Clinicopathologic Study Of Non-squamous Phenotype Undifferentiated Nasopharyngeal Carcinoma

Research Background and purpose:According to the latest edition of the head and neck cancer defined in the WHO classification,nasopharyngeal carcinoma(nasopharyngeal carcinoma,NP C)is a kind of happened in nasopharyngeal mucosa under light microscopy an d ultrastructural change of squamous differentiation in a cancer.The incidence o f the disease was highest in southern China.The incidence of NPC in China is mainly young adults,and the death toll is mainly middle-aged and old people.In the WHO classification of head and neck tumors,NPC are divided into thr ee types:keratinizing squamous cell carcinoma,non-keratinizing squamous cellc arcinoma,and basic-like squamous cell carcinoma.All three types are squamous cell carcinomas.NPC all expressed the markers of squamous cell P63 and P40,and almos t all tumor cells were strongly positive for the expression of total keratin(AE 1/AE3)and high molecular weight keratin(CK5/6,etc),but did not express or had low expression of low molecular weight keratin CK7,CK8/18,CK8,CKL,etc.However,in the daily pathological practice,we found that some of the po orly differentiated or undifferentiated carcinomas occurring in the nasopharynx did not express the squamous cell-specific proteins P63 and P40 in the immun ohistochemical staining,and also rarely expressed another squamous cell marke r CK5/6,which brought us great confusion in the diagnosis.We call this kind of nasopharyngeal carcinoma than squamous phenotypic nasopharyngeal undiffer entiated carcinoma(Non-squamous phenotype nasopharyngeal undifferentiation c arcinoma,NSNPC),whether NSNPC have unique biological properties,whether still belongs to a kind of NPC,or belong to a new type,if there is a unique outcome,are all need to study the problem.Based on the above background,this study selected about,P63 and P40 c ommon negative nasopharyngeal carcinoma with classic cases of nasopharyngea 1 carcinoma(NPC),by comparing the observed two groups of organization for m,identify the immune phenotype,find pathogen ultrastructure,tumor-suppress or genes related to screening,analysis,follow-up and other methods to study,explore types other than the classical nasopharyngeal carcinoma,clear NSNPC parting,study the clinical pathological features of NSNPC,provide the basis fo r the diagnosis of patients with nasopharyngeal carcinoma(NPC).Materials and Methods:1.Clinical data:Clinical data were collected:the patients diagnosed with nasopharyngeal carcinoma(poorly differentiated or undifferentiated under the microscope)from the pathologic database of the first affiliated hospital of zheng university from 2011 to 2019 were screened.Then,the negative P63 and P40 cases were collected from the NSNPC group,with only 25 cases.Only 23 cases were able to carry out the follow-up wax block experiment,accounting for 3.28%of the total number of 762 cases diagnosed as NPC in our hospital during this period.The classic NPC group included 20 cases with similar factors of the same period,gender,age,and positive P63 and P40.The patients in both groups were excluded from the study if they had a history of treatment or sexual activity.2.HE staining and immunohistochemical detection:histological characteristics and immunophenotype were observed by HE staining and immunohistochemical staining(squamous cell related proteins expressed P63,P40,CK,CK5/6 and related proteins used for differential diagnosis CK8/18,CK8,CKL,CK7,Syn,CD56,CgA,sox-10).Meanwhile,20 cases of classic NPC patients(both P63 and P40 were positive)were collected as control group.Tumor suppressor gene detection:immunohistochemistry was used to compare the expression of antibodies of three tumor suppressor genes,RASSF1,BLU and Rbms3,in NSNPC and classic NPC.3.Pathogen detection:detection of the pathogen of NSNPC,EB virus(in situ hybridization)and HPV virus(fluorescence PCR).4.Ultrastructure observation:the histological characteristics of NSNPC ultrastructure were observed by transmission electron microscope.5.Prognosis and clinical relationship:to study the pathological characteristics,prognosis,survival rate and clinicopathological relationship of NSNPC patients.6.Grahppad Prism 7 statistical software was used for data analysis.According to different data processing methods and different requirements of statistics on data statistics,Fisher's accurate test was used to test the difference between the categorical variable group and the continuous variable group,and the P<0.05 was statistically significant.Result:1.Microscopic features and immunophenotypes:NSNPC tumor tissues have two characteristics under microscope.The first type(1/25)of tumor cells are distributed in the form of nest-mass/flake/papillary distribution.The other(24/25)tumor cells are syncytiform and microscopically show two growth patterns:(1)neoplastic epithelial cells form nests with clear boundaries,surrounded by fibrous tissue and lymphocytes;(2)neoplastic epithelial cells showed diffuse growth and were mixed with inflammatory cells,both of which were similar to those under the microscope of classic NPCS.The results of immunohistochemistry showed that NSNPC was mostly expressed in low molecular weight keratin:CK8/18(78.26%),CK8(65.22%),CKL(47.83%),and there was a statistical difference between the NSNPC group and the classic NPC group(P<0.05).Other proteins CK5/6,CK,CK7,Syn,CD56,CgA and sox-10 showed no statistical difference compared with the classic NPC group(P>0.05).2.Etiology:EBER positive 18/23(78.26%),HPV positive(HPV35/HPV38)2/23(8.70%),EB virus infection was the main cause of this type of nasopharyngeal carcinoma,and the P>0.05 was not statistically significant.3.Genetic changes:The expression of tumor suppressor gene BLU in NS NPC tissues was not decreased,and was higher than that in normal nasophary ngeal tissues,which was inconsistent with the expression of classic NPC and P<0.05.The expression of tumor suppressor genes RASSF1 and Rbms3 was decreased in NSNPC tissues,which was consistent with the expression of class ic NPC.4.Ultrastructural features:such overall morphology under the electron mic roscope for nasopharyngeal carcinoma(NPC)closely contact with adjacent cells,cancer cells have big volume and nucleoplasm ratio increases obviously and nu clear assumes the circular or ovoid,vacuolated,and nuclear membrane is smoo th,nucleolus is obvious and more near the side of the nuclear membrane,the rough endoplasmic reticulum increased,which conforms to theultrastructure ch aracteristics of poorly differentiated squamous cell carcinoma.Moreover,desmo somal connections were found between the cells in 5 cases,and no obvious d esmosomal connections were found in the remaining 18 cases.Statistics showed that there was no correlation between the presence or absence of desmosomes and the above indicators,tumor stage and prognosis(P>0.05).5.Staging and prognosis:in this type of NPC patients,T1T2 stage 20/23(86.96%),T3T4 stage 3/23(13.04%),recurrence within 3 years 1/23(4.35%),death within 3 years 3/23(13.04%).The data suggested that compared with the classic NPC,the recurrence rate of such NPC was low,the clinical stage was earlier(P<0.05),the prognosis was better,and there was no significant correlation with age,gender,distant metastasis and death(P>0.05).Conclusion:1.The histological morphology,etiology and genetic changes of nasopharyngeal carcinoma without P63 and P40 expression are similar to those of classic NPC.It often expressed low molecular weight keratin CK8/18,CK8.2.This type of nasopharyngeal carcinoma is less malignant and has a better prognosis.3.The ultrastructural results showed that this kind of nasopharyngeal carcinoma still belonged to the undifferentiated type of non-keratinized squamous cell carcinoma,It provides a new idea for the clinicopathological diagnosis of nasopharyngeal carcinoma.The mechanism of its failure to express P63 and P40 may be that it did not pass through the P63 pathway during the carcinogenesis.