Papillary Hyperplasias Research Articles

An immunohistochemical and molecular analysis of papillary proliferation of the endometrium

Papillary proliferations of the endometrium (PPEs) are uncommon lesions that are often associated with endometrial polyps. PPEs occasionally precede or co-exist with atypical endometrial hyperplasia or adenocarcinoma, but their pathogenesis and relationship to endometrial neoplasia is uncertain. In the present study 11 PPEs, including eight benign papillary proliferations (BPPs) and three complex papillary hyperplasias (CPHs) were examined immunohistochemically for expression of PAX2, BAF250a, p16, β-catenin and DNA mismatch repair (MMR) proteins. Molecular analysis was also performed on the CPHs using targeted next generation sequencing (NGS). All PPEs demonstrated at least one immunohistochemical abnormality with altered expression of p16 and PAX2 in nine and seven cases, respectively, and β-catenin in one case. However, none of the cases showed loss of BAF250a or MMR protein staining. All CPHs showed KRAS mutations with additional mutations in AKT1 and FBXW7 in one case each, and both PIK3CA and CTNNB1 in the remaining case. Therefore, PPEs demonstrate immunophenotypical and molecular overlap with endometrial endometrioid neoplasia, although loss of BAF250a and MMR protein function do not appear to contribute significantly to these lesions. KRAS mutations may be important drivers in CPHs but this finding needs to be confirmed in larger studies.

Comparison of the Classical Method and SEE-FIM Protocol in Detecting Microscopic Lesions in Fallopian Tubes with Gynecological Lesions.

BackgroundThe objective of this study was to compare the classical method and Sectioning and Extensively Examining the Fimbriated End Protocol (SEE-FIM) in detecting microscopic lesions in fallopian tubes with gynecological lesions.MethodsFrom a total of 1,118 cases, 582 with various parts of both fallopian tubes sampled in three-ring-shape sections and 536 sampled with the SEE-FIM protocol were included in this study. Pathological findings of cases with endometrial carcinoma, non-uterine pelvic malignant tumor, ovarian borderline tumors, premalignancy, and benign lesions were compared.ResultsWe detected two tubal infiltrative carcinomas among 40 uterine endometrioid adenocarcinomas, 15 serous tubal intraepithelial carcinomas in 39 non-uterine pelvic serous high-grade carcinoma cases, seven papillary tubal hyperplasias in 13 serous borderline tumor cases, and 11 endometriotic foci and four adenomatoid tumors among all cases sampled with the SEE-FIM protocol. Using the classical method, we detected only one serous tubal intraepithelial carcinoma in 113 non-uterine pelvic serous high-grade carcinoma cases and two papillary tubal hyperplasia cases in 31 serous borderline tumors. We did not identify additional findings in 185 uterine endometrioid carcinoma cases, and neither endometriotic focus nor adenomatoid tumor was shown in other lesions by the classical method.ConclusionsBenign, premalignant, and malignant lesions can possibly be missed using the classical method. The SEE-FIM protocol should be considered especially in cases of endometrial carcinoma, nonuterine pelvic serous cancers, or serous borderline ovarian tumors. For other lesions, at least a detailed examination of the fimbrial end should be undertaken.

Modulation by licofelone and celecoxib of experimentally induced cancer and preneoplastic lesions in mice exposed to cigarette smoke.

Chronic inflammation plays a crucial role in cigarette smoke-related carcinogenesis. Accordingly, anti-inflammatory agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs), provide a rational strategy in cancer chemoprevention. We assayed celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, and licofelone, an inhibitor of COX-1, COX-2, and 5- lipoxygenase (5-LOX), for the ability to modulate carcinogenesis in neonatal mice exposed to mainstream cigarette smoke (MCS) for 4 months and thereafter kept in filtered air for 3.5 months. A preliminary toxicity study and a chemoprevention study involved the use of 591 Swiss H mice. Exposure to MCS caused a variety of pulmonary emphysema, alveolar and bronchial epithelial hyperplasias, proliferation of blood vessels, microadenomas, adenomas and malignant tumors, as well as kidney tubular and urinary bladder papillary epithelial hyperplasias. Celecoxib (1600 mg/kg diet) and even better licofelone (960 mg/kg diet) were able to significantly attenuate the MCS-induced alterations of inflammatory nature, including pulmonary emphysema, alveolar epithelial hyperplasias and microadenomas and urinary tract hyperplastic lesions when given to mice according to a protocol that mimics an intervention in current smokers. Moreover, celecoxib attenuated the yield of lung adenomas and both NSAIDs showed some involvement in lowering the progression to cancer in the lung. Celecoxib exhibited some protective effects even when given according to a protocol involving its administration after discontinuation of exposure to MCS. However, both agents and especially celecoxib showed some hepatotoxicity and affected survival and body weight gain of mice when administered to MCS-exposed mice in the long term.

Xanthine crystals induced by topiroxostat, a xanthine oxidoreductase inhibitor, in rats, cause transitional cell tumors

The present study was performed to elucidate the underlying mechanism of transitional cell tumors found in the carcinogenicity testing of topiroxostat, a xanthine oxidoreductase inhibitor, in which topiroxostat was orally given to F344 rats at 0.3, 1, and 3mg/kg for 2years. In the urinary bladder, transitional cell papillomas and/or carcinomas were seen in males receiving 0.3, 1, and 3mg/kg (1/49, 3/49, and 10/50, respectively). In the kidney, transitional cell papillomas and/or carcinomas in the pelvis were seen in 2/50 males and 1/50 females receiving 3mg/kg. In the mechanistic study by 52-week oral treatment with topiroxostat at 3mg/kg to F344 male rats, with and without citrate, simple and papillary transitional cell hyperplasias of the urinary bladder epithelium were observed in 5/17 in the topiroxostat-alone treatment group, along with xanthine-induced nephropathy, in contrast to neither xanthine crystals nor lesions in urinary organs by co-treatment group with citrate. As for sex differences of urinary bladder tumors, the BrdU labeling index for epithelial cells of the urinary bladder by 5-week oral treatment with topiroxostat at 10mg/kg to F344 rats was increased in males only, showing consistency with histopathological findings. Therefore, the present study indicates that transitional cell tumors induced by topiroxostat in rats were due to physical stimulation to transitional cells of xanthine crystals/calculi and provides that other factors were not implicated in this tumorigenesis. Furthermore, the present study suggests that such tumors do not predict for humans since topiroxostat-induced xanthine deposition is a rodent-specific event.

The prevalence and distribution of human papillomavirus genotypes in oral epithelial hyperplasia: proposal of a concept

Evidence is accumulating for the aetiological role of human papillomavirus (HPV) in the pathogenesis of potentially malignant oral mucosal lesions and squamous cell carcinomas. Paraffin tissue sections from 49 patients with 'white patches' of the oral mucosa were investigated histologically, by broad-spectrum PCR followed by genotyping and chromogenic in situ hybridisation (CISH). Histologically, 33 flat hyperplasias and 16 papillary hyperplasias were diagnosed. Twenty-two of 28 samples studied (78.6%) were positive for HPV DNA by PCR and six were negative. The following HPV types were detected in decreasing order of prevalence: HPV 35, HPV 6, HPV16, HPV 53, HPV 18, HPV 51 and HPV 55. Seventeen samples (60.7%) contained high-risk HPV DNA. Using CISH, >or= 1 HPV signals were detected at least in a few epithelial cells in 95% of cases studied. All but one case were positive with the high-risk HPV probe and all HPV infections contained low viral load. Concordant positive results both by PCR and CISH were detected in 14 of 19 cases (73.7%) analysed. The high prevalence of HPV infection in hyperplastic 'white patches' of the oral mucosa supports the putative role of HPV at an early stage of oral carcinogenesis. These results further indicate that the majority of white oral mucosal lesions - flat, exophytic, wart-like or papillary proliferations - could be considered as the clinical manifestations of oral HPV infection. This finding has clinical relevance regarding therapy and patient management and may help in elucidating the role of HPV infection in oral carcinogenesis.

Canine vascular neoplasia – a population‐based clinicopathologic study of 439 tumours and tumour‐like lesions in 420 dogs

This paper deals with a population-based material collected during the years 1990-1998, and comprises 439 tumours and tumour-like vascular processes from 420 dogs. Anatomic location, age, breed and gender are reported. A distinction is made between benign neoplasms, tumours of intermediate malignancy, and obvious malignant processes (angiosarcomas). Clinical behaviour, comprising recurrence and metastatic disposition, is included. Subclassification is done according to criteria used in human oncology. More than one half (242 of 439) occurred in the skin, and a great majority of skin processes (223 of 242) represented benign tumours or tumour-like lesions. The next most common site of summarised lesions was the spleen, with 110 cases, with only 17 processes in this organ being defined as benign. Splenic involvement was followed by the liver, with 13 out of 17 processes being angiosarcomas. Eleven of 12 heart tumours were angiosarcomas. A majority of skin haemangiomas was of the cavernous type (108 of 211), and more than one half (10 of 14) of the capillary haemangiomas were located on dorsal sites of the extremities. The mixed capillary/cavernous haemangiomas had a more diffuse distribution, although 20 of 31 were found in the skin of the hind limbs. Only one lymphangioma and one case of angiomatosis were observed. Most tumour-like proliferations were papillary endothelial hyperplasias. Recurrence occurred in 17 dogs, some of which had received a primary benign diagnosis. Primary metastases were observed in 63 animals, the majority in the spleen and heart. Dissemination involved a further 23 cases (22 had angiosarcoma). The male/female rate of benign tumours was 0.78, for tumour-like processes 1.83, intermediate malignant tumours 1.65, and angiosarcomas 1.60. With few exceptions, there was an overweight of all subclassified vascular lesions in animals more than 6 years of age.

A Series of Vascular Tumors and Tumorlike Lesions of the Bladder

Vascular tumors of the bladder are rare and a subject of small series and case reports. We retrospectively identified vascular tumors of the urinary bladder from the consultation files from one of the authors. We identified 13 lesions that included 3 hemangiomas, 3 intravascular papillary endothelial hyperplasias (Masson vegetant hemangioendotheliomas), 2 arteriovenous malformations (AVMs), 1 epithelioid hemangioendothelioma (EHE), and 4 angiosarcomas. One of the angiosarcomas was associated with conventional high-grade urothelial carcinoma (sarcomatoid carcinoma). All patients were adults with a range in age from 18 to 85 years old (mean 63.3). There was no statistical difference among the various lesions in terms of age, although angiosarcomas tended to arise in older patients (mean 71 y vs. 60 y of the remainder). Hematuria was the most common presentation of both benign and malignant lesions. Other symptoms included voiding irritation, pelvic pain, and obstruction. Histologically, benign and malignant lesions were similar to their counterparts in other organ systems. Two hemangiomas were of the capillary type and a third one of the cavernous subtype. They measured 1.1, 2.4, and 3.2 cm. Both AVMs were clinically large broad-based masses measuring 5.5 and 5.8 cm in greatest diameter. One of the AVMs was associated with pseudoepitheliomatous hyperplasia of the urothelium. All 3 patients with Masson lesion had history of radiation therapy for other causes. These presented as raised lesions and were all <1.0 cm. Patients with hemangiomas, papillary endothelial hyperplasias, and AVM had an invariably benign prognosis and needed no further therapy. These benign lesions had consistent involvement of the submucosa and spared the muscularis propria of the organ. All cases of angiosarcoma and EHE involved the muscularis propria. Two of four patients with angiosarcoma had a history of prior radiation therapy and all 4 were dead of disease at 6 months. Angiosarcomas measured 3, 4.5, 5, and 5.8 cm in greatest diameter at cystoscopy. The patient with EHE had a single nodule treated by transurethral resection of the bladder and no evidence of disease at 4 years of follow-up. None of the patients experienced marked gross hematuria that resulted in morbidity or mortality. A wide spectrum of benign, intermediate malignant, and malignant vascular lesions primarily involved the bladder. Despite the potential for marked hemorrhage, none of the tumors resulted in marked hematuria. Papillary endothelial hyperplasia occurs in the bladder and must be differentiated from angiosarcoma, which has a rapidly fatal outcome.

Differences in Expression Patterns of Cell Cycle Regulators after Cessation of Genotoxic and Non-genotoxic Carcinogen Treatment in the Rat Forestomach

We have already shown that forestomach lesions induced by 24 weeks administration of genotoxic carcinogens, 8-nitroquinoline (8-NQ), 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or N-methylnitrosourethane (MNUR), do not regress within 24 weeks of cessation of the chemical exposure. In contrast, simple or papillary hyperplasias induced by 24 weeks administration of non-genotoxic carcinogens, butylated hydroxyanisole (BHA), caffeic acid (CA), sesamol or 4-methoxyphenol (4-MP), largely disappear. In the present study, to examine the mechanisms of the reversibility of proliferative forestomach lesions, representative non-genotoxic carcinogens, BHA, CA or 4-MP, and one genotoxic carcinogen, MNUR, were given to male F344 rats for 24 weeks, then their forestomachs were sequentially analyzed after withdrawal of the chemical insult. MNUR-induced proliferative lesions such as hyperplasias, papillomas and squamous cell carcinomas did not regress and the expression level of cell cycle regulators, cyclin D1 and p27 were not altered after cessation of the chemical insult. On the other hand, BHA-, CA- or 4-MP-induced hyperplasias clearly regressed, in association with reduction of cyclin D1 expression. During this process, expressions of p27 and cleaved caspase 3 were not altered. These findings suggest that regression of proliferative lesions induced by non-genotoxic rat forestomach carcinogens is controlled partially by a positive cell cycle regulator, cyclin D1, whereas dysregulation of this mechanism is a characteristic of the irreversible lesions induced by a genotoxic carcinogen.

The role of survivin expression in the differential diagnosis of laryngeal (glottic) verrucous squamous cell carcinoma

Aims Laryngeal verrucous squamous cell carcinoma (VSCC) is a highly differentiated carcinoma (SCC) whose histological diagnosis has many pitfalls in particular considering small biopsies: multiple glottic biopsies may be necessary to conclude for a malignant or benign lesion (papillary hyperplasia). Survivin is a member of the inhibitor of apoptosis protein family. Survivin over-expression has been demonstrated in laryngeal SCCs. The aims of the present study have been to evaluate for the first time survivin expression in glottic VSCC and investigate the potential role of survivin expression in the differential diagnosis of laryngeal VSCC. Methods Survivin expression was determined in 11 consecutive cases of glottic VSCC, in 24 cases of glottic papillary hyperplasia, and in 23 cases of SCC. Results Nuclear survivin reaction predominated in laryngeal VSCCs, papillary hyperplasias, and SCCs. Mean survivin expressions in the VSCC basal layer, hyper-proliferative areas of laryngeal papillary hyperplasia, and SCC were 62.7 %, 68.3 %, and 70.0 %, respectively. Mean survivin expression was 15.6 % in VSCC parakeratosis and 1.5 % in papillary hyperplasia parakeratosis ( p < 0.001). Conclusions Survivin expression was significantly higher in parakeratosis areas of laryngeal VSCC than in parakeratosis areas of laryngeal papillary hyperplasia. Immunohistochemical determination of survivin expression in parakeratosis areas may be a promising tool to substantiate differential diagnosis between glottic VSCC and papillary hyperplasia.

Weak enhancing effects of simultaneous ethanol administration on chemically induced rat esophageal tumorigenesis

Excessive alcohol consumption is associated epidemiologically with an elevated risk of esophageal cancer. In this study, we examined the effects of simultaneous administration of ethanol on N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis. Groups 1-3 were treated with NMBA at a dose of 0.5 mg/kg body weight (high dose), and groups 4-6 received a dose of 0.1 mg/kg body weight (low dose), by s.c.-injection, 3 times per week for the first 5 weeks. Groups 1 and 4 were given ethanol free water as controls. Groups 2 and 5 were treated with 10% ethanol in their drinking water only at the time of NMBA treatment, while groups 3 and 6 were administrated the supplement continuously up to the end of the experiment. Macroscopically, with high dose NMBA-initiation, simultaneous 5-week and continuous 24-week ethanol administration demonstrated a tendency to increase the incidence and multiplicity of tumors, and also microscopically the multiplicity of papillary hyperplasias. In low dose groups, the incidence of esophageal papillary hyperplasias was significantly increased by continuous 24-week ethanol administration. Immunohistochemistry, proliferating cell nuclear antigen (PCNA) positive indices tended to be increased in tumors by simultaneous 5-week and continuous 24-week ethanol administration, but cyclin D1 expression was not affected. These data suggest that simultaneous ethanol administration have weak enhancing effects, and also promoting effects in post-initiation phase is present on NMBA-induced rat tumorigenesis.

Carcinogenicity of dimethylarsinic acid in male F344 rats and genetic alterations in induced urinary bladder tumors.

Arsenic is a well-documented human carcinogen, and contamination with this heavy metal is of global concern, presenting a major issue in environmental health. However, the mechanism by which arsenic induces cancer is unknown, in large part due to the lack of an appropriate animal model. In the present set of experiments, we focused on dimethylarsinic acid (DMA), a major metabolite of arsenic in most mammals including humans. We provide, for the first time, the full data, including detailed pathology, of the carcinogenicity of DMA in male F344 rats in a 2-year bioassay, along with the first assessment of the genetic alteration patterns in the induced rat urinary bladder tumors. Additionally, to test the hypothesis that reactive oxygen species (ROS) may play a role in DMA carcinogenesis, 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in urinary bladder was examined. In experiment 1, a total of 144 male F344 rats at 10 weeks of age were randomly divided into four groups that received DMA at concentrations of 0, 12.5, 50 and 200 p.p.m. in the drinking water, respectively, for 104 weeks. From weeks 97-104, urinary bladder tumors were observed in 8 of 31 and 12 of 31 rats in groups treated with 50 and 200 p.p.m. DMA, respectively, and the preneoplastic lesion, papillary or nodular hyperplasias (PN hyperplasia), was noted in 12 and 14 rats, respectively. DMA treatment did not cause tumors in other organs and no urinary bladder tumors or preneoplastic lesions were evident in the 0 and 12.5 p.p.m.-treated groups. Urinary levels of arsenicals increased significantly in a dose-responsive manner except for arsenobetaine (AsBe). DMA and trimethylarsine oxide (TMAO) were the major compounds detected in the urine, with small amounts of monomethylarsonic acid (MMA) and tetramethylarsonium (TeMa) also detected. Significantly increased 5-bromo-2'-deoxyuridine (BrdU) labeling indices were observed in the morphologically normal epithelium of the groups treated with 50 and 200 p.p.m. DMA. Mutation analysis showed that DMA-induced rat urinary bladder tumors had a low rate of H-ras mutations (2 of 20, 10%). No alterations of the p53, K-ras or beta-catenin genes were detected. Only one TCC (6%) demonstrated nuclear accumulation of p53 protein by immunohistochemistry. In 16 of 18 (89%) of the TTCs and 3 of 4 (75%) of the papillomas, decreased p27(kip1) expression could be demonstrated. Cyclin D1 overexpression was observed in 26 of 47 (55%) PN hyperplasias, 3 of 4 (75%) papillomas, and 10 of 18 (56%) TCCs. As a molecular marker of oxidative stress, increased COX-2 expression was noted in 17 of 18 (94%) TCCs, 4 of 4 (100%) papillomas, and 39 of 47 (83%) PN hyperplasias. In experiment 2, 8-OHdG formation in urinary bladder was significantly increased after treatment with 200 p.p.m. DMA in the drinking water for 2 weeks compared with the controls. The studies demonstrated DMA to be a carcinogen for the rat urinary bladder and suggested that DMA exposure may be relevant to the carcinogenic risk of inorganic arsenic in humans. Diverse genetic alterations observed in DMA-induced urinary bladder tumors imply that multiple genes are involved in stages of DMA-induced tumor development. Furthermore, generation of ROS is likely to play an important role in the early stages of DMA carcinogenesis.

Reduced expression of the CDK inhibitor p27(KIP1) in rat two-stage bladder carcinogenesis and its association with expression profiles of p21(WAF1/Cip1) and p53.

The cyclin-dependent kinase (CDK) inhibitor p27(KIP1) exerts its growth suppressive effects by targeting the cyclin-CDK complexes. Reduced protein levels of p27(KIP1) have been reported in numerous human cancers and this has been attributed to increased degradation. However, few reports have addressed the significance of p27(KIP1) expression in chemical carcinogenesis of rodents. In a rat two-stage urinary bladder carcinogenesis model, with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) initiation followed by promotion with sodium L-ascorbate (Na-AsA), we evaluated the expression of p27(KIP1) protein using immunohistochemistry during various stages of urinary bladder carcinogenesis. In addition, we evaluated the mRNA expression profiles for p27(KIP1), p21(WAF1/Cip1) and p53 in tumors. Fisher 344 rats were initiated with 0.05% BBN in the drinking water for 4 weeks and then administered 5% Na-AsA in the diet. Immunohistochemical examination revealed p27(KIP1) protein to be constitutively expressed in normal urothelium, simple hyperplasia and in most papillary and nodular (PN) hyperplasias and small papillomas, but diminished or absent in large papillomas and in transitional cell carcinomas. An inverse correlation between expression of p27(KIP1) and cell proliferation was generally observed. Quantitation of mRNA by multiplex reverse transcription-PCR showed a significant downregulaton of p27(KIP1), p21(WAF1/Cip1) and p53 mRNA in tumors. More than 50% reduction in p27(KIP1) mRNA expression was observed in 42 and 47% of tumors at weeks 18 and 24, respectively; similar reduction in p21(WAF1/Cip1) mRNA expression was observed in 58 and 73% of tumors at weeks 18 and 24, and in p53 mRNA expression in 50 and 73% of tumors at weeks 18 and 24, respectively. None of the 25 tumors we examined by PCR-single-strand conformational polymorphism analysis had p53 mutations. These data imply that abnormal down-regulation of p27(KIP1), p21(WAF1/Cip1) and/or p53 in tumor cells may contribute to the malignant progression of tumors during rat two-stage bladder carcinogenesis.

Strong promoting activity of phenylethyl isothiocyanate and benzyl isothiocyanate on urinary bladder carcinogenesis in F344 male rats.

Post-initiation effects of phenylethyl isothiocyanate (PEITC) and benzyl isothiocyanate (BITC) on hepatocarcinogenesis and urinary bladder carcinogenesis were examined in rats pretreated with diethylnitrosamine (DEN) and N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Groups of 21 rats received a single intraperitoneal injection of 200 mg/kg body weight of DEN. Starting 2 days thereafter, they were administered 0.05% BBN in the drinking water for 4 weeks. Three days after completion of the carcinogen treatment, they were placed on a diet containing PEITC or BITC at a dose of 0.1%, or a basal diet alone for 32 weeks and then killed for autopsy. Further groups of 6 rats each were similarly treated with PEITC, BITC or basal diet alone for 32 weeks without prior DEN and BBN exposure. In the liver, although the incidences of liver tumors were not significantly affected, the multiplicity of foci larger than 0.5 cm in diameter was slightly increased by PEITC. In the urinary bladder, the incidences of papillary or nodular (PN) hyperplasias and carcinomas were significantly elevated by PEITC or BITC after DEN and BBN initiation. In the groups without initiation, PN hyperplasia was found in all rats of both PEITC and BITC groups, along with papillomas and carcinomas in some animals. Tumors and PN hyperplasias in the groups treated with PEITC and BITC are characterized by downward growth. Our results thus showed PEITC and BITC to be strong promoters of urinary bladder carcinogenesis with some complete carcinogenic potential.

K-ras gene mutations in intrahepatic bile duct tumors of Syrian golden hamsters.

In our laboratory, we have developed a new model of carcinoma of the bile duct in Syrian golden hamsters, using N-nitrosobis(2-oxopropyl)amine (BOP). Morphologic and biologic characteristics of the carcinoma induced in this model are similar to those seen in humans. In order to examine the gene-related carcinogenesis of intrahepatic bile duct carcinoma, we investigated mutations in the K-ras gene in various early hyperplastic and neoplastic lesions of these hamsters, according to the original sites of the lesions. Inbred female hamsters were given a subcutaneous injection of N-nitrosobis(2-oxopropyl)amine (BOP) following dissection of the extrahepatic bile duct on the distal end of the common duct and preparation of a cholecystoduodenostomy (CDDB) or simple laparotomy (SL). Neoplastic lesions arising from the intrahepatic bile duct were histologically examined, and K-ras mutations were investigated. Mutations of K-ras codon 12 were evident in 12% of tubular hyperplasias, 19% of tubular adenocarcinomas, 15% of papillary hyperplasias and 36% of papillary adenocarcinomas. In papillary adenocarcinoma arising from a large bile duct, K-ras mutations occurred more frequently than in tubular adenocarcinoma arising from ductule or ductular proliferation. K-ras mutations were present even in a hyperplasia; the positive rates of the mutations increased in the presence of a carcinoma. Genetic changes in carcinoma of the intrahepatic bile duct varied based on sites of the duct and the histological type. A part of the hyperplastic lesions of the intrahepatic bile duct presented K-ras gene mutation. This suggests that K-ras gene mutation is an early event in the carcinogenic process. In carcinoma of the intrahepatic bile duct, the lesion arising from a large bile duct of the hepatic hilum tended to exhibit a higher frequency of K-ras gene mutation than did a tubular lesion arising from ductule or ductal proliferation. This hamster model is useful to examine the carcinogenesis of human intrahepatic bile duct carcinoma.

Relationship between pulmonary fibrosis and lung proliferative lesions induced by different doses of N-methyl-N-nitrosourethane in syrian golden hamsters.

The relationship of pulmonary fibrosis to development of lung tumors was investigated in Syrian golden hamsters treated with N-methyl-N-nitrosourethane (MNUR). Female animals in groups 1 and 2 received five subcutaneous (sc) injections of 0.6 and 0.2mg, respectively, of the carcinogen, whereas males in group 3 were given a single 0.3mg sc dose. After initiation the animals in each group were maintained, together with controls, without any further treatment for 26 weeks, and then examined for whether proliferative lesions in the lung are secondary to pulmonary inflammatory lesions induced by MNUR. Lung tumors were induced in all hamsters of group 1, but only 56% and 36%, respectively, were accompanied by inflammatory lesions and pulmonary fibrosis. Similar results were also obtained for tumors in group 2 and papillary hyperplasias in the female treated groups, many being observed without any involvement of fibrotic lesions. Glandular metaplasia was observed at high frequency in groups 1-3, but no evidence of a histogenetic link with development of lung tumors was found. A close relation between development of lung tumors and papillary hyperplasias was noted, however. The present study thus suggested that a considerable proportion of lung tumors induced in hamsters by MNUR are independent of toxicity-related changes and presumably due to direct DNA initiating action of the carcinogen.

Monoclonal development of squamous cell carcinomas from polyclonal papillary or nodular hyperplasias in the forestomach of C3H/HeNBALB/c chimeric mice treated with N-methyl-N-nitrosourea or diethylnitrosamine.

The clonality of epithelial proliferative lesions of forestomach carcinogenesis was immunohistochemically investigated in C3H/HeN<-->BALB/c chimeric mice using a specific antibody to C3H strain specific antigen (CSA) and as well as in terms of microsatellite DNA polymorphism patterns. The C3H/HeN<-->BALB/c chimeric mice were produced by an aggregation procedure. Male chimeric, C3H/HeN, and BALB/c animals were given N-methyl-N-nitrosourea (MNU) 0.5 mg/mouse once a week for a total of 10 times by intragastric intubation or 30 p.p.m. diethylnitrosamine (DEN) in their drinking water for 20 weeks. Those treated with MNU were killed at weeks 11, 25 and 45 and with DEN at week 35. Normal chimeric forestomach epithelium was found to demonstrate mixtures of epithelial cell groups composed of either CSA positive or negative cells. The same was the case for all simple hyperplasias. Papillary and nodular (PN) hyperplasias increased with time even after cessation of MNU treatment and many of them consisted of both CSA positive and negative cell groups. In one case, a CSA positive and a negative cancer were observed to have developed independently in the same PN-hyperplasia consisting of both parental cell types. In 28 tumor bearing chimeric mice, all squamous cell carcinomas (SCCs) were composed entirely of either CSA positive or negative tumor cells. However, in two animals with advanced CSA positive cancers and negative cancers, tiny cancer nests composed of both parental type cells were found in association. Microsatellite DNA polymorphism patterns of DNAs sampled from histological sections completely conformed with the outcomes of immunohistochemical staining. The results suggest that PN-hyperplasias are aggregates (polyclonal) of preneoplastic changes from which monoclonal SCCs are derived. Polyclonal cancers may also arise secondarily at low incidence during progression, due to two or more lesions coalescing.

Tubulo-papillary Adenoma (so-called Nephrogenic Adenoma) Arising in the Renal Pelvis: Report of a Case with a Critical Consideration of Histogenesis and Terminology

This is the first detailed clinical and histopathologic report of a tubulo-papillary adenoma (so-called nephrogenic adenoma) arising in the renal pelvis of a 35-year-old woman. The tumor showed a polypoid exophytic growth and consisted of closely packed tubular formations lined by cuboidal to low columnar cells with an admixture of delicate papillary structures. Its benign nature was indicated by the lack of cellular atypias, the extremely low proliferative activity and the absence of invasiveness. We favor the metaplastic theory of origin rather than an embryologic (dysontogenetic) derivation from mesonephric remnants as the underlying histogenetic principle. The descriptive term "tubulo-papillary adenoma" seems more appropriate than the designation "nephrogenic adenoma". True tumors of this type should clearly be distinguished from metaplastic tubular, papillary or tubulo-papillary cuboidal hyperplasias of the urothelium (so-called nephrogenic metaplasia) which are considered preneoplastic and assumed to be immediate precursors of adenomas of the lower urinary tract.

Modification of carcinogenesis by alpha-tocopherol, t-butylhydroquinone, propyl gallate and butylated hydroxytoluene in a rat multi-organ carcinogenesis model.

Effects of the dietary antioxidants alpha-tocopherol (alpha-Toc), t-butylhydroquinone (TBHQ), propyl gallate (PG) and butylated hydroxytoluene (BHT) were examined using a multi-organ carcinogenesis model. Groups of 20 F344 male rats were treated with a single intragastric administration of 100 mg/kg body weight N-methyl-N'-nitro-N-nitrosoguanidine, a single intragastric administration of 750 mg/kg body weight N-ethyl-N-hydroxyethylnitrosamine, two subcutaneous injections of 0.5 mg/kg body weight N-methylbenzyl-nitrosamine and four subcutaneous injections of 40 mg/kg body weight 1,2-dimethylhydrazine. At the same time the rats were given 0.1% N-dibutylnitrosamine for 4 weeks and then 0.1% 2,2'-dihydroxy-di-n-propylnitrosamine for 2 weeks in the drinking water, for a total carcinogen exposure period of 6 weeks. Starting 3 days thereafter the rats received 1% alpha-Toc, 1% TBHQ, 1% PG or 0.7% BHT in the diet, or basal diet alone. Further groups of 10-15 animals each were treated with antioxidant alone or basal diet alone as controls. Surviving animals were killed at the end of week 36. Histopathological examination showed that alpha-Toc increased the incidence of glandular stomach atypical foci but reduced the incidence and multiplicity of kidney atypical tubules. TBHQ significantly elevated the incidences of esophageal papillary or nodular (PN) hyperplasias and papillomas, as well as forestomach papillomas, but significantly decreased the multiplicity of colon adenocarcinomas. PG was only effective in reducing the multiplicity of kidney atypical tubules. BHT enhanced the development of thyroid hyperplasias, but strongly reduced the incidence and multiplicity of colon adenocarcinomas. This compound was also associated with lowered incidence and multiplicity of renal cell tumors. None of the agents studied was unequivocal in exerting either positive or negative influence.

Promoting Effect of the Peroxisome Proliferator, Clofibrate, but Not Di(2‐ethylhexyl)phthalate, on Urinary Bladder Carcinogenesis in F344 Rats Initiated by N‐Butyl‐N‐(4‐hydroxybutyl)nitrosamine

The modifying potential of clofibrate and di(2‐ethylhexyl)phthalate (DEHP) on second stage, N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine (BBN)‐initiated urinary bladder carcinogenesis was investigated in male F344 rats, using a uracil‐accelerated transitional cell proliferation model. Six‐week‐old animals received 0.05% BBN in their drinking water for 4 weeks and then clofibrate (1.0, 0.5, and 0.25%) and DEHP (1.2, 0.6, and 0.3%) were given during experimental weeks 5–8 and weeks 12–20. Uracil was administered during weeks 9–11 at a dietary level of 3.0%. Control rats were treated with BBN and uracil without peroxisome proliferator. Surviving animals were killed at the end of week 20 of the experiment, when the densities of putative preneoplastic, papillary or nodular (PN) hyperplasias (numbers per 10 cm of basement membrane) were significantly increased in all clofibrate‐treated, but not the DEHP groups. The incidences of PN hyperplasia were similar in both treated animals and controls. In a second experiment, rats fed diets containing 1.0% clofibrate or 1.2% DEHP were assessed for levels of DNA synthesis in urinary bladder epithelium by 5‐bromo‐2′‐deoxyuridine immunohistochemistry. Numbers of labeled nuclei remained within normal levels, and no proliferative changes were evident. Thus, the present experiments indicated that while clofibrate, but not DEHP, exerts weak enhancing effects on BBN‐initiated urinary bladder carcinogenesis in rats this is not associated with increased levels of DNA synthesis in the affected epithelium.

Detection of human papillomavirus DNA in oral mucosal lesions using in situ DNA-hybridization applied on paraffin sections

The in situ DNA hybridization technique, carried out under stringent conditions, was used to detect human papillomavirus (HPV) DNA of types 6, 11, and 16 in paraffin sections of 32 surgically treated oral mucosal lesions. Expression of HPV structural proteins was analyzed by means of the immunoperoxidase (IP-PAP) method. A total of 10 (31.3%) of the 32 lesions proved to express HPV antigens, which were found in 4 of 7 squamous cell papillomas, in 2 of 2 classic condylomas, in 2 of 10 papillary hyperplasias, and in 2 of 3 leukoplakia lesions. Two of the squamous cell papillomas contained HPV 6 DNA, and 4 additional lesions were positive for HPV 11 DNA. In one of the condylomas, a double infection by HPV 6 and 11 was found, while the second was positive for HPV 11 alone. Both the HPV antigen-positive papillary hyperplasias contained HPV 6 DNA, as did the HPV antigen-positive leukoplakia lesions. Of the latter, one was infected by HPV 6 and 11. DNA of the “high-risk” HPV 16 was contained in two lesions: one lichen planus lesion and one of the two squamous cell carcinomas. The results confirm the previously reported evidence of HPV involvement in oral mucosal lesions. The implications of these findings are discussed in terms of the well-established premalignant character of oral leukoplakia and oral lichen planus, although far less commonly versus leukoplakia, with special emphasis on the discovery of the “high-risk” HPV 16 in the latter as well as in oral cancer. The use of the in situ DNA hybridization as a powerful tool in detecting the specific HPV DNA sequences in routinely processed oral biopsy specimens is advocated.