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At least 991 records · Page 55Linked to original sources
PubMed1993

Differential localization patterns of myristoylated and nonmyristoylated c-Src proteins in interphase and mitotic c-Src overexpresser cells.

Myristoylation of pp60src is required for its membrane attachment and transforming activity. The mouse monoclonal antibody, mAb327, which recognizes both normal, myristoylated pp60c-src and a nonmyristoylated mutant, pp60c-src/myr-, has been used to compare the effects of preventing myristoylation on the localization of c-Src in NIH 3T3-derived overexpresser cells using immunofluorescence microscopy. During interphase, pp60c-src partitions between the plasma membrane and the centrosome, while pp60c-src/myr- is predominantly cytoplasmic but also partly nuclear. The cytoplasmic, but not the nuclear, staining can be readily washed out by brief pretritonization of the cells before fixation, indicating that the cytoplasmic pool of pp60c-src/myr-, in contrast with the nuclear one, does not associate tightly with structures that are insoluble in the presence of nonionic detergents. We have previously shown that during G2 phase, pp60c-src leaves the plasma membrane and is redistributed diffusely throughout the cytoplasm and to two clusters of patches surrounding the two separating centriole pairs. In contrast, we now find that pp60c-src/myr- translocates to the nucleus in late G2 or early prophase prior to there being any clear evidence of nuclear membrane breakdown or nuclear lamina disassembly. Similar nuclear translocation of pp60c-src/myr-, but not of pp60c-src, is also observed when cells are arrested in G0 or at the G1/S transition. Furthermore, during mitosis, pp60c-src is found primarily in diffuse and patchy structures dispersed throughout the cytoplasm while pp60c-src/myr- more specifically associates with the main components of the spindle apparatus (poles and fibers) and inside the interchromosomal space. These results suggest that a possible role for myristoylation might be to prevent unregulated nuclear transport of proteins whose nonmyristoylated counterparts are readily moved into the nucleus. They also raise the possibility that a subfraction of wild-type pp60c-src may behave, at specific times, like its nonmyristoylated counterpart, and may translocate to the nucleus and exert specific functions in that location.

3T3 Cells↗
PubMed1994

Nuclear calmodulin/62 kDa calmodulin-binding protein complexes in interphasic and mitotic cells.

We report here that a 62 kDa calmodulin-binding protein (p62), recently identified in the nucleus of rat hepatocytes, neurons and glial cells, consists of four polypeptides showing pI values between 5.9 and 6.1. By using a DNA-binding overlay assay we found that the two most basic of the p62 polypeptides bind both single- and double-stranded DNA. The intranuclear distribution of calmodulin and p62 was analysed in hepatocytes and astrocyte precursor cells, and in proliferating and differentiated astrocytes in primary cultures by immunogold-labeling methods. In non-dividing cells nuclear calmodulin was mostly localized in heterochromatin although it was also present in euchromatin and nucleoli. A similar pattern was observed for p62, with the difference that it was not located in nucleoli. p62/calmodulin complexes, mainly located over heterochromatin domains were also observed in interphasic cells. These complexes remained associated with the nuclear matrix after in situ sequential extraction with nucleases and high-salt containing buffers. In dividing cells, both calmodulin and p62 were found distributed over all the mitotic chromosomes but the p62/calmodulin aggregates were disrupted. These results suggest a role for calmodulin and p62 in the condensation of the chromatin.

Animals↗
PubMed1999

Overexpression of normal and mutant Arp1alpha (centractin) differentially affects microtubule organization during mitosis and interphase.

Dynactin is a large multisubunit complex that regulates cytoplasmic dynein-mediated functions. To gain insight into the role of dynactin's most abundant component, Arp1alpha was transiently overexpressed in mammalian cells. Arp1alpha overexpression resulted in a cell cycle delay at prometaphase. Intracellular dynactin, dynein and nuclear/mitotic apparatus (NuMA) protein were recruited to multiple foci associated with ectopic cytoplasmic aggregates of Arp1alpha in transfected cells. These ectopic aggregates nucleated supernumerary microtubule asters at prometaphase. Point mutations were generated in Arp1alpha that identified specific amino acids required for the prometaphase delay and for the formation of supernumerary microtubule asters. The mutant Arp1alpha proteins formed aggregates in cells that colocalized with dynactin and dynein peptides, but in contrast to wild-type Arp1alpha, NuMA localization remained unaffected. Although expression of mutant Arp1alpha proteins had no effect on mitotic cells, in interphase cells expression of the mutants resulted in disruption of the microtubule network. Immunoprecipitation studies demonstrated that overexpressed Arp1alpha interacts with dynactin and NuMA proteins in cell extracts, and that these interactions are destabilized in the Arp1alpha mutants. We conclude that the amino acids altered in the Arp1alpha mutant proteins participate in stabilizing interactions between overexpressed Arp1alpha and components of the endogenous dynactin complex as well as the NuMA protein.

Actins↗
PubMed2001

Mitotic checkpoint proteins HsMAD1 and HsMAD2 are associated with nuclear pore complexes in interphase.

Mad1 was first identified in budding yeast as an essential component of the checkpoint system that monitors spindle assembly in mitosis and prevents premature anaphase onset. Using antibodies to the human homologue of Mad1 (HsMAD1), we have begun to characterize this protein in mammalian cells. HsMad1 is found localized at kinetochores in mitosis. The labeling is brightest in prometaphase and is absent from kinetochores at metaphase and anaphase. In cells where most chromosomes have reached the metaphase plate, those aligned at the plate show no labeling while remaining, unaligned chromosomes are still brightly labeled. We find HsMad1 associated with HsMad2. Association with p55CDC, a protein previously shown to bind HsMad2, was not detected. Surprisingly, unlike any other known mitotic checkpoint proteins, HsMad1 and HsMAD2 were found localized at nuclear pores throughout interphase. This was confirmed by co-labeling with an antibody to known nuclear pore complex proteins and by their co-purification with enriched nuclear envelope fractions. HsMad1 was identified serendipitously by its binding to a viral protein, HTLV-1 Tax, which affects transcription of viral and human proteins. The localization of HsMad1 to nuclear pore complexes suggests an alternate, non-mitotic role for the Mad1/Tax interaction in the viral transformation of cells.

Amino Acid Sequence↗
PubMed1979

A cytochemical and radioautographic study of the ultrastructural organization of puff-like fibrillar structures in plant interphase nuclei (Allium porrum).

Loose, fibrillar, spherical structures have been observed during recent years in interphase nuclei of both animal and plant cells. These nuclear formations have been referred to as karyosomes, fibrillar bodies, micropuffs and centromeres. In order to gain further information on the nature of these structures, a cytochemical and radioautographic investigation was undertaken using plant meristematic cells (Allium porrum). For that purpose roots were fixed with either formaldehyde or glutaraldehyde in order to carry out cytochemical tests for DNA, RNA and proteins. Certain of the preparations were also first digested with DNase, RNase or proteinase K and then stained according to different procedures. Other specimens were labelled with thymidine for high-resolution radioautographic observations. Staining with diaminobenzidine (DAB) revealed that these nuclear puff-like formations consisted partly of a loose fibrillar meshwork containing nucleic acids. Part of this fine fibrillar reticulum persisted whether the preparations were digested with DNase or RNase before staining with DAB, thus indicating that these nuclear structures contained both DNA and RNA. The fact that these formations incorporate thymidine furnished additional support for the view that they correspond to specific chromosome segments. Staining with ethanolic phosphotungstic acid or digestion of specimens with proteinase K showed that these loose fibrillar structures also consisted of proteins. Judging from their ultrastructure, their association with the chromatin reticulum as well as from their cytochemical characteristics, these nuclear formations most likely correspond to centromeres. In view of the presence of DNA within these structures, it is possible to distinguish them from other equally spherical nuclear formations, observed in certain plant species, that have generally been referred to as karyosomes or micronucleoli and that appear to consist of ribonucleoproteins.

Cell Cycle↗
PubMed1984

Nuclear pores and interphase chromatin: high-resolution image analysis and freeze etching.

Computer-enhanced analysis of electron micrographs of thin-sectioned rat liver nuclei, combined with three-dimensional reconstruction of the same Feulgen-stained nuclei, points to a unique clustering of chromatin DNA fibres near the nuclear border. Computer-enhanced image analysis has been applied to electron micrographs of the envelopes of the same rat liver nuclei prepared by freeze etching and a few essential geometrical parameters characterizing the pores and their distribution have been determined. During interphase, clusters of nuclear pores, closely paralleling the clustering of membrane-attached chromatin fibres, have been identified on the envelope, the number of these being similar to the number of homologus pairs of metaphase chromosomes. Furthermore, rapid changes induced in chromatin distribution appear to be associated with rapid changes in pore number, but not in the number of pore clusters.

Animals↗
PubMed1987

The microtubule-organizing complex and the Golgi apparatus are co-localized around the entire nuclear envelope of interphase cardiac myocytes.

In most animal cells, the microtubule-organizing centre (MTOC) and the Golgi apparatus (GA) are co-localized on one side of the nucleus, an arrangement that allows these cells to acquire a functional polarity. An exception has been reported in the skeletal muscle myotube, where the MTOC and GA exhibit a circumnuclear distribution. We wished to determine if this unusual distribution of the MTOC and GA was peculiar to syncytial myotubes or reflected a pattern found in muscle cells generally. Immunofluorescence microscopic studies of cultured chicken skeletal muscle, cardiac muscle and gizzard smooth muscle cells were carried out using preimmune sera that recognized the pericentriolar material, anti-tubulin antibodies to label the MTOC, and fluorescent wheat-germ agglutinin to label the GA. These studies have shown that cardiac myocytes possess a circumnuclear distribution of their MTOC and GA as do skeletal myotubes, but smooth muscle cells exhibit the centrosomal MTOC and GA distribution found in most other cells. The circumnuclear MTOC/GA distribution therefore is associated with striated muscle cells. We also found that as embryonic cardiac myocytes pass through the cell cycle the microtubule-organizing activity in these cells switches from a circumnuclear distribution in interphase to the conventional centrosomal location during mitosis. Thus, cardiac myocytes provide a rare example of mononucleated animal cells that do not display a centrosomal MTOC or a polarized GA, and also reveal a system in which the MTOC structure can be reversibly altered in a cell cycle-dependent manner.

Animals↗
PubMed1989

Ki-67 detects a nuclear matrix-associated proliferation-related antigen. I. Intracellular localization during interphase.

Ki-67 is a commercially available mouse monoclonal antibody, which reacts with a nuclear antigen in proliferating cells. The antibody can be used to determine the growth fraction of human tumours in situ and has been shown to be of prognostic importance. In this study it is shown that in interphase cells Ki-67 reacts with an antigen, mainly present in the nucleoli. Confocal scanning laser microscopy and immunoelectron microscopy on human MR65 monolayer cells revealed that this nucleolar antigen is predominantly localized in the nucleolar cortex and in the dense fibrillar components. The Ki-67 antigen appeared to be preserved in nuclear matrix preparations obtained after in situ fractionation of MR65 cells. Despite many efforts, we could not identify the antigen in immunoblotting or immunoprecipitation assays. Testing of cell cultures of different species by means of indirect immunofluorescence revealed that the antibody reacted with human cells and with the Rhesus monkey kidney-derived cell line LLC-MK2.

Antibodies, Monoclonal↗
PubMed1990

Interphase microtubule dynamics are cell type-specific.

The rate and pattern of microtubule polymer loss in interphase cells have been examined using nocodazole to block microtubule assembly. Cells were incubated with high concentrations of nocodazole for various times and the pattern of microtubule disassembly was determined using tubulin immunofluorescence. Polymer loss was quantitated by measuring the decrease in percentage of cell area occupied by microtubules. The results demonstrate that microtubules in diverse cells disassemble individually and asynchronously. In addition, these quantitative measurements reveal that epithelial and fibroblast cells display strikingly different kinetics of polymer loss. In fibroblasts, polymer loss is rapid, with a half-time of 4 min at 37 degrees C. In epithelial cells, loss of 60% of the microtubules occurs with a half-time of 18 min; the remaining 40% of the microtubules disassemble much more slowly (average half-time of 72 min). To demonstrate that these differences were not due to species differences among various cells assayed in these experiments, epithelial and fibroblast cells derived from primary cultures of newt lung have been examined. Again, fibroblast and epithelial cell microtubule dynamics could be readily distinguished. To determine if modifications to epithelial cell microtubules contribute to their stability, microtubules were completely disassembled and allowed to regrow. The rate of polymer loss for recently regrown microtubules was more rapid than microtubules in control cells, indicating that stability increases with time after assembly.

Animals↗
PubMed1998

Inhibition of nuclear envelope reconstitution in Xenopus interphase egg extract by hemin.

Addition of hemin to the nuclear reconstitution system of Xenopus interphase egg extract using sperm head chromatin resulted in abnormal pseudonuclei exhibiting flattened membrane patches randomly distributed both on the surface and inside the nuclei. The structures that resembled nuclear pores were observed on these flattened membrane patch structures. Although the nucleosome structure was formed as revealed by the micrococcal nuclease digestion, the B-type lamin uptake into the nuclei was inhibited by hemin. Using heminagarose affinity chromatography, we isolated several hemin-binding proteins from fully reconstituted pseudonuclei. Some of the hemin-binding proteins bound concanavalin A (Con A). Comparison of hemin-binding proteins with those isolated from both fractions of supernatant and pellet separated by high speed centrifugation of the egg extract showed that the hemin-binding proteins of pseudonuclei were supplied from both fractions. The uptake of nuclear hemin-binding proteins did not occur in the incompletely reconstituted nuclei resulting from addition of excess sperm chromatin to the system. These results suggest that the hemin-binding proteins participate in the late steps of nuclear reconstitution during formation of the nuclear envelope.

Animals↗
PubMed2005

The variation of aneuploidy frequency in the developing and adult human brain revealed by an interphase FISH study.

Despite the lack of direct cytogenetic studies, the neuronal cells of the normal human brain have been postulated to contain normal (diploid) chromosomal complement. Direct proof of a chromosomal mutation presence leading to large-scale genomic alterations in neuronal cells has been missing in the human brain. Large-scale genomic variations due to chromosomal complement instability in developing neuronal cells may lead to the variable level of chromosomal mosaicism probably having a substantial effect on brain development. The aim of the present study was the pilot assessment of chromosome complement variations in neuronal cells of developing and adult human brain tissues using interphase multicolor fluorescence in situ hybridization (mFISH). Chromosome-enumerating DNA probes from the original collection (chromosomes 1, 13 and 21, 18, X, and Y) were used for the present pilot FISH study. As a source of fetal brain tissue, the medulla oblongata was used. FISH studies were performed using uncultured fetal brain samples as well as organotypic cultures of medulla oblongata tissue. Cortex tissues of postmortem adult brain samples (Brodmann area 10) were also studied. In cultured in vitro embryonic neuronal brain cells, an increased level of aneuploidy was found (mean rate in the range of 1.3-7.0% per individual chromosome, in contrast to 0.6-3.0% and 0.1-0.8% in uncultured fetal and postmortem adult brain cells, respectively). The data obtained support the hypothesis regarding aneuploidy occurrence in normal developing and adult human brain.

Aneuploidy↗
PubMed2006

The transcriptional regulator CBP has defined spatial associations within interphase nuclei.

It is becoming increasingly clear that nuclear macromolecules and macromolecular complexes are compartmentalized through binding interactions into an apparent three-dimensionally ordered structure. This ordering, however, does not appear to be deterministic to the extent that chromatin and nonchromatin structures maintain a strict 3-D arrangement. Rather, spatial ordering within the cell nucleus appears to conform to stochastic rather than deterministic spatial relationships. The stochastic nature of organization becomes particularly problematic when any attempt is made to describe the spatial relationship between proteins involved in the regulation of the genome. The CREB-binding protein (CBP) is one such transcriptional regulator that, when visualised by confocal microscopy, reveals a highly punctate staining pattern comprising several hundred individual foci distributed within the nuclear volume. Markers for euchromatic sequences have similar patterns. Surprisingly, in most cases, the predicted one-to-one relationship between transcription factor and chromatin sequence is not observed. Consequently, to understand whether spatial relationships that are not coincident are nonrandom and potentially biologically important, it is necessary to develop statistical approaches. In this study, we report on the development of such an approach and apply it to understanding the role of CBP in mediating chromatin modification and transcriptional regulation. We have used nearest-neighbor distance measurements and probability analyses to study the spatial relationship between CBP and other nuclear subcompartments enriched in transcription factors, chromatin, and splicing factors. Our results demonstrate that CBP has an order of spatial association with other nuclear subcompartments. We observe closer associations between CBP and RNA polymerase II-enriched foci and SC35 speckles than nascent RNA or specific acetylated histones. Furthermore, we find that CBP has a significantly higher probability of being close to its known in vivo substrate histone H4 lysine 5 compared with the closely related H4 lysine 12. This study demonstrates that complex relationships not described by colocalization exist in the interphase nucleus and can be characterized and quantified. The subnuclear distribution of CBP is difficult to reconcile with a model where chromatin organization is the sole determinant of the nuclear organization of proteins that regulate transcription but is consistent with a close link between spatial associations and nuclear functions.

Acetylation↗
PubMed2005

Sister chromatids are often incompletely aligned in meristematic and endopolyploid interphase nuclei of Arabidopsis thaliana.

We analyzed whether sister chromatids are continuously aligned in meristematic and endopolyploid Arabidopsis interphase nuclei by studying sister-chromatid alignment at various chromosomal positions. FISH with individual BACs to flow-sorted 4C root and leaf nuclei frequently yielded more than two hybridization signals, indicating incomplete or absent sister-chromatid alignment. Up to 100% of 8C, 16C, and 32C nuclei showed no sister-chromatid alignment at defined positions. Simultaneous FISH with BACs from different chromosomal positions revealed more frequent sister-chromatid alignment in terminal than in midarm positions. Centromeric positions were mainly aligned up to a ploidy level of 16C but became separated or dispersed in 32C nuclei. DNA hypomethylation (of the whole genome) and transcriptional activity (at FWA gene position) did not impair sister-chromatid alignment. Only 6.1% of 4C leaf nuclei showed sister-chromatid separation of the entire chromosome 1 top arm territories. Homozygous transgenic tandem repeat (lac operator) arrays showing somatic homologous pairing more often than average euchromatic loci did not promote an increased frequency of sister-chromatid alignment. The high frequency of separated sister-chromatid arm positions in > or =4C nuclei suggests that sister-chromatid cohesion is variable, dynamic, and not obligatory along the entire chromosome arm in meristematic and differentiated Arabidopsis nuclei.

Arabidopsis↗
PubMed2002

A model for interphase chromosomes and evaluation of radiation-induced aberrations.

We have developed a theoretical model for evaluating radiation-induced chromosomal exchanges by explicitly taking into account interphase (G(0)/G(1)) chromosome structure, nuclear organization of chromosomes, the production of double-strand breaks (DSBs), and the subsequent rejoinings in a faithful or unfaithful manner. Each of the 46 chromosomes for human lymphocytes (40 chromosomes for mouse lymphocytes) is modeled as a random polymer inside a spherical volume. The chromosome spheres are packed randomly inside a spherical nucleus with an allowed overlap controlled by a parameter Omega. The rejoining of DSBs is determined by a Monte Carlo procedure using a Gaussian proximity function with an interaction range parameter sigma. Values of Omega and sigma have been found which yield calculated results of interchromosomal aberration frequencies that agree with a wide range of experimental data. Our preferred solution is one with an interaction range of 0.5 microm coupled with a relatively small overlap parameter of 0.675 microm, which more or less confirms previous estimates. We have used our model with these parameter values and with resolution or detectability limits to calculate yields of translocations and dicentrics for human lymphocytes exposed to low-LET radiation that agree with experiments in the dose range 0.09 to 4 Gy. Five different experimental data sets have been compared with the theoretical results. Essentially all of the experimental data fall between theoretical curves corresponding to resolution limits of 1 Mbp and 20 Mbp, which may reflect the fact that different investigators use different limits for sensitivity or detectability. Translocation yields for mouse lymphocytes have also been calculated and are in good agreement with experimental data from 1 cGy to 10 cGy. There is also good agreement with recent data on complex aberrations. Our model is expected to be applicable to both low- and high-LET radiation, and we include a sample prediction of the yield of interchromosomal rejoining in the dose range 0.22 Gy to 2 Gy of 1000 MeV/nucleon iron particles. This dose range corresponds to average particle traversals per nucleus ranging from 1.0 to 9.12.

Animals↗
PubMed2003

Biological effectiveness of accelerated particles for the induction of chromosome damage measured in metaphase and interphase human lymphocytes.

Chromosome aberrations were investigated in human lymphocytes after in vitro exposure to 1H-, 3He-, 12C-, 40Ar-, 28Si-, 56Fe-, or 197Au-ion beams, with LET ranging from approximately 0.4-1393 keV/microm in the dose range of 0.075-3 Gy. Dose-response curves for chromosome exchanges, measured at the first mitosis postirradiation using fluorescence in situ hybridization (FISH) with whole-chromosome probes, were fitted with linear or linear-quadratic functions. The relative biological effectiveness (RBE) was estimated from the initial slope of the dose-response curve for chromosomal damage with respect to low- or high-dose-rate gamma rays. Estimates of RBEmax values for mitotic spreads, which ranged from near 0.7 to 11.1 for total exchanges, increased with LET, reaching a maximum at about 150 keV/microm, and decreased with further increase in LET. RBEs for complex aberrations are undefined due to the lack of an initial slope for gamma rays. Additionally, the effect of mitotic delay on RBE values was investigated by measuring chromosome aberrations in interphase after chemically induced premature chromosome condensation (PCC), and values were up to threefold higher than for metaphase analysis.

Chromosome Aberrations↗
PubMed2002

Interphase fluorescence in-situ hybridization in the diagnosis of bladder cancer.

Interphase FISH is a technique that uses fluorescent molecules to detect chromosomes or specific regions of DNA. It is a rapid and powerful technique for detection of cytogenetic abnormalities in malignant cells independent of their cell cycle status. Using variety of pericentromeric and locus-specific probes, numerical chromosomal changes (aneusomy) as well as loss or gain/amplification of specific genetic regions can be detected in clinical samples. Numerous studies have identified genetic alterations at the DNA level, occurring in the pathogenesis of variety of human neoplasms including bladder cancer, some of which can be used for detection, prognosis, and as intermediate endpoints for evaluating the response to therapy. Recently, sensitivity and specificity of a multicolor FISH assay consisting of four probes (3, 7, 17 and 9p21) was analyzed in several prospective and retrospective studies. The data suggest that this method applicable to voided urine specimens may allow safe extension of the interval between cystoscopies in routine surveillance of patients with transitional cell carcinoma of the bladder. FISH analysis of cells isolated from bladder washings or voided urine is also holding promise for monitoring of treatment outcome and predicting recurrence and progression of the disease. Therefore, this technique can be an important aid in the efforts to reduce mortality from transitional cell carcinoma of the bladder, since it increases our ability to prevent progression to incurable muscle invasive disease.

In Situ Hybridization, Fluorescence↗
PubMed1996

Acidification and recovery results in nuclear accumulation of supravital dyes during interphase.

Recent studies using real time imaging demonstrated relative nuclear insulation for ion-size particles. We show here that acidification and recovery converted the insulated interphase nuclei of KB carcinoma and nontumorigenic Chang cells into intense nuclear accumulating states marked by sequestration of the exogenous supravital dyes neutral red, methylene blue, and brilliant cresyl blue. The phenomenon was not affected by Na(+)-free and HCO3(-)-free conditions nor by the presence of cationic and anionic antiport regulators of cytosolic pH. Cytological, microspectrophotometric, and flow cytometric evaluation of whole cell populations showed that the nuclear influx was abolished by omitting the pH recovery response, and by modulating the recovery response. The abolition of nuclear influx in the presence of the P-ATPase and Fzero-ATPase inhibitors, vanadyl(IV) ions and oligomycin, respectively, suggest that H(+)-translocating ATPase pumps are involved in regulating cytosolic acidification in Na(+)-free and HCO3-conditions vanadyl(IV) inhibited nuclear uptake of supravital dyes in a dose dependent manner. Nuclear uptake of dyes, however, was not affected by up to 1 mM of genistein even though tyrosine-specific phosphorylation and DNA synthesis were abolished. Upgradient nuclear influx involving proton pump is novel. KB cancer cells and nontumorigenic Chang cells had differential dye accumulations induced by acidification and recovery.

Cell Line↗
PubMed1999

Deletion monitoring in skin tumors by interphase-FISH using band-specific DNA probes.

Thin sections from archival paraffin blocks of various skin tumors (26 melanomas, 15 squamous cell carcinomas, 5 keratoacanthomas, 5 basal cell carcinomas) were subjected to interphase-FISH (I-FISH) with DNA probes which are specific for chromosomal regions often involved in deletions in human cancer. These were probes for chromosome 3p21, the p53 gene on chromosome 17p13, and, in a few selected cases, a probe for chromosome 9p21. It was demonstrated that deletions of these regions could be reliably detected and related to tumor type and histology, i.e. grading. The most common deletion was that of 3p21 which was found in all studied squamous cell carcinomas (SCC) of low differentiation, in 60% of the Bowen carcinomas, in 70% of the metastatic melanomas less than 1.5 mm thick, and in over 55% of those which thickness over 2 mm. In contrast, FISH-detected p53 deletion was a rare finding in the investigated tumors. However, this gene was even found in an increased copy number in 60% of the poorly differentiated SCCs (grade 4) and in 50% of the non-metastatic melanomas less than 1.5 mm thick. Deletion of 9p21 was detected in 13 of the 14 tumors on which pertinent examinations could be performed. I-FISH was shown to be a reliable technique for the rapid detection of chromosome band specific deletions in archival material of human skin tumors.

Adult↗