Miettinen M
Department of Pathology and Cell Biology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Mod Pathol. 1995 May;8(4):384-8.
Keratin 20 is a recently identified keratin protein distributed particularly in the epithelial cells of the gastrointestinal tract. In this study, keratin 20 was immunohistochemically evaluated in 788 epithelial tumors of different organs. Keratin 20 was consistently present in colonic adenocarcinomas and their metastases in lymph nodes, liver, lung, and ovaries; most primary and metastatic colon carcinomas showed high numbers of positive cells independent of their level of differentiation. Adenocarcinomas of the upper gastrointestinal tract, pancreas, and cholangiocarcinomas showed variable reactivity. Hepatocellular carcinomas and carcinoid tumors often showed focal reactivity limited to scattered tumor cells. In contrast, keratin 20 was virtually absent in primary adenocarcinomas of lung, ovaries, and endometrium. Notable exceptions among ovarian tumors were the mucinous neoplasms that showed variable, sometimes significant keratin 20 reactivity. Transitional cell carcinomas irrespective of grade were usually positive, whereas most prostatic and renal adenocarcinomas were negative or showed only single positive cells. Typically negative were squamous cell carcinomas of all organs and carcinomas of the breast. Merkel cell carcinomas of the skin showed consistent reactivity, whereas small cell carcinomas of the lung were negative. On the basis of these observations, keratin 20 seems to be a suitable adjunct marker to evaluate the primary origin of carcinomas in specific contexts, especially to separate adenocarcinomas of gastrointestinal versus nongastrointestinal origin.
角蛋白20是一种最近发现的角蛋白，特别分布于胃肠道的上皮细胞中。在本研究中，采用免疫组织化学方法对788例不同器官的上皮性肿瘤中的角蛋白20进行了评估。角蛋白20在结肠腺癌及其在淋巴结、肝脏、肺和卵巢的转移灶中持续存在；大多数原发性和转移性结肠癌显示大量阳性细胞，与分化程度无关。上消化道腺癌、胰腺癌和胆管癌显示出不同的反应性。肝细胞癌和类癌肿瘤常显示局限于散在肿瘤细胞的局灶性反应性。相反，肺、卵巢和子宫内膜的原发性腺癌中几乎不存在角蛋白20。卵巢肿瘤中值得注意的例外是黏液性肿瘤，其显示出不同程度的、有时显著的角蛋白20反应性。无论分级如何，移行细胞癌通常为阳性，而大多数前列腺癌和肾腺癌为阴性或仅显示单个阳性细胞。所有器官的鳞状细胞癌和乳腺癌通常为阴性。皮肤的默克尔细胞癌显示一致的反应性，而肺小细胞癌为阴性。基于这些观察结果，角蛋白20似乎是一种合适的辅助标志物，可在特定情况下评估癌的原发起源，尤其是区分胃肠道与非胃肠道起源的腺癌。
