Jaffee Ian M, Rahmani Mahdis, Singhal Maria G, Younes Mamoun
Department of Pathology, Baylor College of Medicine, and The Methodist Hospital, Houston, Tex 77030 , USA.
Arch Pathol Lab Med. 2006 Oct;130(10):1522-6. doi: 10.5858/2006-130-1522-EOTITF.
Carcinoid tumors are classified according to their site of origin into foregut, midgut, or hindgut carcinoids, which have different presentations and prognosis. The intestinal transcription factor CDX2 has been found to be expressed in most intestinal adenocarcinomas but in less than one half of the gastrointestinal carcinoids according to 1 study.
To determine whether CDX2 expression in carcinoid tumors varies by the site of origin and whether CDX2 expression is retained in metastatic disease. Design.-Sections of formalin-fixed and paraffin-embedded tissue from 36 primary carcinoid tumors and 5 cases of metastatic carcinoid to the liver were immunohistochemically stained for CDX2. The percent of cells with nuclear immunoreactivity and the intensity of staining were assessed.
All 18 foregut carcinoids (10 pulmonary and 8 gastric) were negative (0%) for CDX2. All 11 midgut carcinoids (100%) were positive for CDX2 with moderate to strong staining in more than 50% of the cells. Only 2 (29%) of 7 of hindgut carcinoids were CDX2-positive with the 2 positive cases showing weak to moderate staining intensity in less than 10% of the cells. Expression of CDX2 in more than 50% of tumor cells was seen only in midgut carcinoids (P < .001). CDX2 expression in metastatic tumors was consistent with the site of origin.
Midgut carcinoid tumors and their metastases are distinct from foregut and hindgut carcinoids in that they express high levels of CDX2. Additional studies are needed to determine whether CDX2 immunostaining may be helpful in determining the primary site of metastatic carcinoid tumors of unknown origin.
类癌肿瘤根据其起源部位分为前肠、中肠或后肠类癌，它们具有不同的表现和预后。根据一项研究，肠道转录因子CDX2已被发现在大多数肠道腺癌中表达，但在不到一半的胃肠道类癌中表达。
确定类癌肿瘤中CDX2的表达是否因起源部位而异，以及CDX2表达在转移性疾病中是否保留。设计：对36例原发性类癌肿瘤和5例肝转移性类癌的福尔马林固定石蜡包埋组织切片进行CDX2免疫组织化学染色。评估细胞核免疫反应阳性细胞的百分比和染色强度。
所有18例前肠类癌（10例肺部和8例胃部）CDX2均为阴性（0%）。所有11例中肠类癌（100%）CDX2均为阳性，超过50%的细胞呈中度至强染色。7例后肠类癌中只有2例（29%）CDX2阳性，2例阳性病例中不到10%的细胞呈弱至中度染色强度。仅在中肠类癌中可见超过50%的肿瘤细胞表达CDX2（P <.001）。转移性肿瘤中CDX2的表达与起源部位一致。
中肠类癌肿瘤及其转移灶与前肠和后肠类癌不同，它们表达高水平的CDX2。需要进一步研究以确定CDX2免疫染色是否有助于确定不明起源的转移性类癌肿瘤的原发部位。
