Quantitative analysis of centromeric FISH spots during the cell cycle by image cytometry

FISHing for Chromosome Instability and Aneuploidy in the Alzheimer's Disease Brain

Fluorescence in situ hybridization (FISH) is the method of choice for visualizing chromosomal DNA in post-mitotic cells. The availability of chromosome-enumeration (centromeric), site-specific, and multicolor-banding DNA probes offers opportunities to uncover genomic changes, at the chromosomal level, in single interphase nuclei. Alzheimer's disease (AD) has been associated repeatedly with (sub)chromosome instability and aneuploidy, likely affecting the brain. Although the types and rates of chromosome instability in the AD brain remain a matter of debate, molecular cytogenetic analysis of brain cells appears to be important for uncovering mechanisms of neurodegeneration. Here, we describe a FISH protocol for studying chromosome instability and aneuploidy in the AD brain.

FISHing for Damage on Metaphase Chromosomes

Fluorescence in situ hybridization (FISH) is used to examine chromosomal abnormalities and DNA damage. Developed in the early 1980s, this technique remains an important tool for understanding chromosome biology and diagnosing genetic disease and cancer. Use of FISH on metaphase chromosomes allows the visualization of chromosomal abnormalities at specific loci. Here, we describe methods for creating metaphase chromosome spreads and the use of telomere FISH probes to detect chromosome ends.

Quantitative Fluorescence In Situ Hybridization (QFISH)

Fluorescence in situ hybridization (FISH) has a wide spectrum of applications in current molecular cytogenetic and cancer research. This is a unique technique that can be used for chromosomal DNA analysis in all cell types, at all stages of the cell cycle, and at molecular resolution. Recent developments in microscopy and imaging systems have allowed quantification of digital FISH images (quantitative FISH or QFISH) and have provided a new way for molecular cytogenetic analysis at single-cell level. QFISH can be applied for studying chromosome imbalances in interphase nuclei or metaphase spreads, measuring relative DNA content at chromosomal loci and identifying parental origin of homologous chromosomes. Here, a QFISH protocol suitable for the majority of DNA probes using the popular US National Institute of Health developed ImageJ software is described.

Analysis of centromere signal patterns in breast cancer cells with chromosomal instability using image cytometry combined with centromere fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) with centromeric probes is a method used to detect chromosomal instability (CIN), a hallmark of most cancers. However, no studies thus far have investigated the relationship between centromeric FISH signals and the cell cycle in cancer cells. In this study, the chromosome content in each cell cycle phase was evaluated with respect to the number of centromeric FISH signals in two breast cancer cell lines and eight surgically resected breast cancer specimens using image cytometry. Variations in chromosome number were detected at each phase of the cell cycle but were not associated with proliferative capacity in the cell lines. Furthermore, the chromosome doubling frequency differed in each cell line and clinical specimen. These results reveal two aspects of centromeric FISH signal variation in breast cancers that exhibit CIN, and suggest that chromosome doubling is a remarkable occurrence that may increase the heterogeneity of tumors.