Yi Ning

Multicolor spectral karyotyping of human chromosomes

The simultaneous and unequivocal discernment of all human chromosomes in different colors would be of significant clinical and biologic importance. Whole-genome scanning by spectral karyotyping allowed instantaneous visualization of defined emission spectra for each human chromosome after fluorescence in situ hybridization. By means of computer separation (classification) of spectra, spectrally overlapping chromosome-specific DNA probes could be resolved, and all human chromosomes were simultaneously identified.

Autosomal XX Sex Reversal Caused by Duplication of SOX9

SOX9 is one of the genes that play critical roles in male sexual differentiation. Mutations of SOX9 leading to haploinsufficiency can cause campomelic dysplasia and XY sex reversal. We report here evidence supporting that SOX9 duplication can cause XX sex reversal. A newborn infant was referred for genetic evaluation because of abnormal male external genitalia. The infant had severe penile/scrotal hypospadias. Gonads were palpable. Cytogenetic analysis demonstrated a de novo mosaic 46,XX,dup(17)(q23.1q24.3)/46, XX karyotype. Fluorescent in situ hybridization (FISH) with a BAC clone containing the SOX9 gene demonstrated that the SOX9 gene is duplicated on the rearranged chromosome 17. The presence of SRY was ruled out by FISH with a probe containing the SRY gene and polymerase chain reaction with SRY-specific primers. Microsatellite analysis with 13 markers on 17q23-24 determined that the duplication is maternal in origin and defined the boundary of the duplication to be approximately 12 centimorgans (cM) proximal and 4 cM distal to the SOX9 gene. Thus, SOX9 duplication is the most likely cause for the sex reversal in this case because it plays an important role in male sex determination and differentiation. This study suggests that extra dose of SOX9 is sufficient to initiate testis differentiation in the absence of SRY. Other SRY-negative XX sex-reversed individuals deserve thorough investigation of SOX9 gene.

An Optimized Set of Human Telomere Clones for Studying Telomere Integrity and Architecture

Telomere-specific clones are a valuable resource for the characterization of chromosomal rearrangements. We previously reported a first-generation set of human telomere probes consisting of 34 genomic clones, which were a known distance from the end of the chromosome ( approximately 300 kb), and 7 clones corresponding to the most distal markers on the integrated genetic/physical map (1p, 5p, 6p, 9p, 12p, 15q, and 20q). Subsequently, this resource has been optimized and completed: the size of the genomic clones has been expanded to a target size of 100-200 kb, which is optimal for use in genome-scanning methodologies, and additional probes for the remaining seven telomeres have been identified. For each clone we give an associated mapped sequence-tagged site and provide distances from the telomere estimated using a combination of fiberFISH, interphase FISH, sequence analysis, and radiation-hybrid mapping. This updated set of telomeric clones is an invaluable resource for clinical diagnosis and represents an important contribution to genetic and physical mapping efforts aimed at telomeric regions.

Identification of a Gene That Reverses the Immortal Phenotype of a Subset of Cells and Is a Member of a Novel Family of Transcription Factor-Like Genes

ABSTRACT Based on the dominance of cellular senescence over immortality, immortal human cell lines have been assigned to four complementation groups for indefinite division. Human chromosomes carrying senescence genes have been identified, including chromosome 4. We report the cloning and identification of a gene, mortality factor 4 (MORF 4), which induces a senescent-like phenotype in immortal cell lines assigned to complementation group B with concomitant changes in two markers for senescence. MORF 4 is a member of a novel family of genes with transcription factor-like motifs. We present here the sequences of the seven family members, their chromosomal locations, and a partial characterization of the three members that are expressed. Elucidation of the mechanism of action of these genes should enhance our understanding of growth regulation and cellular aging.

Effect of dietary and lifestyle factors on the risk of gestational diabetes: review of epidemiologic evidence

Gestational diabetes mellitus (GDM), defined as glucose intolerance with onset or first recognition in pregnancy, is a common pregnancy complication and a growing health concern. GDM has been related to significant short-term and long-term adverse health outcomes for both mothers and offspring. Importantly, this number is increasing with the increasing burden of obesity among women of reproductive age. Collectively, these data highlight the significance of understanding risk factors, in particular modifiable factors, for GDM and of preventing GDM among high-risk populations. Research in the past decade has identified a few diet and lifestyle factors that are associated with GDM risk. This review provides an overview of emerging diet and lifestyle factors that may contribute to the prevention of GDM. It also discusses major methodologic concerns about the available epidemiologic studies of GDM risk factors.

Cytogenetic and molecular characterization of random chromosomal rearrangements activating the drug resistance gene, MDR1/P-glycoprotein, in drug-selected cell lines and patients with drug refractory ALL

Drug resistance, both primary and acquired, is a major obstacle to advances in cancer chemotherapy. In vitro, multidrug resistance can be mediated by P‐glycoprotein (PGY1), a cell surface phosphoglycoprotein that acts to efflux natural products from cells. PGY1 is encoded by the MDR1 gene located at 7q21.1. Overexpression of MDR1 has been demonstrated in many cancers, both in patient tumors and in cell lines selected with a variety of chemotherapeutic agents. Recent studies in drug‐selected cell lines and patients samples have identified hybrid mRNAs comprised of an active, but apparently random, gene fused 5′ to MDR1. This observation indicates that random chromosomal rearrangements, such as translocations and inversions, leading to “capture” of MDR1 by constitutively expressed genes may be a mechanism for activation of this gene following drug exposure. In this study, fluorescence in situ hybridization (FISH) using whole chromosome paints (WCP) and bacterial artificial chromosome (BAC)‐derived probes showed structural rearrangements involving 7q in metaphase and interphase cells, and comparative genomic hybridization (CGH) revealed high levels of amplification at chromosomal breakpoints. In an adriamycin‐selected resistant colon cancer line (S48–3s/Adr), WCP4/WCP7 revealed t(4;7)(q31;q21) and BAC‐derived probes demonstrated that the breakpoint lay between MDR1 and sequences 500–1000 KB telomeric to it. Similarly, in a subline isolated following exposure to actinomycin D (S48–3s/ActD), a hybrid MDR1 gene composed of heme oxygenase‐2 sequences (at 16p13) fused to MDR1 was identified and a rearrangement confirmed with WCP7 and a subtelomeric 16p probe. Likewise, in a paclitaxel‐selected MCF‐7 subline where CASP sequences (at 7q22) were shown to be fused to MDR1, WCP7 showed an elongated chromosome 7 with a homogeneously staining regions (hsr); BAC‐derived probes demonstrated that the hsr was composed of highly amplified MDR1 and CASP sequences. In all three selected cell lines, CGH demonstrated amplification at breakpoints involving MDR1(at 7q21) and genes fused to MDR1 at 4q31, 7q22, and 16p13.3. Finally, in samples obtained from two patients with drug refractory ALL, BAC‐derived probes applied to archived marrow cells demonstrated that a breakpoint occurred between MDR1 and sequences 500–1000 KB telomeric to MDR1, consistent with a random chromosomal rearrangement. These results support the proposal that random chromosomal rearrangement leading to capture and activation of MDR1 is a mechanism of acquired drug resistance. Genes Chromosomes Cancer 23:44–54, 1998.

Multiple myeloma patients with CKS1B gene amplification have a shorter progression-free survival post-autologous stem cell transplantation

The prevalence and prognostic relevance of recurrent gains of CKS1B (cyclin kinase subunit 1B) gene at chromosome 1q21 region was investigated by interphase fluorescence in situ hybridisation in a cohort of 99 multiple myeloma (MM) patients treated with intensive chemotherapy followed by autologous stem cell transplantation. CKS1B amplification (3–8 CKS1B signals) was detected in 31of 99 (31%) patients and was associated with deletions of p53 (P = 0·003) and 13q (P = 0·039) but not with translocation t(11;14) or t(4;14). CKS1B amplification was associated with bone marrow plasmacytosis (P = 0·02), but there was no correlation with patient age, gender, disease stage, lytic bone lesions, albumin, creatinine, C‐reactive protein or beta‐2 microglobulin levels. Patients with CKS1B amplification had a significantly shorter progression‐free survival than those without such amplification (18·5 vs. 25·7 months, P = 0·035). Likewise, a shorter overall survival (44·8 months vs. not reached) was observed; however, the difference did not reach statistical significance (P = 0·20). Seven patients had paired bone marrows obtained at diagnosis and at relapse, the percentage of cells with CKS1B amplification and the level of amplification were significantly increased in the relapse marrows. In this cohort of patients, CKS1B was frequently amplified in MM and may represent genetic instability associated with disease progression.

Myeloid sarcomas: a histologic, immunohistochemical, and cytogenetic study

Context. -Myeloid sarcoma (MS) is a neoplasm of immature granulocytes, monocytes, or both involving any extramedullary site. The correct diagnosis of MS is important for adequate therapy, which is often delayed because of a high misdiagnosis rate.Objective. -To evaluate the lineage differentiation of neoplastic cells in MS by immunohistochemistry, and to correlate the results with clinicopathologic findings and cytogenetic studies.Design. -Histologic and immunohistochemical examinations were performed on formalin-fixed paraffin-embedded tissue samples from 13 cases of MS. They were classified according to the World Health Organization criteria. Chromosomal analysis data were available in 11 cases. Clinical, pathological, and cytogenetic findings were analyzed.Results. -The study included six male and seven female patients with an age range of 25 to 72 years (mean, 49.3 years) and a male to female ratio of 1:1.2. MS de novo occurred in 4/13 (31%) of cases examined. The most sensitive immunohistochemical markers were CD43 and lysozyme present in all cases with MS (13/13, 100%). All de novo MS showed a normal karyotype, monoblastic differentiation, and lack of CD34. The most common chromosomal abnormalities in MS associated with a hematopoietic disorder were trisomy 8 and inv(16) (2/11, 18%).Conclusion. -An immunohistochemical panel including CD43, lysozyme, myeloperoxidase (MPO), CD68 (or CD163), CD117, CD3 and CD20 can successfully identify the vast majority of MS variants in formalin-fixed paraffin-embedded tissue sections. The present report expands the spectrum of our knowledge showing that de novo MS has frequent monoblastic differentiation and frequently carries a normal karyotype.

A novel NUP98-PHF23 fusion resulting from a cryptic translocation t(11;17)(p15;p13) in acute myeloid leukemia.

A novel NUP98-PHF23 fusion resulting from a cryptic translocation t(11;17)(p15;p13) in acute myeloid leukemia

Chromosome 1p21 deletion is a novel prognostic marker in patients with multiple myeloma

The combination of fluorescence in situ hybridization with cytoplasmic light chain detection identified chromosome 1p21 deletion in 18 (20%) of 87 patients with multiple myeloma. 1p21 deletion was associated with higher serum calcium level, 13q deletion, and t(4;14). Patients with 1p21 deletions had a significantly shorter progression‐free survival (PFS) (median 10·5 vs. 22·3 months, P = 0·0002) and shorter overall survival (OS) (median 33·9 months vs. not reached, P = 0·002) than those without 1p21 deletions. On multivariate analysis, which included deletions of 13q, TP53, t(4;14) and CKS1B amplification, 1p21 deletion remained as an independent risk factor for PFS (P = 0·01) and OS (P = 0·04).