Comparison of results from mouse bone marrow chromosome aberration and micronucleus tests

Tests for the induction of chromosomal aberrations (ABS) and micronuclei (MN) in bone marrow cells of mice have been conducted on 65 chemicals. Although these tests were not conducted with the purpose of comparing the outcomes of these two in vivo genetic toxicity end-points, the availability of these test results permits such a comparison. Based on studies to date, results from the 2 tests agree for more than 80% of the chemicals; 17 gave positive results in both tests, and 36 gave negative results in both. Seven chemicals were positive only for ABS and 5 were positive only for MN. Three chemicals that were originally concluded to be positive for ABS but not for MN were found to induce MN when the MN protocol was modified to more closely reflect the ABS protocol. Among the 12 chemicals for which there are discrepant results, there are only 2 for which the difference is convincing. One of these, selenium sulfide (MN negative, ABS positive) remains an enigma; further studies are being conducted. The second, isoprene (MN positive, ABS negative) will be difficult to pursue because the studies reported here were done by inhalation exposure. Based on the outcomes of these comparisons, protocol factors, rather than endpoint specificity, appear to be the major source of discrepant test results. Thus, these results do not support a recommendation that both tests be conducted in a primary testing scheme for genetic toxicity. © 1995 Wiley-Liss, Inc

1 This article is a US Government work and, as such, i s in the public domain in the United States of America.

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Triple approach for diagnosis and grading of meningiomas: Histology,morphometry of Ki-67/feulgen stainings,and cytogenetics

Summary With regard to meningioma grading and the recently introduced atypical meningioma, we evaluated 160 cases retrospectively by conventional histology and image analysis. For that, the cell nuclei were stained with a Ki-67 (MIB1)/Feulgen-method on paraffin sections, thus enabling the assessment of both the Ki-67 proliferation index and nuclear morphometric features, such as tumour cell arrangement, nuclear pleomorphism, and cellularity.It could be demonstrated that the Ki-67 proliferation index is the most important criterion for distinguishing anaplastic meningiomas (WHO grade III) (mean Ki-67 index: 11%) from those of common type (WHO grade I) (mean Ki-67 index: 0.7%). The parameter for the relative volume weighted mean nuclear volume is another valuable morphometric feature. The atypical meningioma (WHO grade II) which should represent an intermediate category between common type and anaplastic meningiomas is characterized by a mean Ki-67 proliferation index of 2.1%. Common type meningiomas which comprise almost 50% of the cases of this series have a relapse rate of 9%. Atypical and anaplastic meningiomas recurred in 29% and 50%, respectively. Since the term atypical meningioma is confusing in the context of tumour grading, the term intermediate type meningioma is proposed.Furthermore, the results of cytogenetic analyses of 142 cases of this series were evaluated and compared with the meningioma grades. Thereby, 25 cases disclosed, independent of the typical loss of one chromosome 22, cytogenetic features assumed to be progression-associated, e.g., the gain or loss of different chromosomes and the deletion of the short arm of one chromosome 1 (hyperdiploidy, increased hypodiploidy, Ip-), when correlated to the histological and morphometric findings or the high relapse rate.For meningioma diagnosis and grading, a practical guideline is proposed based upon histology, morphometry (Ki-67), and cytogenetics.     

CARD In Situ Hybridization: Sights and Signals

During the last decade, several strategies have been developed to improve the detection sensitivity ofin situ hybridization (ISH) by amplification of either target nucleic acid sequences prior to ISH (e.g.,in situ PCR), or the detection signals after the hybridization procedures (signal amplification). Here we outline the principles of tyramide signal amplification using the catalyzed reporter deposition (CARD) technique, summarize applications as well as possible limitations of CARD ISH, and discuss some future directions ofin situ nucleic acid detection using this amplification strategy.     

Cytogenetics of benign breast lesions

This review summarizes the cytogenetic information on benign breast lesions of various histologies, i.e., fibrocystic lesions from women with and without a known hereditary predisposition to breast cancer, fibroadenomas, phyllodes tumors, and papillomas, and relate the chromosomal features with those in breast carcinoma. In general, the frequency of chromosome abnormalities is lower in benign lesions than in breast cancer, and seems to correlate with the histologic features of the tissue, and the corresponding risk of developing invasive mammary carcinoma; aberrations are more common in proliferative than in nonproliferative lesions. The karyotypes are generally less complex than those detected in invasive carcinoma, and more often involve balanced rearrangements. No lesion-specific aberration has so far been detected; on the contrary, changes repeatedly encountered in breast cancer samples can be found in benign lesions as well, e.g., gain of 1q, interstitial deletion of 3p, and trisomies 7, 18, and 20. Especially intriguing is the prevalence of rearrangements of the short arm of chromosome 3, with the minimally deleted bands 3p13–14, in proliferative lesions from prophylactic mastectomies in breast cancer families. The potential tumor suppressor gene(s) in this region remains, however, to be identified.     

耐药肺腺癌细胞株A549/CDDP生物学特性及染色体核型分析

目的 建立氯氨顺铂诱导肺腺癌耐药细胞株A549／CDDP。分析A549／CDDP生物学特性及染色体核型，为肺腺癌的治疗提供实验依据。方法 采用氯氨顺铂（Cis—diaminodichloroplatin，CDDP）大剂量冲击加逐步诱导法建立肺腺癌耐药细胞株A549／CDDP，MTT法检测细胞耐药指数．生物发光法测定细胞能量代谢，流式细胞仪测试细胞周期，染色体G显带技术和光谱核型分析（spectral karyotyping，SKY）技术分析染色体变化。结果 MTT检测结果表明。A549／CDDP对7种不同的化疗药物表现了不同的耐药性，其ATP、ADP、AMP含量显著降低，细胞周期无明显变化。G显带结果表明A549／CDDP染色体为亚三倍体，SKY分析出现数条衍生染色体。结论 CDDP可以成功诱导肺腺癌耐药细胞株A549／CDDP，A549／CDDP衍生染色体可能与肺腺癌耐药有关。     

Identification of a recurrent t(4;6) chromosomal translocation in prostate cancer

PURPOSE: We developed and describe a practical method by which primary prostate cancer specimens can be screened for recurrent chromosomal translocations, which is a potential source of fusion genes, as well as a process by which identified translocations can be mapped to define the genes involved. MATERIALS AND METHODS: A series of 7 prostate cancer cell lines and 25 transiently established primary cell cultures, which were sourced from tissue harvested at 16 radical prostatectomies and 9 channel transurethral prostate resections, were screened for chromosomal translocations using multiplex-fluorescence in situ hybridization technology. A series of fluorescence in situ hybridization based breakpoint mapping experiments were performed to identify candidate genes involved in regions associated with recurrent translocation. RESULTS: Our analysis identified the repetition of 2 translocations in prostate cancer lines, that is t(1;15) and t(4;6), at a frequency of 28% and 57%, respectively. More significantly 4 of the 25 subsequently established primary cultures (16%) also revealed a t(4;6) translocation. Using the LNCaP cell line the breakpoints involved were mapped to the t(4;6)(q22;q15) region and a number of candidate genes were identified. CONCLUSIONS: We found that the t(4;6) translocation is also a repeat event in primary cell cultures from malignant prostate cancer. Breakpoint mapping showed that the gene UNC5C loses its promoter and first exon as a direct result of the translocation in the 4q22 region. As such, we identified it as a possible contributor to a putative fusion gene in prostate cancer.     

男性生精障碍的细胞遗传学和分子遗传学检测

目的从遗传学角度分析男性生精障碍的病因,为临床提供治疗和遗传咨询的依据。方法对91例无精子症患者和42例严重少精子症患者,采用外周血染色体核型分析和Y染色体AZF区域微缺失联合检测。结果91例原发性无精子症患者中,染色体数量异常者16例,占总数17.5%;染色体平衡易位5例,占总数5%;10例AZF区域STS位点缺失,占总数11%;二项检测异常发生率为34%。42例严重少精子症患者检出染色体平衡易位4例,占总数9.5%;AZF区域STS位点缺失5例,占总数11.9%,二项检测异常发生率为21.4%。结论染色体核型分析和Y染色体微缺失是男性生精障碍重要的遗传检测指标。     

High‐risk cytogenetics in multiple myeloma: Further scrutiny of deletions within the IGH gene region enhances risk stratification

Multiple myeloma is a clonal malignancy of plasma cells in the bone marrow. Risk stratification is partly based on cytogenetic findings that include abnormalities of the IGH locus as determined by fluorescence in situ hybridization (FISH), such as rearrangements that result in either standard‐risk or high‐risk gene fusions. IGH deletions have been evaluated as a group in multiple myeloma patients with respect to cumulative outcomes but have provided limited guidance. Whether these deletions have the potential to result in gene fusions and thus further stratify patients is unknown. We identified 229 IGH deletions in patients referred for plasma cell dyscrasia genetic testing over 5.5 years. Follow‐up was conducted on 208 of the deletions with dual fusion FISH probes for standard‐risk (IGH‐CCND1) and high‐risk IGH gene fusions (IGH‐FGFR3, IGH‐MAF, IGH‐MAFB). Of all deletions identified with follow‐up, 44 (21%) resulted in a gene fusion as detected by FISH, 15 (7%) of which were fusion partners associated with high‐risk multiple myeloma. All fusion‐positive 3′‐IGH deletions (6 fusions) resulted in high‐risk IGH‐FGFR3 fusions. Of the 15 high‐risk fusion‐positive cases, eight were without other high‐risk cytogenetic findings. This study is the first to evaluate the presence of IGH gene fusions upon identification of IGH deletions and to characterize the deletion locus. Importantly, these findings indicate that follow‐up FISH studies with dual fusion probes should be standard of care when IGH deletions are identified in multiple myeloma.