Diagnostic Utility Of SALL4Expression In Germ Cell Tumors And Wilms Tumors

Objective:(1) To investigate the expression of SALL4in germ cell tumors (GCTs)and utility of SALL4immunohistochemically in diagnosis and differentialdiagnosis of GCTs and relative lesions.(2) To study the clinical significance of SALL4in Wilms’ tumors.Materials and Methods:(1) a total88cases of germ cells tumors (including classicseminoma, yolk sac tumor, embryonal carcinoma) and other relative tumorswere selected from the Institute of Pathology, Tongji Hospital, and the caseswere analyzed immunohistochemically and correlation with the H&Estaining. Immunohistochemical staining for SALL4was performed in allcases and compared with other classical germ cell tumor markers (includingPLAP, AFP, and glypican-3).(2) We collected73cases (including wilms’ tumor, renal cell carcinoma, oncocytoma, renal chromophobe cell carcinoma, metanephric adenoma,T-lymphoblastoid cell lymphoma, B-lymphoblastoid cell lymphoma, PNET/EWING, desmoplastic small round cell tumor and rhabdoid tumor) fromthe archives of Institute of Pathology, Tongji Hospital. SALL4expressionin these tumors was detected and analyzed by immunohistochemistry(Envision methods).Results:(1) SALL4staining can be observed in gonadal and extragonadal GCTs.50of53(94.3%) gonadal GCTs showed positive SALL4staining; StrongSALL4staining was seen in all9extragonadal GCTs.(2) In gonadal GCTs,19of20(95%) classic seminomas showed positiveSALL4staining; Strong SALL4staining was seen in all20yolk sac tumors;6of8(75%) disgerminomas showed positive SALL4staining; strongSALL4staining was also seen in all5embryonal carcinomas.(3) SALL4was negative in other26relative tumors including seropapillarycystadenocarcimas; mucioius papillary cystadenocarcimas, thecofibromasand granulosa cell tumors.(4)12of22cases (54.5%) of Wilms’ tumor were positive for SALL4. Thereis no SALL4expression in renal clear cell carcinoma, chromophobe renalcell carcinoma, oncocytoma, metanephric adenoma.(5)10of17cases (58.8%) of mixed subtype of Wilms’ tumor were positivefor SALL4. SALL4staining was seen in both2epithelial subtype of Wilms’ tumor. There is no SALL4expression in3caese of stromal subtype andblastic subtype of Wilms’ tumor. SALL4expression mainly was located innaive epithelial component.(6) T-lymphoblastoid cell lymphoma, B-lymphoblastoid cell lymphoma,PNET/EWING, desmoplastic small round cell tumor and rhabdoid tumorare negative for SALL4immunohistochemically.Conclusion:(1) SALL4is a novel sensitive and relatively specific marker for GCTs indiagnosis and differential diagnosis.(2)SALL4in Wilms’ tumor has a certain degree of positive expression andmainly was located in epithelial component, which could be used as anancillary marker in differential diagnosis of Wilms’ tumor.