![]() Genomic rearrangements by Alu insertion cause about 0.1% of human diseases and genomic deletions lead to ARMD for 0.3% of human genetic disorders. Like Alu- insertion, Alu-deletion events also occur in human genome by Alu insertion-mediated deletions (AIMD) or Alu recombination-mediated deletions (ARMD). Alu elements modify the gene function by Alu insertion into the exons. During gene expression Alu elements influence the genome and gene activity by insertion mutation, gene conversion, deletion. Accordingly, they produced a group of subfamilies with time. Scientist predicted that over more than 60 million years Alu elements multiply to more than one million copies among the primate genomes. Insertions and deletions of them are detectable by PCR(Polymerase chain reaction). They are described as the most common transposable elements that induce insertion mutagenesis. They are approximately 300 base pair long in sequence and mostly obtained from the introns, untranslated regions of genes and intergenic genomic regions. Through retroposition they can duplicate themselves via an RNA intermediate theory and increase their number. They make a broad family of mobile genetic elements within the human genome. Alu-elements are inherited from the 7SL RNA (Ribonucleic acid) gene. Īlu-elements are sequences of nucleotides which was familiar as SINEs (short interspersed nuclear elements. So they are named after the enzyme Alu-I. The enzyme Alu-I influences the DNA base pair for its existence. Some literatures describe Alu-repeat as the most important and rich repeats in the human genome. Alu elements exist as a group of DNA sequences called inserted repetitive DNA. As a part of that, Alu-element came to the center of discussion which may explain the origin of some diseases including breast cancer. They are also considered as non-allelic homologous recombination factor causing copy number variation and different disease. It may lead to different genetic diseases including cancer. Insertion or loss of a transoposon element in the genome dynamics was amenable for DNA damage interfering with gene activities. Besides these, chromosomal deletions and loss of heterozygosity are responsible for activation of tumor suppressor genes. There are small deletions and insertions which are described as point mutations in different descriptions of genetic disorders. From the day of David Hahnemann (1858–1920) to present days scientist reached to a consensus that genes affect pathways of cell growth, cell signaling, apoptosis and Deoxyribonucleic Acid (DNA) repair which finally lead to oncogenesis. Human cancer undoubtedly recognized now-a-days as genetic disease. Alu-deletion can be presumed as a useful blood-based biomarker for the detection of early breast cancer. Whereas no such banding pattern was observed in cancer tissues and normal breast tissues collected during surgery.Ĭonclusion: This study confirms significant presence of Alu-deletion in women with breast cancer in comparison without cancer. We also found differential DNA banding pattern between breast cancer (7-9) and control blood samples (9-15) which is highly significant (p < 0.0001). Another band was identified as less intensified at the 1700bp, present in 74% cancerous blood samples (p < 0.0001). One of them characterized as deletion at the 2000bp region, found in 83% cancerous blood samples and only 3% in the healthy controls (p < 0.0001), OR 149. Result: Among the 64 patients and equal number (64) of healthy women examined, multiple Alu polymorphic loci have been identified. Alu specific banding patterns of DNA of the samples were examined and compared. After extraction, DNA was amplified by PCR with Alu specific primer and gel electrophoresis was done. For comparison, blood was collected from healthy controls. Methods: To identify Alu-deletion, tissue samples from the operated specimen and blood of the breast cancer patients were collected. This study was aimed to find status of Alu-deletion among breast cancer patients. Objective: Alteration of Alu elements of human DNA may result cancer.
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