutation rate of exon20 was 36.4%and exon21 was 4.5%.There were statistically significant differences in point mutations(P<0.005).3.The expression rate of EGFR protein was different in different grades of phyllodes tumors:benign(30%),borderline(66.7%)and malignant(66.7%).The difference was not statistically significant(P>0.05).4.The mutation rate of EGFR gene was 40.9%;the protein expression rate of EGFR was 50%in stromal;EGFR gene was positively correlated with protein expression rate(P<0.05).5.Epithelial component EGFR protein expression rate 4.5%,no correlation with EGFR protein expression in stromal(P>0.05).6.EGFR gene mutation was not correlated with EGFR protein expression in epithelial cells(P>0.05).Conclusion1.The mutation of EGFR gene increases with the increase of the grade of phyllodes tumors.EGFR gene has high mutation rate in malignant phyllodes tumors(83.3%)and it mutation may be related to the occurrence and development of phyllodes tumors.2.The mutation of EGFR gene is mainly located at exon 20.3.EGFR protein expression is correlated to EGFR gene mutation in The mesenchymal components of a phyllobular tumor of the breast4.There was no correlation between EGFR protein expression in epithelial cells of phyllodes tumors of breast and the mutated stromal components of EGFR,and EGFR does not play a role in the process of epithelial and stromal intertransformation leading tophyllodes tumors.