前沿科技及其它

Many modern analytical methods require little material, which has made feasible biochemical and molecular analyses of small tissue fragments, even individual cells, by microdissection of histological sections (1,2). Polymerase chain reaction (PCR) can potentially be applied ...

Several cell biological studies have shown that the invasiveness of a variety of tumors depend on the regulated expression of proteolytic enzymes that degrade the surrounding extracellular matrix and dissociate cell-cell and/or cell-matrix attachments. One such enzyme, the seri ...

The “two-hit” theory of tumor suppressor gene (TSG) inactivation predicts that loss of function is a result of two separate genetic events, one affecting each allele (1). One hit is commonly a deletion of part of, or the entire allele sequence and can be detected by loss of heterozygosity (LOH) analysis in ...

Study of loss of heterozygosity (LOH) is widely used to identify chromosomal locations of putative tumor suppressor genes. In this type of analysis, DNA extracted from tumor tissue is compared with constitutive DNA from the same patient by the use of polymorphic DNA markers (1). This approach has ...

The p53 tumor suppressor gene encodes a 53-kD nuclear phosphoprotein and is the most commonly altered gene in human cancers (1). There are a large variety of methods currently employed for detection of alterations in thep53 gene. The reported abnormalities in p53 have been detected with a variety ...

Mutations of the p53 tumor suppressor gene are the most common alterations associated with malignancy identified so far. Inactivation of the p53 gene contributes to loss of a cell-cycle check point at the G1-S boundary and to genetic instability of the cell eventually allowing cells to replic ...

Earlier studies with somatic cell hybrids had clearly shown that when malignant cells were fused with normal cells, the resulting hybrid cells were nontumorigenic and that reexpression of tumorigenicity was often associated with the loss of specific chromosomes derived from the nor ...

An association of a loss of DNA replication control and the activation of erbB oncogenes can be deduced from studies with different cancers (1-5). In the first study on ovarian cancer 26% of the tumors had c-erbB-2 amplifications (6). The correlation between c-erbB-2 amplification and expression ...

Although cancer is fundamentally a genetic disease, in the majority of cancers the mutations occur somatically (i.e., only in the tissue from which the cancer is derived). However, for many types of cancer, for example, breast, ovarian, and colorectal cancer there are a small number of cases that ari ...

Genomic changes are a frequent underlying event in many malignancies, including ovarian cancers, and are intrinsic to the process of oncogenesis and tumor progression. Identification of recurrent nonrandom changes that affect specific genomic regions may provide prognostic i ...

Microsatellites are simple, tandemly repeated DNA sequences that are abundantly distributed throughout the human genome, and because of their polymorphic nature have been widely utilized as genetic markers (1). They consist of a repeating unit of 1 to 5 basepairs, averaging 25 to 60 bases in l ...

The loss of the function in any one of four human DNA mismatch repair genes, hMSH2, hMLH1, hPMS1, and hPMS2, is thought to lead to deficient mismatch repair (MMR) of DNA in the somatic cells leading to increased mutations and thereby cancer development. Microsatellite instability (MI) detected by PCR ...

This section deals with techniques of mRNA analysis, both qualitative and quantitative. The technical details for the techniques described in this section are included in the chapters themselves. In this overview, some of the fundamentals that researchers need to understand in approa ...

The association of c-erbB-2 oncogene amplification and prognostic factors was intensively studied in human gynecological carcinomas, especially in mammary carcinoma (1). Positive lymph nodes, estrogen and progesterone receptor negative tumors, and short survival time cor ...

Immunohistochemical techniques and molecular hybridization enable demonstration of specific proteins and DNA or RNA sequences, respectively. In situ hybridization is a variant of molecular hybridization that allows detection of specific DNA or RNA sequences in tissue secti ...

RNase protection assays provide a level of sensitivity some 20-50-fold greater than Northern blots, and can be used to accurately identify and quantify different mRNA species within gene families even when a high degree of sequence homology exists. Sequence homology between TGFβ1, TGFβ2, ...

In situ polymerase chain reaction (PCR) is a recently developed technique whereby DNA (or cDNA) is enzymically amplified within cells or tissue sections, enabling the localization of specific low copy number sequences within a heterogeneous cell population. In situ reverse transcri ...

Heat shock protein 60 (HSP60, HSPD1) is a “chaperonin” that facilitates folding of nascent proteins into proper conformations (1). It is thought to play a critical role in the assembly, folding, and transport of proteins in the mitochondria. HSP60 also interacts with nascent cellular proteins ...

Two hypothetical concepts are discussed as means to cure cancer: 1) extinction of the neoplastic cell pool which forms the tumor and 2) induction of terminal differentiation to park tumor cells in growth arrest (1). Sodium butyrate (NaB) has been shown to promote differentiation of HL-60 cells to m ...

In common with other tumor types, ovarian cancer is a genetic disease and work at the DNA or RNA level is crucial to gain an understanding of the genetic changes leading to tumor formation. Phenotypic change, however, is the result of loss or aberrant expression of normal protein or expression of a mutated ...