Differential Diagnosis Of Classical Hodgkin Lymphoma And Anaplastic Large Cell Lymphoma With Aberrant T/B Cell Antigen Expression

Objective:Classic Hodgkin’s lymphoma and anaplastic large cell lymphomas are two independent types of diseases,and they have great differences in cell origin,clinical biological behavior,prognosis and treatment,however,there are some overlap and similarity in histomorphology,immunophenotype and molecular genetics which creates a clinical diagnosis of difficult or even misdiagnosis.Because the treatment and prognosis of these two diseases are completely different,it is very important to correctly recognize and distinguish these two diseases in clinical work.The aim of this study was to explore markers that could be used clinically to help identify the two types of tumors.In the experiment,there is a certain ratio of T cell antigen(T-cell antigen,TCA)aberrant expression,and found one case of ALCL aberrant in B cell antigen(B-cell antigen,BCA)expression.We further summarized the morphological,immunohistochemical and genetic characteristics of cHL and ALCL with abnormal TCA/BCA expression,providing certain reference basis for the differential diagnosis of the two diseases.Methods:1.Collection of qilu hospital of shan dong university archive cases between 2013-2016,including 68 patients with classical Hodgkin’s lymphoma(including 31 cases of nodular sclerosis type,24 cases of mixed cell type,9 cases of lymphocytic rich type,4 cases of lymphocyte depleted type)and 30 cases of anaplastic large cell lymphoma.The histomorphological characteristics of cHL and ALCL were observed and compared by HE staining of paraffin sections under optical microscope.2.Immunohistochemical staining was used to detect the expression of 25 immunohistochemical markers in cHL and ALCL.3.The expression of EBV in cHL and ALCL was detected by in situ hybridization.4-After screening with the above methods,we further analyzed the aberrant expression of cHL and ALCL cases by genome-wide exon sequencing,and compared them with the cases without aberrant expression.We performed WES for 18 samples.Four were cHL samples that exhibited aberrant expression in more than 1 TCA(namely,S1,S2,S3,and S4),1 was an ALCL sample with aberrant BCA-expression(named as S5),5 were cHL cases without aberrant TCA expression(cHL group);and the following cases were EBER-:5 were ALK-ALCL cases without aberrant BCA expression(ALCL group)and 3 were reactive hyperplasia of lymph node cases(control group).The data were intersected for the cHL group and the ALCL group.The data were merged for the control group.Each group was compared with the control group before comparison between the 2 groups.5.The data were analyzed using the Statistical Package for Social Sciences(SPSS;version 20)statistical program(SPSS,Chicago,IL).The frequencies between the groups were-compared using the X2 test and Fisher exact method.A 1-way analysis of variance was applied for comparison between the groups of the sample.The results were considered statistically significant when P<0.05.Results:1.Immunohistochemical results showed that in 68 cHL cases,we found 10(14.71%)cases that expressed 1 or more TCAs,and the frequency of TCA expression was as follows:CD4(8 cases)>CD2(6 cases)>CD3(3 cases)>CD5(2 cases)=CD7(2 cases).Only 1(3.33%)of 30 ALCL cases expressed BCA.2.Histomorphological results showed that(1)the main subtypes are LD and NS2;(2)multiple focal tumor necrosis is more common than those cases without aberrant expression(40%versus 5.17%,P<0.01);and(3)these aberrant TCA expression tumor cells have some morphologic featuresof ALCL cells:numerous tumor cells,high cohesiveness,more pleomorphic with a horseshoe nucleus,and sinusoidal growth pattern.However,ALCL tumor cells with aberrant expression of BCA showed some cHL characteristics:tumor cells were significantly larger than those without abnormal expression.The nuclei were ring-shaped and the cytoplasm was highly acidophilic,showing the morphological characteristics of cHL cells.3.In situ hybridization results showed that in 68 cHL cases,the positive rate of EBER was 27.94%(19/68).In 30 ALCL cases,only one patient had aberrant expression of BCA and the abnormally expressed tumor cells were EBER positive,and the other 29 ALCL cases were all negative.4.The results of whole exon sequencing showed that only 2 mutation sites(GNE and CACNB2)were identified in the cHL group compared with the control group.In the ALCL group,135 mutation sites(112 genes involved)were identified compared with the control group,suggesting more complex molecular changes in ALCL than those in cHL,and the mutation sites in cHLs and ALCLs did not overlap.We found that 64,75,50 and 68 mutations occurred in sl-s4 of cHL patients with aberrant expression of TCA,all of which were high-frequency mutations in ALCL,and CACNB2 mutation could be seen in S5 of BCA positive ALCL patients.This site was high-frequency mutations in all cHLs patients,but not in BCA negative ALCLs patients.Conclusions:1.There are a certain number of cHLs with aberrant TCA expression,especially in the LD and NS2 subtypes.The frequency of aberrant BCA expression of ALCL was much lower than that of cHL.2.These aberrant TCA expressing cHL tumor cells exhibited some ALCL features,and the aberrant BCA-expressing ALCL tumor cells displayed cHL characteristics.3.The results of this analysis showed that GNE and CACNB2 mutations,involved in the MAPK signaling pathway,may play an important role in cHL.The molecular changes of ALCL are more complex than those of cHL,involving multiple signaling pathways,including chemical carcinogenic drug metabolism,starch and sucrose metabolism,and biosynthesis of steroid hormones.In the cases of abnormally expressed cHL and ALCL,the morphological and molecular characteristics are between those of cHL and ALCL.