Objective To investigate the clinical pathological characteristics and prognosis of primitive neuroectodermal tumor (PNET) of breast.Methods Patients with breast PNET were retrieved from CNKI,Pubmed,Europe PMC and other databases from Jan.1980 to Dec.2016.The clinical data of one patient with breast PNET in our hospital were analyzed retrospectively.Results 18 cases had painless,rapid growth mass as the main clinical features.The pathological morphology showed small round cell tumors,PAS staining positive.Immunohistochemistry CD99 and Fli-1 characteristic expression were the main indexes for the diagnosis of breast PNET.The positive expression of Vimentin,NSE,Syn and negative expression of CK,EMA,Desmin,CgA,LCA,S-100 also played an important role in the diagnosis of breast PNET.The positive expression of genetic marker EWSRI was the golden standard for diagnosis of breast PNET.The size of the tumor,surgical treatment,lymph node metastasis,distant metastasis and chemotherapy were the important factors that affect the prognosis of the PNET.The survival rates of 1 and 3 years were 71.4％ and 33.3％ respectively.Conclusions Breast PNET is a rare tumor with poor prognosis,and its diagnosis is highly dependent on pathology.Surgery can significantly improve the prognosis of the patients.Surgery should be the main treatment,combined with radiotherapy and chemotherapy.The current study does not show evidence of effectiveness in terms of endocrine or targeted drug therapy for breast PNET patients.

Objective To assess the prognostic value of HER2 (human epidermal growth factor receptor-2) somatic mutations S310F and V777L in breast cancer patients.Methods HER2 somatic mutations S310F and V777L was screened in 338 consecutive patients with operable primary breast cancer using direct Sanger sequencing analysis.Results A total of 12 carriers of HER2 gene S310F and V777L mutations were found,10 were HER2-negative and 2 were HER2-positive.The median follow-up was 43 months (range from 1 to 61 months).4 were found with local or distant metastasis,and all were HER2-negative patients.Survival analysis found significantly lower survival rates in patients with S3 10F and V777L mutations than in non-carriers (RFS,unadjusted hazard ratio [HR]:5.89,95％ confidence interval [CI]:1.96-17.71,P ＜ 0.001;DRFS,unadjusted HR:5.53,95％ CI:1.56-19.55,P =0.003) and this difference was more manifest in the HER2-negative patients (RFS,unadjusted HR:8.93,95％ CI:2.79-28.62,P ＜ 0.001;DRFS,unadjusted HR:9.89,95％ CI:2.54-38.49,P ＜ 0.001).HER2 somatic mutations S310F and V777L are independent predictors of poor prognosis in breast cancer.Conclusion The prognosis of breast cancer patients carrying HER2 somatic mutations S310F and V777L is significantly worse than that of non-carriers,especially in HER2-negative patients.