PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Neoplasms, Squamous Cell”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2002

Epidemiology of skin cancer.

The skin is the most common site of malignancy. Due to several mostly unknown factors, the frequency of skin tumors is increasing. Except for malignant melanoma, reliable statistical data on the frequency of skin tumors are scarce. Discussion on the epidemiology of skin tumors may take different aspects and factors into consideration: (1) histogenetic type; (2) race, (3) sex; (4) age, (5) localization; (6) environment. Moreover, precancerous conditions also may play an important role in this context. Epithelial tumors, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the most frequent tumors of the skin. Figures show a wide range between 40 and over 700 or 5 and 250 respectively per 100 000 inhabitants per year depending on the country or area of report. Malignant melanoma is more frequently seen in Caucasians living in sunny regions (40) than in northern countries or in dark skinned races (4-12 per 100 000 per year), representing 4% of all skin tumors, but being responsible for 79% of skin cancer deaths. Other types of skin tumors like cutaneous lymphoma, Kaposi sarcoma, lipomas, adnexal tumors etc. are either not reported regularly and reliable epidemiologic data is not available, or are rare cutaneous tumors (taken all together < 1%).

Bowen's Disease↗
PubMed1991

Inhalation of tetranitromethane causes nasal passage irritation and pulmonary carcinogenesis in rodents.

Fischer 344 rats and B6C3F1 mice were exposed for 2 years to vapors of tetranitromethane at concentrations below (0.5 ppm) and slightly above (2 or 5 ppm) the current U.S. recommended occupational exposure limit. Under the conditions of exposure of 6 h/day, 5 days/week, tetranitromethane was found to cause mild irritation and hyperplastic lesions in the nasal passages, but not nasal cavity neoplasms were observed. In contrast, nearly all animals exposed to the higher TNM concentrations, and the majority of animals exposed to the lower concentrations developed alveolar/bronchiolar adenoma or carcinoma; squamous cell neoplasms of the lung also occurred in exposed rats. The extent of the lung tumor response, and the low concentrations of tetranitromethane required for this response, are unprecedented in National Toxicology Program (NTP) studies.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1993

Inhibition of 4-nitroquinoline-1-oxide-induced rat tongue carcinogenesis by the naturally occurring plant phenolics caffeic, ellagic, chlorogenic and ferulic acids.

The modifying effects of dietary administration of the plant phenolic antioxidants caffeic acid (CA), ellagic acid (EA), chlorogenic acid (CGA) and ferulic acid (FA) during the initiation phase on 4-nitroquinoline-1-oxide (4-NQO)-induced tongue carcinogenesis and on the number and area of silver-stained nucleolar organizer region proteins (AgNORs), a new cell proliferation marker, of the tongue squamous epithelium were investigated in male F344 rats. Rats were fed the diet containing 500 p.p.m. CA, 400 p.p.m. EA, 250 p.p.m. CGA or 500 p.p.m. FA for 7 weeks. One week after the commencement of the diets, 4-NQO (20 p.p.m.) was administered in the drinking water for 5 weeks. Feeding of four phenolic compounds significantly reduced the incidences of tongue neoplasms (squamous cell papilloma and carcinoma) and preneoplastic lesions (hyperplasia and dysplasia) by 32 weeks, and rats fed CA or EA had no tongue neoplasms. The number and area of AgNORs per nucleus were decreased significantly by dietary treatment with these four phenolics. Thus, CA, EA, CGA and FA inhibited the tongue carcinogenesis induced by 4-NQO when they were administered concurrently with the carcinogen. These results might suggest possible application of these natural substances for cancer chemoprevention in tongue in addition to other tissues (skin, lung, liver and esophagus).

4-Nitroquinoline-1-oxide↗
PubMed1994

Chemoprevention of 4-nitroquinoline 1-oxide-induced oral carcinogenesis by dietary protocatechuic acid during initiation and postinitiation phases.

The modifying effects of three doses of dietary protocatechuic acid (PCA) given the initiation and postinitiation phases of oral carcinogenesis initiated with 4-nitroquinoline 1-oxide (4-NQO) were investigated in male F344 rats. At 6 weeks of age, rats were divided into experimental and control groups and fed the diet containing PCA at various doses of 0 g/kg diet (basal diet alone), 0.5 g/kg diet (500 ppm), 1 g/kg diet (1000 ppm), and 2 g/kg diet (2000 ppm). At 7 weeks of age, all animals except PCA alone and control groups were given 4-NQO (20 ppm) in the drinking water for 8 weeks to induce oral cancer. Seven days after the 4-NQO exposure, groups of animals fed the PCA diets were switched to the basal diet and continued on this diet until the end of the study. Starting 1 week after the end of 4-NQO exposure, the groups given 4-NQO and a basal diet were switched to the diets containing PCA and maintained on these diets for 22 weeks. The other groups consisted of rats given 2000 ppm PCA alone or untreated rats. All animals were necropsied at the termination of the experiment (week 32). The incidences of tongue neoplasms and preneoplastic lesions, polyamine levels in the tongue tissue, and cell proliferation activity estimated by bromodeoxyuridine-labeling index and by morphometric analysis of silver-stained nucleolar organizer regions' protein were compared among the groups. Feeding of PCA at all doses during initiation or postinitiation phase significantly decreased the development of tongue neoplasms (squamous cell papilloma and carcinoma) and preneoplasia (hyperplasia and dysplasia) (P < 0.05). There were no such lesions in rats treated with 2000 ppm PCA alone or those in an untreated control group. Dietary administration of PCA also caused significant decreases in the labeling index of bromodeoxyuridine and the number and area of silver-stained nucleolar organizer regions per cell nucleus, known as cell proliferation indices, of the tongue squamous epithelium (P < 0.05). In addition, PCA exposure during either initiation or postinitiation phase decreased polyamine levels in the oral mucosa (P < 0.05). These results clearly indicated that PCA inhibited rat oral carcinogenesis in both initiation and postinitiation phases, when administered in these respective phases together with or following treatment with 4-NQO, and such inhibition might be related to suppression of cell proliferation by PCA.

4-Nitroquinoline-1-oxide↗
PubMed1995

Skin cancer in heart transplant recipients.

BACKGROUND: The frequency of skin cancer in organ transplant recipients is high, up to 15%. OBJECTIVE: Our purpose was to determine the incidence of skin cancer in patients who underwent immunosuppression after heart transplantation and to determine the factors important in the appearance of skin cancer. METHODS: We studied the frequency of skin cancer in 92 of 111 patients after they underwent heart transplantation between January 1984 and December 1993. RESULTS: At least one cutaneous neoplasm (squamous cell carcinoma and/or basal cell carcinoma) developed in 14 patients (15.2%). The basal cell carcinoma to squamous cell carcinoma ratio was 1:1.5. The skin cancer appeared an average of 31.5 months after transplantation; the average was 36 months for squamous cell carcinoma and 25.3 months for basal cell carcinoma. Cumulative risk rose from 4.3% at 1 year up to 43.8% at 7 years after transplantation. The overall incidence of both types of skin cancer was 45.3 per 1000 posttransplant person-years, with an incidence of 25.8 for basal cell carcinoma and 29.1 for squamous cell carcinoma. Most skin cancers developed between 2 and 3 years after transplantation. All patients were exposed to a significant amount of ultraviolet radiation and had skin type II or III. We did not find a significant association between skin cancer and haplotype HLA-A3, HLA-A11, HLA-DR, and the number of mismatches for HLA-B. CONCLUSION: We found an increased progressive cumulative incidence of skin cancer in heart transplant recipients for two reasons: (1) immunosuppression and increased exposure to ultraviolet radiation in some patients, and (2) the skin type of certain patients. We emphasize the need for photoprotection in this group of patients and regular skin cancer screening examinations.

Adult↗
PubMed1985

[Immunological deficiency syndromes, immunosuppression by drugs and occurrence of neoplasms: a casual association?].

Although supported by a number of experimental models, the assumption assigning a crucial role to the immune system in the antineoplastic defense mechanisms has not been convincingly demonstrated so far for human tumors. Should the theory be correct, severe functional impairment of the immune system would obviously result in the occurrence of tumors with abnormally high frequency. Registry holdings systematically collecting pertinent information on the malignancies developed in patients with primary immunodeficiency diseases or in organ transplant recipients maintained on therapeutically-induced immune depression, as well as the observation of tumors occurring in patients treated with immunosuppressive agents and of second malignancies arising after radio- and/or chemotherapy of the primary tumor consistently indicate that depressed immunity is usually associated with an increased incidence of cancer as compared with that expected in the general control populations. However, not all types of tumors are increased to the same extent, in that lymphoreticular neoplasias (especially non-Hodgkin's lymphomas), acute leukemias as second tumors and, among solid neoplasms, squamous cell carcinomas are those most frequently reported. These observations suggest that even deeply impaired tumoricidal immune mechanisms may facilitate the growth of certain tumors only, especially of those arising from the cells of the immune system itself, in remarkable contrast with their frequency in the general population. Oncogenesis may be favoured in various states of depressed immunity by a number of ways. Their elucidation might have bearing on the comprehension of the more general phenomenon of the neoplastic transformation.

Carcinoma, Squamous Cell↗
PubMed1992

Inhibitory effects of the natural products indole-3-carbinol and sinigrin during initiation and promotion phases of 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis.

The modifying effects of indole-3-carbinol (I3C) and sinigrin (SIN) on the initiation and post-initiation phases of tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4-NQO) were investigated in male ACI/N rats. Rats were divided into eight groups: group 1 was given 4-NQO (10 ppm) in the drinking water for 12 weeks, starting at 7 weeks of age; groups 2 and 3 were given 4-NQO and fed the diets containing I3C (1,000 ppm) and SIN (1,200 ppm) for 14 weeks, respectively, starting at 6 weeks of age; groups 4 and 5 were given 4-NQO and then they were fed I3C and SIN containing diets for 23 weeks, respectively, starting one week after 4-NQO exposure; groups 6 and 7 were given I3C and SIN alone, respectively, during the experiment; group 8 served as an untreated control. At the termination of the experiment (week 37), the incidence of tongue neoplasms (squamous cell papilloma and carcinoma) in group 2 (1/15, 7%), group 3 (1/15, 7%), group 4 (3/15, 20%) or group 5 (2/15, 13%) was significantly smaller than that in group 1 (12/17, 71%) (P = 0.0003, P = 0.005 or P = 0.002). No tongue carcinomas developed in rats of groups 2, 3, and 5. Similarly, the incidence of preneoplastic lesions (hyperplasia and dysplasia) of the tongue in group 2 (11/15, 73%), group 3 (10/15, 67%), group 4 (11/15, 73%) or group 5 (10/15, 67%) was significantly lower than that in group 1 (17/17, 100%) (P = 0.04 or P = 0.02). There were no tongue neoplasms in rats of groups 6, 7, and 8. Administration of I3C and SIN also caused significant decreases in the number and area of silver-stained nucleolar organizer regions protein (AgNORs), a new cell proliferation index, of tongue squamous epithelium. Thus, I3C and SIN inhibited rat tongue carcinogenesis in both the initiation and post-initiation phases, when administered in these respective phases together with, or following treatment with, 4-NQO.

4-Nitroquinoline-1-oxide↗
PubMed1997

High prevalence of human papillomavirus types 16 and 18 in middle-ear carcinomas.

Chronic suppurative otitis media, averaging 20 or more years of duration, has been associated with cancer in this region in 40%-80% of cases. Although human papillomaviruses (HPV) have been implicated in many human squamous-cell neoplasms, their role in the pathogenesis of middle-ear malignancies remains unexplored. In this study, we investigated the presence and subtypes of HPV in middle-ear carcinomas. Formalin-fixed and paraffin-embedded tumor tissues were sampled for DNA extraction. PCR was done with consensus primers, capable of detecting HPV 16, 18, 31, 33, 52b and 58. Typing of the products generated by consensus primers was performed with restriction enzyme digestion. It was found that a resulting 89% (8/9) of the middle-ear carcinomas contained HPV DNA. Coexistence of HPV 16 and 18 was detected in 3 squamous-cell carcinomas. HPV 16 was detected in 4 squamous-cell carcinomas and 1 adenocarcinoma. The high prevalence of high-risk-type HPV in carcinomas of the middle ear suggests that viral infection may be an important etiologic component in the carcinogenic process.

Adenocarcinoma↗
PubMed1990

Mortality and tumour incidence of Han:SPRD rats.

In a longevity study a total of 394 Han:SPRD rats (200 males and 194 females) were kept in a barrier type animal quarter from weaning until their natural death. The mean life span of males was 29.6 +/- 5 months, that of females 27.6 +/- 6.2 months. The most frequent neoplasms in females were mammary gland tumours (63.4%). Neoplasms of endocrine organs were common in animals of both sexes. Thyroid neoplasms, predominantly of C-cell origin, occurred in 60% of the males and 51.5% of the females. Pituitary gland tumours were observed in 53% of male and 45.1% of female rats. Further frequent tumours of the endocrine system included phaeochromocytomas (23% in males, 15.5% in females), adrenal cortex neoplasms (6% in males, 13.5% in females) and tumours of islet cells of the pancreas (20.8% in males, 8.2% in females). An uncommonly high incidence of squamous cell neoplasms (16% in males; 9.3% in females) of the preputial and clitoral gland was observed in this stock. Further organs frequently affected by neoplasms were the skin/subcutis and brain.

Animals↗
PubMed1994

[Immunohistochemical analysis of the basement membrane expression in squamous epithelial carcinoma of the larynx].

Epithelial structures are separated from the stroma by a basement membrane (BM) which serves as a barrier for the epithelial cells. Invasive tumour growth as in laryngeal carcinoma, involves the degradation of this barrier. In our present immunohistochemical analysis, we evaluated both the quantitative and the qualitative changes in the BM composition of 50 laryngeal carcinomas. This analysis comprised the localisation of the BM components collagen IV, laminin, and fibronectin. Furthermore, we applied antibodies against BM components that have not, or only very rarely, been analysed in malignant squamous cell neoplasms--particularly collagen VII and heparan sulfate proteoglycan (HSPG). In this study we provide considerable evidence that varying amounts of preserved BM material can be found in laryngeal carcinoma of different grades of tumour differentiation. Especially by comparison of the different staining patterns for collagen IV and collagen VII, we recognised far more gaps in the staining of the BM by collagen VII than by collagen IV. This fact is underlined by the observation that even in G1 carcinomas collagen VII showed in almost 40% of the cases a complete loss of BM staining. In general, we found a correlation between the amount of preserved BM deposition and the grade of tumour differentiation. This fact may underline the significance of the immunohistochemically detectable amount of BM components as a prognostically relevant parameter.

Adult↗
PubMed1985

[Effect of sex hormone on the experimental induction of esophageal cancer].

The occurrence and the prognosis of human esophageal cancer shows a sex difference. It is assumed that sex hormone is one of the many causes of that sex difference. The effects of sex hormone on the experimental induction of esophageal cancer were investigated by the administration of chemical carcinogen. Multiple squamous cell neoplasms of the esophagus were induced by oral administration of 0.25% N-methylbenzylamine (MBeA) and 0.16% NaNO2 for 100 days or by subcutaneous (s.c.) injection of N-methylbenzyl nitrosamine (MBeN) at a dose level of 2.5mg/kg weekly for 16 weeks. The incidence of esophageal cancer in oral administration group was 42.9% in nontreated male rats, 30.0% in castrated male rats, 18.2% in estradiol s.c. injected male rats, 0% in castrated and estradiol s.c. injected male rats, 8.0% in nontreated female rats, 33.3% in castrated female rats, 33.3% in testosterone s.c. injected female rats and 36.4% in castrated and testosterone s.c. injected female rats. The incidence of esophageal cancer in s.c. injection group was 47.1% in nontreated male rats, 14.3% in early castrated and estradiol s.c. injected male rats, 23.1% in lately castrated and estradiol s.c. injected male rats, 7.7% in nontreated female rats, 33.3% in early castrated and testosterone s.c. injected female rats and 12.5% in lately castrated and testosterone s.c. injected female rats. These results showed a suppressing effect of estrogen and a promoting effect of androgen on the experimental induction of esophageal cancer.

Animals↗
PubMed1991

PRAD1, a candidate BCL1 oncogene: mapping and expression in centrocytic lymphoma.

Rearrangement of the BCL1 (B-cell lymphoma 1) region on chromosome 11q13 appears to be highly characteristic of centrocytic lymphoma and also is found infrequently in other B-cell neoplasms. Rearrangement is thought to deregulate a nearby protooncogene, but transcribed sequences in the immediate vicinity of BCL1 breakpoints had not been identified. PRAD1, previously designated D11S287E, was identified on 11q13 as a chromosomal breakpoint region rearranged with the parathyroid hormone gene in a subset of parathyroid adenomas; this highly conserved putative oncogene, which encodes a novel cyclin, has been linked to BCL1 and implicated also in subsets of breast and squamous cell neoplasms with 11q13 amplification. We report pulsed-field gel electrophoresis data showing BCL1 and PRAD1 to be no more than 130 kilobases apart. PRAD1 mRNA is abundantly expressed in seven of seven centrocytic lymphomas (Kiel classification), in contrast to 13 closely related but noncentrocytic lymphomas. Three of the seven centrocytic lymphomas had detectable BCL1 DNA rearrangement. Also, two unusual cases of CLL with BCL1 rearrangement overexpressed PRAD1, in contrast to five CLL controls. Thus, PRAD1 is an excellent candidate "BCL1 oncogene." Its overexpression may be a key consequence of rearrangement of the BCL1 vicinity in B-cell neoplasms and a unifying pathogenetic feature in centrocytic lymphoma.

Chromosomes, Human, Pair 11↗
PubMed1992

Spindle cell neoplasms coexpressing cytokeratin and vimentin (metaplastic squamous cell carcinoma).

Spindle cell squamous carcinoma (SCSC) and atypical fibroxanthoma (AFX) are both spindle cell neoplasms (SCN) that usually arise in areas of solar or ionizing radiation of elderly patients. Both lesions have a similar biologic behavior. In addition, the morphologic and ultrastructural similarities found in AFX and the spindle cell component of SCSC, have led some investigators to conclude that these tumors have a similar cell of origin. We studied 15 SCNs with no evidence of epithelial origin and no morphologic epithelial component, that showed immunohistochemical and ultrastructural evidence that would support metaplastic changes of a squamous cell carcinoma to a neoplasm with mesenchymal characteristics.

Aged↗
PubMed1989

Inhibitory effects of non-steroidal anti-inflammatory drugs, piroxicam and indomethacin on 4-nitroquinoline 1-oxide-induced tongue carcinogenesis in male ACI/N rats.

The effects of the non-steroidal anti-inflammatory drugs (NSAIDs), piroxicam and indomethacin on 4-nitroquinoline 1-oxide-(4-NQO)-induced tongue carcinogenesis in male ACI/N rats were examined. Rats were given 4-NQO (10 ppm) in the drinking water for 12 weeks and followed by either diet containing 150 ppm piroxicam or the drinking water containing 10 ppm indomethacin for 24 weeks. The incidence of tongue neoplasms (squamous cell papilloma and carcinoma) in rats given 4-NQO plus piroxicam (4/13, 31%) and those given 4-NQO plus indomethacin (3/13, 23%) were significantly lower than that of animals given 4-NQO alone (12/17, 71%) (P less than 0.05 and P less than 0.005). Rats given piroxicam or indomethacin alone had no neoplasms in the tongue. Thus, piroxicam and indomethacin significantly inhibited the development of tongue neoplasms in male ACI/N rats.

4-Nitroquinoline-1-oxide↗
PubMed1986

Human monoclonal antibodies that distinguish cutaneous malignant melanomas from benign nevi in fixed tissue sections.

Human monoclonal antibodies were generated by fusing a nonsecretory variant of murine myeloma cells with lymphocytes obtained from the lymph nodes of patients with metastatic cutaneous malignant melanoma. Two human IgG monoclonal antibodies, designated 2-139-1 and 6-26-3, were extensively studied for their patterns of binding to cells in 64 specimens of formalin-fixed, paraffin-embedded tissue sections. These comprised: 23 cutaneous and 2 ocular melanomas; 4 specimens of lentigo maligna; 27 benign nevi; 2 basal and 2 squamous cell neoplasms of the skin; and 4 specimens of normal skin. A direct avidin-biotin-immunoperoxidase staining method was used. Under these conditions, the antibodies reacted with variable intensity to all 18 primary cutaneous malignant melanomas, 5 metastatic cutaneous melanomas, and both ocular melanomas. Antibody 2-139-1 reacted with 1 of 4 specimens and 6-26-3 with 3 of 4 specimens of lentigo maligna. Two of 5 dysplastic nevi reacted with both antibodies, each with a smaller proportion of cells than with melanomas. There was no reactivity with the 22 other nevi representing a spectrum of histologic types or with normal melanocytes. Basal cell and squamous cell carcinomas of the skin also were not stained. These human monoclonal antibodies appear to be useful in distinguishing malignant melanomas from benign nevi, with the exception of dysplastic nevi, and from basal and squamous cancers of the skin in routinely prepared tissue sections. They may also help to identify the cytoplasmic antigens that are immunogenic in humans.

Antibodies, Monoclonal↗
PubMed1986

NTP Toxicology and Carcinogenesis Studies of 3-Chloro-2-methylpropene (Technical grade containing 5% dimethylvinyl chloride) (CAS No. 563-47-3) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

Toxicology and carcinogenesis studies of technical-grade 3-chloro-2-methylpropene (containing 5% dimethylvinyl chloride), a widely used insecticide and a chemical intermediate, were performed on F344/N rats and B6C3F1 mice. In the 13-week studies, 50%-100% mortality occurred in groups of male and female rats receiving 400 mg/kg, male rats receiving 300 mg/kg, and male and female mice receiving 500-1,250 mg/kg. Inflammation and necrosis of the liver were seen in rats and mice, and necrosis of cortical tubules of the kidney was seen in mice. Based on these observations, groups of 50 male and 50 female rats were administered 3-chloro-2-methylpropene in corn oil by gavage at doses of 0, 75, or 150 mg/kg body weight, 5 days per week for 103 weeks, and groups of 50 male and 50 female mice received 3-chloro-2-methylpropene at 0, 100, or 200 mg/kg on the same schedule. In the 2-year studies, the mean body weight of high dose male rats was consistently 10%-15% lower than that of the vehicle control group, and late in the study there was a marginal reduction in survival of high dose male rats. Mean body weights and survival in low dose male rats and in both dosed groups of female rats were comparable to those of their vehicle control groups. Mean body weights of high dose male mice and of both dosed groups of female mice were slightly (5%-9%) lower than those of the vehicle controls, whereas survival in both male and female mice was not affected by 3-chloro-2-methylpropene administration. Dose-related increases in the incidence of forestomach inflammation were observed in male and female mice (male: vehicle control, 0/49; low dose, 9/49; high dose, 7/49; female: vehicle control, 2/50; low dose, 3/48; high dose, 9/44). Increased incidences of forestomach basal cell hyperplasia were observed in rats and mice of each sex. 3-Chloro-2-methylpropene induced forestomach squamous cell papillomas and squamous cell carcinomas in rats and mice as shown in the table. Invasion or metastasis of the squamous cell carcinomas to other organs was observed in two low dose male, three high dose male, and one high dose female mice. Renal tubular cell adenocarcinomas (1/49), renal transitional cell carcinomas (1/49), and transitional cell papillomas (1/49) of the urinary bladder were observed in high dose male rats, and renal tubular cell adenomas (1/50) and renal tubular cell adenocarcinomas (1/50) were seen in low dose male rats. These urinary tract neoplasms were not observed in vehicle controls. The incidences of inflammation of the nasal cavity and of nephropathy/nephrosis were greater in the two dosed groups than in the vehicle control groups of rats and mice of each sex. Negative trends or lower incidences of pheochromocytomas of the adrenal gland and C-cell adenomas or carcinomas (combined) of the thyroid gland were observed in dosed male rats. Negative trends were observed in the incidences of hepatocellular adenomas or carcinomas (combined) in dosed male mice and of hemangiomas or hemangiosarcomas (combined) in dosed female mice. 3-Chloro-2-methylpropene was weakly mutagenic in Salmonella typhimurium strain TA1537 with 10% rat liver S9; results in strain TA100 with 10% Syrian hamster liver S9 or with 10% or 30% rat liver S9 were judged equivocal. Mutagenicity tests with S. typhimurium strains TA1535 and TA98 were negative with or without metabolic activation. 3-Chloro-2-methylpropene was mutagenic in the mouse lymphoma L5178/TK+/- forward mutation assay without exogenous metabolic activation. Cytogenetics tests with cultured Chinese hamster ovary cells were positive for induction of chromosomal aberrations and sister-chromatid exchanges (SCE's) in the absence of rat liver S9. With metabolic activation, SCE levels remained significantly elevated, but the number of chromosomal aberrations was reduced. An audit of the experimental data was conducted for these 2-year carcinogenesis studies on 3-chloro-2-methylpropene. No data discrepancies were found that influenced the final interpretations. Under the conditions of these 2-year gavage studies, d the final interpretations. Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenicity for 3-chloro-2-methylpropene as shown by the increased incidences of squamous cell neoplasms in the forestomach of male and female F344/N rats and of male and female B6C3F1 mice. Synonyms: 2-methallyl chloride; methyl allyl chloride; b-methallyl chloride; pi-chloroisobutylene; isobutenyl chloride; 3-chloro-2-methyl-1-propene; 2-methyl-2-propenyl chloride

Journal Article↗
PubMed2002

Use of tanning devices and risk of basal cell and squamous cell skin cancers.

Use of artificial tanning devices that emit UV radiation, such as tanning lamps and tanning beds, has become increasingly popular in the United States. Although an excess risk of nonmelanoma skin cancers might be predicted from this exposure, little epidemiologic data exist. We conducted a population-based, case-control study that included 603 basal cell carcinoma (BCC) case patients, 293 squamous cell carcinoma (SCC) case patients, and 540 control subjects. Study participants were interviewed in person to obtain information on tanning device use, sun exposure history, sun sensitivity, and other risk factors for skin cancer. Overall, any use of tanning devices was associated with odds ratios of 2.5 (95% confidence interval [CI] = 1.7 to 3.8) for SCC and 1.5 (95% CI = 1.1 to 2.1) for BCC. Adjustment for history of sunburns, sunbathing, and sun exposure did not affect our results. Our findings suggest that the use of tanning devices may contribute to the incidence of nonmelanoma skin cancers. They highlight the need to further evaluate the potential risks of BCC and SCC that are associated with tanning lamp exposure and the appropriate public health response.

Adult↗