Pathological Significance Of NY-ESO-1 Expression In The Diagnosis And Differential Diagnosis Of Myxoid Liposarcoma

Objective: Myxoid liposarcoma is a common mesenchymal myxoid tumor characterized by histological features of myxoid background,arborizing capillaries,and lipoblasts at different stages.Unlike well-differentiated liposarcoma and other types of mesenchymal myxoid tumor,it is assoaciated with high risk of metastasis,especially to some unusual areas.Therfore,it is very important to make an accurate diagnosis.The diagnosis of myxoid liposarcoma needs to be combined with morphology,S-100 staining result,and DDIT3 gene fluorescence in situ hybridization(FISH)if necessary.According to our clinical experience,we found that a variety of soft tissue tumor stroma can be widely mucoid degeneration.When it is abundant with blood vessels or vacuole-like cells,the tumor may look suspiciously like a myxoid liposarcoma.In addition,when a myxoid liposarcoma is predominantly round cell differentiation,the morphology has some similarities with other round cell tumors.Moreover,S-100 immunostaining is not specific and is also expressed in other adipose-derived tumors.FISH is not only costly,but also requires high laboratory conditions,which is not conducive to primary hospitals.It has been previously reported that New York Esophageal Squamous Cell Carcinoma-1(NY-ESO-1)is positively expressed in myxoid liposarcoma,but the expression characteristics and its clinical significance in the diagnosis and differential diagnosis are not clear.The aim of this study is to further investigate the expression characteristics of NY-ESO-1 in myxoid liposarcoma,and to investigate the pathological significance of NY-ESO-1 expression in the differential diagnosis of mesenchymal myxoid tumor,and to identify the relationship between NY-ESO-1 expression and the clinical features of patients with liposarcoma.Methods: The pathology diagnosis of myxoid liposarcoma and other mesenchymal myxoid tumor documented by Qingdao Municipal Hospital and Affiliated Hospital of Qingdao University from 2010 to 2018 were collectedafter querying the pathological database.By reviewing the slides,a total of 58 soft tissue tumors with mucin-like morphology were included in the study.We detected the DDIT3 status by FISH separation probe to further clarify the diagnosis of myxoid liposarcoma.The expression of NY-ESO-1 protein was detected by En Vision immunohistochemistry,and the expression of NY-ESO-1 m RNA was detected by reverse transcription PCR.We also examined the expression of S-100 and Ki-67 in myxoid liposarcoma and investigated the correlation between NY-ESO-1 expression levels and these indicators.In addition,we followed up patients with myxoid liposarcoma and analyzed the correlation between NY-ESO-1 expression and clinical pathological features and prognosis.Results: Of the 58 cases of mesenchymal myxoid tumors,we performed FISH on 37 cases,of which 26 were positive,and 11 cases were negative.Histopathology and FISH results confirmed that there were 11 cases of myxoid liposarcoma and 32 cases of other types of tumors(including 7 cases of well-differentiated liposarcoma,1 case of dedifferentiated liposarcoma,3 cases of lipoma,2 cases of lipoblastoma,and 19 cases of non-lipomatous tumors).The other mucin-like soft tissue tumors were negative.FISH result was negative in 5 cases of well-differentiated liposarcoma with myxoid appearance,but amplified red and green signals was noted.There was no breakapart or amplification signal in other tumors.Immunohistochemistry showed that the positive expression rate of NY-ESO-1 in myxoid liposarcoma was 92.3%(24/26).The positive site was located in the cytoplasm and nucleus of lipoblasts,and the expression intensity was higher in the area with round cell differentiation.Of the 32 other types of tumors,only one well-differentiated liposarcoma expressed NY-ESO-1.NY-ESO-1 m RNA expression was detected in 7(7/11)myxoid liposarcoma and one(1/7)well differentiated liposarcoma,while was not detected in the remaining tumors.S-100 was expressed in adipocytes and lipoblasts at various stages;however,the staining intensity was not related to the classification of lipomatous tumor,and was not related to the expression level of NY-ESO-1.The positive rate of Ki-67 in round cell differentiation was higher.This is consistent with the expression patterns of NY-ESO-1.Correlation analysis showed that the staining intensity of NY-ESO-1 was not related to the patients' age,gender,location and size.Survival analysis found that the expression intensity of NY-ESO-1 was correlated with the postoperative tumor-free survival.Conclusion: NY-ESO-1 has a high expression rate in myxoid liposarcoma and can be served as a specific diagnostic marker for myxoid liposarcoma.Immunohistochemical staining with NY-ESO-1 and S-100 can greatly improve the diagnostic accuracy of myxoid liposarcoma.Univariate survival analysis showed that there was a correlation between the proportion of round cell differentiation and Ki-67 expression and the prognosis of myxoid liposarcoma,suggesting that the proportion of round cell differentiation and Ki-67 expression rate were both influential factors for the survival of myxoid liposarcoma without recurrence and metastasis.In addition,NY-ESO-1 can be used as a prognostic factor for myxoid liposarcoma.In view of the strong immunogenicity of NY-ESO-1,it can be explored as a therapeutic target for myxoid liposarcoma.