Cytokeratins 7 and 20 in primary and secondary mucinous tumors of the ovary: analysis of coordinate immunohistochemical expression profiles and staining distribution in 179 cases

Coordinate expression profiles for cytokeratins 7 and 20 (CK7 and CK20) are useful for distinguishing certain types of adenocarcinomas but use for distinction of primary and secondary mucinous tumors in the ovary is limited due to the existence of a number of tumor types exhibiting overlapping CK7/CK20 immunoprofiles; the use of staining distribution patterns in the distinction of tumors with shared profiles has not been evaluated in detail. We report analysis of both coordinate expression profiles and staining distribution in 179 rigorously classified mucinous tumors in the ovary, including 53 primary tumors [35 atypical proliferative (borderline) mucinous tumors of gastrointestinal type and 18 invasive mucinous carcinomas] and 126 secondary tumors [28 colorectal adenocarcinomas, 54 appendiceal tumors (23 adenocarcinomas, 31 low-grade adenomatous mucinous tumors associated with pseudomyxoma peritonei), 14 pancreatic adenocarcinomas, 8 endocervical adenocarcinomas, 5 gastric adenocarcinomas, 4 gallbladder/biliary tract adenocarcinomas, and 13 adenocarcinomas of unknown primary sites). A CK7+/CK20+ immunoprofile was the most common profile in primary ovarian tumors (74%), upper gastrointestinal tract tumors (78%), and endocervical tumors (88%) but was occasionally observed in lower intestinal tract tumors (colorectal: 11%; appendiceal: 13% of low-grade tumors, 35% of carcinomas). A CK7-/CK20+ immunoprofile was the most common profile in lower intestinal tract tumors (79%) and was uncommon in upper gastrointestinal tract tumors (9%), rarely seen in primary ovarian tumors (4%), and not seen in endocervical tumors. A CK7+/CK20- profile was observed in some primary ovarian (23%), upper gastrointestinal tract (13%), and endocervical tumors (13%) but not in lower intestinal tract tumors. For CK7+ tumors, staining distribution was very frequently diffuse (>50% of tumors cells positive) in primary ovarian, upper gastrointestinal tract, and endocervical tumors, whereas staining distribution was often focal (<50% of tumors cells positive) when present in colorectal and appendiceal carcinomas but not in low-grade appendiceal tumors. For CK20+ tumors, staining distribution was variable but often focal in primary ovarian tumors and nonlower intestinal tract tumors, whereas the pattern was almost always diffuse in lower intestinal tract tumors. Immunohistochemical staining distribution can supplement CK7/CK20 coordinate expression profiles to distinguish subsets of primary ovarian and metastatic lower intestinal tract mucinous tumors having overlapping immunoprofiles but neither coordinate expression profiles nor staining distribution distinguishes primary ovarian tumors from the nonlower intestinal tract metastases.

Immunohistochemical distinction between merkel cell carcinoma and small cell carcinoma of the lung

We assessed the usefulness of several immunohistochemical stains in distinguishing these two neoplasms, including cytokeratin 7, cytokeratin 20 (CK20), neuron-specific enolase, chromogranin, synaptophysin, neurofilaments (NF), thyroid-transcription factor-1 (TTF-1), CD56 antigen, S-100 protein, vimentin, c-erbB-2 oncoprotein, and CD117 antigen. All 13 cases of Merkel cell carcinoma evaluated were positive for CK20, and negative for TTF-1. Twelve of 13 Merkel cell carcinoma cases were positive for NF. Eleven of 13 cases of small cell lung carcinoma were positive for TTF-1. All small cell lung carcinoma cases were negative for NF, and all but one were negative for CK20. In terms of the remaining antigens, there were no differences of significance between the two neoplasms. These findings suggest that a set of three immunohistochemical stains, including CK20, NF, and TTF-1, is useful in affording a distinction between Merkel cell carcinoma and small cell lung carcinoma.

The clinicopathological and prognostic relevance of cytokeratin 7 and 19 expression in hepatocellular carcinoma. A possible progenitor cell origin

AIMS

Cytokeratin (CK) 7 and CK19 expression, present in hepatic progenitor cells (HPCs) and in cholangiocytes but not in normal hepatocytes, has been reported in some hepatocellular carcinomas (HCCs); however, the incidence and relevance of this expression in HCC in Caucasians is not known. Therefore, our aim was to study the occurrence and clinicopathological characteristics of HCC expressing CK7 and/or CK19 in 109 Caucasian patients.

METHODS AND RESULTS

The expression of hepatocellular differentiation markers (Hepar, canalicular polyclonal carcinoembryonic antigen), biliary/progenitor cell markers (CK7, CK19), alpha-fetoprotein (AFP), p53 and beta-catenin in HCC was semiquantitatively assessed by immunohistochemistry. Of 109 HCCs, 78 were CK7-/CK19- (72%), 13 CK7+/CK19- (12%), seven CK7-/CK19+ (6%), 11 CK7+/CK19+ (10%). CK19 expression was significantly associated with elevated serum AFP (400 ng/ml) (P = 0.023), tumour AFP expression (P < 0.0001), presence in serum of anti-hepatitis B core (P = 0.016), less fibrosis in non-neoplastic parenchyma (P = 0.009) and less nuclear beta-catenin expression (P = 0.021). CK7 expression was significantly associated with elevated serum bilirubin (> 2 mg/dl) (P = 0.0005) and less nuclear beta-catenin expression (P = 0.003). HCC expressing CK19 had a higher rate of recurrence (P = 0.009, hazard ratio 12.5, n = 31) after liver transplantation compared with CK19- tumours.

CONCLUSIONS

In our series, 28% of HCCs contained cells expressing CK7 and/or CK19. They potentially derive from HPCs. The higher recurrence rate of CK19+ HCC after transplantation suggests a worse prognosis for these HCCs compared with CK19- HCC.

Dimethylarginine dimethylaminohydrolase (DDAH) regulates trophoblast invasion and motility through effects on nitric oxide

BACKGROUND

Invasion of trophoblast into the uterine environment is crucial for establishing a successful pregnancy. Physiological production of nitric oxide (NO) by extravillous trophoblasts results in significant pro-invasive effects. NO synthesis is competitively inhibited by methylated arginine analogues such as asymmetric dimethylarginine (ADMA) but not the enantiomer symmetric dimethylarginine (SDMA). Within cells, the concentration of ADMA is regulated by the activity of the enzyme dimethylarginine dimethylaminohydrolase (DDAH). The aim of this study was to examine DDAH expression and function in trophoblasts.

METHODS AND RESULTS

DDAH-1 and DDAH-2 messenger RNA and protein were demonstrated in first trimester placental tissue, primary extravillous trophoblasts and extravillous trophoblast-derived cell lines. DDAH activity was demonstrated in both cells and tissue. Overexpression of DDAH-1 in trophoblasts led to a number of significant changes, including an 8-fold increase in enzymatic activity, a 59% decrease in production of ADMA (but not SDMA), a 1.9-fold increase in NO and a 1.6-fold increase in cyclic guanosine monophosphate (cGMP) production. Functional assays showed that increased DDAH activity led to significantly increased cell motility and invasion in response to hepatocyte growth factor (HGF).

CONCLUSIONS

DDAH may play an important role in the regulation of extravillous trophoblast function via its effects on ADMA and NO production.

OPC-12759 increases proliferation of cultured rat conjunctival goblet cells

PURPOSE

To determine if the gastroprotective drug OPC-12759 increased proliferation of rat conjunctival goblet cells in culture.

METHODS

Cultured goblet cells were incubated with 10(-12) to 10(-8) M OPC-12759 for 1 to 7 days. Fetal bovine serum (FBS) was used as a positive control. Cell proliferation was determined by a MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay and by immunohistochemical staining with anti-Ki-67, a marker of cell division. Goblet cells were identified by double-labeling with anti-Ki-67, a marker of cell division, and Ulex europaeus agglutinin I lectin, anti-MUC5AC and anticytokeratin 7. Stratified squamous cells were identified by using Griffonia (Bandeiraea) simplicifolia lectin and anticytokeratin 4 antibody.

RESULTS

As determined by MTT conversion to formazan, OPC-12579 at 10(-11) M induced an almost 2-fold increase in goblet cell proliferation on Days 1 and 3 of incubation but not on Days 5 and 7. The FBS at 10% increased cell proliferation by 2- to 3-fold at each time point. Daily replenishment of OPC-12579 for 3 consecutive days induced cell proliferation at all concentrations. Proliferation as determined by the number of Ki-67 positive cells increased by 4- and 3-fold at Days 1 and 3, respectively with addition of 10(-11) M OPC-12579. The FBS at 10% induced a 10-fold increase in goblet cell proliferation on Days 1, 3, and 5. Colocalization of Ulex europaeus agglutinin I, MUC5AC and anticytokeratin 7 with Ki-67 indicated that proliferating cells were goblet cells. Proliferating cells were negative for the nongoblet cell markers Bandeiraea lectin and anticytokeratin 4.

CONCLUSIONS

The OPC-12759 stimulates proliferation of conjunctival goblet cells in primary culture.

Long-term survival after incomplete resection of immunohistochemically diagnosed T0N1 lung cancer: report of a case

A 63-year-old man who had undergone resection of colon cancer 15 years previously was found to have a right hilar mass on chest X-ray, and an elevated serum carcinoembryonic antigen level. The hilar lymph nodes were resected with the right upper lobe, and the initial diagnosis was colon cancer metastasis to the right hilar lymph nodes. Although the resection was incomplete, and no additional treatment was given, the patient remained free of recurrence for 10 years. This prompted us to reconsider our diagnosis using immunohistochemistry. The resected lymph nodes were found to be positive for thyroid transcription factor 1 (TTF-1) and cytokeratin 7, and negative for surfactant apoprotein (SAP), cytokeratin 20, and napsin A. The neuroendocrine markers and thyroglobulin were also negative. These findings led us to diagnose T0N1 lung cancer. There are reports of patients with clinical T0N1,2 lung cancer having exceptionally good prognoses despite noncurative treatment; however, to our knowledge, this is the first case of a patient with T0N1 lung cancer diagnosed by immunohistochemistry, with a good prognosis despite incomplete resection. In this case, TTF-1 and cytokeratin staining was particularly helpful in the differential diagnosis.

Diagnostic value of cytokeratin 7 and parvalbumin in differentiating chromophobe renal cell carcinoma from renal oncocytoma

OBJECTIVE

To investigate the diagnostic value of cytokeratin 7 (CK7) and parvalbumin at mRNA and protein levels.

STUDY DESIGN

CK7 and parvalbumin mRNA expression levels in 23 oncocytomas and 32 chromophobe renal cell carcinomas (RCCs) were examined using gene expression microarrays. Immunohistochemistry was performed using monoclonal antibodies specific for CK7 or parvalbumin in 41 chromophobe RCCs and 55 oncocytomas.

RESULTS

CK7 mRNA was overexpressed in 18 of 32 chromophobe RCCs but only 3 of 23 oncocytomas. Parvalbumin mRNA was overexpressed in 15 of 32 chromophobe RCCs and only 4 of 23 oncocytomas. In contrast, CK7 mRNA underexpression was noted in 13 of 23 oncocytomas and only 6 of 32 chromophobe RCCs, while parvalbumin underexpression was seen in 14 of 23 oncocytomas but only 6 of 32 chromophobe RCCs. By immunohistochemistry, 27 of 41 (66%) chromophobe RCCs expressed CK7 diffusely compared to only 3 of 55 (5%) oncocytomas. Diffuse parvalbumin expression was seen in all 41 of 41 (100%) chromophobe RCCs and only in 26 of 55 (47%) oncocytomas.

CONCLUSION

Both mRNA and protein expression levels of CK7 appear significantly higher in chromophobe RCC compared to oncocytoma (p < 0.001). Parvalbumin expression is less specific but often displays a patchy pattern in oncocytomas. Our study provides further evidence that CK7 and parvalbumin immunostains may be useful in differentiating oncocytoma from chromophobe RCC in problematic cases. Negative or patchy staining (< 50% cells) for CK7 and/or parvalbumin strongly favors the diagnosis of oncocytoma.

Ectopic expression of neurogenin 3 in neonatal pig pancreatic precursor cells induces (trans)differentiation to functional alpha cells

AIMS/HYPOTHESIS

Neurogenin 3 (NEUROG3), a basic helix-loop-helix transcription factor that is needed for endocrine cell development in the embryonic pancreas, has been shown to induce transdifferentiation of duct cells from adult pancreas towards a neuro-endocrine phenotype. Our study explored the endocrine transdifferentiation potential of NEUROG3 in neonatal pancreatic precursor cells.

MATERIALS AND METHODS

A replication-deficient adenovirus expressing Neurog3 and green fluorescent protein (GFP) (Ad-NEUROG3) was used to infect neonatal pig pancreatic cell preparations enriched for endocrine islet and cytokeratin-positive precursor cells. GFP-positive cells were sorted using flow cytometry on days 3 and 8 after infection and characterised at the transcript and protein level. For in vivo experiments, the total population of Ad-NEUROG3-infected pancreatic cells was transplanted, then later removed for determination of graft hormone content and immunohistochemistry.

RESULTS

Among the GFP-positive cells, the fraction of precursor cells decreased by more than 85% at day 8 after infection, while the fraction of glucagon-positive cells increased 2.5-fold and the beta cell number remained the same. Transplantation of the Ad-NEUROG3-infected pancreatic cell preparation failed to reverse streptozotocin-induced hyperglycaemia, while non-infected cells and a control cell preparation infected with replication-deficient adenovirus expressing only GFP were able to do so. At day 109 after transplantation, kidneys grafted with Ad-NEUROG3-infected pancreatic cells contained significantly decreased insulin and increased glucagon levels. Abundant glucagon-immunopositive cells were seen in Ad-NEUROG3-infected grafts, which were virtually devoid of proliferating insulin-positive cells.

CONCLUSIONS/INTERPRETATION

In summary, adenoviral delivery of NEUROG3 to pancreatic precursor cells from neonatal pig pancreas promotes alpha cell differentiation in vitro and in vivo.

Intestinal adenocarcinoma arising in a mature cystic teratoma of the ovary: A case report

Gastrointestinal adenocarcinoma arising in mature cystic teratomas of the ovary is extremely rare. We report a case of well-differentiated intestinal adenocarcinoma arising in a mature cystic teratoma of the ovary in a 77-year-old woman, presenting as acute abdomen with ovarian torsion. An immunohistochemical study revealed expression of CK20 and CK7, and the tumor was also positive for MUC2. The patient had no evidence of disease after 12 months of follow-up.

[Female genital tract polyneoplasia: primary multiple neoplasms or metastases?]

The analysis of 49 cases of synchronous and metachronous malignant mucinous tumors of the colon (rectum) and ovaries in the patients treated in 1990 to 2004 again has confirmed the data that metastatic ovarian cancer occurs from a primary focus in the colorectal region. Immunohistochemical studies (using cytokeratin 7 and cytokeratin 20) may be used in the differential diagnosis of ovarian mucinous ovarian carcinoma from metastatic colonic mucinous tumors.

Identification of biomarkers of human pancreatic adenocarcinomas by expression profiling and validation with gene expression analysis in endoscopic ultrasound-guided fine needle aspiration samples

AIM: To compare gene expression profiles of pancreatic adenocarcinoma tissue specimens, human pancreatic and colon adenocarcinoma and leukemia cell lines and normal pancreas samples in order to distinguish differentially expressed genes and to validate the differential expression of a subset of genes by quantitative real-time RT-PCR (RT-QPCR) in endoscopic ultrasound-guided fine needle aspiration (EUS-guided FNA) specimens.

METHODS: Commercially dedicated cancer cDNA macroarrays (Atlas Human Cancer 1.2) containing 1176 genes were used. Different statistical approaches (hierarchical clustering, principal component analysis (PCA) and SAM) were used to analyze the expression data. RT-QPCR and immunohistochemical studies were used for validation of results.

RESULTS: RT-QPCR validated the increased expression of LCN2 (lipocalin 2) and for the first time PLAT (tissue-type plasminogen activator or tPA) in malignant pancreas as compared with normal pancreas. Immunohistochemical analysis confirmed the increased expression of LCN2 protein localized in epithelial cells of ducts invaded by carcinoma. The analysis of PLAT and LCN2 transcripts in 12 samples obtained through EUS-guided FNA from patients with pancreatic adenocarcinoma showed significantly increased expression levels in comparison with those found in normal tissues, indicating that a sufficient amount of high quality RNA can be obtained with this technique.

CONCLUSION: Expression profiling is a useful method to identify biomarkers and potential target genes. Molecular analysis of EUS-guided FNA samples in pancreatic cancer appears as a valuable strategy for the diagnosis of pancreatic adenocarcinomas.

Immunohistochemical differential diagnosis between large cell neuroendocrine carcinoma and small cell carcinoma by tissue microarray analysis with a large antibody panel

To elucidate additional phenotypic differences between large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC), we performed tissue microarray (TMA) analysis of surgically resected LCNEC and SCLC specimens. Immunostaining with 48 antibodies was scored based on staining intensity and the percentage of cells that stained positively. Four proteins were identified as significantly expressed in LCNEC as compared with SCLC: cytokeratin (CK)7, 113 vs 49 (P < .0301); CK18, 171 vs 60 (P < .0008); E-cadherin, 77 vs 9 (P < .0073); and beta-catenin, 191 vs 120 (P < .0286). Immunostaining of cross-sections containing LCNEC and SCLC components revealed significant expression of CK7, CK18 and beta-catenin in the LCNEC component compared with the SCLC component in 2 of 3 cases. Our results indicate that significant expression of CK7, CK18, E-cadherin, and beta-catenin is more characteristic of LCNEC than of SCLC, and these findings provide further support that these tumor types are separate entities morphologically and immunophenotypically, if not biologically.

Gastric signet-ring adenocarcinoma presenting with breast metastasis

Breast metastases from gastric cancer are extremely rare. A case report of a 37-year-old female with breast inflammatory invasion and ascites is described. Breast biopsy revealed carcinomatous invasion of the lymphatics from adenocarcinoma cells with signet-ring features. Estrogen (ER) and progesterone receptors (PR) and c-erb-B2 were negative. Upper gastrointestinal endoscopy revealed a prepyloric ulcerative mass. Histopathologic examination of the lesion showed infiltration from a high-grade adenocarcinoma, identical with that of the breast. Immunostaining was positive for cytokeratins CK-7 and CK-20 and CEA and negative for ER and PR. Ascitic fluid cytology was positive for adenocarcinoma cells. Mammography was not diagnostic. Abdominal CT scanning revealed large ovarian masses suggestive of metastases (Krukenberg’s tumor). A cisplatin-based regimen was given but no objective response was observed. The patient died six months after initial diagnosis. A review of the literature is performed.

Adenomyoma with goblet and Paneth cells of the ileum

A case of ileal adenomyoma with goblet and Paneth cells is reported. A 75-year-old man died of ruptured hepatocellular carcinoma. As an incidental finding at autopsy, a 9 x 7 x 6 mm(3)-sized nodule was found in the ileal wall. Histologically, the lesion occupied the submucosa and muscularis propria, and consisted of glandular structures of various sizes and interlacing smooth muscle bundles surrounding the glandular elements. Goblet cells and Paneth cells were interspersed in the glandular element. Immunohistochemically, the glandular element was positive for cytokeratin (CK) 7 and negative for CK 20. This is the first reported case of adenomyoma of the gastrointestinal tract that contained Paneth cells. The result of the immunohistochemical staining favored the heterotopic pancreas theory concerning its pathogenesis. The appearance of goblet and Paneth cells might be the result of metaplasia.

Lack of evidence that bone marrow cells contribute to cholangiocyte repopulation during experimental cholestatic ductal hyperplasia

BACKGROUND

Ductopenia is observed in end-stage human cholestatic diseases. The limited capability of cholangiocytes for proliferation is suggested to be the principal reason. Recently, bone marrow cells (BMCs) have been reported to behave as hepatic stem cells; however, their capability to differentiate into cholangiocytes in cholestasis remains unclear.

METHODS

Normal mice were lethally irradiated to suppress the proliferation of self-BMCs; thereafter, the BMCs from enhanced green fluorescent protein (EGFP)-transgenic mice were transferred to recipients. Chronic cholestasis was induced by 0.1%alpha-naphtylisothiocyanate (ANIT) feeding. The proliferation of cholangiocytes and oval cells was assessed morphologically and immunohistchemically (cytokeratin-7 (CK-7), A6). Proliferative activity (proliferating cell nuclear antigen (PCNA) protein expression), hepatic growth factor (HGF) receptor (c-Met), stem cell factor receptor (c-kit), Notch2 and Hes1 expression were also evaluated.

RESULTS

Marked cholangiocyte proliferation was observed in ANIT-fed mice. However, no EGFP/CK-7 double positive cells were identified in any of the liver specimens after BMCs transfer (Tx). In hepatic parenchyma, there were scattered EGFP-positive cells, although none of them were positive for CK-7.

CONCLUSIONS

In spite of the significant ductular proliferations after ANIT feeding, no EGFP-positive cholangiocytes were confirmed by any other means in this chronic cholestasis model. Thus, different from hepatocytes, BMCs Tx seems not to contribute to the differentiation of cholangiocytes. Future studies are feasible to clarify the origin of proliferative cholangiocytes observed in this chronic cholestatic ductular hyperplasia model.

Expression of p63, keratin 5/6, keratin 7, and surfactant-A in non–small cell lung carcinomas

In this study, we sought to validate the importance of p63, CK5/CK6, CK7, and surfactant-A (SP-A) to classify 42 non-small cell lung cancers in autopsy and surgical resection specimens and to study the usefulness of these markers in distinguishing between squamous cell carcinomas and adenocarcinomas because of their different implications regarding treatment and prognosis. All adenocarcinoma cases were negative for p63; 9 (56.2%) of 16 were CK5/CK6 positive, 16 (94.1%) of 17 were CK7 positive, and 4 (26.6%) of 15 were SP-A positive. In squamous cell carcinoma, 1 case was CK7 and SP-A positive and 14 (77.8%) of 18 were p63 positive. The latter appears to be useful in differentiating squamous cell carcinoma from adenocarcinoma of the lung in small biopsies without keratinization or glandular differentiation; thus, for advanced-stage cases, where there is no possibility of surgical resection and the treatment of choice is radiotherapy plus chemotherapy, we would be able to differentiate between the two histological types, establishing then a different therapy.

Metastatic colon cancer from intrahepatic cholangiocarcinoma

A 62-year-old man had been followed because of an elevated serum level of carcinoembryonic antigen without the detection of any cancer lesions. However, there was a sudden increase in the serum level of carcinoembryonic antigen, and abdominal imagings showed a hepatic tumor with peripheral intrahepatic bile duct dilatation, and a submucosal tumor at the sigmoid colon with intact mucosa. Histopathological findings showed that the hepatic tumor had perineural invasion, suggesting an intrahepatic cholangiocarcinoma, and that the colon tumor infiltrated the submucosa, while its mucosa was intact. Both tumors showed similar pathological features and were positive for cytokeratin 20 and 7. These findings suggested intrahepatic cholangiocarcinoma with metastatic sigmoid colon cancer.

Role of TTF-1, CK20, and CK7 immunohistochemistry for diagnosis of primary and secondary lung adenocarcinoma

Thyroid transcription factor-1 (TTF-1), and cytokeratin 7 (CK7) and cytokeratin 20 (CK20) have recently been reported to be useful to distinguish between primary and metastatic lung adenocarcinoma. The aim of this study was to determine the usefulness of the staining patterns of pulmonary adenocarcinoma with antibodies to TTF-1, CK7, and CK20 in differentiating primary from metastatic pulmonary adenocarcinoma. Of the 66 lung adenocarcinoma specimens that were enrolled in our study, there were 40 primary lung adenocarcinomas, 12 metastatic adenocarcinomas from breast, 13 metastatic adenocarcinomas from colon, and 1 metastatic adenocarcinoma from stomach. The expression of TTF-1, CK7, and CK20 was assessed by immunohistochemistry. We found that 73% of primary lung adenocarcinomas expressed TTF-1, whereas all nonpulmonary adenocarcinomas lacked TTF-1 staining. CK7 expression was significantly more frequent in adenocarcinomas of pulmonary and breast origin than gastrointestinal (GI) origin (p < 0.001). In contrast, CK20 expression was significantly more prevalent in adenocarcinoma that originated in the GI tract than that of pulmonary or breast origin (p < 0.001). A combination of TTF-1+CK7+CK20- was highly significantly associated with primary adenocarcinoma of lung (vs GI tract, p < 0.001; vs breast, p < 0.001). A combination of TTF-1-CKCK20+ was highly significantly associated with adenocarcinoma of GI origin (vs lung, p < 0.001; vs breast, p < 0.001). Our study has confirmed that expression of CK7, CK20, and TTF-1 is a useful immunohistochemical marker for diagnosis of lung tumors and for differential diagnosis of primary pulmonary adenocarcinomas from extrapulmonary adenocarcinomas metastatic to the lung. Application of this panel of antibodies might be expected to increase the accuracy of diagnosis.

Metastatic chest wall tumor suspected to be of lung origin by immunoreactivity for cytokeratin 7 and 20

We report a rare case of unknown primary carcinoma. A 36-year-old man was admitted to the hospital because of a chest wall tumor. Serum carcinoembryonic antigen level was 160 ng/ml. The resected chest wall tumor was pathologically diagnosed as metastatic adenocarcinoma, showing positive immunoreactivity for cytokeratin 7 and negative immunoreactivity for cytokeratin 20, suggesting lung origin. Serum carcinoembryonic antigen level returned to normal limits. Twenty-one months later, a chest X-ray showed a nodular lesion in the left upper lobe and serum carcinoembryonic antigen level increased to 12.3 ng/ml. Left upper lobectomy was performed 23 months after chest wall resection. The resected tumor was pathologically diagnosed as primary lung adenocarcinoma, showing the same immunoreactivity as in the chest wall tumor. The combination of immunohistochemistry for cytokeratin 7 and 20 appeared to be a useful tool in determining the site of origin and helpful for premortem diagnosis of the origin of unknown primary carcinoma.

Cytokeratin 7/20 and mucin core protein expression in ulcerative colitis-associated colorectal neoplasms

Different histogenetic pathways have been suggested between ulcerative colitis (UC)-associated neoplasia and sporadic colorectal neoplasia. Little is known about the cytokeratin (CK) and mucin expression in UC-associated neoplasms. To clarify the characteristics of UC-associated colorectal carcinogenesis, we examined the immunohistochemical expression of CK7, CK20, MUC2, MUC5AC and MUC6 in 90 colorectal neoplasms, including 22 UC-associated adenocarcinomas (colitic cancer; CC), ten high-grade dysplasias (HGD) in UC, nine low-grade dysplasias (LGD) in UC, 24 sporadic tubular adenomas (TA) and 25 adenocarcinomas (AC). CK7 was positive in most of UC-associated neoplasms: 59% of CC cases, 80% of HGD and 89% of LGD, respectively, whereas, in non-UC associated neoplasia, 21% of TA and 12% of AC. The frequency of MUC6 expression in UC-associated neoplasia was 32% in CC, 30% in HGD and 44% in LGD, respectively, whereas, in non-UC associated neoplasia, 4.2% in TA and 0% in AC. MUC5AC expression in UC-associated neoplasia was detectable in 73% of CC, 90% of HGD and 89% of LGD, respectively; in non-UC associated neoplasia 67% in AC and 20% in TA. There were obvious differences in the expression of CK7 and MUC6 between UC-associated neoplasms and sporadic tumors. The incidence of MUC5AC expression in UC-associated neoplasms was also higher than sporadic tumors. These results suggest that gastric-type mucins play an important role in the initial step of CC-tumorigenesis, and CK7 and gastric-type mucins may be useful in the differential diagnosis between UC-associated neoplasms and sporadic ones.