细胞技术

Defective DNA mismatch repair (MMR) occurs in the majority of tumors from patients with hereditary non-polyposis colorectal cancer (HNPCC) and approx 15% of sporadic colorectal cancer (CRC) (1,2). In HNPCC-associated tumors, defective MMR is most often due to inactivating mutations of t ...

Microsatellites are tandem repeats of simple sequences that occur abundantly and are randomly interspersed throughout the human genome. They typically consist of 10-50 copies of 1-6 bp motifs, and are characterized by a high degree of polymorphism. Despite the variability observed am ...

Telomeres are very important structures that protect chromosomal ends from recombination, but the structure itself induces irreversible reduction without the presence of telomerase activity. Researchers are now collecting evidence of telomere dynamics in clinical sampl ...

Telomere length is now known to be directly responsible for limiting the capacity of cellular division in a number of human cell types (1,2). Comparison of telomere length in tumors and matched normal tissue from the same individual has indicated that the telomere repeat array is often shorter in t ...

The understanding that human neoplasms are clonal cell proliferations ultimately derived from a single transformed somatic cell represents a major advance in cancer biology. A cell population is designated as clonal if it can be demonstrated to have arisen from a single parent or progeni ...

Patients with acute leukemia have a total of approx 1012 leukemic cells at the time of diagnosis, and still have as many as 1010 leukemic cells in complete remission. The most important problem in the treatment of leukemia patients is the uncertainty of whether leukemic cells have been totally erad ...

The principle of cDNA microarray hybridization takes advantage of the property of DNA to form duplex structures between two complementary strands. In this technique (Fig. 1), the cDNA probes, which are arrayed onto a glass slide and represent the sequence of known genes or expressed sequence t ...

Understanding when and where the constellation of genes in a genome are expressed provides important information about the state of a tissue. Changes in gene expression are a driving force in cell differentiation, proliferation, and death. Abnormal gene expression as a direct consequen ...

It is estimated that the human genome contains 25,000–35,000 genes; however, only about 15% of these are expressed in any given cell and different cells and tissues express different gene subsets. Gene expression is tightly regulated under normal physiologic conditions but is often disrup ...

There are a variety of methods for the detection and definition of mutations in disease states including cancer. For the detection of unknown mutations, several screening techniques are available including single-strand connformation polymorphism (ssCP) (1), protein truncati ...

Nonisotopic RNase cleavage assay (NIRCA) is an RNase-cleavage-based method for mutation scanning that detects mutations as double-stranded cleavage products in duplex RNA targets. A central requirement for NIRCA is the ability to produce large amounts of double-stranded target R ...

Denaturing gradient gel electrophoresis (DGGE) was introduced 20 years ago (1) as a gel system to separate DNA fragments. The seminal principle of this methodologic conquest was that DNA molecules were not separated according to size, as in conventional electrophoresis, but rather, acco ...

In recent years, we have seen a dramatic improvement in our ability to detect nucleotide changes in tumor DNA using a number of techniques for mutation detection that have become routine instruments in many laboratories. The choice of a suitable method or methods of mutation analysis is governed ...

The polymerase chain reaction (PCR) has revolutionized the isolation and analysis of nucleic acid fragments from a wide variety of sources. PCR-based methods for nucleic acid detection and fingerprinting have become vital to modern molecular genetics, whether for the analysis of popu ...

Many types of human leukemias and lymphomas are associated with specific chromosomal translocations that correlate with specific histologic and immunologic phenotypes (1). Anaplastic large-cell lymphoma (ALCL) of T-cell or null-cell lineage is a clinically aggressive non-H ...

A number of leukemia-specific chromosomal translocations have been identified that have been cloned and are appropriate markers for molecular studies (Table 1) (1–4). In addition, leukemia nonspecific clonality markers, such as the junctional region of the rearranged immunoglo ...

Microsatellites are tandem repeats of simple sequence, 2–6 bp, that occur abundantly and at random throughout most eukaryotic genomes. They are typically short, often

Cancer is a genetic disease. Gene mutations are not only responsible for rare hereditary forms of human cancer, but for the sporadic forms of human malignancies as well. Many of these specific genetic defects in cancer cells can be visualized as chromosomal aberrations. Conventional cytoge ...

Molecular genetic investigations of human tumors have increased our understanding of the mechanistic relationship between chromosome abnormalities and cancer. In leukemias and lymphomas, for which extensive karyotypic analysis has been possible, specific translocat ...

Cytogenetic analysis plays a pivotal role in the diagnosis and management of patients with hematologic malignancies. In research, the identification of specific chromosomal rearrangements associated with defined clinical groups has led to an explosion in the knowledge of basic m ...