The first wave of information from the analysis of the human genome revealed SNPs to be the main source of genetic and phenotypic human variation. However, the advent of genome-scanning technologies has now uncovered an unexpectedly large extent of what we term 'structural variation' in the human genome. This comprises microscopic and, more commonly, submicroscopic variants, which include deletions, duplications and large-scale copy-number variants - collectively termed copy-number variants or copy-number polymorphisms - as well as insertions, inversions and translocations. Rapidly accumulating evidence indicates that structural variants can comprise millions of nucleotides of heterogeneity within every genome, and are likely to make an important contribution to human diversity and disease susceptibility.

Structural variation in the human genome

We have developed epifluorescence filter sets and computer software for the detection and discrimination of 27 different DNA probes hybridized simultaneously. For karyotype analysis, a pool of human chromosome painting probes, each labelled with a different fluor combination, was hybridized to metaphase chromosomes prepared from normal cells, clinical specimens, and neoplastic cell lines. Both simple and complex chromosomal rearrangements could be detected rapidly and unequivocally; many of the more complex chromosomal abnormalities could not be delineated by conventional cytogenetic banding techniques. Our data suggest that multiplex-fluorescence in situ hybridization (M-FISH) could have wide clinical utility and complement standard cytogenetics, particularly for the characterization of complex karyotypes.

Karyotyping human chromosomes by combinatorial multi-fluor FISH

With 5-year survival rates remaining constant at 6% and rising incidences associated with an epidemic in obesity and metabolic syndrome, pancreatic ductal adenocarcinoma (PDAC) is on track to become the second most common cause of cancer-related deaths by 2030. The high mortality rate of PDAC stems primarily from the lack of early diagnosis and ineffective treatment for advanced tumors. During the past decade, the comprehensive atlas of genomic alterations, the prominence of specific pathways, the preclinical validation of such emerging targets, sophisticated preclinical model systems, and the molecular classification of PDAC into specific disease subtypes have all converged to illuminate drug discovery programs with clearer clinical path hypotheses. A deeper understanding of cancer cell biology, particularly altered cancer cell metabolism and impaired DNA repair processes, is providing novel therapeutic strategies that show strong preclinical activity. Elucidation of tumor biology principles, most notably a deeper understanding of the complexity of immune regulation in the tumor microenvironment, has provided an exciting framework to reawaken the immune system to attack PDAC cancer cells. While the long road of translation lies ahead, the path to meaningful clinical progress has never been clearer to improve PDAC patient survival.

/pdf/genetics-and-biology-of-pancreatic-ductal-adenocarcinoma-2k15657c9p.pdf

Genetics and biology of pancreatic ductal adenocarcinoma

Metastasis can be viewed as an evolutionary process, culminating in the prevalence of rare tumour cells that overcame stringent physiological barriers as they separated from their original environment and developmental fate. This phenomenon brings into focus long-standing questions about the stage at which cancer cells acquire metastatic abilities, the relationship of metastatic cells to their tumour of origin, the basis for metastatic tissue tropism, the nature of metastasis predisposition factors and, importantly, the identity of genes that mediate these processes. With knowledge cemented in decades of research into tumour-initiating events, current experimental and conceptual models are beginning to address the genetic basis for cancer colonization of distant organs.

Genetic determinants of cancer metastasis

https://www.cell.com/trends/genetics/pdf/S0168-9525(06)00175-2.pdf

Gene amplification in cancer

Disclosed are new methods comprising the use of in situ hybridization to detect abnormal nucleic acid sequence copy numbers in one or more genomes wherein repetitive sequences that bind to multiple loci in a reference chromosome spread are either substantially removed and/or their hybridization signals suppressed. The invention termed Comparative Genomic Hybridization (CGH) provides for methods of determining the relative number of copies of nucleic acid sequences in one or more subject genomes or portions thereof (for example, a tumor cell) as a function of the location of those sequences in a reference genome (for example, a normal human genome). The intensity(ies) of the signals from each labeled subject nucleic acid and/or the differences in the ratios between different signals from the labeled subject nucleic acid sequences are compared to determine the relative copy numbers of the nucleic acid sequences in the one or more subject genomes as a function of position along the reference chromosome spread. Amplifications, duplications and/or deletions in the subject genome(s) can be detected. Also provided is a method of determining the absolute copy numbers of substantially all RNA or DNA sequences in subject cell(s) or cell population(s).

https://www.annualreviews.org/doi/pdf/10.1146/annurev.genom.6.080604.162140

Comparative genomic hybridization

Detection of chromosomal abnormalities associated with breast cancer

Disclosed are new methods comprising the use of in situ hybridization to detect abnormal nucleic macid sequence copy numbers in one or more genomes wherein repetitive sequences that bind to multiple loci in a reference chromosome spread are either substantially removed and/or their hybridization signals suppressed. The invention termed Comparative Genomic Hybridization (CGH) provides for methods of determining the relative number of copies of nucleic acid sequences in one or more subject genomes or portions thereof (for example, a tumor cell) as a function of the location of those sequences in a reference genome (for example, a normal human genome). The intensity(ies) of the signals from each labeled subject nucleic acid and/or the differences in the ratios between different signals from the labeled subject nucleic acid sequences are compared to determine the relative copy numbers of the nucleic acid sequences in the one or more subject genomes as a function of position along the reference chromosome spread. Amplifications, duplications and/or deletions in the subject genome(s) can be detected. Also provided is a method of determining the absolute copy numbers of substantially all RNA or DNA sequences in subject cell(s) or cell population(s).

Comparative genomic hyridization

The present invention provides a method of detecting nucleotide sequence differences between two nucleic acid samples. The method employs a comparative genomic hybridization (CGH) technique to analyze the sequence differences between the samples. This method permits the identification of small sequence differences (e.g., sequence divergence of 1% or less) in nucleic acid samples of high complexity (e.g., an entire genome).

Detection of nucleic acid sequence differences by comparative genomic hybridization

Cancer markers are developed to detect diseases characterized by increased expression of apoptosis-suppressing genes, such as aggressive cancers Genome wide analyses of genome copy number and gene expression in breast cancer revealed 66 genes in the human chromosomal regions, 8pl 1, 1 Iql3, 17ql2, and 20ql3 that were amplified Diagnosis and assessment of amplification levels of genes shown to be amplified are useful in prediction of patient outcome of a of patient's response and drug resistance in breast cancer Certain genes were found to be high priority therapeutic targets by the identification of recurrent aberrations involving genome sequence, copy number and/or gene expression are associated with reduced survival duration in certain diseases and cancers, specifically breast cancer Inhibitors of these genes will be useful therapies for treatment of these non-responsive cancers

Frederic Waldman

Papers

Comparative genomic hybridization

Detection of chromosomal abnormalities associated with breast cancer

Comparative genomic hyridization

Detection of nucleic acid sequence differences by comparative genomic hybridization

Targets in breast cancer for prognosis or therapy