Proposal for a new classification for perihilar cholangiocarcinoma based on tumour depth.

BACKGROUND: The T system for distal cholangiocarcinoma has been revised from a layer-based to a depth-based approach in the current American Joint Committee on Cancer (AJCC) classification. In perihilar cholangiocarcinoma, tumour depth in the staging scheme has not yet been addressed. The aim of this study was to propose a new T system using measured tumour depth in perihilar cholangiocarcinoma. METHODS: Patients who underwent hepatectomy for perihilar cholangiocarcinoma between 2001 and 2014 were reviewed retrospectively. The vertical distance between the top of the tumour and deepest invasive cells was measured as invasive tumour thickness (ITT) by two independent pathologists. Log rank statistics were used to determine cut-off points, and the concordance (C) index was used to assess survival discrimination of each T system. RESULTS: ITT was measurable in all 440 patients, with a median value of 6·0 (range 0-45) mm. The median difference in ITT between observers was 0·6 (range 0-20) mm. Cut-off points for prognosis were 1, 5 and 8 mm. Five-year survival decreased with increasing ITT (P < 0·001): 67 per cent for ITT less than 1 mm (25 patients), 54·9 per cent for ITT 1 mm and over to less than 5 mm (138 patients), 43·4 per cent for ITT 5 mm and over to less than 8 mm (118 patients), and 32·2 per cent for ITT 8 mm and over (159 patients). The C-index of this classification was comparable to that of the current AJCC T classification (0·598 versus 0·589). CONCLUSION: ITT is a reliable approach for making a depth assessment in perihilar cholangiocarcinoma. A four-tier ITT classification with cut-off points of 1, 5 and 8 mm is an adequate alternative to the current layer-based T classification.

Clinical value of additional resection of a margin-positive distal bile duct in perihilar cholangiocarcinoma.

BACKGROUND: Little is known about the effect of additional resection for a frozen-section-positive distal bile duct margin (DM) in perihilar cholangiocarcinoma. METHODS: Patients who underwent surgical resection for perihilar cholangiocarcinoma between 2001 and 2015 were analysed retrospectively, focusing on the DM. RESULTS: Of 558 consecutive patients who underwent frozen-section examination for a DM, 74 (13·3 per cent) had a frozen-section-positive DM with invasive cancer or carcinoma in situ. Eventually, 53 patients underwent additional resection (bile duct resection in 44 and pancreatoduodenectomy in 9), whereas the remaining 21 patients did not. Ultimately, R0 resection was achieved in 30 of the 53 patients (57 per cent). No patient who underwent additional resection died from surgical complications. The 44 patients with additional bile duct resection had a 5-year overall survival rate of 31 per cent. Overall survival of the nine patients who had pancreatoduodenectomy was better, with a 10-year rate of 67 per cent. Survival of the 21 patients without additional resection was dismal: all died within 5 years. Multivariable analyses identified nodal status and additional resection as independent prognostic factors (lymph node metastasis: hazard ratio (HR) 2·26, 95 per cent c.i. 1·26 to 4·07; bile duct resection versus no additional resection: HR 0·32, 0·17 to 0·60; pancreatoduodenectomy versus no additional resection: HR 0·08, 0·02 to 0·29). CONCLUSION: Additional resection for frozen-section-positive DM in perihilar cholangiocarcinoma frequently yields R0 margins. It offers a better chance of long-term survival, and thus should be performed in carefully selected patients.

Benign hilar bile duct strictures resected as perihilar cholangiocarcinoma.

BACKGROUND: Differentiation between perihilar cholangiocarcinoma (PHCC) and benign strictures is frequently difficult. The aim of this study was to investigate the incidence and long-term outcome of patients with tumours resected because of suspicion of PHCC, which ultimately turned out to be benign (malignancy masquerade). METHODS: Patients who underwent surgical resection with a diagnosis of PHCC between 2001 and 2016 were reviewed retrospectively. RESULTS: Among 707 consecutive patients, 685 had PHCC and the remaining 22 (3·1 per cent) had benign biliary stricture. All patients with benign disease underwent major hepatectomy, with no deaths. Preoperative histological assessment using bile duct biopsy or aspiration cytology had a high specificity (90 per cent), low sensitivity (62 per cent) and unsatisfactory accuracy (63 per cent). Despite the increasing use of histological assessment, the incidence of benign strictures resected did not decrease over time, being 0·9 per cent in 2001-2004, 4·0 per cent in 2005-2008, 3·8 per cent in 2009-2012 and 2·9 per cent in 2013-2016. The final pathology of benign strictures included IgG4-related sclerosing cholangitis (9 patients), hepatolithiasis (4), granulomatous cholangitis (3), non-specific chronic cholangitis (3), benign strictures after cholecystectomy (2), and a benign stricture possibly caused by parasitic infection (1). The 10-year overall survival rate for the 22 patients with benign stricture was 87 per cent, without recurrence of biliary stricture. CONCLUSION: The incidence of benign strictures resected as PHCC as a proportion of all resections was relatively low, at 3·1 per cent. Currently, unnecessary surgery for suspected PHCC is unavoidable.

ANTECEDENTES: La diferenciación entre colangiocarcinoma perihilar (perihilar colangiocarcinoma, PHCC) y estenosis benignas es con frecuencia difícil. El objetivo de este estudio fue investigar la incidencia y el resultado a largo plazo de los tumores resecados con sospecha diagnóstica de PHCC, que finalmente resultaron ser benignos (malignidad enmascarada). MÉTODOS: Se revisaron retrospectivamente los pacientes con diagnóstico de PHCC que se sometieron a resección quirúrgica entre 2001 y 2016. RESULTADOS: Entre 707 pacientes consecutivos, 685 pacientes presentaban PHCC y los 22 restantes (3,1%) tenían una estenosis biliar benigna. Todos los pacientes con patología benigna se sometieron a una hepatectomía mayor, sin mortalidad. La evaluación histológica preoperatoria mediante biopsia de conducto biliar o citología por aspiración tuvo una alta especificidad (90%), una baja sensibilidad (62%) y una exactitud diagnóstica insatisfactoria (63%). A pesar del uso creciente de la evaluación histológica, la incidencia de estenosis benignas resecadas no disminuyó con el tiempo, con un 0,9% en 2001-2004, un 4,0% en 2005-2008, un 3,8% en 2009-2012 y un 2,9% en 2013-2016. La patología final de las estenosis benignas incluyó colangitis esclerosante relacionada con IgG4 (n = 9), hepatolitiasis (n = 4), colangitis granulomatosa (n = 3), colangitis crónica no específica (n = 3), estenosis benignas tras una colecistectomía (n = 2) y una estenosis benigna posiblemente causada por una infección parasitaria (n = 1). Los resultados a largo plazo de los 22 pacientes con estenosis benigna fueron mejores (tasa de supervivencia a 10 años; 87,4%) sin recidiva de la estenosis biliar. CONCLUSIÓN: La incidencia de pacientes con estenosis benignas resecadas como PHCC en comparación con todas las resecciones fue relativamente baja, del 3,1%. Actualmente, la cirugía "innecesaria" por sospecha de PHCC es inevitable.

Role of anatomical right hepatic trisectionectomy for perihilar cholangiocarcinoma.

BACKGROUND: Right-sided hepatectomy is often selected for perihilar cholangiocarcinoma because the extrahepatic portion of the left hepatic duct is longer than that of the right hepatic duct. However, the length of resected left hepatic duct in right-sided hepatectomy has not been reported. METHODS: Patients who underwent right-sided hepatectomy for perihilar cholangiocarcinoma were reviewed retrospectively. Trisectionectomies were performed according to a previously reported technique of anatomical right hepatic trisectionectomy. Right hepatectomy was performed according to standard operative procedures. The length of resected left hepatic duct was measured. RESULTS: Thirty-three patients underwent right trisectionectomy and 141 had a right hemihepatectomy. Patients having a trisectionectomy had more advanced tumours and so required combined portal vein resection more frequently. Duration of surgery and blood loss were similar in the two groups. Morbidity and mortality rates tended to be higher following hemihepatectomy than after trisectionectomy. The mean(s.d.) length of resected left hepatic duct was significantly greater in trisectionectomy than in hemihepatectomy (25·0(6·9) versus 14·8(5·3) mm; P < 0·001). In patients with Bismuth type IV tumours, the percentage of negative left hepatic duct margins was significantly higher for trisectionectomy than for hemihepatectomy (89 versus 57 per cent; P = 0·021). Achievement of R0 resection was similar and survival did not differ between the two groups, despite different tumour load. CONCLUSION: Compared with right hemihepatectomy, anatomical right hepatic trisectionectomy provides a greater length of resected hepatic duct, leading to a high proportion of negative proximal ductal margins even in patients with Bismuth type IV tumours.

Uterine sutures at prior caesarean section and placenta accreta in subsequent pregnancy: a case-control study.

OBJECTIVE: To clarify the effects of uterine myometrial suture techniques at prior caesarean section on the incidence of pathologically diagnosed placenta accreta in placenta praevia with prior caesarean section (PPPC). DESIGN: Case-control study. SETTING: Eleven tertiary referral hospitals in central Japan. POPULATION: A total of 98 cases of placenta praevia, a history of one or more prior caesarean sections, and a history of uterine transverse incision and usage of only absorbable thread for myometrial sutures at the prior caesarean section. Exclusions were a history of myomectomy or Strassmann's operation. METHODS: Cases were grouped into a pathologically diagnosed placenta accreta group (38 cases) and a no accreta group (60 cases). Clinical characteristics including uterine suture methods at prior caesarean section were compared (single-layer versus double-layer closure; continuous versus interrupted sutures in the inner myometrial layer). MAIN OUTCOME MEASURE: The incidence of placenta accreta. RESULTS: No difference was found comparing single-layer with double-layer closure in the incidence of placenta accreta (37.1 versus 39.7%, P = 0.805); however, a significant difference was found comparing continuous with interrupted sutures (58.1 versus 29.9%, P = 0.008). Multivariable logistic regression analysis with stepwise selection for the eight factors meeting the criterion of P < 0.10 in univariate analysis was used, and four independent factors were selected, as follows: gravidity ≥ 3 (adjusted odds ratio, aOR, 3.4, 95% confidence interval, 95% CI, 0.99-11.6, P = 0.050); total praevia (versus non-total, aOR 18.4, 95% CI 3.2-107.0, P = 0.001); anterior/centre placenta (versus posterior, aOR 16.4, 95% CI 3.7-72.2, P < 0.001); and continuous sutures (versus interrupted, aOR 6.0, 95% CI 1.4-25.2, P = 0.015). CONCLUSIONS: In this limited study, a history of continuous sutures on the inner side of the uterine wall showed potential to influence the development of placenta accreta in PPPC patients.

Gastrointestinal symptoms in idiopathic pulmonary fibrosis patients treated with pirfenidone and herbal medicine.

Pirfenidone is an antifibrotic agent for patients with pulmonary fibrosis, but this drug has adverse gastrointestinal (GI) effects. The first aim of this study was to assess GI symptoms due to pirfenidone by using a new questionnaire for reflux symptoms and dismotility symptoms. Whether adding herbal medicine of rikkunshi-to improved GI symptoms due to pirfenidone therapy was also investigated. This was a randomized controlled trial performed on 17 IPF patients. The patients were assigned to two groups, and the study period was 8 weeks. The pirfenidone group received pirfenidone therapy for 8 weeks with add-on rikkunshi-to from 4 weeks, while the control group did not receive either of these agents. To assess the effects of RK, plasma levels of acyl-ghrelin and des-acyl-ghrelin, serum KL-6 and surfactant protein-D, and pulmonary function tests were monitored. GI symptoms were most severe during the initial 2 weeks of pirfenidone therapy at a dose of 600 mg/day. Both reflux symptoms and dismotility symptoms deteriorated. Rikkunshi-to improved GI symptoms to the level prior to pirfenidone therapy. Plasma levels of des-acyl-ghrelin and acyl-/des-acyl-ghrelin ratio changed significantly at 8 weeks compared to 2 weeks. GI adverse events due to PFD were most severe in the first 2 weeks of treatment at a dose of 600 mg/day, and both reflux and dismotility symptoms deteriorated, but the drug was well tolerated at 1200 mg/day. Rikkunshi-to contributed to improvement of GI symptoms, but plasma ghrelin levels did not reflect the improvement of GI symptoms.

Propeptide processing and proteolytic activity of proenzymes of the staphylococcal and enterococcal GluV8-family protease.

Proenzymes with various lengths of propeptides have been observed in GluV8 from Staphylococcus aureus and GluSE from S. epidermidis. However, the production mechanism of these proenzymes and roles of truncated propeptides have yet to be elucidated. Here we demonstrate that shortening of propeptide commonly occurs in an auto-catalytic manner in GluV8-family members, including those from coagulase negative Staphylococci and Enterococcus faecalis. Accompanied with propeptide shortening, the pro-mature junction (Asn/Ser_1-Val1) becomes more susceptible towards the hetero-catalytic maturation enzymes. The auto-catalytic propeptide truncation is not observed in Ser169Ala inert molecules of GluV8-family members. A faint proteolytic activity of proenzymes from Staphylococcus caprae and E. faecalis is detected. In addition, proteolytic activity of proenzyme of GluV8 carrying Arg-3AlaAsn.1 is demonstrated with synthetic peptide substrates LLE/Q-MCA. These results suggest that GluV8-family proenzymes with shortened propeptides intrinsically possess proteolytic activity and are involved in the propeptide shortening that facilitates the final hetero-catalytic maturation.

Prospective study of biliary cytology in suspected perihilar cholangiocarcinoma.

BACKGROUND: The diagnostic value of biliary cytology for hilar bile duct stricture is uncertain. This study prospectively examined three methods for the evaluation of biliary cytology in a consecutive group of patients. METHODS: Preoperative bile sampling by aspiration through a drainage catheter (aspiration samples), saline flush through a drainage catheter (saline samples) or direct sampling from a drainage bag (bag samples) was performed in consecutive patients with suspected perihilar cholangiocarcinoma who underwent resection after endoscopic nasobiliary drainage or percutaneous transhepatic biliary drainage. All bile sampling was performed three times on separate days. The accuracy of cytology in the diagnosis of carcinoma was determined. RESULTS: Of 100 consecutive patients with hilar strictures, 97 had histologically proven cholangiocarcinoma. The proportion of these 97 patients who had a positive finding on cytology in at least one of three sampling sessions was 55 per cent for aspiration samples, 48 per cent for bag samples and 38 per cent for saline samples (P = 0·021, aspiration versus saline). Tumour length correlated significantly with overall positivity. For aspiration samples, sensitivity was 55 per cent, specificity was 100 per cent and accuracy 56·0 per cent. CONCLUSION: For biliary cytology, sampling by catheter aspiration is more effective than catheter flushing or sampling from a drainage bag. Repeated sampling increases sensitivity. Biliary cytology has modest diagnostic yield, but is easy to perform, highly specific, and can provide a definitive diagnosis.

High-density magnetic-vacancy inclusion in Co2MnGa single crystal probed by spin-polarized positron annihilation spectroscopy.

Co2MnGa is a Weyl semimetal exhibiting giant anomalous Hall and Nernst effects. Using spin-polarized positron annihilation spectroscopy, we examined a Bridgman-grown Co2MnGa single crystal with a nearly perfectL21-ordered structure and a reference Co2MnAl polycrystal with a Mn-Al-disorderedB2 structure. We found that a large amount of magnetic vacancies (more than 100 ppm) were included in the Co2MnGa crystal but not the Co2MnAl crystal. We discuss possible reasons for the inclusion of vacancies, the role of vacancies in the development of the ordered structure, and the electronic states associated with the vacancies. Toward the development of Co2MnGa-based devices, the manners for reducing vacancies as well as the influence of vacancies on the electrical transport properties should be considered.

Txk, a nonreceptor tyrosine kinase of the Tec family, is expressed in T helper type 1 cells and regulates interferon gamma production in human T lymphocytes.

Differentiation of human T cells into T helper (Th)1 and Th2 cells is vital for the development of cell-mediated and humoral immunity, respectively. However, the precise mechanism responsible for the Th1 cell differentiation is not fully clarified. We have studied the expression and function of Txk, a member of the Tec family of nonreceptor tyrosine kinases. We found that Txk expression is restricted to Th1/Th0 cells with IFN-gamma producing potential. Txk transfection of Jurkat T cells resulted in a several-fold increase of IFN-gamma mRNA expression and protein production; interleukin (IL)-2 and IL-4 production were unaffected. Antisense oligodeoxynucleotide of Txk specifically inhibited IFN-gamma production of normal peripheral blood lymphocytes, antigen-specific Th1 clones, and Th0 clones; IL-2 and IL-4 production by the T cells was unaffected. Txk cotransfection led to the enhanced luciferase activity of plasmid (p)IFN-gamma promoter/enhancer (pIFN-gamma[-538])-luciferase-transfected Jurkat cells upon mitogen activation. Txk transfection did not affect IL-2 and IL-4 promoter activities. Thus, Txk specifically upregulates IFN-gamma gene transcription. In fact, Txk translocated from cytoplasm into nuclei upon activation and transfection with a mutant Txk expression plasmid that lacked a nuclear localization signal sequence did not enhance IFN-gamma production by the cells, indicating that nuclear localization of Txk is obligatory for the enhanced IFN-gamma production. In addition, IL-12 treatment of peripheral blood CD4(+) T cells enhanced the Txk expression, whereas IL-4 treatment completely inhibited it. These results indicate that Txk expression is intimately associated with development of Th1/Th0 cells and is significantly involved in the IFN-gamma production by the cells through Th1 cell-specific positive transcriptional regulation of the IFN-gamma gene.

Molecular cloning of a human Ca2+-dependent cell-cell adhesion molecule homologous to mouse placental cadherin: its low expression in human placental tissues.

P-cadherin is a subclass of Ca2+-dependent cell-cell adhesion molecules present in mouse placenta, where its localization suggests a function of connecting the embryo to the uterus (Nose, A., and M. Takeichi. 1986. J. Cell Biol. 103:2649-2658). We recently identified a human cadherin detected by an mAb capable of disrupting cell-cell adhesion of A-431 cells, and found that it was closely related immunochemically to mouse P-cadherin. Curiously, this cadherin was undetectable in human placenta by immunohistochemical examination (Shimoyama, Y., S. Hirohashi, S. Hirano, M. Noguchi, Y. Shimosato, M. Takeichi, and O. Abe. 1989. Cancer Res. 49:2128-2133). We here report the cloning and sequencing of cDNA clone encoding the human homologue of mouse P-cadherin. The deduced amino acid sequence of the human P-cadherin consists of 829 amino acid and shows striking homology with mouse P-cadherin. On Northern blot analysis, human P-cadherin was scarcely expressed in human placenta in contrast to mouse P-cadherin, which was abundantly expressed in mouse placenta throughout pregnancy, and it was shown that E-cadherin, but not P-cadherin, was the major cadherin molecule in human placenta. Moreover, NIH3T3 cells transfected with human P-cadherin cDNA expressed the functional cadherin molecule, which was identical to the cadherin we had previously identified using the mAb, showing that this molecule really does mediate cell-cell adhesion and that the cadherin we detected immunochemically is undoubtedly human P-cadherin. The results obtained in this study support the idea that P-cadherin plays little role, if any, in Ca2+-dependent cell-cell binding in human placental tissue at least after several weeks of pregnancy.

Factors related to the advantageous effects of wearing a wetsuit during swimming at different submaximal velocity in triathletes.

This study was designed to compare the effects of wetsuit (WS) to swimsuit (SS) at identical relative velocities in a swimming flume. Thirteen triathletes performed a continuous progressive swimming test and submaximal steady state swimming tests with a WS and with a SS. Maximal oxygen uptake (VO2max) and the associated velocity at which the VO2max was achieved (VVO2max) were determined during the continuous progressive tests. Two 5 min swims (at 60% VVO2max (V(60%)) and 80% VVO2max (V(80%))) were then conducted to measure VO2max, blood lactate concentration (LA), rating of perceived exertion (RPE), the energy cost of swimming (Cs), stroke rate (SR) and stroke length (SL). No difference was found in VO2max, but VVO2max with a WS was 5.4% higher than with a SS. VO2 with a WS was lower than with a SS alone at V(60%), but not at V(80%). Cs with a WS was lower by 14.4% at V(60%) and 7.5% at V(80%) than with a SS. No differences were found in LA and RPE between suit conditions during both submaximal swims. Wearing a WS did not affect SL, but SR tended to be higher in a WS for both submaximal velocities. These results suggest that the benefits of wearing a WS are not only improvement in swimming performance and propulsion efficiency, but reduction in gross energy consumption in the swimming portion of triathlon races. Furthermore, when wearing a WS, incremental changes in SR rather than SL are associated with improved swimming performance.

Association between reflux oesophagitis and features of the metabolic syndrome in Japan.

BACKGROUND: There have been many reports about the relationship between reflux oesophagitis and obesity, but not the metabolic syndrome. AIM: To review upper gastrointestinal endoscopic findings and screening data obtained in healthy subjects, and assess relations between reflux oesophagitis and features of the metabolic syndrome. METHODS: In 3599 men and 1560 women, the prevalence of reflux oesophagitis was assessed in relation to the age, body mass index, blood pressure, triglycerides and fasting blood glucose. Logistic regression analysis was used to calculate odds ratio for risk factors. RESULTS: The overall prevalence of reflux oesophagitis was 4%, and it increased with age in women. Prevalence of reflux oesophagitis increased significantly with an increase of body mass index, blood pressure, triglycerides and fasting blood glucose. On multivariate analysis, male sex (odds ratio: 2.5; 95% confidence interval: 1.6-3.8), obesity (1.9; 1.4-2.5), hyperglycaemia (1.7; 1.2-2.4) and hypertension (1.5; 1.1-2.1) were independent risk factors for reflux oesophagitis. Among both men and women, those with reflux oesophagitis were significantly more likely to have two or more of these risk factors than non-reflux oesophagitis subjects. CONCLUSIONS: Components of the metabolic syndrome are associated with the occurrence of reflux oesophagitis. Therefore, some risk factors may be common to reflux oesophagitis and the metabolic syndrome.

High-viscosity liquid meal accelerates gastric emptying.

Adding pectin to an elemental formula increases its viscosity through gelatinization, thus presumably preventing gastro-oesophageal reflux and aspiration pneumonia. We investigated the influence of the viscosity of an elemental formula on gastric emptying. Eleven healthy volunteers underwent three tests at intervals of >1 week. After fasting for >8 h, each subject received a test meal (enteral nutrition solution, enteral solution plus pectin, or water). Then gastric emptying (continuous (13)C breath test), gastro-oesophageal intraluminal pressures, oesophageal pH, and blood levels of glucose, insulin and gastrin were all measured simultaneously. The gastric emptying coefficient was significantly increased by adding pectin to enteral nutrition (3.01 +/- 0.10 vs 2.78 +/- 0.10, mean +/- SE, P < 0.05). The antral motility index was also significantly higher with pectin than without at 45-60 min and 60-75 min after the test meal (526 +/- 237 vs 6.5 +/- 4.6 mmHg s(-1) and 448 +/- 173 vs 2.3 +/- 2.3 mmHg s(-1) respectively; P < 0.05). Plasma glucose was significantly higher with pectin than without it at 60 min after ingestion (141.5 +/- 6.03 vs 125.8 +/- 4.69 microM mL(-1), P < 0.05). In healthy individuals, pectin increased the viscosity of enteral nutrition and accelerated gastric emptying.

Pleomorphic adenoma of the salivary gland in two dogs.

Pleomorphic adenomas of the salivary gland were diagnosed in two dogs. The tumours were single, firm and well circumscribed, with a smooth cut surface. Metastatic tumours were not detected. Histopathological examination revealed that the tumours contained multiple cysts lined with luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues. Immunohistochemical examination demonstrated labelling of luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues with antibodies to cytokeratin LU-5, AE1/AE3, CK-14, CALP, a-SMA, vimentin, GFAP, and S-100. Labelling for GFAP indicated stromal transformation into myxoid and chondroid tissues.

Expression of E- and P-cadherin in gastric carcinomas.

The expression pattern of two Ca2(+)-dependent intercellular adhesion molecules, E- and P-cadherin, in 54 surgically resected gastric adenocarcinomas was examined immunohistochemically. E-cadherin was expressed uniformly at the cell-cell borders of most of the differentiated and adherent-type undifferentiated gastric adenocarcinomas, showing that E-cadherin serves as the main cadherin molecule responsible for intercellular binding in these carcinomas. Scattered-type undifferentiated gastric adenocarcinomas which apparently lacked this tight intercellular adhesion were divisible into two groups on the basis of E-cadherin expression. In a minor group composed of 4 carcinomas, E-cadherin could not be detected, suggesting that the absence of E-cadherin made the cancer cells separate. In contrast, cancer cells of 19 carcinomas which belonged to the major group showed similar scattering but had definite expression of E-cadherin on their cell surfaces, suggesting that there was some mechanism(s) disturbing the function of E-cadherin in these carcinomas. However, immunoblotting showed no evidence of gross alterations of the E-cadherin molecule, such as partial deletion, in these carcinomas. P-cadherin was expressed in 29 (54%) of the examined gastric carcinomas, and the expression was unstable in most of them, a characteristic feature compared with the stable expression of E-cadherin. Since P-cadherin is known to be expressed temporarily in the foregut during embryogenesis and was proved to be occasionally expressed, although weakly, in the proliferative zone of noncancerous gastric epithelia in this study, expression of P-cadherin in gastric carcinomas may be an oncofetal phenomenon and/or may reflect their marked proliferative potential.

Isolation and sequence analysis of human cadherin-6 complementary DNA for the full coding sequence and its expression in human carcinoma cells.

The expression pattern of E- and P-cadherin in human carcinomas has been reported by many laboratories. However, little is known about the involvement of other cadherin types in human carcinomas. cDNA clones for a cadherin molecule were isolated from a cDNA library of human hepatocellular carcinoma cells which lacked E- and P-cadherin expression but exhibited cell aggregation activity mediated by an unknown cadherin, and they were subjected to sequence analysis. The overlapped clones covered 4315 nucleotides and were found to encode a typical cadherin molecule consisting of 790 amino acids. Since the deduced amino acid sequence was identical to a partially available human cadherin-6 sequence except for two amino acid residues, the clones were considered to be human cadherin-6 cDNAs encoding the entire open reading frame. The deduced amino acid sequence also showed extremely high homology with recently reported rat K-cadherin, 97% for the putative mature protein, suggesting that cadherin-6 is the human counterpart of rat K-cadherin. Expression of cadherin-6 in various human normal tissues and carcinoma cells was examined by Northern blot analysis using a specific probe corresponding to the signal and precursor sequence. Among normal tissues examined, brain, cerebellum, and kidney showed strong expression of cadherin-6, whereas lung, pancreas, and gastric mucosa showed weak expression. Transcripts of cadherin-6 were not detected in normal liver, whereas four of six hepatocellular carcinoma cell lines examined expressed cadherin-6 abundantly. As reported for rat K-cadherin, three renal carcinoma cell lines also expressed cadherin-6 strongly. The most interesting finding was obtained for small cell lung carcinoma lines. Among 15 of such cell lines examined, all of 11 cadherin-6-positive lines were classified into the classic type, whereas the negative cell lines were all of the variant type. The present results suggest that besides E- and P-cadherin, other cadherin molecules are expressed in human cancers and are responsible for additional biological properties of the carcinoma cells.

Cadherin cell-adhesion molecules in human epithelial tissues and carcinomas.

Two distinct calcium-sensitive cell-cell adhesion molecules were identified in human epithelial tissues and carcinomas using two monoclonal antibodies raised against vulvar epidermoid carcinoma A-431 and human mammary carcinoma MCF-7 and selected on the basis of their activities to disrupt cell-cell adhesion. In immunoblot analysis, these antibodies, designated NCC-CAD-299 and HECD-1, detected main bands of Mr 118,000 and 124,000, respectively. Purified tryptic fragments of the antigen recognized by NCC-CAD-299 showed cross-reactivity with a rabbit antiserum against mouse P-cadherin, indicating that this molecule was the human homologue of P-cadherin. On the other hand, the antigen recognized by HECD-1 showed essentially the same tissue distribution pattern as E-cadherin in the mouse, suggesting that this molecule is the human homologue of E-cadherin. Availability of these monoclonal antibodies to human P- and E-cadherin allowed us to examine their distributions in human tissues immunohistochemically. Both antigens were detected in epithelial tissues, but they showed distributions that were distinct from each other. The antigen recognized by HECD-1 was expressed in almost all epithelial tissues, while distribution of the other one recognized by NCC-CAD-299 was restricted to the basal or lower layers of stratified epithelia in which both antigens were coexpressed. Moreover, immunohistochemical examination of 44 lung carcinomas showed that both molecules were coexpressed in all of them, and suggested that expression of P-cadherin was closely related to the differentiation of carcinoma cells.

Cadherin dysfunction in a human cancer cell line: possible involvement of loss of alpha-catenin expression in reduced cell-cell adhesiveness.

A human lung cancer cell line, PC 9, was analyzed to elucidate the molecular mechanisms of dysfunction of cadherin-mediated cell-cell adhesion in cancer. Although PC 9 cells strongly expressed E-cadherin at the cell membrane, which was indistinguishable immunochemically from functional E-cadherin, they did not show tight cell-cell adhesion and had reduced E-cadherin-mediated aggregation activity. Immunoprecipitation with E-cadherin and Western blot analysis revealed that PC 9 cells did not express alpha-catenin, a cadherin-associated protein, suggesting that this was the cause of the cadherin dysfunction in the cell line. In addition, Northern and Southern blot analyses disclosed homozygous deletion of part of the alpha-catenin gene, which might have resulted in the loss of alpha-catenin expression in PC 9 cells.