Types Of Chromosomal Translocations Research Articles

Familial 1p36.3 microduplication resulting from a 1p-9q non-reciprocal translocation

Unlike the 1p36 microdeletion syndrome, which has been extensively described, 1p36 microduplications have rarely been reported. We describe a three years old boy presenting with a severe global developmental delay and a few dysmorphic features. Cytogenetic analyses revealed a maternally inherited 3.35 Mb microduplication of chromosomal band 1p36.3. The maternal grandfather is also carrier of the same chromosomal rearrangement.Interestingly, the duplicated 1p36.3 segment was found to be localized at the telomeric end of the long arms of a chromosome 9, probably deriving from a 1p36.3-9qter non-reciprocal translocation. This particular type of chromosomal translocation has rarely been reported, and its mechanism is unclear. The phenotypical features associated with 1p36.3 microduplication vary due to the non-recurrent breakpoints of the rearrangements in this particular region. However when compiling the few described cases the phenotypical spectrum seems to include mainly developmental delay, mild facial dysmorphism, and neurological, cardiac and skeletal anomalies. The description of new patients carrying a 1p36.3 duplication like ours will lead to further delineation of the phenotypical spectrum and may help to find critical regions and causative genes implicated in the phenotype.

Molecular Mechanism and Malignant Clonal Evolution of Multiple Myeloma

Almost all patients with multiple myeloma (MM) have chromosomal translocation which can result in genetic variation. There are mainly five types of chromosomal translocations, involving the IGH gene translocation to 11q13 (CCND1), 4p16 (FGFR/MMSET), 16q23 (MAF), 6p21 (CCND3) and 20q11 (MAFB). It is possible that all IGH translocations converge on a common cell cycle signal pathway. Some MM develops through a multistep transformation from monoclonal gammopathy of undetermined significance (MGUS) to smoldering MM (SMM) and eventually to MM and plasma cell leukemia (PCL). Similarly to what Darwin proposed in the mid-19th century-random genetic variation and natural selection in the context of limited resources, MM clonal evolution follow branching and nonlinear mode. The failure of MM treatment is usually related with the minimal subclone which is hardly found at newlydiagnosed.

Abstract 627: Detection of chromosomal rearrangements in clinical tissue samples by chromosome conformation capture

Abstract Background The detection of recurrent and specific chromosomal rearrangements has become an important element in the diagnostic evaluation of tumors and in decisions pertaining to their therapy. Several detection methods applicable to routine clinical samples currently exist, including in situ hybridization (FISH), RT-PCR, and direct DNA sequence analysis–all of which are associated with various drawbacks. An approach that has not been extensively explored for the detection of chromosomal rearrangements in clinical samples is the analysis of changes in chromatin conformation due to alterations of chromosomal structure. However, the extensive formalin fixation and paraffin embedding that these samples routinely undergo would appear to pose special challenges for analysis of chromatin in such tissues. Design To investigate the practicality and potential value of chromatin conformation assays for detecting chromosomal rearrangements in formalin-fixed and paraffin-embedded (FFPE) samples, we have analyzed fixed and embedded cell lines and FFPE biopsy specimens containing two different types of chromosomal translocations: the t(8;14)(q24;q32) found in Burkitt's lymphoma and the t(14;18)(q32q21) found in follicular B cell lymphoma. These two translocations place DNA of the IGH locus near that of oncogenes MYC and BCL-2, respectively. The strong enhancers of IGH induce the overexpression of the two oncogenes, presumably by looping of chromatin to permit interactions with the oncogene promoters. Utilizing primers designed to be complementary to DNA within IGH enhancers and MYC or BCL-2 promoters, we performed chromosome conformation capture (3C) to interrogate the possible chromatin interactions between the IGH enhancer and the two promoters in FFPE samples. Results Since conventional 3C procedures worked poorly with FFPE cell lines, probably because of heavy fixation (16 hours, 10% buffered formalin), we modified the procedures by partially de-crosslinking the specimens using heat and mild alkali. The 3C procedure modified in this manner can efficiently and specifically detect the t(8; 14) and t(14; 18) in FFPE cell lines and, at a lower sensitivity, in clinical biopsy specimens. In follicular lymphoma samples, the detection of t(14; 18) achieved high specificity with an analytic sensitivity of at least 10% tumor cells within a volume of ∼1000 total cells. The sensitivity with the Burkitt's samples was lower, probably because of differences in preservation of the tissue and chromatin, as suggested by results of FISH. Conclusions We report a modified 3C workflow that successfully detected chromosome rearrangements in clinical samples. In addition to diagnostic applications, this method, with possible further improvements, may permit study of chromatin interactions in clinical samples to increase understanding of epigenetic and other basic genomic features in many forms of cancer. Citation Format: Xiaobin Gao, Jianhui Wang, Jinglan Wang, Lynnette Tumwine, Jeffrey Sklar. Detection of chromosomal rearrangements in clinical tissue samples by chromosome conformation capture. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 627. doi:10.1158/1538-7445.AM2015-627

Impact of Chromosomal Translocations on Male Infertility, Semen Quality, Testicular Volume and Reproductive Hormone Levels

To analyse the relationship between male infertility and chromosomal translocations, and the influence of different types of chromosomal translocations on semen quality, testicular volume and hormone levels. A retrospective cohort of infertile men was recruited for chromosomal analysis using standard Giemsa stain banding. Physical examinations, semen analysis, hormonal analysis and the detection of azoospermia factor (AZF) microdeletions were carried out. Men with normal fertility were used as controls. Among the 1056 infertile men, 22 had chromosomal translocations (2.1%), including seven with Robertsonian translocations (0.7%), 11 with autosome-autosome reciprocal translocations (1.0%) and four with gonosome-autosome reciprocal translocations (0.4%). Left and right testicular volumes of patients with chromosomal translocations were significantly smaller than those in the fertile control group. There were no significant differences in hormone levels between patients with chromosomal translocations and fertile controls, except for significantly lower testosterone levels in patients with Robertsonian and gonosome-autosome reciprocal translocations compared with the controls. All AZF microdeletion analyses showed normal results. Chromosomal translocations may cause reductions in testicular volume and testosterone level, which may impact spermatogenesis, resulting in azoospermia or oligozoospermia and male infertility.

A specific linkage between the incidence of TP53 mutations and type of chromosomal translocations in B‐precursor acute lymphoblastic leukemia cell lines

Chromosomal translocation plays an essential role in leukemogenesis of childhood B-precursor acute lymphoblastic leukemia (ALL) in combination with specific gene mutations. Although several reports suggest correlation of TP53 mutation with the type of chromosomal translocation in childhood B-precursor ALL, it has not been directly confirmed in a single cohort study due to the limited incidence of TP53 mutation in primary samples at diagnosis. Leukemia cell lines generally show higher incidence of gene mutations compared with primary samples. Thus, to clarify possible differences in cooperation of the p53 pathway for leukemogenesis with the type of chromosomal translocation, TP53 gene mutation was analyzed in 32 B-precursor ALL cell lines. TP53 mutation was observed in 40.6% (13 cell lines), and missense mutation of R248Q was the most commonly observed (5 cell lines). Of note, TP53 mutation was frequently observed among MLL-rearranged and t(1;19)-positive ALL cell lines, but was very rare among Philadelphia chromosome-positive and t(17;19)-positive ALL cell lines. Although the number of samples analyzed is limited, this is the first direct observation of the correlation between the incidence of TP53 mutation and types of translocation in B-precursor ALLs, suggesting a functionally different fusion gene product in the p53 pathway for leukemogenesis.

Abnormal BCL10 nuclear expression and chromosomal translocation in ocular adnexal mucosa-associated lymphoid tissue lymphomas

To detect the BCL10 expression and several types of chromosomal translocations [including t (11;18)/API2-MALT1; t (1;14)/IgH- BCL10 and t (14;18)/MALT1-IgH] in ocular adnexal mucosa-associated lymphoid tissue lymphomas (OA-MALT lymphomas). Sixty OA-MALT lymphomas were collected from Cancer Hospital of Fudan University. BCL10 was detected by immunohistochemical studies, and API2-MALT1 fusion gene, BCL10, MALT1 and IgH chromosomal abnormalities were detected by fluorescent in situ hybridization (FISH). Fisher's exact test was used to analyze the relation between nuclear BCL10 expression and chromosomal translocation. BCL10 expressed in 85.0% (51/60) OA-MALT lymphomas. Among these positive cases, 25 cases (41.7%) were expressed in the cytoplasm, and 26 cases (43.3%) were expressed in the nucleus. FISH results showed that no chromosomal abnormalities related with BCL10 and IgH genes, except 2 cases with API2-MALT1 fusion gene. Under statistic of Fisher exact test, nuclear BCL10 expression and API2-MALT1 fusion gene were two independent factors (P > 0.05). BCL10 nuclear expression is common in OA-MALT lymphomas and may be used as a potential marker for the diagnosis of MALT lymphomas arising from ocular adnexa. Aberrant chromosomal translocations reported in the other sites MALT lymphomas are rare in OA-MALT lymphomas.

Subcellular localization of immunohistochemical signals: knowledge of the ultrastructural or biologic features of the antigens helps predict the signal localization and proper interpretation of immunostains.

In the literature, sufficient attention has not been paid to the precise subcellular localization of immunohistochemical signals, the knowledge of which is essential for proper interpretation of immunostains and distinction of genuine staining from biotin-associated or other nonspecific stainings. The subcellular localization of the signals can in fact be easily deduced from the known biologic or ultrastructural characteristics of the antigens. Extracellular antigens obviously are located in the extracellular compartment. Cellular antigens fall into 3 major groups: membranous, nuclear, and cytoplasmic. Membranous antigens include cell adhesion molecules (such as E-cadherin, N-CAM), cell surface/transmembrane receptors and proteins (such as tyrosine kinase receptors, most leukocyte antigens, CD10, CEA), and molecules linking surface molecules to cytoskeleton (such as beta-catenin, dystrophin). Nuclear antigens include cell cycle-associated proteins (such as cyclins, p16, Ki-67), nuclear enzymes (such as TdT), transcription factors (such as TTF-1, CDX-2, myogenin, PAX-5), tumor suppressor gene products (such as p53, p63, WT1, Rb), steroid hormone receptors (such as ER, PR), calcium-binding proteins (such as S-100 protein, calretinin), and some viral proteins (such as CMV, herpes). Cytoplasmic antigens can take up a granular pattern due to localization in organelles, granules, or secretory vesicles (such as chromogranin, hormones, lysozyme, HMB-45), fibrillary pattern attributable to the filamentous nature of the molecules (intermediate filaments and microfilaments), or diffuse or patchy pattern due to localization in the cytosol or large vesicles (such as myoglobin, albumin, thyroglobulin). Aberrant localization of the molecules, when present, can provide important insight into disease processes and aid in their diagnosis, such as loss of membranous E-cadherin expression in lobular breast carcinoma, aberrant nuclear localization of beta-catenin in colorectal adenocarcinoma, pattern of ALK staining in anaplastic large cell lymphoma correlating with the different types of chromosomal translocations, presence of additional cytoplasmic CD10 staining in the enterocytes indicative of microvillous inclusion disease, and "reversed" staining for EMA in micropapillary mammary carcinoma.

Segmental Jumping Translocation in Leukemia and Lymphoma with a Highly Complex Karyotype

In order to identify the oncogene associated with malignant transformation 141 leukemia and malignant lymphoma patients were studied by FISH. Specific chromosome regions were translocated onto structurally abnormal chromosomes, resulting in partial tri-, tetra-, or pentasomy of these regions. We designated this type of chromosomal translocation as a “segmental jumping translocation (SJT)”. These SJTs were found in several chromosomal regions such as 8q24, 9q34, 11q13, 11q23, 13q14, 14q24-q32, 21q22 and 22q11. The SJT at 9q34, which involved the ABL oncogene, was found in three of nine secondary leukemia patients who were treated with anticancer drugs and radiation. Non-Hodgkin's lymphoma and acute myeloid leukemia (AML) patients had 3–7 copies of SJT at 11q13 or 11q23. SJT at 14q32 and 21q22 were predominantly detected in the acute type of adult T-cell leukemia (8 of 27 patients) and in AML (5 of 17 patients). The size of the SJT regions varied among the patients. The overlapping region within the SJT could involve oncogene(s) associated with transformation to the advanced stage in leukemia and lymphoma patients. The SJT provides evidence of a new mechanism for gene amplification and formation of unidentified marker chromosomes in the advanced disease stage.

Clinical implications of cytogenetic classification in adult acute lymphoblastic leukaemia patients.

Cytogenetic analysis performed on pretreated unstimulated, bone marrow/peripheral blood samples of 46 adult patients with acute lymphoblastic leukaemia (ALL) showed sufficient metaphases in 39 patients and insufficient metaphases in 7 patients. G-banded karyotype analysis of these 39 patients revealed non-random clonal chromosome abnormalities in 31 patients and apparently normal karyotypes in 8 patients. Numerical abnormalities involving chromosome trisomies and structural abnormalities involving different types of chromosomal translocations and deletions were encountered in varying percentages. These patients were grouped into various cytogenetic subsets on the basis of their karyotype pattern and followed-up to evaluate their prognosis. Patients with apparently normal karyotypes showed good prognosis and those with 6q- showed intermediate prognosis. But all other patients with hyperdiploid, pseudodiploid and hypodiploid karyotypes were associated with poor prognosis. Cytogenetic classification of ALL patients is thus of clinical importance, as it helps the early identification of clinically important prognostic groups.

Distinct Reactivity of Burkitt's Lymphoma Cell Lines With Eight Monoclonal Antibodies Correlated With the Ethnic Origin

Twenty-eight Burkitt's lymphoma(s) (BL) cell lines were analyzed with anti-human immunoglobulins and monoclonal antibodies: Y29/55, B1, and BA1 are slightly different pan-B-reagents; TU1 and BL13 are two discriminating markers of the follicle; RFT1 is a pan-T-reagent expressed on the follicle mantle; AL2 reacts with the common acute lymphoblastic leukemia antigen gp100; and 38:13 recognizes a BL-associated antigen. Those lines were classified into 3 groups according to their membrane phenotype. In the first 2 groups, cell lines were derived from BL of germinal center origin, whereas in the last group they were established from BL cells originating in the bone marrow. All cell lines in the last group were from Caucasian BL, whereas lines from African BL of a high-incidence area were in group 1. North African cases were in group 2. Those distinct subgroups were not related specifically to the reactivity with Epstein-Barr virus nuclear antigen, the type of chromosomal translocation, or the clinical features. The variations induced by growth culture as well as the clinical implications were discussed.

A new type of familial chromosome translocation involving 3p and 6q in two unrelated families

In two unrelated families a new type of chromosomal translocation [t(3;6)(3qter~3p21::6q26~6qter; 6p ter~6q26: :3p21~ 3pter)] has been observed. From a clinical point of view, it is associated with repeated spontaneous abortions in the mothers as well as with severe malformations in the index patients, e.g., arhinencephaly, ethmocephaly, absence of the falx cerebri, and brain malformation presenting as holoprosencephaly in a German case and hydrocephalus internus in a Czechoslovakian affected fetus. We would like to contact other colleagues who have observed similar cases, for more detailed analysis and for eventual joint publication.