Diagnostic utility of SALL4 in primary yolk sac tumors

ZHANG Chun-fang; CHEN Hao; ZHANG Chang; NIE Yan-hong; QI Dong-xue

doi:10.3969/j.issn.1007-8096.2017.04.012

Abstract：Purpose To investigate the diagnostic utility of SALL4 as a potential diagnostic marker in primary yolk sac tumors (YSTs).Methods The expression of SALL4 protein was detected by EnVision immunohistochemical method in 32 cases of gonadal and extragonadal primary yolk sac tumors,including 14 testicular,12 ovarian,5 sacrococcygeal and 1 cerebral.In addition,10 cases of ovarian granulosa cell tumor,5 cases of ovarian clear cell carcinoma,and 10 cases of normal testis and ovary tissue were selected as control.Meanwile,the immunohistochemical markers AFP and glypican-3 were also evaluated in these tumors and tissues.Results All YSTs were positive for SALL4 (100％) with moderate to strong grade staining.87.5％ (28/32) of the YSTs were positive for Glypican-3,with 75％ median or strong positivity,and 12.5％ weak positivity.AFP-positive staining was observed in 78.1％ (25/32) of tumors,with 68.8％ (22/32) weak or median positivity,and 9.4％ (3/32) strong positivity.Both expression rate and intensity of SALL4 were higher than that of AFP and Glypican-3.The difference was statistically significant (P ＜ 0.05).In the control group,10 granulosa cell tumors showed scattered focal weak positivity of AFP and Glypican-3 in 1 case,while SALL4 was negative.And ovarian clear cell carcinoma showed scattered focal weak positivity of AFP,while SALL4 and Glypican-3 were both negative.Immunoreactivity for SALL4,Glypican-3 and AFP were entirely negative in 10 normal testicular and ovarian tissues.Conclusions SALL4 is a highly specific immunohistochemical marker for YSTs,with better expression rate and intensity than that of AFP and Glypican-3,and particularly useful to distinguish YSTs from ovarian granulosa cell tumors or clear cell carcinoma.