Evaluation of LIN28 as a Pan-Germ Cell Tumor Marker Using Germ Cell Tumor Tissue Microarrays
Arivarasan Karunamurthy, Somak Roy, Sarangarajan Ranganathan, Anil Parwani. University of Pittsburgh Medical Center, Pittsburgh, PA
Background: LIN28 a predominantly RNA-binding cytoplasmic protein, plays important role in gene expression regulation and maintainence of the pluripotency of embryonic stem cells. Recent studies have shown the role of LIN28 in malignant transformation of germ cells in animals. Our aim was to evaluate the diagnostic utility of LIN28 expression in testicular germ cell tumors (GCT).
Design: Two tissue microarrays constructed from various primary and metastatic testicular GCTs were stained with LIN28 antibody. The cytoplasmic staining was considered positive and scored as negative, weak, moderate, or strong staining.
Results: A total of 69 GCTs were obtained of which 52 (75%) were primary testicular GCTs (35 seminomas; 14 embryonal carcinomas; 3 yolk sac tumors; 6 teratomas and 20 intratubular germ cell neoplasias) and 17(25%) were metastatic testicular germ cell tumors containing (1 seminomas; 5 embryonal carcinomas; 3 yolk sac tumors; 8 teratomas and 1 choriocarcinoma) along with 19 normal testicular tissue cores adjacent to the above tumors. Strong LIN28 staining is observed in 30 (83%) seminomas, 25 (100%) embryonal and yolk sac tumors, 19 (95%) ITGCNs and 1 (100%) choriocarcinoma without any significant difference between primary and metastatic. Teratomas showed either negative (50%) or weak (50%) staining due to presence of mature epithelial or mesenchymal tissues. Normal testicular germ cells showed mostly (95%) weak staining.
|Primary or Metastatic||Negative||Weak Staining||Moderate staining||Strong Staining|
|Seminoma (n=36||Primary||0||0||6 (17%)||29 (83%)|
|Embryonal Carcinoma(n=19||Primary||0||0||0||14 (74%)|
|Yolk sac tumor(n=6)||Primary||0||0||0||3 (50%)|
|Teratoma(n=14)||Primary||3 (25%)||1 (8%)||0||0|
|Metastatic||3 (25%)||5 (42%)||0||0|
|ITGCN(n=19)||0||0||1 (5%)||19 (95%)|
|Normal testicular tissue (n=19)||1 (5%)||18 (95%)||0||0|