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Oncogenes and Cancer
Published in Pimentel Enrique, Oncogenes, 2020
Chromosomal aberrations are found in a number of patients with chronic lymphocytic leukemia (CLL).269,270 In the majority of patients with CLL the neoplastic cells contain B-cell markers and only less than 5% have monoclonal T-cell markers. Structural and/or numerical chromosome abnormalities have been found in up to 74% of the patients with chronic B-cell lymphocytic leukemia, the most frequent abnormality consisting in the presence of an extra chromosome 12. An extra chromosome 12 is associated with a more aggressive behavior of CLL and two proto-oncogenes have been assigned to this chromosome, namely, c-K-ras and c-int-1, but their possible participation in the pathogenetic phenomena of the disease is unknown. In rare cases of CLL a 14q+ marker chromosome is detected. In a human chronic lymphocytic leukemia cell line (CLL-271), a reciprocal translocation was observed between chromosomes 11q13 and 14q32 and it was suggested that a new proto-oncogene, bcl-1 would be located on chromosome 11q13 and that this putative cellular oncogene would contribute, after translocation to the rearranged IgH locus on chromosome 14+, to the neoplastic transformation of B-cells.271,272 No direct proof of the existence of the new proto-oncogene was presented but the oncogene c-ets is located on human chromosome region 11q23-q24. In general, the possible role of proto-oncogenes in CLL is unknown.
Clinical Cytogenetics and Testing for Developmental Disabilities
Published in Merlin G. Butler, F. John Meaney, Genetics of Developmental Disabilities, 2019
Joan H. M. Knoll, Linda D. Cooley
Marker chromosomes derived from either chromosome 15 or 22 are the most common. They are often bisatellited (see Fig. 2, marker chromosomes) as detected by NOR staining. Those derived from chromosome 15 (often referred to as inverted duplicated chromosome 15s) have little or no effect on phenotype if they do not include the Angelman/Prader–Willi syndrome chromosome region (38). They may result in an abnormal phenotype if the Angelman/Prader–Willi syndrome region is present(39). Distinction between these two classes of chromosome 15 markers can be determined by FISH, with probes for genes that localize to the Angelman/Prader–Willi syndrome region. Similarly, markers derived from chromosome 22 can be distinguished by size and location to identify those that have an effect from those that do not (40).For most other marker chromosomes of known chromosomal origin, the correlation between genotype and phenotype is limited (36,37) and in most cases will need more precise characterization for gene content of that particular marker chromosome.
Studies on the Relationship Between Epstein-Barr Virus (EBV) and Nasopharyngeal Carcinoma (NPC) in China
Published in D. V. M. Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
Lymphoblastoid cell lines were established from carcinoma tissue of NPC patients in Beijing, Shanghai, and Guangdong in 1973 to 1974.11 Group A marker chromosome was detected only in lymphoblastoid cell lines from NPC patients. With the exception of one lymphoblastoid cell line derived from a normal donor, the group A marker chromosome could not be found in the cell lines from other sources, including P3HR-1, B95-8, Raji, and lymphoblastoid lines from tonsils and so on. The submetacentric group A chromosome was formed by translocation of the short arm of chromosome 3, breaking at the point near to, or even involving, its centromere, to the distal light band region of the long arm of chromosome 1. Group A marker chromosome was also found in biopsies from NPC and suspected NPC patients. These results suggest that the group A marker chromosome might be associated with NPC.31
Retrospective analysis of 4761 cases who underwent amniocentesis in southeast China
Published in Journal of Obstetrics and Gynaecology, 2018
Hehua Tao, Jianping Xiao, Canfeng Yang, Jun Wang, Ye Tang, Caiqin Guo, Junfeng Wang
This study includes a retrospective evaluation of the clinical indications and the cytogenetic results of 4761 second-trimester AS cases performed at Wuxi Maternity and Child Health Hospital Affiliated to Nanjing Medical University between June 2014 and July 2016. The ages of our patients ranged between 17 and 51 and the week of gestation ranged from 17 to 23 weeks. Before AS, the procedure, possible complications and risk evaluation were known by pregnant women and their spouses, and approval forms were signed by all couples who accepted the procedure. Clinical indications of AS for cytogenetic analysis were grouped as: (1) increased risk at maternal serum screening (MSS); (2) advanced maternal age (AMA) (≥35 years at the expected time of delivery); (3) poor obstetric history (POH); (4) pathological ultrasound finding (PUF); (5) positive results from non-invasive prenatal testing (NIPT); (6) parental translocation or marker chromosome carriage (PTC); and (7) other cases except the mentioned situations. All patients were <35 years of age at the expected time of delivery except those in the AMA group. AMA patients with PUF or other additional findings were included in the AMA group.
Confirmatory test versus screening test analyses for fetal mosaic variations; a large scale study
Published in Alexandria Journal of Medicine, 2022
Seyed Akbar Moosavi, Behnam Hasannejad-Asl, Masoumeh Kourosh Arami, Mahsa Nasuti, Mehmet Cemal Oguz, Abdol-Hossain Naseri
Ideally, mosaicism should be diagnosed by screening a large number of karyotype metaphases in order to decrease the error and produce a statistically more confident result but we were also limited in the quantity of metaphase. Our study, however, indicated a wide variety of frequencies of abnormal cells within eight cases of the identified mosaic condition. Hence, other complementary PTs should be explored to compensate for the shortcoming in metaphases. Interestingly, we found one new case of marker chromosome mosaicism with ambiguous morphology that generated a more challenging situation for genetic counseling than those with known characterized morphology. We also had a new mosaic case of monosomy of 21 with an unknown fate for genetic counseling (Tables 3 and 4).
Clinical Observation of a Child with Prenatally Diagnosed De Novo Partial Trisomy of Chromosome 20
Published in Fetal and Pediatric Pathology, 2019
Agnieszka Stembalska, Justyna Gil, Izabela Laczmanska, Maria Sasiadek
To determine which parental chromosome contributed to the de novo marker chromosome the STR (short tandem repeats) analysis method can be employed. Marker chromosomes usually arise from gametogenesis errors, trisomic rescue, centromere misdivision that creates a pericentromeric deletion or so-called McClintock mechanism [3, 20]. Determining the parent contribution to the extra material may be important in case of uniparental disomy (UPD) and therefore genetic imprinting. There are only a few studies on UPD in connection with sSMC derived from chromosome 20. Most of them present maternal UPD with growth restriction [21]. We did not determine the origin of the marker chromosome in our patient.