胃肠道癌单克隆抗体在鉴别原发性与移性卵巢癌中的意义

在实验利用对胃癌、结肠癌选择性很强的单克隆抗体MG_7及MC_3,通过免疫组化实验检测原发性与转移性卵巢癌的相应抗原。实验结果33例卵巢(原发性)上皮性癌全部为阴性,18癌例卵巢转移性癌总阳性率为94.4％,提示本实验有可能用于鉴别原发性与转移性(来源于胃肠道癌)卵巢癌、对协助病理诊断(实验对2例病理诊断困难的病例明确了诊断)、判定原发病灶及指导治疗具有一定的意义。     

TTF-1在肺腺癌中的表达及其诊断意义

目的：评价甲状腺转录因子－1（TTF－1）在鉴别肺原发性腺癌与转移性腺癌中的临床病理应用价值。方法：20例肺原发性腺癌：10例高分化，包括3例乳头状、3例腺泡状、3例混合型腺癌和1例细支气管肺泡癌；10例低分化，包括4例黏液腺癌（其中1例为印戒细胞癌）和6例混合型腺癌。另选20例的胃肠道及卵巢腺癌，免疫组化应用TTF－1抗体。结果：95％的肺原发性腺癌表达TTF－1，而胃肠道及卵巢腺癌完全不表达。结论：对于确定肺原发或转移性腺癌的病理诊断。TTF－1是一个有用的特异性抗体，特别是在体积较小的肺活检标本或原发灶不明而仅有肺内转移时。     

恶性上皮性肿瘤中CK20的表达及其临床意义

目的　研究单克隆抗体CK2 0在恶性上皮性肿瘤和卵巢转移性腺癌组织中的表达及其意义。方法　应用S P法对鼻咽非角化性癌、乳腺浸润性导管癌、肺的鳞癌和腺癌、卵巢黏液性囊腺癌、胃腺癌和结肠直肠腺癌各组总计 6 7例和 4 1例分别进行了CK2 0和CK19检测。结果　CK2 0阳性率 :肺腺癌 1/ 7(14 3% ) ,卵巢浆液性和黏液性腺癌 3/ 12 (33 3% ) ,胃腺癌 3/ 9(33 3% ) ,结肠直肠腺癌组 2 1/ 2 2 (95 5 % ) ,其他癌组织均呈阴性。结肠直肠腺癌组组与其他各组间比较差异有显著性 (P <0 0 1)。CK19在上述 4 1例癌组织中均呈强阳性表达。结论　CK2 0表达对鉴别结肠腺癌和直肠腺癌与肺腺癌和乳腺浸润性导管癌具有高度特异性和较高的敏感性 ;CK2 0高表达对鉴别卵巢原发性腺癌与卵巢的结肠腺癌或直肠腺癌转移具有一定的意义     

细胞角蛋白7和20在卵巢转移癌中的表达

目的 观察卵巢转移癌的临床资料、病理形态和免疫组织化学改变,为鉴别卵巢转移癌与原发癌提供依据。方法 对27例卵巢转移癌（其中胃癌12例,结肠癌11例,其他4例）进行了临床和病理形态观察,同时采用免疫组织化学（SP法）对其分别进行细胞角蛋白[CK（AE1/AE3）]、细胞角蛋白7（CK7）、细胞角蛋白20（CK20）、癌胚抗原、波形蛋白、nm23抗原检测。结果 卵巢转移性胃癌12例中11例为双侧实性,卵巢转移性结肠癌11例中7例为单侧囊实性,组织学检查胃癌卵巢转移12例全部以印戒细胞癌或低分化腺癌散在分布为特征,而结肠癌卵巢转移则11例中8例与子宫内膜样癌相似,CK20阳性染色使卵巢转移性胃癌7例及结肠癌8例得到明确诊断,在转移性结肠癌中CK20有稳定的表达,卵巢转移性胃肠道癌中CK7多数阴性,癌胚抗原、波形蛋白、nm23的联合使用使转移性胃癌11例,结肠癌10例得到明确诊断,结论 CK7和CK20在鉴别来自胃肠道的卵巢转移癌中具有重要意义。当几种抗体联合使用时意义更大。     

MG_7和MC_3单克隆抗体在鉴别原发性与转移性卵巢癌中的意义

转移性卵巢癌约85％来源于胃肠道癌,如果原发癌灶表浅或隐匿,以及少见的卵巢原发性克氏瘤单靠普遍病理组织学诊断就非常困难,容易造成误诊。实验取53例石蜡切片,其中卵巢上皮性癌33例、转移性腺癌18例、诊断原发或继发卵巢癌困难者2例。以胃癌为免疫原     

联合检测CK7、CK20和SATB2在卵巢原发性黏液腺癌和转移性结直肠腺癌中的表达及鉴别意义

目的探讨联合检测CK7、CK20和SATB2在卵巢原发性黏液腺癌和转移性结直肠腺癌中的表达及鉴别意义。方法收集安徽医科大学第一附属医院2011～2016年确诊的卵巢原发性黏液腺癌26例、卵巢转移性结直肠腺癌29例、结直肠原发性黏液腺癌50例。采用免疫组化EnVision两步法检测CK7、CK20和SATB2的表达。结果 CK7在卵巢原发性黏液腺癌中的阳性率显著高于卵巢转移性结直肠腺癌和结直肠原发性黏液腺癌,差异有统计学意义(P0.05);CK20和SATB2在卵巢转移性结直肠腺癌和结直肠原发性黏液腺癌中的阳性率显著高于卵巢原发性黏液腺癌,差异有统计学意义(P0.05);CK7~+/CK20~-、CK7~-/CK20~+和CK7~+/CK20~+在卵巢原发性黏液腺癌和转移性结直肠腺癌中的表达,差异有显著性(P0.05);CK7~-/CK20~-在两者中的表达差异无显著性(P0.05),卵巢原发性黏液腺癌以CK7~+/CK20~-常见,卵巢转移性结直肠腺癌以CK7~-/CK20~+常见;CK7、CK20和SATB2检测的灵敏度分别为82.8%、75.9%、65.5%,特异度分别为80.8%、61.5%、100%。结论 SATB2是鉴别卵巢原发性黏液腺癌和转移性结直肠腺癌高度特异性的免疫组化标志物,可以联合检测CK7、CK20和SATB2提高卵巢黏液性腺癌病理诊断的准确性。     

54例颅内肿瘤CD56（Leu7）表达的免疫组化观察

应用抗ＣＤ５６单克隆抗体和ＡＢＣ技术观察了５４例颅内肿瘤细胞的ＣＤ５６表达状况，３４例胶质瘤中３１例（９１．２％）阳性，其中包括小脑髓母细胞瘤２例，大脑ＰＮＥＴ１例，１０例脑膜瘤中３例阳性，原发性恶性淋巴瘤２例均阳性，胚生殖细胞瘤１例、转移癌７例均阴性，本组结果表明ＣＤ５６并非神经鞘细胞、少突胶质细胞及其肿瘤的特异性标记物，但可作为颅内原发性肿瘤、特别是胶质癌与转移癌鉴别的重要参考指标。     

SATB2表达模式有助于卵巢转移性结直肠或阑尾肿瘤与卵巢原发性黏液性或子宫内膜样肿瘤的鉴别

正由于部分卵巢外的转移性肿瘤可显示出相似的显微镜下特点及免疫表型特征,给卵巢黏液性肿瘤的确诊带来困难,如原发于结直肠、阑尾、胃、胰腺、子宫内膜样腺癌的转移可与卵巢原发性黏液性囊腺瘤、交界性黏液性肿瘤及黏液腺癌相似。近年研究证明,SATB2是正常结直肠上皮细胞及结直肠腺癌的高度敏感标志物。因此,作者对SATB2鉴别卵巢转移性结直肠腺癌、卵巢原发性黏液性肿瘤及子宫内膜样癌的作用进行分析。结果显示,在卵巢原发性肿瘤中,22例缺乏     

早期胃印戒细胞癌免疫表型的临床病理意义

目的 探讨胃、肠免疫表型标志物在早期胃印戒细胞癌中的表达及其与临床病理参数和预后的相关性.方法 免疫组织化学EnVision法检测91例早期胃印戒细胞癌中胃免疫表型标志物MUCI、MUCSAC、MUC6和肠免疫表型标志物MUC2、CDX2的表达,并根据肿瘤细胞胃、肠免疫表型标志物表达水平的差异,将早期胃印戒细胞癌分为3种类型:胃型、肠型和混合型.结果 胃型、混合型和肠型印戒细胞癌分别为53例(58.2%)、22例(24.2%)和16例(17.6%).胃、肠免疫表型标志物表达水平与印戒细胞癌形态学分型无相关性(P>0.05).两种肠免疫表型标志物MUC2和CDX2在早期黏膜下层浸润癌中阳性表达率均显著高于黏膜内癌,差异有统计学意义(均P<0.01).两种胃免疫表型标志物MUCSAC和MUC6在早期黏膜下层浸润癌中的阳性表达率分别为52.9%(18/34)和20.6%(7/34)均显著低于黏膜内癌91.2%(52/57)和31.6%(18/57),差异有统计学意义(P<0.01和P<0.05).在淋巴结转移阳性组和脉管浸润阳性组中,MUC2和CDX2的阳性表达率均明显高于无淋巴结转移组和无脉管浸润组,差异有统计学意义(P<0.05).随着肿瘤病变范围的扩大,CDX2阳性表达率明显增高,差异有统计学意义(P<0.05).肠型印戒细胞癌比胃型印戒细胞癌更多见于早期黏膜下层浸润癌且有更高的淋巴结转移率(P=0.000和P=0.003).生存分析显示,肠型和混合型印戒细胞癌5年生存率明显低于胃型印戒细胞癌(P<0.05).结论 肠型胃印戒细胞癌临床生物学行为和预后均较胃型印戒细胞癌差.胃、肠免疫表型标志物的胃印戒细胞癌分型有助于评估预后并有可能指导治疗.     

p16在原发性卵巢黏液性和子宫内膜样肿瘤和转移性腺癌中的表达

原发性卵巢上皮性肿瘤与转移性腺癌的鉴别有时比较困难，特别是肿瘤显示黏液样、子宫内膜样或混合性子宫内膜样／黏液性分化时。伴有这些类型分化的转移性腺癌可来自于多个部位，如胃肠道和子宫（子宫内膜和宫颈）。大多数宫颈内膜腺癌显示黏液性和（或）宫内膜样分化，它们转移至卵巢比较少见，而且常表现为转移性癌的一些特征，如双侧卵巢累及，结节行生长。     

The usefulness of CDX-2 for differentiating primary and metastatic ovarian carcinoma: an immunohistochemical study using a tissue microarray

Distinguishing primary ovarian carcinoma from metastatic carcinoma to the ovary is often difficult by histologic examination alone. Recently an immunohistochemical marker CDX-2 was found to be of considerable diagnostic value in establishing the gastrointestinal origin of metastatic tumors. The aim of this study was to determine whether CDX-2 can distinguish between these malignancies. Paraffin-embedded tissue sections from 57 primary ovarian tumors and 40 metastatic tumors to the ovary were immunostained for CDX-2, and results were compared to the ancillary immunohistochemical results for CK7/CK20, CEA, CA125, and her-2/neu. CDX-2 immunoreactivity was observed in most of metastatic carcinomas with colorectal (91%) and appendiceal (100%) origin, however CDX-2 was negative in all primary ovarian carcinomas, except for the mucinous subtype. Almost all primary ovarian carcinomas including the mucinous subtype showed diffuse and strong immunoexpression for CK7. CEA and CA125 were mainly found in metastatic and primary ovarian carcinoma, respectively. Her-2/neu overexpression was only noted in a small proportion of primary and metastatic ovarian carcinomas. These results suggest that CDX-2 is very useful immunohistochemical marker for distinguishing metastatic colorectal carcinoma to the ovary from primary ovarian carcinoma, including the mucinous subtype. Furthermore, combination with CDX-2 and CK7 strengthen the differential diagnosis between these tumors.     

Differentiation of ovarian mucinous carcinoma and metastatic colorectal adenocarcinoma by immunostaining with beta-catenin

AIMS: To investigate whether localization of beta-catenin is helpful in differentiating primary ovarian mucinous carcinoma and colorectal adenocarcinoma metastatic to the ovary. Extra-ovarian cancers which metastasize to the ovaries, especially from colorectal adenocarcinoma, frequently mimic primary ovarian carcinomas, particularly endometrioid and mucinous types. Distinguishing primary ovarian carcinoma from metastatic colorectal carcinoma is important for both therapeutic and prognostic reasons. Even after thorough histological examination, metastatic colorectal adenocarcinomas are still often mistaken for primary ovarian adenocarcinomas. Although some tumour makers have been advocated and are helpful in most cases, sometimes the distinction between primary mucinous carcinoma and metastatic colorectal carcinoma remains a problem. Activation of Wnt signalling through mutations of APC or beta-catenin is a key event in the development of colorectal cancer. These mutations lead to nuclear localization of beta-catenin, which can be demonstrated immunohistochemically. METHODS AND RESULTS: Formalin-fixed paraffin-embedded specimens from 43 primary ovarian mucinous carcinomas and 23 metastatic colorectal adenocarcinomas were included in this study. Sections were immunostained with antibodies to beta-catenin, cytokeratin (CK)7, CK20 and carcinoembryonic antigen (CEA). Nuclear localization of beta-catenin was found in 83% (19/23) of metastatic colorectal cancers and 9% (4/43) of ovarian mucinous carcinomas. Ovarian mucinous carcinomas were usually positive for CK7 (34/43, 79%). For comparison, 40 non-mucinous carcinomas of the ovary and 42 metastatic adenocarcinomas from other organs were also immunostained with antibodies against beta-catenin. Although nuclear localization of beta-catenin was occasionally seen in non-mucinous carcinoma of the ovary and metastatic adenocarcinoma from other organs, such tumours were usually distinguishable by their clinicopathological picture and rarely raised diagnostic problems. CONCLUSIONS: Immunostaining of beta-catenin is a useful marker for differentiating between ovarian mucinous carcinoma and metastatic colorectal adenocarcinoma.     

Utility of CDX-2 in distinguishing between primary and secondary (intestinal) mucinous ovarian carcinoma: an immunohistochemical comparison of 43 cases.

Primary and secondary mucinous tumors can involve the ovaries and have similar histologic appearances. The differential diagnosis is important for surgical and chemotherapeutic treatment and for the prognosis, but often it is extremely difficult. This article discusses an immunohistochemical panel that includes carcinoembryonic antigen (CEA), cytokeratin (CK) 7, CK20, CA125, CA19.9, and a new marker, CDX-2, for the distinction between primary ovarian mucinous carcinomas and metastatic (intestinal) ovarian tumors. Forty-three cases representing primary and secondary ovarian tumors were considered and consisted of 14 primary mucinous ovarian carcinomas (PMOCs) and 29 secondary (intestinal) ovarian tumors (SIOTs). Fisher exact test was performed to evaluate the reliability of the respective antibodies to discriminate between PMOCs and SIOTs. CDX-2 was diffusely positive in all SIOTs and was expressed focally in 3 cases (21.42%) of PMOCs. CK7 was diffusely positive in 13 cases (44.82%) of SIOTs and in 13 cases (92.85%) of PMOCs. CK20 was diffusely positive in 17 cases (58.62%) of SIOTs and in 6 cases (42.85%) of PMOCs. CEA was diffusely positive in 28 cases (96.55%) of SlOTs and in 12 cases (85.71%) of PMOCs. CA 19.9 was positive in all SIOTs and in 12 cases (85.71%) of PMOCs. CA125 was positive in 3 cases (10.34%) of SIOTs and in 4 cases (28.57%) of PMOCs. CK7 and especially CDX-2, a specific and sensitive marker, can aid pathologists in making a differential diagnosis (P = 0.003 and P < 0.0005, respectively), whereas CEA, CK20, CA125, and CA 19.9 markers are not high enough to distinguish between primary and secondary mucinous ovarian tumors.     

Distinction between hepatocellular carcinoma, cholangiocarcinoma, and metastatic carcinoma based on immunohistochemical staining for carcinoembryonic antigen and for cytokeratin 19 on paraffin sections

An antiserum to carcinoembryonic antigen (CEA) and a monoclonal antibody to cytokeratin 19 (CK 19) were studied for their suitability as diagnostic reagents for the differential diagnosis of primary and secondary malignant epithelial tumours of the liver, on paraffin sections. With the antiserum to CEA, positive bile canalicular structures were found in 60 per cent of the hepatocellular carcinomas. All the cholangiocarcinomas and 66.6 per cent of the metastatic carcinomas were positive for CEA, without displaying a canalicular staining pattern. All the hepatocellular carcinomas were negative for CK 19. All the cholangiocellular carcinomas and the metastatic carcinomas were positive for CK 19. This staining profile may prove helpful in difficult diagnostic cases.     

Cytokeratin 7 and cytokeratin 20 in primary urinary bladder carcinoma and matched lymph node metastasis.

BACKGROUND:-Cytokeratin 7 (CK7) and cytokeratin 20 (CK20) are 2 types of intermediate filament protein. Expression of CK7 is seen in the majority of primary urinary bladder carcinomas. CK20 is restricted to superficial and occasional intermediate cells of the normal urothelium of the bladder. Aberrant CK20 expression has been documented in urothelial carcinoma and has proved useful as an ancillary diagnostic aid for urinary bladder tumor. Our hypothesis is that the pattern of CK7 and CK20 expression in metastatic urothelial carcinoma duplicates the expression of the same markers in the primary tumors. Therefore, immunohistochemical staining of metastatic tumors for these 2 markers may be helpful for differential diagnosis in ambiguous metastatic tumor deposits. OBJECTIVE:-To determine the concordance of CK7 and CK20 expression in primary bladder urothelial carcinoma and the matched lymph node metastasis. DESIGN:-We studied 26 patients with lymph node metastases who underwent radical cystectomy and bilateral lymphadenectomy for bladder carcinoma. Immunohistochemical staining for CK7 and CK20 was performed on formalin-fixed paraffin-embedded tissues containing primary cancers and lymph node metastases. RESULTS:-In all cases, there was a concordant expression of CK20 in the primary cancer and its matched lymph node metastasis. Twelve cases (46%) showed positive CK20 immunoreactivity in the primary tumor and its matched lymph node metastases, whereas 14 cases (54%) were negative for CK20 in both the primary tumor and lymph node metastasis. All cases showed positive CK7 immunoreactivity in the primary cancers and matched lymph node metastases. CONCLUSIONS:-CK20 immunoreactivity is reliably observed in metastases from bladder cancer when the primary tumor expresses CK20.     

Expression of cytokeratins 7 and 20 in primary carcinomas of the stomach and colorectum and their value in the differential diagnosis of metastatic carcinomas to the ovary

The expressions of cytokeratin (CK) 7 and 20 have been studied in various primary and metastatic carcinomas, and their determination may help distinguish the site of origin of metastatic carcinomas. However, little is known about the factors that determine variations in their expression patterns in primary gastric and colorectal carcinomas. We investigated the expressions of CK7 and CK20 in 289 cases of gastric carcinoma and 225 cases of colorectal carcinoma using a tissue microarray. To evaluate CK7 and CK20 expression patterns of ovarian metastases from gastric or colorectal carcinomas, 54 cases of metastatic carcinomas to the ovary were examined. It was found that 71% (207 of 289) of the gastric carcinomas stained positively for CK7, whereas only 9% (21 of 225) of the colorectal carcinomas proved to be CK7 positive, and that 41% (117 of 289) of the gastric carcinomas and 73% (165 of 225) of the colorectal carcinomas were CK20 positive. The proportion of CK7+/CK20- was highest in the gastric carcinomas at 46% (132 of 289), and was independent of the histologic classification of Lauren (46% of the intestinal type, 45% of the diffuse type). The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histologic grade and location of the tumor. CK7-/CK20+ had the greatest proportion (68%) in colorectal carcinomas, and this was dependent on the tumor's histologic grade (75% of low-grade versus 52% of high-grade) and location (46% of right-sided versus 76% of left-sided). Moreover, 42% (18 of 43) of gastric carcinomas metastatic to the ovary were CK7+/CK20-, whereas 19% (8 of 43) were CK7-/CK20+. All colorectal cancers metastatic to the ovary were CK7-/CK20+, except 1 case that was CK7-/CK20-. In conclusion, the CK7 and CK20 expression patterns in primary gastric carcinomas vary considerably, and those in colorectal carcinomas are associated with histologic grade and tumor location. The CK7-/CK20+ expression pattern is specific for metastatic colorectal carcinomas to the ovary, but has low predictability for colorectal origin in metastatic ovarian carcinoma.     

Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours

AIMS: The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis. METHODS AND RESULTS: Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2). CONCLUSION: CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.     

Metastasis from papillary renal cell carcinoma masquerading as primary ovarian clear cell tumor

A 73-year-old female presented with a left ovarian tumor mass. Microscopic examination disclosed cystic spaces lined by abundant clear and eosinophilic tumor cells with pleomorphic nuclei. Differential diagnosis included primary ovarian oxyphilic-type clear cell carcinoma and sex-cord tumor with extensive luteinization. However, analysis of the patient's past history revealed that in 2003, she had undergone nephrectomy for a papillary renal cell carcinoma, and a histological comparison between the primary and the present tumor exhibited in the latter a substantially larger number of clear cells and loss of papillary architecture. Immunohistochemistry demonstrated a characteristic renal immunophenotype for a type II tubulopapillary tumor metastatic to ovary. The tumor cells were strongly positive for CD10 and AMACR, and negative for cytokeratin 7. This confirmed the renal origin of the ovarian tumor despite its divergent morphology of the renal primary. This is the first reported case of ovarian metastases of type II tubulopapillary carcinoma of the kidney.     

Metastatic ovarian carcinoma of large intestinal origin simulating primary ovarian carcinoma. A clinicopathologic study of 25 cases.

The distinction of metastatic ovarian carcinoma from a primary malignant ovarian neoplasm is crucial to its subsequent management. The most common metastatic carcinoma that mimics primary ovarian carcinoma is that of large bowel origin. The clinical and pathologic features of 25 cases of intestinal adenocarcinoma metastatic to the ovaries were analyzed. The patients ranged in age from 47 to 80 years (average age, 60 years). Most patients had abdominal pain and a pelvic mass. In 56%, the ovarian tumors and the large bowel carcinomas were discovered synchronously; 44% were metachronous. Seventy-five percent of the tumors were unilateral. Gross examination revealed that all the ovarian tumors were solid and cystic with smooth outer surfaces. Most of the tumors showed hemorrhage and necrosis. Histologic examination showed that 13 cases had a predominantly endometrioid-like pattern, four cases were predominantly mucinous, and the rest demonstrated a mixed pattern. The presence of a garland pattern with cribriform areas and "dirty" necrosis were the most distinctive features that were helpful in correctly differentiating these tumors from primary endometrioid ovarian carcinoma, with which they are often confused. Immunohistochemical stains for carcinoembryonic antigen showed strong intracytoplasmic positive staining in all the cases of intestinal adenocarcinoma metastatic to the ovaries, in contrast to primary ovarian endometrioid carcinoma, which stain negatively for carcinoembryonic antigen or show only intraluminal or apical positivity. As expected, intestinal adenocarcinoma metastatic to the ovaries had a very poor prognosis. Seventy percent of the patients died within a period of 1 to 19 months (average, 8.2 months). Its distinction from primary ovarian carcinoma is crucial because the management and prognosis of metastatic ovarian carcinoma of large intestine origin is different.     

Expression of cytokeratins 7 and 20 in ovarian neoplasia

To further delineate specific staining patterns and refine the differential usefulness of cytokeratin (CK) 7/20 staining, we studied multiple ovarian tumors and primary nongynecologic neoplasms likely to metastasize to the ovary. Immunohistochemical analysis with semiquantitative grading to give quartile scores (0-4) was performed on 127 cases. Subsequent analysis indicated that a more informative diagnostic segregation could be achieved with a biphasic grading system (>50% staining, positive; 50% or less, negative). Lower intestinal tumors were CK7- and usually CK20+, while upper gastrointestinal tumors, including those of pancreatobiliary origin, were mostly CK7+ and CK20-. Serous papillary ovarian tumors were all CK7+ and CK20-. Mucinous ovarian carcinomas were all CK7+ and slightly more often CK20-, whereas the small number of ovarian borderline mucinous tumors studied were the most problematic, with no clear pattern. Multiple different tumor types from all nonovarian gynecologic sites were fairly consistently CK7+ and almost always CK20-. Differential CK staining of mucinous tumors of the female genital tract using CK7 and CK20 is useful for predicting the site of origin, provided samples are adequate in size. The most specific usefulness is the identification of lower gastrointestinal vs "other" neoplasms.