Lee Michael J, Vogt Adam P, Hsiao Wayland, Osunkoya Adeboye O
Department of Pathology, Emory University School of Medicine, Room H174, 1364 Clifton Road, NE, Atlanta, GA 30322, USA.
Tumour Biol. 2012 Dec;33(6):2185-8. doi: 10.1007/s13277-012-0479-z. Epub 2012 Aug 16.
CDX-2 is a caudal-type homeobox gene, encoding a transcription factor that plays an important role in proliferation and differentiation of intestinal epithelial cells. The utility of antibodies to CDX2 in the identification of adenocarcinomas of the gastrointestinal tract, particularly colorectal adenocarcinomas, in both primary and metastatic settings is well established. It is well-known that patients with testicular tumors may occasionally lack an obvious palpable mass. However, the expression of CDX2 in malignant germ cell tumors of the testes which have metastatic potential has not been previously studied in a large series. A tissue microarray was constructed from 52 malignant germ cell tumors of the testes including: 29 cases of classic seminoma, 8 cases of embryonal carcinoma, 8 cases of yolk sac tumor, 4 cases of malignant teratoma, 2 cases of choriocarcinoma, and 1 case of spermatocytic seminoma. Ten cases of intratubular germ cell neoplasia and seven cases of benign testicles with normal seminiferous tubules were also included in tissue microarray. Immunohistochemical stains for CDX2 was performed and analyzed. Only nuclear staining was considered positive. Positive expression of CDX2 was identified in 2/2 cases (100 %) of choriocarcinoma, 4/8 cases (50 %) of teratoma, 3/8 cases (38 %) of embryonal carcinoma, 3/8 cases (38 %) of yolk sac tumor, and 1/29 cases (3 %) of classic seminoma. CDX2 was negative in all cases of intratubular germ cell neoplasia, normal seminiferous tubules, and the only case of spermatocytic seminoma. The role of CDX-2 in the differentiation of intestinal/enteric epithelial cells may contribute to the formation of trophoblastic, glandular, villous, or cystic structures in germ cell tumors of the testes. This study suggests that the expression of CDX2 in a variety of malignant germ cell tumors of the testes may be a potential pitfall in metastatic tumors of unknown primary, which are thought to be of gastrointestinal/colorectal origin but are actually from a clinically occult testicular tumor.
CDX-2是一种尾型同源盒基因，编码一种转录因子，该转录因子在肠道上皮细胞的增殖和分化中起重要作用。CDX2抗体在原发性和转移性胃肠道腺癌（尤其是结直肠癌）的鉴别诊断中的应用已得到充分证实。众所周知，睾丸肿瘤患者偶尔可能没有明显可触及的肿块。然而，此前尚未对大量具有转移潜能的睾丸恶性生殖细胞肿瘤中CDX2的表达进行研究。构建了一个组织芯片，包含52例睾丸恶性生殖细胞肿瘤，其中包括：29例经典型精原细胞瘤、8例胚胎癌、8例卵黄囊瘤、4例恶性畸胎瘤、2例绒毛膜癌和1例精母细胞性精原细胞瘤。组织芯片中还包括10例小管内生殖细胞肿瘤和7例生精小管正常的良性睾丸组织。进行了CDX2的免疫组化染色并分析。仅细胞核染色被视为阳性。在2/2例（100%）绒毛膜癌、4/8例（50%）畸胎瘤、3/8例（38%）胚胎癌、3/8例（38%）卵黄囊瘤和1/29例（3%）经典型精原细胞瘤中鉴定出CDX2阳性表达。在所有小管内生殖细胞肿瘤、正常生精小管以及唯一的1例精母细胞性精原细胞瘤病例中，CDX2均为阴性。CDX-2在肠道/肠上皮细胞分化中的作用可能有助于睾丸生殖细胞肿瘤中滋养层、腺体、绒毛或囊性结构的形成。本研究表明，CDX2在多种睾丸恶性生殖细胞肿瘤中的表达可能是不明原发灶转移瘤诊断中的一个潜在陷阱，这些转移瘤被认为起源于胃肠道/结直肠，但实际上来自临床上隐匿的睾丸肿瘤。
