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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lonidiamine is a novel indazole-carboxylic acid with antitumour properties; it has been studied for potential mutagenicity in a comprehensive battery of tests. In assays for the induction of gene mutations in prokaryotes (Ames test) and eukaryotes (induction of HPRT mutations in CHO cells), negative results were obtained. There was no evidence of the induction of chromosomal damage in cultured mammalian cells in vitro. No mutagenic activity was observed in tests for chromosomal damage in vivo, in somatic cells (micronucleus test) or in germinal cells (dominant lethal test). These negative results are consistent with observations indicating that lonidamine affects cellular energy processes, rather than the mechanisms of cell division. The lack of mutagenic properties suggests that lonidamine may present significant advantages in treatment of some tumours, offering a reduced risk of resistant clones, secondary cancer and heritable genetic damage.
Carcinogenesis 1990 Sep
PMID:Lonidamine: a non-mutagenic antitumor agent. 240 Oct 42

To lay the groundwork for subsequent chapters in this monograph of multiple primary cancers in Connecticut and Denmark, we present a description of the historical significance of previous studies, focusing on key surveys that have enhanced our understanding of the origins of multiple cancers. Case reports, hospital series, and cancer registry studies have progressively sharpened our perspective on the patterns and causes of multiple cancers. These findings in turn have generated hypotheses about host and environmental determinants of various combinations of cancer and have provided clues to the actual mechanisms of carcinogenesis. The registries of Connecticut and Denmark which began in the 1930s and 1940s, respectively, afford investigators a unique opportunity to analyze the cancer experience of well-defined populations, followed for long periods. The major contribution of this monograph is the evaluation of second cancer risks among long-term survivors of cancer, including relatively rare tumors about which little information currently exists. For patients with a particular cancer, the number of observed second cancers are tabulated over time and compared with those expected if the patients experienced the same rates prevailing in the corresponding general population. We have discussed problems in distinguishing statistical artifacts from biologically plausible associations in light of the potential biases inherent in follow-up surveys of cancer patients; for example, heightened medical surveillance and mistaken metastases could result in false indications of elevated risk. Several differences in the reporting, follow-up, and coding practices between the Connecticut and Denmark registries are described and probably account for many differences in the reported findings.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Introduction to the study of multiple primary cancers. 408 4

Recent advances in molecular biology have revealed that the alteration of multiple genes, eg., APC, K-ras, p53, DCC, are involved in multistep colorectal carcinogenesis. Some of these alterations can be used as molecular markers in genetic diagnosis. Genetic diagnoses for colorectal cancer are classified into three categories, eg., 1. identification of the career in the family of patient with hereditary disease such as FPC (Familial Polyposis Coli) or HNPCC (Hereditary Non-Polyposis Colorectal Cancer), 2. early diagnosis of colorectal cancer by identifying gene mutations in the stool, 3. assist for histopathological diagnosis, or risk assessment of the metastasis, recurrence or secondary cancer by molecular means. However, there are several problems in these genetic diagnoses. These consist of two categories, eg., 1. problems in the method of gene analyses or assay system and 2. problems in performing genetic diagnoses itself. The former includes the problem of contamination of different tissue, false positive or negative result in PCR-based analyses, heterogeneity of gene mutation in tumor tissue, and the latter includes the social, ethical or economical problems mainly related to the genetic diagnosis for hereditary colorectal cancers. In this paper, we describe the possibility of genetic diagnosis for colorectal cancers and the current problems, especially from the molecular pathological aspect, in genetic diagnosis.
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PMID:[Molecular-pathological problems of genetic diagnosis for colorectal cancer]. 910 43

Breast cancer is the most common cancer and the second most frequent cause of cancer death in women. Despite extensive research, the precise mechanisms of breast carcinogenesis remain unclear. One of the reasons for this is due, at least in part, to a lack of a suitable animal model which can closely mimic the breast carcinogenesis in normal situations without using chemical carcinogens. We have developed an animal model of mammary gland carcinogenesis using a combination of oestradiol and testosterone, and succeeded in inducing a high percentage of female Noble rats to develop mammary cancer in a relatively short time (approximately 6 months). The results showed that androgens might work as a promoter to shorten the latency time of mammary gland carcinogenesis. Histopathological examination revealed that hyperplasia and dysplasia were first observed 2 months after treatment, in situ carcinoma after 3 months, and fully developed carcinoma of various forms including cribriform, papillary and camedo types were observed from 5 to 6 months after hormone implantation. Animals implanted with oestrogen or testosterone alone also developed mammary cancers, though with a lower overall incidence than the two hormones combined. They ranged from well differentiated to poorly differentiated forms with predominantly infiltrating ductal carcinoma. We have also observed a case of secondary cancer in the uterus. In addition to the high incidence of carcinoma, there was also a peculiar unexplained ipsilateral correlation between the site of hormonal implantation and the location of tumours, and the highest incidence of carcinogenesis was found to be in thoracic mammary gland. The study showed that both oestrogens and androgens are important in mammary cancer development. The animal model would prove to be a useful model for analysis of the mechanism(s) of hormonal carcinogenesis.
Carcinogenesis 1999 Jun
PMID:Induction of high incidence of mammary tumour in female Noble rats with a combination of 17beta-oestradiol and testosterone. 1123 97

To assess the role of family history in the development of multiple primary cancer, the Swedish Family-Cancer Database was used to analyze second primary cancer in patients born in 1935 to 1996 with an initial primary cancer of the colon, breast and skin (melanoma) by familial cancer in first-degree relatives. Standardized incidence ratios (SIRs) were calculated from site-, sex- and age-specific rates for all persons (offspring) born in 1935 to 1996. Familial risk (SIR) was calculated for the first and second primary cancers in offspring. A Poisson regression analysis was also performed to assess the risk factors for occurrence of second primary cancer. The familial proportion of multiple primary cancers was 29.0% (9/31) for colon, 16.3% (122/747) for female breast and 14.5% (17/117) for melanoma. Compared with all offspring, patients with family history were at a much higher and significantly increased risk for subsequent primary cancer at colon (SIR = 59.1), skin (SIR = 48.2) and female breast (SIR = 7.9). The corresponding SIRs in patients without family history were 13.8, 10.5 and 5.2 at the three sites. The ratios for incidence of second primary to first primary were highest when diagnosis age was less than 40 years. A Poisson regression analysis showed that family history was one of the major risk factors for occurrence of multiple primary cancers at colon, breast and skin. The high risk of second cancer, even in the absence of family history, would be consistent with a polygenic model of carcinogenesis.
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PMID:Multiple primary cancers of the colon, breast and skin (melanoma) as models for polygenic cancers. 1135 11

The purpose of this study is to report carcinogenesis risk factor evaluation in vertebral hemangioma patients treated by radiotherapy. Between 1975 and 1995, 29 patients received 20-30 Gy total irradiation dose using conventional fractionation scheme. All the patients had measurements with thermoluminescent dosimeters (TLD 100 ), placed on multiple randophantom sites in vivo within the irradiated volume, to verify irradiation accuracy and calculate carcinogenesis risk factor. Twenty nine still-alive patients who had a minimum 6-year and maximum 26-year follow-up (median 14.34 years) have been evaluated by carcinogenic radiation risk factor on the basis of tissue weighting factors as defined by International Commission on Radiological Protection Publication 60. Reasonable pain relief has been obtained in all 29 patients. Calculated mean carcinogenesis risk factor is 0.6% for single irradiation portals and 0.9% for double irradiation portals in the whole group, whilst no secondary cancer has been detected. Radiotherapy is an effective treatment modality in relieving pain of vertebral hemangioma patients. Estimated secondary cancer risk factor for this benign neoplasm irradiation is not as high as can be feared.
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PMID:Evaluation of radiation carcinogenesis risk in vertebral hemangioma treated by radiotherapy. 1245 34

Patients who have undergone distal gastrectomy for peptic ulcer are at higher risk of developing gastric remnant cancer, and chronic bile reflux is believed to increase the risk of cancer in remnant stomach. In remnant stomach, carcinogenesis may be prevented by selecting the anastomosis method with a few reflux of intestinal juice including a bile acid. How Helicobacter pylori(H. pylori) infection participate in stomal gastritis and gastric remnant cancer, same as early gastric cancer in the intact stomach, is attended. H. pylori positive rate of remnant stomach is different by examination method and a report, but its rate is decreased every year after gastrectomy and in particular low in Billroth-II(B-II) anastomosis. B-II anastomosis is followed by a significantly lower rate than B-1. This may reflect the role of bile reflux because bile reflux interferes with colonization by H. pylori. Gastric cancer excision usual increase complicates gastric remnant stomach and H. pylori infection, but while H. pylori infection lasts after gastrectomy for gastric cancer, cell proliferation increase in remnant stomach. In remnant stomach after gastrectomy for gastric cancer, while H. pylori infection continues, H. pylori infection may cause remnant gastritis and a second cancer of remnant stomach. H. pylori infection and bile reflux seem to have a synergistic effect on cell proliferation in remnant stomach and may explain the increased risk of gastric remnant cancer. The cancer-causing dominant role might changed from H. pylori infection predominance to bile reflux every year after gastrectomy. Furthermore, a prophylactic effect to carcinogenesis by H. pylori eradication therapy is expected. Eradication of H. pylori after gastrectomy for gastric cancer has been recommended.
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PMID:[Helicobacter pylori infection in gastric remnant cancer after gastrectomy]. 1260 11

Successes in cancer therapy are leading to an increasing incidence of second cancers, which may be due to the same factors that cause first cancers or to the effect of therapy for the first cancer. There are also a number of specific methodological and sampling problems that have to be controlled before informative studies can be embarked upon. The risk of a second cancer is higher than that for the first one, which may be an indication of a particular exposure, an inherited set of genes, or both. We show clustering of multiple cancers caused by tobacco, alcohol and infections. We discuss familial aggregation of cancer as one of the causes of multiple primary cancers. However, multiple primary cancers may particularly be a manifestation of polygenic susceptibility, which cannot easily be recognized as familial clustering, and multiple cancers may offer a model for understanding the complex etiology of human cancer and for generating and testing hypotheses on mechanisms of carcinogenesis.
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PMID:Multiple primary cancers as clues to environmental and heritable causes of cancer and mechanisms of carcinogenesis. 1505 2

Intensity-modulated radiation therapy (IMRT) for head and neck (HN) tumors refers to a new approach to the whole treatment procedure from patient immobilization to beam delivery. Implementation of IMRT thus requires knowledge of setup uncertainties, adequate selection, and delineation of target volumes based on optimal imaging modalities, appropriate specification, and dose prescription regarding dose-volume constraints and ad hoc quality control of both the clinical and physical aspects of the whole procedure. A large number of issues still need to be resolved and/or further refined, such as the optimal selection and delineation of the target volume, in particular, with the introduction of functional imaging, and a better integration of improved dose distribution into the fractionation strategy. IMRT is associated with a potentially increased incidence of carcinogenesis, although in the HN area this risk is relative to the intrinsic risk of comorbidity and secondary cancer associated with the patient's lifestyle. Currently, the implementation of IMRT into routine clinical practice for HN cancers may not be a straightforward matter and should probably be restricted to selected institutions with adequate resources and experience. This review emphasizes these aspects and provides some recommendations for the future use of IMRT in patients with HN tumors.
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PMID:Intensity-modulated radiation therapy in head and neck squamous cell carcinoma: an adaptation of 2-dimensional concepts or a reconsideration of current clinical practice. 1509 57

Recent molecular pathology studies in head and neck cancer support a carcinogenesis model in which the development of a field with genetically altered cells plays a central role. This preneoplastic field is of monoclonal origin and expands non-invasively superseding normal epithelium. Clonal divergence and selection within the field ultimately leads to the development of cancer. These fields can be large (over 7 cm diameter) and are often not visible for the surgeon explaining that they may remain after resection of the primary tumor. When not removed, a field is an important risk factor for secondary cancer.
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PMID:Expanding fields of genetically altered cells in head and neck squamous carcinogenesis. 1565 56


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