Significance Of Chromosome Research Articles

Significance of chromosome 7 abnormalities in myeloid malignancies

Chromosome 7 abnormalities are the most common cytogenetic alterations found in myeloid malignancies. Myeloid malignancies exhibiting monosomy 7/del (7q) have been confirmed to associate with high susceptibility to infections, poor response to chemotherapy, and short survival time, so speculating that chromosome 7 has important tumor suppressor genes. Commonly deleted segments (such as 7q22) of chromosome 7 have been identified by FISH and other technologies. Genes (EZH2, MLL5, DOCK4, SAMD9L/SAMD9) located in commonly deleted segments of 7q have been cloned and characterized along with the advance of molecular biology.This review summaries the current advancement about myeloid malignancies associated with monosomy7/del(7q).

Basal cell carcinoma of the skin: whole genome screening by comparative genome hybridization revisited

Basal cell carcinoma (BCC) of the skin is considered to be the most common malignancy in people of European ancestry. It is often not clinically aggressive and has been regarded as genetically stable. However, histopathologic subtypes of BCC differ in their ability to invade surrounding tissues and recur. The aim of this work was to present a comprehensive study of chromosomal imbalances of cutaneous BCC and to correlate the findings with their histopathologic and clinical features. In all, 101 tumor samples were classified according to the current microscopic classification of BCC and then analyzed by comparative genomic hybridization (CGH). Over 60% of BCC were found to carry chromosomal imbalances - partial or whole chromosome gains and losses. Different subtypes of BCC presented common chromosomal alterations. No single chromosomal imbalance was found to be characteristic of a particular subtype of BCC, although the frequency of some chromosomal changes differed from one group to the other. The significance of chromosome 2 gains as a phenomenon that does not coexist with the losses in 9q is discussed.

Sarcoma arising as a distinct nodule within glioblastoma: a morphological and molecular perspective on gliosarcoma

Gliosarcoma is a variant of glioblastoma and is characterized by distinct glial and sarcomatous components. Typically, there is no macroscopic boundary between the components and special stains are often required to distinguish the glial and sarcomatous elements. Some studies suggest similar genetic alterations in both components pointing to a common origin. We present an extreme case of gliosarcoma arising as a discrete fibrous nodule adjacent to a typical glioblastoma. A 65 year-old woman presented with progressive weakness, seizures and right-sided hemiparesis. CT scan demonstrated an irregular enhancing left frontal lobe mass and an adjacent discrete nodule with different imaging characteristics. The unique nature of this macroscopically biphasic neoplasm allowed us to compare the molecular characteristics of glial and sarcomatous elements which were strikingly similar except for small losses and gains in Chr 3. Studies are under way to determine the significance of chromosome 3 alterations in gliosarcomas.

Numerical chromosomal changes and risk of development of myelodysplastic syndrome–acute myeloid leukemia in patients with Fanconi anemia

Fanconi Anemia (FA) is an inherited bone marrow failure syndrome characterized by congenital abnormalities, progressive marrow failure and predisposition to myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumors. The most common acquired chromosomal aberrations in FA patients are trisomy of 1q and monosomy of chromosome 7; the latter is known to be associated with poor prognosis. A few reports also suggest that gains of 3q are associated with progression to MDS–AML and overall poor prognosis. It is not uncommon for patients with Fanconi anemia to have easily detectable (oligoclonal) chromosomal alterations in their still normal (nonmalignant) marrow, which makes it even more challenging to determine the import of such alterations. We conducted a retrospective longitudinal analysis of fluorescent in situ hybridization (FISH) analysis for gains in 1q and 3q and for monosomy 7 and 7q deletions on 212 bone marrow samples from 77 children with FA treated at our institution between 1987 and 2007. Given the baseline increased chromosomal instability and defective DNA repair in patients with FA, which leads to unbalanced chromosomal aberrations such as deletions, insertions, and translocations, for the purpose of this analysis an abnormal clone was defined as ≥10% abnormal cells. Chromosome 3 and 7 aberrations were associated with increased risk of developing MDS–AML ( P = 0.019 and P < 0.001 respectively), although the significance of chromosome 3 aberrations disappeared when different observation times were accounted for. Gain of 1q alone did not predict development of MDS–AML. In conclusion, children with FA should be followed closely with FISH analyses, because some of the clonal chromosomal abnormalities may be early indicators of progression toward MDS–AML and thus also of the need for hematopoietic stem cell transplantation.

Analysis of HER2 gene status in breast cancer with HER2 protein overexpression

To study the HER2 gene status (by fluorescence in situ hybridization (FISH) in breast cancer with HER2 protein overexpression, the correlation between gene amplification and protein overexpression, as well as the rate and significance of chromosome 17 aneusomy. One hundred and twenty archival cases of breast cancer with formalin-fixed and paraffin-embedded tumor tissues with 2+ (42 cases) and 3+ (78 cases) HER2 protein overexpression by immunohistochemistry (IHC, HercepTest, Dako) were tested by FISH (PathVysion, Vysis) for HER2 gene status. The rate of chromosome 17 aneusomy was also analyzed. Amongst the 42 samples with IHC 2+, HER2 gene amplification was identified in 32 cases (76.19%), which included 11 cases with low amplification (ratio 2 approximately 4), 20 cases with moderate amplification (ratio 4 approximately 10) and 1 case with high amplification (ratio>10). Amongst the 78 samples with IHC 3+, HER2 gene amplification was identified in 71 cases (91.03%), which included 9 cases with low amplification, 48 cases with moderate amplification and 14 cases with high amplification. Chromosome 17 aneusomy was found in 83 cases (83/120, 69.17%), in which 14 cases (11.67%) showed hypodisomy (chromosome 17 copy number per cell<or=1.75), 52 cases (43.33%) showed low polysomy (chromosome 17 copy number per cell=2.26 approximately 3.75) and 17 cases (14.17%) showed high polysomy (chromosome 17 copy number per cell>or=3.76). Amongst the 42 cases with IHC 2+, 25 samples (59.52%) had chromosome 17 aneusomy, including 3 cases with hypodisomy, 18 cases with low polysomy and 4 cases with high polysomy. Amongst the 78 cases with IHC 3+, 58 samples (74.36%) had aneusomy 17, including 11 cases with hypodisomy, 34 cases with low polysomy and 13 cases with high polysomy. Most of IHC 2+ and FISH-positive cases had low or moderate HER2 gene amplification, while most of the IHC 3+ and FISH-positive cases had moderate or high gene amplification (P=0.0003). Six of the 7 samples with IHC 3+ and FISH-negativity had chromosome 17 aneusomy and 5 of the 10 samples with IHC 2+ and FISH-negativity had such aneusomy. A high concordance rate is noted between IHC 3+ and FISH positive results. The rate of FISH positive in IHC 2+ patients was higher than reported in other studies. Low or moderate HER2 gene amplification in IHC 2+ and moderate or high gene amplification in IHC 3+ occurs quite frequently. Chromosome 17 aneusomy (including hypodisomy, low polysomy and high polysomy) is also a relatively common phenomenon in our cohort with HER2 overexpression, with predominance of low polysomy.

Significance of chromosome 5 and 17 changes in the development of carcinoma of the cervix uteri

Two chromosomes that undergo nonrandom changes in carcinoma of the cervix and have been studied for several decades in this laboratory are discussed. The first, chromosome 5, is discussed in view of the frequent appearance of an isochromosome for 5p, often in two or more copies and commonly associated with fewer that the expected number of normal copies of this chromosome. The second is chromosome 17, where a translocation involving another chromosome may result in a 17p+, and the significant change appears to be a loss from 17p that may include the p53 gene (TP53) and/or other tumor-suppressor genes located on this chromosome arm.

Paracentric inversion of chromosome 3 (q21q26) in a patient with chronic myelomonocytic leukemia and a normal platelet count

Clonal chromosomal abnormalities occur in about one-third of patients with chronic myelomonocytic leukemia (CMMoL) and are usually those found in other myelodysplastic syndromes. Abnormalities of chromosome 3, which have been associated with abnormal thrombopoiesis, are relatively uncommon. A patient with CMMoL with inv(3)(q21q26) and normal thrombopoiesis is presented, and the cytogenetics of CMMoL are reviewed. The possible significance of chromosome 3 in thrombopoiesis is discussed.

Significance of chromosome 8 breakpoint location in Burkitt's lymphoma: correlation with geographical origin and association with Epstein-Barr virus.

Burkitt’s lymphoma (BL) is a B cell neoplasm, which occurs throughout the world, predominantly in children and young adults [Magrath 1983]. Its relatively high incidence in equatorial Africa has led to the African form of the disease being designated as “endemic” (eBL), while cases outside equatorial Africa are referred to as “sporadic” (sBL) Burkitt’s lymphoma. A number of differences between eBL and sBL have been described [Magrath 1986] and are summarized in table 1.

Significance of chromosome 14 anomaly at band 14q11 in Japanese patients with adult T-cell leukemia.

The chromosomes of leukemic blood cells in eight Japanese patients with acute adult T-cell leukemia (ATL) were examined by a direct method or short-term culture method without any mitogens. Six patients showed a chromosome 14 anomaly with a break at band q11-13: inv(14)(q11q32) in two patients, t(11;14)(p13;q13) in one patient, t(14;14)(q11;q32) in addition to del(14)(q11q13) in another, and only del(14)(q11q13) in two patients. Thus, a proximal 14q rearrangement exists in ATL as in other types of T-cell malignancies. Based on these facts, the pathogenesis of ATL is discussed in reference to the literature.