Clinicopathological And Genetic Studies Of Anaplastic Large Cell Lymphoma

Objective: Anaplastic large cell lymphoma(ALCL)is a heterogeneous T cell lymphoma with different molecular subtypes that have different clinical prognosis and genetic characteristics.This study summarized the clinical,pathological and genetic characteristics of systemic ALK-positive anaplastic large cell lymphoma(ALK+ALCL),systemic Al K-negative anaplastic large cell lymphoma(ALK-ALCL)and primary cutaneous anaplastic large cell lymphoma(PC-ALCL),compared the differences in clinical and pathological characteristics,immunophenotypes,molecular genetics and prognosis of the three subtypes,and explore the clinicopathological significance of the expression of p63 and TOPK proteins in ALCL,as well as the rearrangement of DUSP22 and TP63 genes,so as to find biomarkers for diagnosis,typing and prognosis assessment of ALCL to provide a basis for clinical diagnosis and treatment.Methods :1.25 paraffin tissue specimens of ALCL were selected from January 2010 to June 2020,and clinicopathological and follow-up data of the patients were collected.Immunohistochemistry was used to detect the expression of T cell markers,cytotoxic markers,EMA,MUM-1,CD56,p53,p63 and TOPK in tumor cells,and fluorescence in situ hybridization(FISH)was used to detect the rearrangement of DUSP22 and TP63 genes in ALK-ALCL and PC-ALCL patients;Statistical methods were used to analyze and compare the clinical and pathological differences and prognosis of ALCL molecular subtypes.2.30 Paraffin tissues of T-cell lymphoma from 2019 to 2021 were selected,including 15 cases of NK/ T-cell lymphoma(NKTCL),9 cases of vascular immunoblastic T-cell lymphoma(AITL)and 6 cases of T lymphoblastic leukaemia/lymphoma(T-ALL/LBL).Immunohistochemistry was used to detect the expression of TOPK;Statistical methods were used to analyze and compare the expression differences of TOPK in ALCL and other T cell lymphomas.Results:1.Clinical features: The 25 ALCL patients included 15 ALK+ALCL patients,6 ALK-ALCL patients and 4 PC-ALCL patients.Among the 15ALK+ALCL patients,the male to female ratio was 3:2,and the median age was29 years old.There were 9 cases(60%)with first occurrence in lymph nodes and6 cases(40%)with first occurrence in external nodes.Among the 6 cases of ALK-ALCL,the male to female ratio was 5:1,and the median age was 43.5years.There were 2 cases(33%)of first occurrence in lymph nodes and 4 cases(67%)of first occurrence in external nodes.Among the 4 cases of PC-ALCL,the male to female ratio was 1:1,and the median age was 61 years.Statistical analysis showed that there were no significant differences in clinical characteristics among the three subtypes of ALCL in this study.2.Morphological features: Among the 25 cases of ALCL,23 cases(92%)were classical type.In ALK+ALCL,two cases were small cell type.The tumor cells of PC-ALCL cases did not break through the epidermis,showing intradermic invasive growth,agitation of the epidermis and pseudo-epitheliomatous hyperplasia,which was easily misdiagnosed as squamous cell carcinoma.3.Immunohistochemistry: By statistical analysis,ALK+ALCL was more likely to lose CD2 than ALK-ALCL(P < 0.05);The expression rate of TIA-1 in ALK+ALCL was higher than that in ALK-Al CL(P < 0.05);The expression rate of EMA in ALK+ALCL was higher than that in PC-ALCL(P < 0.05);the expression rate of CD56 in ALK+ALCL was higher than that in ALK-ALCL and PC-ALCL(P < 0.05).The expression of p53 protein in this group of cases was wild-type.4.Expression of p63 and detection of DUSP22 and TP63 rearrangements:immunohistochemical staining of p63 was performed in 6 cases of ALK-ALCL and 4 cases of PC-ALCL,and the expression rate was 50%,with no statistical difference(P > 0.05).FISH detection of TP63 gene was performed in p63-positive ALK-ALCL and PC-ALCL cases,and TP63 rearrangement was detected in only one case(1/5).FISH detection of DUSP22 gene was performed on all ALK-ALCL and PC-ALCL cases,and it was found that:(1)the case with TP63 rearrangement had DUSP22 rearrangement;(2)Among the other four cases with p63-positive and TP63 rearrangements negative,one case with DUSP22 rearrangement was detected;(3)DUSP22 rearrangement was detected in one case with p63-negative.(4)Multiple copies of DUSP22 gene were detected in three patients,and one of them was p63-positive.5.Prognosis analysis: SPSS 22.0 software was used to analyze and compare the prognosis of ALK+ALCL,ALK-Al CL and PC-Al CL,and the results showed no significant difference in the prognosis of the three subtypes of ALCL in this study(P=0.135).Comparison of the prognosis of ALCL aged < 40 years and ≥40 years showed that the former had a better prognosis and the latter had a worse prognosis,the difference was statistically significant(P=0.045).6.Expression of TOPK in ALCL,NKTCL,AITL and T-ALL/LBL:Immunohistochemical staining of TOPK protein was performed on 25 cases of ALCL,15 cases of NKTCL,9 cases of AITL and 6 cases of T-ALL/LBL.The expression rate of TOPK in NKTCL,AITL and T-ALL/LBL was 47%(7/15),44%(4/9)and 0%(0/6),respectively,while the expression rate in ALCL was100%(23/23).Statistical analysis showed that the expression of TOPK in ALCL was higher than that of NKTCL,AITL and T-ALL/LBL(P= 0.000).Conclusions:1.For ALK-ALCL and PC-ALCL patients,TP63 rearrangements are not necessarily found in patients with the expression of p63.Ddetection of p63 protein can be clinically used to select cases for FISH gene detection.2.For ALCL cases with ALK-negative,if p63 expression is positive,it is recommended to detect both DUSP22 and TP63 rearrangement status;If p63 expression is negetive,it is recommended to detect DUSP22 rearrangement status,which is conducive to comprehensive evaluation of molecular characteristics and prognosis of the tumors.3.ALCL patients aged < 40 years have a better prognosis,while ALCL patients aged ≥40 years have a worse prognosis.4.TOPK protein was highly expressed in ALCL cells,and the positive expression rate was significantly higher than that of NKTCL,AITL and T-ALL/LBL,suggesting that the abnormal expression of TOPK protein may be related to the pathological type of T-cell lymphoma,but not to the degree of malignancy.