Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The vesicant agents of the unitary chemical munitions stockpile include various formulations of sulfur mustard [bis-(2-chloroethyl) sulfide; agents H, HD, and HT] and small quantities of the organic arsenical Lewisite [dichloro(2-chlorovinyl) arsine; agent L]. These agents can be dispersed in liquid, aerosol, or vapor form and are capable of producing severe chemical burns upon direct contact with tissue. Moist tissues such as the eyes, respiratory tract, and axillary areas are particularly affected. Available data summarizing acute dose response in humans and laboratory animals are summarized. Vesicant agents are also capable of generating delayed effects such as chronic bronchitis, carcinogenesis, or keratitis/keratopathy of the eye under appropriate conditions of exposure and dose. These effects may not become manifest until years following exposure. Risk analysis derived from carcinogenesis data indicates that sulfur mustard possesses a carcinogenic potency similar to that of benzo[a]pyrene. Because mustard agents are alkylating compounds, they destroy individual cells by reaction with cellular proteins, enzymes, RNA, and DNA. Once begun, tissue reaction is irreversible. Mustard agents are mutagenic; data for cellular and laboratory animal assays are presented. Reproductive effects have not been demonstrated in the offspring of laboratory rats. Acute Lewisite exposure has been implicated in cases of Bowen's disease, an intraepidermal squamous cell carcinoma. Lewisite is not known to generate reproductive or teratogenic effects.
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PMID:Toxicity of vesicant agents scheduled for destruction by the Chemical Stockpile Disposal Program. 148 58

To evaluate the role of human papillomaviruses (HPV) in the development of premalignant lesions and cancers of the skin in the general population, 314 biopsies obtained from 227 patients with benign neoplasms, premalignant lesions, and cancers of the skin and from 25 patients with squamous cell carcinoma of the lip were analyzed by Southern blot hybridization. DNA probes specific for various cutaneous and genital HPV types were used in hybridizations conducted under nonstringent or stringent conditions. HPV DNA sequences were only detected in eight specimens obtained from six patients: HPV 34 in one case of periungual Bowen's disease, HPV 36 and an as yet uncharacterized HPV in two cases of actinic keratosis, HPV 20 in one case of basal cell carcinoma, an as yet unrecognized HPV in one case of squamous cell carcinoma, and HPV 16 in one case of squamous cell carcinoma of the lip. None of the specimens of cutaneous horn and keratoacanthoma contained detectable HPV DNA. In contrast, HPV DNA sequences, mostly HPV 16, were detected in 13 of 23 cases of anogenital Bowen's disease and invasive Bowen's carcinoma. HPV DNA sequences were not detected in 90 cutaneous samples further analyzed by the polymerase chain-reaction technique, using amplification primers that contain conserved sequences among the genomes of HPV. These results strongly suggest that the known HPV types play only a minor role, if any, in skin carcinogenesis in the general population.
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PMID:Premalignant lesions and cancers of the skin in the general population: evaluation of the role of human papillomaviruses. 217 90

The expression of human placental type glutathione S-transferase (GST-pi) was investigated in human cutaneous carcinoma in situ, that is, actinic keratosis and Bowen's disease, and compared with that in normal skin, using Northern blot and immunohistochemical analysis. In Northern blot examination, the expression of GST-pi transcript was recognized in all instances. Carcinoma in situ showed significantly higher expressions of GST-pi than normal skin. In the immunohistochemical examination, nuclear staining of GST-pi was noticed in some dysplastic cells of carcinoma in situ, especially in Bowen's disease. In actinic keratosis, a framework appearance was noticed in the staining pattern at a lower magnification because the lower part of the cytoplasm of dysplastic cells lining the stratum basale was positive for GST-pi, and all cells of the stratum granulosum and more cells of the stratum spinosum showed stronger GST-pi positive reaction than normal skin. In Bowen's disease, GST-pi positive, dysplastic cells existed throughout the epidermis. Because GST-pi positive, dysplastic cells and GST-pi positive, normal looking squamous cells made the GST-pi positive cell nests throughout the epidermis, and GST-pi positive, dysplastic cells, and GST-pi negative, normal looking cells coexisted in the parabasal layer, they showed a sawtooth appearance in the staining pattern at a lower magnification. These findings suggest that GST-pi is involved in the process of carcinogenesis.
Carcinogenesis 1995 Oct
PMID:The expression of placental-type glutathione S-transferase (GST-pi) in human cutaneous carcinoma in situ, that is, actinic keratosis and Bowen's disease, compared with normal human skin. 758 30

Microsatellite instability secondary to replication errors (RER), characterized by length changes at repetitive loci scattered throughout the genome, is a recently recognized genetic mechanism important in the development of some human cancers. Although RER has been reported in sebaceous gland tumors from patients with the Muir-Torre syndrome, the frequency of RER in human non-melanoma and melanoma skin cancers is not known. In this study, we investigated the importance of RER in human skin carcinogenesis. RER was identified in three of four actinic keratoses from a patient belonging to a kindred with documented Muir-Torre syndrome, which indicates that defective DNA replication may contribute to skin cancer development in such patients. Examination of a series of tumors from patients without Muir-Torre, including 137 skin cancers (47 basal cell carcinomas, 49 squamous cell carcinomas, and 41 primary malignant melanomas), 19 actinic keratoses, and 20 cases of Bowen's disease, using 10 or more microsatellite markers, identified repeat-sequence instability in less than 5% of the tumors studied. In six of the eight tumors, the sole change was an alteration 2 base pairs in length at a single locus. One patient with a squamous cell carcinoma showed changes at multiple loci suggesting defective mismatch repair. Although the low frequency of RER found in this study of a large series of human skin tumors suggests that this phenomenon is uncommon in patients with skin cancer, the identification of RER at multiple loci in two patients suggests that error-prone replication may be important in skin cancer development in some individuals.
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PMID:Microsatellite instability in human non-melanoma and melanoma skin cancer. 786 Sep 92

ras mutations have been reported as an early event in some human malignancies and in the mouse skin model of multistep carcinogenesis; early studies in human non-melanoma skin cancers have reported variable rates of ras mutations. A recent study, however, has reported a high frequency of activating mutations of the Harvey-ras proto-oncogene in non-melanoma skin cancers, and the site specificity of the mutation at the second position of codon 12 prompted us to re-examine the importance of Ha-ras codon 12 mutations as an early event in the development of these tumours, using a combination of PCR and restriction fragment polymorphism of codon 12 of the Ha-ras gene. Dilution experiments confirmed that the method was sensitive and capable of detecting mutations at this codon when only 4% of the total alleles are mutated. We were surprised to find no mutations in the 40 basal cell carcinomas, 12 squamous cell carcinomas and 12 cases of Bowen's disease studied. We conclude that Ha-ras codon 12 mutations are rare events in human non-melanoma skin cancer in the U.K. The marked differences in the frequency of codon 12 Ha-ras mutations in published studies may relate to either technical artefacts, or differences in the molecular epidemiology between areas of low and high sun exposure.
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PMID:Codon 12 Harvey-ras mutations are rare events in non-melanoma human skin cancer. 809 49

Transplant recipients successively develop benign, premalignant and malignant skin lesions on sun-exposed areas. It has been suggested that UV radiations might induce mutations in ras oncogenes and p53 tumour-suppressor gene, responsible for skin cancers. With PCR and oligoprobe hybridization, we investigated c-Ha-ras gene mutations at codons 12 and 61 in 120 cutaneous lesions from grafted patients, since they could represent a marker of the evolution of benign skin lesions towards malignancy in this population; 29 similar skin biopsies from non-immunosuppressed patients were also analyzed. In transplant recipients, we detected mutations at codon 12 only in 1/42 non-melanoma skin cancers and 2/29 pre-cancerous keratoses. No mutation was detected in 11 cases of cutaneous Bowen's disease from grafted patients and in pre-malignant and malignant skin samples from control patients. Benign warts exhibited an overall incidence of 18% and 15% of mutations at codon 12 of c-Ha-ras gene in grafted and control patients respectively. We detected only one mutation at codon 61 in a plantar wart. Human papillomaviruses (HPV) are thought to be involved in the malignant evolution of cutaneous disorders in transplant recipients and cooperate with a ras oncogene to induce malignancy in vitro. The presence of HPV DNA in our series of skin samples from grafted patients showed no correlation with the occurrence of c-Ha-ras mutations. Our findings indicate that c-Ha-ras-gene activation by mutations is rare in cutaneous lesions from transplant recipients, and is unlikely to play a crucial role in transformation towards malignancy in skin carcinogenesis among grafted patients.
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PMID:Low incidence of c-Ha-ras gene mutations in benign and malignant cutaneous lesions from transplant recipients. 825 28

Extensive study of the p53 gene has established its role as a tumour-suppressor gene, and the involvement of mutant p53 in a wide spectrum of human malignancy. Many mutations of p53 result in a protein product that is abnormally stable, so that it becomes readily detectable by immunocytochemistry. In contrast, under normal conditions, it has been considered that levels of wild-type p53 were too low to be detectable. Although positive immunocytochemistry has been used as a marker of mutation, recent evidence suggests that this assumption may not always be valid. We have carried out both PCR-sequencing of exons 5-8 of the p53 gene in 20 basal cell carcinomas (BCC), and immunocytochemistry of these tumours with the anti-p53 antibody DO7. Twenty cases of Bowen's disease, in which we had previously documented mutations, were also immunostained. We report a low rate of p53 mutation in the BCCs we examined (2/20), and a discrepancy between tumours with positive immunostaining and those with mutation in both Bowen's disease and BCC. Of eight tumours in which we detected mutation, only four were immunopositive: of 19 immunopositive samples, only four showed detectable mutation. We discuss the implications of our results for the use of positive immunostaining in clinical diagnosis, and the involvement of p53 in skin carcinogenesis.
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PMID:The relation between p53 mutation and p53 immunostaining in non-melanoma skin cancer. 828 19

Precancerous skin lesions are categorized into three groups; (1) carcinoma in situ, (2) hereditary precancerous lesions, and (3) non-hereditary precancerous lesions. Carcinoma in situ includes Bowen's disease, actinic keratosis and leukoplakia as squamous cell carcinoma in situ, Paget's disease as adenocarcinoma in situ, and melanoma in situ. Hereditary precancerous lesions include xeroderma pigmentosum, epidermodysplasia verruciformis and porokeratosis. The mechanisms of carcinogenesis in these diseases are investigated intensively. Chronic radiodermatitis and other scars are treated as non-hereditary precancerous lesions.
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PMID:[Reevaluation of precancerous lesions of the skin]. 860 16

Through yet unidentified mechanisms, squamous epithelial cells become committed to terminal differentiation after detachment from the basement membrane. In squamous cell carcinoma, these mechanisms seem to be disturbed. A murine monoclonal antibody, designated NCC-Lu-226 (IgG1, K), which recognizes an antigen expressed in basal cells of squamous epithelium at the epithelio-connective tissue border, was obtained. A cDNA clone encoding the antigen was isolated from a cDNA library by immunoselection. DNA sequencing and a database search revealed that this cDNA clone was identical to a hemidesmosomal transmembrane protein, bullous pemphigoid antigen 2 (BPA-2; also known as BPAG2, BP180, or type XVII collagen). Immunoelectron microscopy validated the specific reactivity of this monoclonal antibody with skin hemidesmosomes. Enhanced expression and abnormal distribution of BPA-2 was revealed immunohistochemically in various precancerous and cancerous tissues, including solar keratosis (4 of 5), Bowen's disease (3 of 5), invasive squamous cell carcinoma (7 of 7) of the skin, and squamous cell carcinoma of the lung (14 of 14), esophagus (12 of 13), and cervix (14 of 17). The specific expression of BPA-2 protein in squamous cell carcinoma was confirmed by RT-PCR and Northern hybridization. BPA-2 has possible phosphorylation sites and is actually phosphorylated in cultured keratinocytes and squamous cell carcinoma. The aberrant expression of BPA-2 may reflect dysfunction of the hemidesmosome that occurs as a relatively early event in multistep carcinogenesis of squamous epithelium.
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PMID:Aberrant expression of a hemidesmosomal protein, bullous pemphigoid antigen 2, in human squamous cell carcinoma. 887 89

Abnormal control of the cell cycle is closely linked to carcinogenesis. p21WAF1/CIP1 protein is a universal inhibitor of G1 cyclin-dependent kinase and is induced by p53-dependent and -independent pathways. In order to elucidate the role of p21WAF1/CIP1 in human skin carcinogenesis, protein expression in squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), actinic keratosis (AK), keratoacanthoma (KA), seborrheic keratosis (SK), and normal skin was examined using an immunohistochemical method. In normal skin, a few positive cells were seen in some cases in the upper spinous layer of the epidermis; sebaceous glands also had positive cells. In cases of SK and KA, positive cells were found in the basal and suprabasal epidermal layers (proliferation pattern), and in cases of BD and AK, positive cells were seen mainly in the upper spinous layer (differentiation pattern). Cases of SCC had more positive cells and showed two staining patterns: proliferation, or mixed. Cases of BCC had no positive cells. p21WAF1/CIP1 has some unidentified role in keratinocyte tumorigenesis, which may not be related directly to carcinogenesis.
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PMID:p21WAF1/CIP1 expression in non-melanoma skin tumors. 913 13


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