Enhanced malignant tumorigenesis in Cdk4 transgenic mice

In a previous study, we reported that overexpression of cyclin-dependent kinase-4 (CDK4) in mouse epidermis results in epidermal hyperplasia, hypertrophy and severe dermal fibrosis. In this study, we have investigated the susceptibility to skin tumor formation by forced expression of CDK4. Skin tumors from transgenic mice showed a dramatic increase in the rate of malignant progression to squamous cell carcinomas (SCC) in an initiation-promotion protocol. Histopathological analysis of papillomas from transgenic mice showed an elevated number of premalignant lesions characterized by dysplasia and marked atypia. Interestingly, transgenic mice also developed tumors in initiated but not promoted skin, demonstrating that CDK4 replaced the action of tumor promoters. These results suggest that expression of cyclin D1 upon ras activation synergizes with CDK4 overexpression. However, cyclin D1 transgenic mice and double transgenic mice for cyclin D1 and CDK4 did not show increased malignant progression in comparison to CDK4 transgenic mice. Biochemical analysis of tumors showed that CDK4 sequesters the CDK2 inhibitors p27Kip1 and p21Cip1, suggesting that indirect activation of CDK2 plays an important role in tumor development. These results indicate that, contrary to the general assumption, the catalytic subunit, CDK4, has higher oncogenic activity than cyclin D1, revealing a potential use of CDK4 as therapeutic target.

[Correlation of E2F-1 and Rb expression with papillomatosis and ductal carcinoma in situ of the breast]

OBJECTIVE

E2F-1 and Rb are involved in cell cycle regulation. This study was to illustrate the mechanism of transformation from benign papillomatosis to ductal carcinoma in situ (DCIS) of the breast in relation to E2F-1 and Rb expression.

METHODS

In situ hybridization (ISH) was used to determinate the expression of E2F-1 and Rb mRNA of mild papillomatosis (MP, n = 40), severe papillomatosis (SP, n = 40) and DCIS (n = 40). Immunohistochemistry (IHC) was used to examine the expression of E2F-1 and Rb protein.

RESULTS

The positive rate of E2F-1 mRNA expression in MP, SP and DCIS was 17.5%, 45.0% and 80.0%, and that of E2F-1 protein expression was 20.0%, 47.5% and 77.5%, respectively. There were significant differences among the three groups (P < 0.01), and between any two groups (P < 0.01). The positive rate of Rb mRNA expression in MP, SP and DCIS was 90.0%, 50.5% and 20.0%, and that of Rb protein expression was 85.0%, 52.5% and 22.5%, respectively, with statistically significant difference similar with that of E2F-1. With the progression of papillomatosis to DCIS, the expression of E2F-1 mRNA and protein increased, while that of Rb decreased. The protein expression by IHC was positively correlated with the mRNA expression by ISH. However, that of E2F-1 was negatively correlated with Rb.

CONCLUSION

E2F-1 and Rb might provide a valuable basis for screening high risk papillomatosis and new target of gene therapy for pre-cancerous lesions of the breast.

Molecular characterization of mutations in patients with benign and aggressive recurrent respiratory papillomatosis: a preliminary study

This study was performed to determine whether genetic polymorphisms within the human papillomavirus (HPV) can predict the disease course in patients with recurrent respiratory papillomatosis. The HPV type and genomic variations were determined by comparing the sample sequence to a prototypical HPV in the database of the National Center for Biotechnology Information. The results were correlated with the clinical course. Seven children and 6 adults were studied. Six of the 7 children had aggressive disease associated with HPV type 11. The remaining child had HPV type 6. Five of the 6 adult patients had HPV type 6; 1 had a history of juvenile recurrent respiratory papillomatosis. The remaining adult had an aggressive disease course associated with HPV type 11. The HPV type and specific polymorphisms were conserved over time in serial isolates. The age of onset and medical therapy did not appear to affect the polymorphisms present. Future studies may find that the presence of certain polymorphisms is associated with different geographic locations and possibly with the disease course.

Multicenter initiative seeking critical genes in respiratory papillomatosis

OBJECTIVES

To determine the host genes that govern susceptibility to recurrent respiratory papillomatosis (RRP). RRP is caused by human papillomavirus (HPV) 6 and 11. Millions of babies are exposed during the birthing process, but relatively few develop the disease and the aggressiveness of the course is highly variable. Genetically encoded host susceptibility is postulated. Determining the host genes that govern susceptibility will enhance our understanding not only of RRP but also of host-viral interaction in general.

STUDY DESIGN

A genome-wide association study on familial triads consisting of an RRP-affected child and his or her parents. Using the HapMap data from the human genome project, we will identify those alleles that are over-transmitted by the parents to their affected offspring as compared to those alleles that are under-transmitted.

METHODS

Approximately 400 patients and their parents will be recruited through a collaboration between the Center for Genomic Sciences and the RRP Task Force. DNA will be extracted from blood specimens and viral typing will be performed on biopsy specimens. Patients will be genotyped using single nucleotide polymorphism (SNP) markers and compared to their respective parents' genotype using the transmission disequilibrium test. Both a genome scan and a candidate gene approach will be utilized. RESULTS Institutional Review Board authorization has been obtained at three hospitals and the process is underway at 18 more. Patient and parent recruitment has begun. Specimens have been forwarded to Pittsburgh, Pennsylvania, where the DNA has been extracted and is being stored.

CONCLUSIONS

A novel approach combining a nationwide patient resource and the mapping power of the sub-centimorgan human haplotype map has been developed to elucidate the biological mechanisms of RRP by determining the genetically encoded susceptibilities of host-virus interaction.

Human Papillomavirus Genotyping by the DNA Chip in the Cervical Neoplasia

Human papillomavirus (HPV) is implicated as an etiologic agent in neoplasitc lesions of the cervix. In this study, we used an HPV DNA chip to detect the type-specific sequence of HPV from cervical swabs in women with biopsy- proven neoplastic lesions of the cervix. Four hundred seventy-one patients were involved and classified into four groups based on the cytopathologic diagnosis: group I (normal, n = 290), group II (low-grade squamous intraepithelial lesions (SIL), n = 68), group III (high-grade SIL, n = 51), and group IV (invasive cervical cancer, n = 55). HPV detection rates were 17.6% (51 of 290), 73.5% (50 of 68), 92.2% (47 of 51), and 95.2% (59 of 62) in patients of group I to group IV, respectively. HPV-16 was the most frequent type (21.8%) in all specimens tested, and significantly increased the prevalence by advancing the grade of the cervical lesions (P < 0.01). The next frequent virus types were HPV-18 and HPV-58. The prevalence of multiple HPV infections was 37.3, 43.7, 27.7, and 28.8%, and no significant difference was detected between each group (P > 0.05). This suggests that the HPV DNA chip is a sensitive diagnostic tool for the detection of HPV in cervical specimens, and that it would provide more useful information on viral genotype and multiple HPV infections. Taken together, molecular biological data on HPV might be beneficial for the prevention and management of cervical neoplastic lesions.

Human papillomavirus DNA presence of the upper respiratory tract mucosa of healthy children

The papillomaviruses are a group of small DNA (8 kbp) viruses which induce papillomas in human and animals. Most of them can also transform epithelial cells of human and other vertebrates. Examinations of children with Recurrent Respiratory Papillomatosis (RRP), using PCR method with specific primers, revealed HPV type 6 or/and 11 in 98%-100% tissue samples. Little is known about HPV infection in upper respiratory tract of healthy children. The group of 201 healthy children (from 3 to 10 years old) was laryngologically examined. The smears from noses and throats were studied for the presence of HPV viruses DNA. PCR was performed as described by Tucker et al. 28.8% of children from the study group were HPV positive. The presence of HPV in respiratory tract in children is relatively high. "High risk" HPV are not observed in the respiratory tract in children. The Human Papillomavirus in children may be transmitted by direct contacts.

Laser capture microdissection analysis reveals frequent allelic losses in papillary urothelial neoplasm of low malignant potential of the urinary bladder

BACKGROUND

In the 1999 World Health Organization classification system, papillary tumors of the urinary bladder were classified as papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), and as Grade 1, Grade 2, and Grade 3 urothelial carcinoma. The biologic potential of PUNLMP of the urinary bladder is controversial. To the authors' knowledge, information regarding the genetic changes of PUNLMP tumors of the bladder is limited.

METHODS

The authors examined loss of heterogygosity (LOH) at 5 polymorphic microsatellite markers on chromosome 9q32-33 (D9S177), 9p22 (IFNA), 17p13.1 (TP53), 12q14-24 (D12S1051), and 3p25-26 (D3S3050) from 26 patients who were diagnosed with PUNLMP tumors of the urinary bladder. Tumors were microdissected from sections prepared from formalin-fixed, paraffin-processed tissue specimens using laser capture microdissection.

RESULTS

LOH was found in 21 of 26 (81%) patients with PUNLMP. The rate of LOH was 41% with D9S177, 32% with IFNA, 29% with TP53, 26% with D12S1051, and 44% with D3S3050. Allelic loss of multiple chromosome loci was often present in patients with PUNLMP tumors.

CONCLUSIONS

Genetic changes that commonly occur in advanced bladder carcinoma (> or = pT2) are frequently found in PUNLMP of the urinary bladder.

HLA-DQ alleles in white and African American patients with juvenile-onset recurrent respiratory papillomatosis

OBJECTIVE

To determine HLA-DQalpha and -DQbeta1 allele associations in juvenile-onset recurrent respiratory papillomatosis (RRP) for risk, disease course, and human papillomavirus type.

DESIGN

A nonrandomized controlled study was performed on DNA extracted from papilloma specimens of children with a history of RRP, and from peripheral blood of African American and white children without RRP. The frequencies of DQalpha and DQbeta1 alleles were compared between patients and ethnically matched controls.

SUBJECTS

Records of 48 children treated for RRP at Children's Hospital of Michigan in Detroit (26 African American and 22 white) were reviewed. Control subjects consisted of 80 African American and 80 white children seen at the hospital for conditions other than RRP.

RESULTS

African American and white patients with DQbeta1*050X (not *0501, *0502, *0503, *0504, or *0505) were at higher risk to develop RRP than controls (P =.01 and.03, respectively). DQbeta1*0402 was protective for African Americans (P =.01). Whites with DQalpha*0102 were at risk for RRP (P =.03). This allele was associated with disease remission in African Americans (P =.03). DQalpha*0101/0104 conferred protection in whites (P =.047). No association was seen for allele frequency and human papillomavirus type. Whites with haplotype DQalpha*0501/DQbeta1*0201 were at high risk for RRP (P =.002). No relationships were seen for African Americans or whites between haplotype frequencies and disease course or human papillomavirus type.

CONCLUSIONS

HLA-DQalpha and -DQbeta1 alleles occur at different frequencies in African American and white children with RRP than controls. Specific alleles influence risk for RRP. Allele and haplotype frequencies have some influence on disease course, but were independent of human papillomavirus type.

Smad7 but not Smad6 cooperates with oncogenic ras to cause malignant conversion in a mouse model for squamous cell carcinoma

Smad7 and Smad6 are inhibitory Smads that block transforming growth factor-beta (TGF-beta) superfamily signal transduction. Smad7 is overexpressed in chemically induced mouse epidermal tumors, where oncogenic activation of c-ras is a frequent event. To test the role of Smad7 overexpression in tumor progression, we used retroviruses to transduce Smad7 or Smad6 and v-ras(Ha) into primary mouse keratinocytes. By itself, Smad7 transiently enhanced keratinocyte proliferation, blocked normal differentiation, and induced keratin 8, a marker of malignant conversion, but did not cause tumor formation. Smad7 extended the in vitro life span, suppressed senescence, and increased transformation frequency 3-fold of primary keratinocytes coexpressing v-ras(Ha). Smad7/v-ras(Ha) coinfected keratinocytes rapidly progressed to squamous cell carcinomas in vivo, whereas pBabe/v-ras(Ha)- or Smad6/v-ras(Ha)-transduced keratinocytes formed only benign papillomas. Smad7/v-ras(Ha) tumors had elevated proliferation and defective nuclear localizaton of Smad2, Smad3, and Smad5, whereas only Smad5 was altered in Smad6/v-ras(Ha) tumors. Smad7 overexpression in vitro induced epidermal growth factor (EGF)-like growth factors TGF-alpha, heparin binding-EGF, amphiregulin, and EGF receptor tyrosine phosphorylation as well as the EGF-CFC growth factor cripto-1. TGF-alpha and cripto-1 were also overexpressed in Smad7/v-ras(Ha) tumors. These results suggest that Smad7 overexpression accelerates tumor progression through inhibition of TGF-beta superfamily signaling and up-regulation of the EGF-like superfamily of growth factors. This is the first demonstration that Smad7 overexpression can cause malignant conversion in a multistage cancer model and suggests that it may have an important role in the pathogenesis of human cancer.

[The expression and clinical implication of inducible nitric oxide synthase mRNA in laryngeal carcinoma and hypopharyngeal carcinoma]

OBJECTIVE

To study the expression of inducible nitric oxide synthase(iNOS) mRNA in laryngeal carcinoma and hypopharyngeal carcinoma and its clinical significance.

METHOD

The tissue samples (laryngeal carcinoma, 40; hypopharyngeal carcinoma, 12; adjacent tissue, 50; laryngeal papilloma, 10; amyloidosis of larynx, 2; and normal laryngeal mucosa, 7) were examined by reverse transcription-polymerase chain reaction(RT-PCR).

RESULT

1. The target gene of iNOS were detected in 41 of 52 tumor tissues, 10 of 50 adjacent tissues, 5 of 12 benign tumor tissues and 0 of 7 normal tissues. The difference was significant (P < 0.0001, P < 0.005, P < 0.0001); 2. No significant difference was found among the expression of iNOSmRNA in different primary locations, there was significant statistical difference between the early clinical stages (T1-T2) and the advanced stages (T3-T4); 3. The poorly differentiated tumor cell showed a higher iNOSmRNA expression than that in moderate differentiated tumor cell (P < 0.05) and the iNOSmRNA expression in the lymph node metastasis group was higher than the non-metastasis group (P < 0.05).

CONCLUSION

It suggests that iNOS gene expression occurs in human laryngeal carcinoma and hypopharyngeal carcinoma, it might involve in the development of head and neck neoplasms in gene level by generating NO.

A PMLRARA transgene results in a retinoid-deficient phenotype associated with enhanced susceptibility to skin tumorigenesis

The construction of transgenic FVB/N mice targeting the PMLRARA fusion gene under the control of a human MRP8 promoter recapitulated the phenotype of acute promyelocytic leukemia but had the unexpected result of multiple squamous papillomas of the skin (Brown et al., PROC: Natl. Acad. Sci. USA, 94:2551-2556, 1997). In addition, transgenic MRP8-PMLRARA mice exhibited a skin phenotype characteristic of vitamin A deficiency. The severity of the skin phenotype and spontaneous papilloma development correlated with the level of transgene expression. Papilloma formation was preceded by follicular hyperplasia and the expression of epidermal differentiation markers in the follicular epithelium. Mutations in the Ha or Ki alleles of ras were not detected in papillomas that developed on transgenic skin, and papilloma formation was accentuated on the C57/Bl6 background, unlike the usual resistance of this strain to skin tumor induction. Analysis of liver extracts from transgenic mice indicated a deficiency in the production of retinoic acid. Furthermore, affected transgenic epidermis had reduced levels of retinoic acid receptoralpha (RARalpha) and retinoic X receptor (RXRalpha), and supplementation with exogenous retinoic acid prevented the skin phenotype. When transgenic keratinocytes were grafted to nude mice, the resulting integument was normal, and conversely, when transgenic bone marrow was grafted to normal mice, a skin phenotype did not develop. Together these results suggest that local interruption of PML and RARalpha signaling in the skin, together with a systemic retinoid deficiency, initiates a tumor induction pathway that is independent of ras activation.

Evaluation of the Tg.AC assay: specificity testing with three noncarcinogenic pharmaceuticals that induce selected stress gene promoters in vitro and the inhibitory effects of solvent components

Understanding the strengths and limitations of alternative models, such as the Tg.AC assay, for evaluation of the potential carcinogenicity of pharmaceuticals requires assessment of assay specificity through studies that specifically target biologically active compounds that are known to not be carcinogens in rodents. To identify drugs that might provoke a false positive response in the Tg.AC assay, we screened pharmaceuticals for in vitro induction of the gadd153 promoter and the zeta-globin promoter. We have previously found a high correlation between induction of the gadd153 promoter in HepG2 cells and activity in the Tg.AC assay. The three drugs selected through screening 99 noncarcinogenic pharmaceuticals were amiloride, dipyridamole, and pyrimethamine. A 26-week skin paint study was conducted in hemizygous Tg.AC mice with the three drugs at two doses selected by a 4-week dose range finding study. Evidence of systemic toxicity was observed in animals dosed chronically with pyrimethamine or amiloride, but no skin papillomas were observed in mice treated with amiloride, dipyridamole, or pyrimethamine for 26 weeks. All male mice and 80% of female mice treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) in acetone developed a maximal tumor burden. However, mice treated with TPA in a vehicle containing 2.4% DMSO had greatly reduced incidences of papillomas. In summary, the correct negative response was shown in the Tg.AC assay for three noncarcinogenic pharmaceuticals, which adds further favorable evidence of appropriate specificity of this model system. However, vehicle composition must be carefully selected because the outcome of this assay can be confounded by certain commonly used solvents.

Deficiency of kinase suppressor of Ras1 prevents oncogenic ras signaling in mice

In Drosophila and Caenorhabditis elegans, kinase suppressor of ras (KSR) positively modulates Ras/Raf-mitogen-activated protein kinase (MAPK) signaling. The precise signaling mechanism of mammalian KSR1 and its role in Ras-mediated transformation, however, remain uncertain. To gain insight into KSR1 function in vivo, we generated mice homozygous null for KSR1. ksr1-/- mice are viable and without major developmental defects. However, an unusual disorganized hair follicle phenotype manifest in epidermal growth factor receptor knockout mice is recapitulated in ksr1-/- mice, providing genetic support for the notion that epidermal growth factor receptor, Ras, and KSR1 are on the same signaling pathway in mammals. Furthermore, ksr1-/- mice allow for the definition of KSR1-dependent and -independent mechanisms of c-Raf-1 activation. In embryonic fibroblasts, epidermal growth factor and 12-O-tetradecanoylphorbol-13-acetate activated the MAPK cascade to a similar extent, yet only c-Raf-1 activation by epidermal growth factor depended on KSR1. Moreover, whereas the genesis of polyomavirus middle T antigen (MT)-driven mammary cancer appears independent of KSR1, KSR1 is obligate for v-Ha-ras-mediated skin tumor formation. The growth of MT-driven mammary tumor was moderately slowed in ksr1-/- mice, however, consistent with a decreased rate of proliferation of ksr1-/- cells (T cells and embryonic fibroblasts). Nonetheless, all ksr1-/- animals succumbed to mammary cancer. In contrast, papilloma formation in Tg.AC mice, resulting from skin-specific v-Ha-ras expression, was completely abrogated in the ksr1-/- background. Hence, MT-driven mammary tumor genesis, which is signaled through src and phosphatidylinositol 3'-kinase, appears KSR1 independent, whereas v-Ha-ras-mediated skin cancer, signaled through the Raf-1/MAPK cascade, requires KSR1. These results suggest KSR1 may represent a therapeutic target for Ras/MAPK signaling of human tumorigenesis.

Smad3 regulates senescence and malignant conversion in a mouse multistage skin carcinogenesis model

Transforming growth factor beta (TGF-beta) is a growth-inhibitory cytokine for epithelial cells. In the mouse multistage skin carcinogenesis model, defects in TGF-beta 1 signaling reduce senescence in vitro and accelerate malignant progression in vivo. However, the precise postreceptor signaling pathways and specific roles played by Smad proteins in this process have not been defined. Here we show that senescence of v-ras(Ha)-transduced Smad3 null keratinocytes is delayed, whereas overexpression of Smad3, but not Smad2 or Smad4, induced senescence. The TGF-beta 1 target genes c-myc and p15(ink4b) were deregulated in the absence of Smad3. When transplanted to a graft site on nude mice, the v-ras(Ha)-transduced Smad3 null keratinocytes underwent rapid conversion from benign papilloma to malignant carcinoma, whereas wild-type keratinocytes predominantly formed papillomas. These results link Smad3-mediated regulation of growth control genes to senescence in vitro and tumor suppression in vivo.

H-ras mutations at codon 61 or 13 in tumors initiated with a NO donor in mouse skin

The tumor-initiating activity of nitric oxide (NO) in carcinogenesis was assessed using (+/-)-(E)-4-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexenamide (NOR1), a synthetic NO donor. Topical application of NOR1 followed by 12-O-tetradecanoylphorbol 13-acetate (TPA) treatment twice a week for 20 weeks resulted in the development of papillomas in mice. All of the papillomas examined contained H-ras mutations at codons 61 or 13. At codon 61, CAA-CTA and CAA-TTA mutations were seen in 42/46 and 1/46 of the papillomas, respectively. Three papillomas without a mutation at codon 61 were mutated at codon 13. A GGC-CGC mutation was found in two of these samples while the third possessed a GGC-GTC mutation. These results suggest that NO possesses tumor-initiating activity through a process that induces mutation in H-ras.

IL-1 alpha, innate immunity, and skin carcinogenesis: the effect of constitutive expression of IL-1 alpha in epidermis on chemical carcinogenesis

Tumor promoters such as the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) are proinflammatory agents, and their mechanism of action in epithelial carcinogenesis has been linked to the release of IL-1 alpha and the induction of chronic inflammation in skin. To test the role of IL-1 alpha and inflammation in models of cutaneous carcinogenesis, we used our previously described FVB/N transgenic mice overexpressing 17-kDa IL-1 alpha in the epidermis under the keratin 14 (K14) promoter. Strikingly, the K14/IL-1 alpha mice were completely resistant to papilloma and carcinoma formation induced by a two-stage DMBA/TPA protocol, while littermate controls developed both tumor types. K14/IL-1 alpha mice crossed with the highly sensitive TG.AC mice, constitutively expressing mutant Ha-Ras, also failed to develop papillomas or carcinomas. When the K14/IL-1 alpha transgene was bred onto a recombinase-activating gene-2-deficient background, the resistance persisted, indicating that innate, but not acquired, mechanisms may be involved in the resistance to the initiation/promotion model. As an alternative approach, a complete carcinogenesis protocol using repetitive application of DMBA alone was applied. Surprisingly, although the IL-1 alpha mice still did not develop papillomas, they did develop carcinomas de novo at an accelerated rate compared with controls. We conclude that constitutive IL-1 alpha expression rendered FVB mice completely resistant to carcinomas that required evolution from prior papillomas, but facilitated carcinomas that did not evolve from papillomas, as in the complete carcinogenesis protocol. Thus, the role of IL-1 alpha and, by extension that of other proinflammatory factors, in epithelial carcinogenesis are more complex than previously appreciated. These mice may provide a mechanism to investigate the validity of these models of human skin tumorigenesis.

[New WHO classification of urothelial carcinoma of the urinary bladder]

The WHO classification of urothelial carcinomas of the urinary bladder (1999) presents the papillary urothelial neoplasia of low malignant potential (PUNLMP) as a new entity in between the papillomas and the papillary urothelial carcinomas. This neoplasia shows a typical basal palisading, a low mitotic rate, and a low MIB-1-proliferation index. The PUNLMP is said to have an increased risk of development of recurrent papillary lesions with the possibility of malignant transformation. At present, there is an intensive discussion on this new entity. The participants of a meeting on the consensus classification on urothelial tumors held in Ancona in 2000 have meanwhile split in two discussion groups. One favors the new WHO classification with the papillary urothelial carcinomas G I, G II, and G III, but without PUNLMP, whereas the other group favors the consensus classification of 1998 with papillomas, papillary urothelial neoplasia of low malignant potential, and non invasive as well as invasive low-grade and high grade papillary urothelial carcinomas. Future long term prospective studies will show the significance of PUNLMP compared to well differentiated non invasive papillary urothelial urinary bladder carcinoma G I (G Ia). Otherwise, there is no significant difference in the classification of carcinomas and non epithelial lesions compared with the previous classification of 1973. The new WHO does however discriminate the minimally invasive papillary urothelial carcinomas in those with infiltration of the lamina propria above the muscularis mucosae (pT1a), the infiltration of the lamina muscularis mucosae (pT1b), and the extension beyond the muscularis mucosae (pT1c). The recurrence rate increases from stage pT1b. This substaging may be of therapeutical relevance.

Biliary papillomatosis arising in a congenital choledochal cyst: report of a case

We report a rare case of biliary papillomatosis arising in a congenital choledochal cyst, with an anomalous junction of the pancreatobiliary ductal system (AJPBDS). A 50-year-old woman was admitted to our department with epigastralgia, and imaging studies showed two masses in the cystic common bile duct and an AJPBDS. We made a preoperative diagnosis of biliary tract cancer, considering the size of the masses and the presence of the AJPBDS, and performed a pylorus-preserving pancreatoduodenectomy. The resected specimen contained two papillary tumors, which were subsequently diagnosed as benign papillomas. Histopathological and oncological examinations indicated that the lesions were involved in the development and progression of carcinogenesis because a point mutation of the K- ras gene and overexpression of p53 protein were detected. These findings suggest that biliary papillomatosis is a precancerous lesion induced by an AJPBDS.

Expression of enhancing factor/phospholipase A2 in skin results in abnormal epidermis and increased sensitivity to chemical carcinogenesis

Enhancing factor (EF), a growth factor modulator, is the mouse homologue of human secretory group II phospholipase A(2). EF exhibits growth-promoting activity in vitro, in the presence of epidermal growth factor, and also brings about phenotypic transformation of normal cells. In order to ascertain the role of EF in vivo, a human keratin-14 promoter was used to drive the expression of EF ectopically to squamous epithelial cells. The founder mouse and its progeny showed abnormal whiskers and a scaly, beaded tail. In these mice, keratinization pattern of the epidermis was disturbed and parakeratosis and acanthosis were noted. The transgenic mice, TgK14-EF, expressed EF in the suprabasal layers of tail epidermis as well as in the epithelial cells of hair follicle and sebaceous glands of skin. Expression of EF along with hyperplasia was also observed in other squamous epithelia such as buccal mucosa, tongue and oesophagus. TgK14-EF mice homozygous for the transgene showed delayed and scanty hair growth although the mice were healthy and fertile. The hemizygous TgK14-EF mice were sensitive to a two-stage chemical carcinogenesis and developed a higher number of papillomas than their normal littermates over the course of the experiment. The conversion rate of papilloma to carcinoma was two fold higher in the transgenic mice.

Molecular transformation of recurrent respiratory papillomatosis: viral typing and p53 overexpression

Recurrent respiratory papillomatosis (RRP) is a histologically benign disease of the larynx, trachea, and bronchi. Here we report on the histologic and molecular characteristics of 7 cases of malignant transformation of RRP to squamous cell carcinoma (SCCA). The clinical histories of 7 patients with RRP who developed SCCA were carefully reviewed. Sequential biopsies were available from 5 of the 7 cases of spontaneous transformation of RRP to SCCA and were reviewed. In addition, p53 protein overexpression and human papillomavirus (HPV) typing for all cases was examined. The average age of patients with juvenile-onset RRP was 3 years, and that of patients with adult-onset RRP was 31 years. The average age of onset of transformation to SCCA was 28 years. All patients had laryngeal involvement with RRP, and 3 of the 7 patients had tracheal extension of disease. Five patients were tracheotomy-dependent. Four of the 7 patients developed SCCA of the lung, while 3 patients developed laryngeal SCCA. There was no consistent histologic progression from squamous papilloma to papilloma with dysplasia, and all but 1 of the SCCAs were well differentiated. The overexpression of p53 protein was variable in each of the 5 patients. We detected HPV types 6/11 in papillomas from 3 patients, and HPV types 6/11, 16/18, and 31/33/51 in a papilloma of a fourth patient. No HPV DNA was detected in papillomas of 2 patients. We found HPV 6/11 in 4 of the carcinomas. We conclude that the spontaneous transformation of RRP to SCCA is not characterized by a histologic progression through dysplasia over time. Transformation can result in the loss of HPV expression. It does not appear that p53 is a molecular marker for monitoring the transformation process. Thus, these cancers may be very difficult to diagnose histologically and clinically early in the course of the transformation of the disease.

Anaesthetic implications of Costello syndrome

Costello syndrome is a disorder that primarily involves ectodermal tissues and is characterized by mental and growth retardation, distinctive coarse facies, redundant skin (neck, palms and soles), and papillomata (perioral, nasal and anal). Of primary concern to anaesthesiologists are potential airway difficulties related a short neck, macroglossia, hypertrophied tonsillar and supraglottic tissues, laryngeal papillomata and choanal atresia. A significant percentage of patients also have cardiac involvement which may manifest as congenital heart defects, arrhythmias, valvular dysfunction, or hypertrophic cardiomyopathy. Central nervous system involvement includes developmental delay and seizure disorders while endocrine abnormalities have been reported including hypothalamic-pituitary dysfunction resulting in hypopituitarism, hypothyroidism, and hypoadrenalism. The authors present a 2-year old child with Costello syndrome who required anaesthesia for direct laryngoscopy, rigid bronchoscopy, bilateral pressure equalization tubes and tonsillectomy. The perioperative implications of the syndrome are discussed.

DNA repair protein MGMT protects against N-methyl-N-nitrosourea-induced conversion of benign into malignant tumors

Tumor formation is a multi-step process that can be divided into the stages of tumor initiation, promotion and progression. Previously, we showed that overexpression in skin of mice of the DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) protects against N-methyl-N-nitrosourea (MNU)-induced tumor initiation without affecting tumor promotion. This indicated that O(6)-methylguanine, which is specifically repaired by MGMT, is a major tumor-initiating lesion. Here we extended this transgenic approach to the study of tumor progression. Benign papillomas that arose on the skin of CkMGMT transgenic mice upon initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) expressed higher levels of MGMT than papillomas that appeared on DMBA/TPA treated non-transgenic NMRI mice. Treatment of papillomas with MNU resulted in the formation of malignant carcinomas to a significantly lower frequency in CkMGMT mice as compared with the non-transgenic control. The data provide evidence that increased DNA repair protects against the conversion of benign into malignant tumors. They show at the same time that a particular type of damage induced in DNA, namely O(6)-methylguanine, is decisively involved in triggering tumor progression. This supports the concept that the major cause of both tumor initiation and tumor progression is mutation. Data also indicate that alkylating anti-neoplastic drugs may provoke tumor progression in case of failure of tumor therapy, which is attenuated by DNA repair.

Tumor initiating activity of Helicobacter pylori water extract on mouse skin carcinogenesis

Helicobacter pylori (H. pylori) infection has been associated with gastric carcinogenesis, but responsible and detail mechanisms are insufficient by the absence of adequate data. To obtain direct evidence regarding the carcinogenicity of H. pylori, we investigated the initiating and promoting activity of H. pylori water extract (HPE) in two-stage mouse skin carcinogenesis model. HPE treatment, as an initiation, significantly enhanced tumor formation compared with control group. Moreover, HPE treatment increased production of 8-hydroxydeoxyguanosine in epidermal cells and HPE-initiated/TPA-promoted papillomas demonstrated a point mutation of the Ha-ras gene. These results suggest an initiating activity of HPE on two-stage mouse skin carcinogenesis.

[Expression and significance of proliferation marker and apoptosis-related genes in benign and malignant epithelial lesions of the larynx]

OBJECTIVE

In order to study the ki-67, bcl-2, bax proteins expression and significance in the benign and malignant epithelium of the larynx.

METHOD

An immunohistochemical S-P assay was used to detect the expression of ki-67, bcl-2, bax in LSCCs, epithelial dysplasia, papillomas, simple hyperplasia and normal laryngeal epithelium.

RESULT

The mean value of ki-67 was 52.0%, 50.0%, 47.8%, 41.6%, 10.0% respectively. The different was statistically significant between LSCCS or dysplasia and normal laryngeal epithelial (P < 0.05). The mean value of bcl-2 was 44.0% in LSCCs, 11.0% in dysplasia, 0% in other three epithelial lesions of the larynx. Bcl-2 was highly positive in LSCCs compared to the other lesions (P < 0.05, P < 0.01, P < 0.01). The expression of bax was 76.0%, 77.8%, 69.6%, 58.3%, 80.0%. In papillomas, there was statistically significant positive correlation between Bcl-2 and ki-67.

CONCLUSION

Ki-67 and Bcl-2 coexpression may play a role in the uncontrolled proliferation in papillomas. Ki-67, bax, Bcl-2 could help in estimation the premalignant stages of the larynx.