摘要:

The termadrenal incidentalomarefers to an adrenal mass occasionally and unexpectedly discovered by an abdominal imaging procedure performed for reasons a priori unrelated to adrenal dysfunction. The prevalence of adrenal incidentalomas as discovered by computed tomographic scan examination is estimated to be between 1% and 4%. The vast majority of these lesions are of adrenocortical origin, most often adenomas. Identification of steroid or catecholamine-secreting tumors is important but usually solved with appropriate endocrinologic investigations. A difficult problem, however, is to distinguish between benign and malignant primary or secondary tumors. Size less than 4 cm and an unenhanced computed tomographic attenuation under 10 Hounsfield Units (HU) are findings in favor of a benign adrenocortical adenoma, as is a positive NP 59 scintigraphic examination. The pathogenesis of adrenal tumors is not well understood. However, alterations of the cyclic AMP signalling pathway have recently been observed in benign adrenocortical lesions and molecular defects associated with insulin-like growth factor-II overexpression in malignant adrenocortical tumors.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

High frequency of chromosomal deletions elicited as losses of heterozygosity is a hallmark of genomic instability in cancer. Functional losses of tumor suppressor genes caused by loss of heterozygosity at defined regions during clonal selection for growth advantage define the minimally lost regions as their likely locations on chromosomes. Loss of heterozygosity is elicited at the molecular or cytogenetic level as a deletion, a gene conversion, single or double homologous and nonhomologous mitotic recombinations, a translocation, chromosome breakage and loss, chromosomal fusion or telomeric end-to-end fusions, or whole chromosome loss with or without accompanying duplication of the retained chromosome. Because of the high level of specificity, loss of heterozygosity has recently become invaluable as a marker for diagnosis and prognosis of cancer. The molecular defects for the occurrence of loss of heterozygosity are derived from disabled caretaker genes, which protect the integrity of DNA, or chromosome segregator genes, which mediate faithful chromosome disjunction.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

One of the most productive areas of biologic research has been the utilization of model organisms for the systematic study of gene function. Although the experimental manipulation of these model genetic systems has provided important insights into the function of homologous genes in humans, such studies are necessarily limited by the need to extrapolate among divergent species and cell types. Researchers have now begun to apply the technology of gene targeting to human cell lines. Recently, studies of human cell knockouts have yielded important new information about how the cell cycle is regulated and how this regulation can go awry in cancer cells. The targeting of human genes promises to be a powerful tool in the characterization of the molecular pathways relevant to cancer.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Genetic and environmental factors are responsible for the genomic lesions that cause cancer, a complex genetic disease associated with genomic instability. Studies aimed at deciphering the lesions in cancer have focused mainly on one or a few genes, despite the genomic scope of the disease. The recently decoded human DNA sequence is anticipated to foster understanding of human evolution and disease and the role of environment and heredity in the human condition. This review addresses the opportunities and challenges that the availability of the human genome sequence holds for cancer research.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The tumor suppressorp53controls numerous downstream targets that can result in variable outcomes, including apoptosis, transient growth arrest, and sustained growth arrest or senescence. The activation ofp53, followed by its ability to play multiple roles in the control of genomic integrity or the elimination of damaged or tumorigenic cells, is performed by a complex process of cross-talk orchestrated to occur in the different compartments of the cell. Controlling performance of the many roles ofp53is a goal of many research groups and the focus of this review.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Despite recent improvements in the breast cancer mortality rate, breast cancer remains the most common cancer and the second leading cause of cancer-related deaths in US women. A decreasing trend in mortality rates is caused by advances in early detection and, to a lesser degree, in cancer therapies. With the increased utilization of mammography, one of the earliest detectable breast tumors, ductal carcinomain situ, has become the most rapidly increasing subset of breast cancers. Contrary to the dramatic improvement in our ability to detect ductal carcinomain situ, the pathophysiology of this disease is still poorly understood. Many molecular studies have been performed in ductal carcinomain situlesions with the aims of identifying genes involved in breast cancer initiation and progression, defining the relation betweenin situand invasive carcinomas, and identifying clinically useful markers for breast cancer diagnosis, prognostication, prevention, and treatment.

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1040-8746    

出版商:OVID    

年代:2002

数据来源: OVID