Expression of γ-H2AX and patient prognosis in breast cancer cohort

H2AX phosphorylation is a novel marker of DNA double-stranded breaks. In the present study, we assessed the γ-H2AX expression, its association with other clinicopathologic characteristics, and the prognosis in a cohort of 97 patients with breast cancer. Ninety-seven specimens of tumor tissue and 77 adjacent normal tissues from patients with breast cancer were examined. All patients underwent modified radical mastectomy or local tumor resection without lymph node dissection. γ-H2AX expression was assessed by standard immunohistochemistry. Patients were followed after surgery for a mean duration of 70.1 ± 18.7 months (range, 6-93 months). The γ-H2AX staining was positive in 27 (27.8%) patients. The positive rates of H2AX were 26.0% and 2.6% in tumor tissue and adjacent normal tissues, respectively. γ-H2AX positive status was negatively associated with TNM staging, with 24 positive cases (32.4%) in TNM staging I-II, while no positive cases in TNM staging III-IV (P = 0.026). Sixteen patients (16.5%) died during the follow-up. No significant association between γ-H2AX expression and patient survival was detected. The unadjusted HR (hazard ratio) for γ-H2AX positive was 0.84 (95% CI: 0.27, 2.60). In TNM staging subgroup analysis, death only occurred in γ-H2AX negative patients. Our study is the first study to demonstrate that expression of γ-H2AX is associated with TNM staging. Due to the small sample and limited follow-up time, we did not observe a significant association between γ-H2AX and patient survival. γ-H2AX expression could be a potential biomarker for cancer diagnosis and prediction, and further studies are in need.     

Chromosome studies in patients with ulcerative colitis

Summary Chromosome preparations from 16 patients with ulcerative colitis showed a significant increase in structural chromosome abnormalities as compared to controls. The most striking finding was the high incidence of breaks affecting both chromatids at the same locus (7.1% of mitoses in patients, 0.6% in controls). There was also an excess of chromatid breaks, gaps of one or both chromatids, acentric fragments and morphologically abnormal chromosomes. The possible causes of chromosomal breakage and the eventual relationship of this breakage to the high incidence of colon carcinoma in these patients are discussed.

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Zusammenfassung Chromosomenpräparationen von 16 Patienten mit Colitis ulcerosa zeigten eine signifikante Vermehrung struktureller Chromosomenanomalien im Vergleich mit den Kontrollen. Das auffälligste Ergebnis war die hohe Häufigkeit von Isochromatidenbrüchen (7,1% der Mitosen bei Patienten, 0,6% bei Kontrollen). Chromatidenbrüche sowie gaps einer oder beider Chromatiden sowie azentrische Fragmente und morphologisch abnorme Chromosomen waren ebenfalls vermehrt. Die möglichen Ursachen der Chromosomenbrüchigkeit und ihre möglichen Beziehungen zu der hohen Häufigkeit des Coloncarcinoms bei diesen Patienten werden diskutiert.

     

Short arm deletion of chromosome 14

Summary 3 cases with a Do-chromosome, designated by autoradiography as a No. 14, are presented by the authors. The first case was a mentally retarded boy with minor malformations. Cases 2 and 3 had normal phenotypes and were detected by cytogenetic investigation of family members of a mentally retarded boy with a ring G chromosome. The 14 p-was the only caryotype abnormality in the father (case 2). It was associated with other abnormalities in the daughter (case 3) who had a D/G translocation of the centric fusion type (46, XX, 15-,21-, t(15p21p)+, t(15q21q)+).

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Zusammenfassung 3 Fälle mit einem Dp-Chromosom, das durch Autoradiographie als ein Nr. 14 identifiziert werden konnte, werden dargestellt. In dem ersten Fall bestanden Debilität und unbedeutende morphologische Anomalien. Fall 2 und 3 hatten einen normalen Phänotyp und wurden im Verlaufe von cytogenetischen Untersuchungen von Familienangehörigen eines debilen Jungen mit einem Ring 22 entdeckt. Das 14p-Chromosomwar die einzige Anomalie im Karyoy[ des Vaters (Fall 2). Bei der Tochter (Fall 3) bestand außerdem eine D/G-Translokation (46,XX,15-,21-,t(15p21p)+,t(15q21q)+).

     

Hydroxynonenal, a component of clastogenic factors?

Exposure of human lymphocyte cultures to superoxide generated by the xanthine-xanthine oxidase (X-XO) system, resulted in formation of a clastogenic factor (CF), as expected from previous work. We speculated that arachidonic acid (AA), the major polyunsaturated fatty acid of biological membranes, was oxidized via the cyclooxygenase-lipoxygenase pathways or nonenzymatically by oxygen free radicals in the culture medium to products with clastogenic properties. In the present study, we analyzed CF for AA-derived products and tested corresponding commercial standards for their clastogenic properties. The results show that prostaglandins, thromboxane, and H(P)ETEs were not increased in supernatants from X-XO treated cultures compared to untreated cultures. Synthetic H(P)ETEs added to the medium of lymphocyte cultures were only slightly or not clastogenic. In contrast hereto, the degradation product 4-hydroxynonenal was found in 50% of CF samples, while it was absent in all 43 control samples. The kinetics of detectability in the culture medium was similar to that of CF. Also, the clastogenic effect of synthetic 4-hydroxynonenal at concentrations as low as 0.1 microM suggested that this aldehyde, known for its genotoxic effects, was a clastogenic component of CF. The indirect action mechanisms of 4-hydroxynonenal via inactivation of functional SH groups in DNA polymerases, may explain why chromatid-type damage is predominant in lymphocytes exposed to CF in the Go-G1 phase of the cell cycle. This particularly was already stressed 20 years ago in the first observations of radiation-induced CF. However, 4-hydroxynonenal is not the only clastogenic component of CF.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clastogenic factors in plasma of HIV-1 infected patients

The objective of this study was to investigate the clastogenic activity of plasma ultrafiltrates from HIV-I infected patients. Clastogenic factors are chromosome-damaging agents with low molecular weight (<10,000 daltons) which cause chromosome aberrations, sister chromatid exchanges, DNA strand breakage, and gene mutation. They have first been described in the plasma of irradiated persons, but they are also found in hereditary breakage syndromes and chronic inflammatory diseases with autoimmune reactions. Their formation and their clastogenic effects are modulated by superoxide anion radicals. We analyzed a total of 22 HIV-1 positive patients in comparison to 20 reference plasma samples from healthy HIV negative blood donors of similar age. The plasma ultrafiltrates (filter cutoff 10,000 daltons) from patients induced a statistically significant increase in chromosomal breakage in the cytogenetic test system (20.5 ± 6.8 aberrations per 100 cells), while no increase was observed in test cultures exposed to plasma ultrafiltrates from healthy blood donors (6.3 ± 2.9 aberrations per 100 cells). The breakage values were slightly, but not significantly, lower in the 10 patients with more than 200 T-helper cells/ml (18 ± 4 aberrations per 100 cells), than in the 12 patients with less than 200 T-helper cells/ml (22.3 ± 7.9 aberrations per 100 cells). HIV patients with high clastogenic activity (induction of more than 20 aberrations per 100 cells, range 20 to 39) showed higher plasma levels for malondialdehyde than those with lower clastogenic activity (less than 20 aberrations per 100 cells, range 12 to 18). However, the difference was statistically not significant. Another lipid peroxidation product, 4-hydroxynonenal, was increased equally in both groups. There were no significant differences in water- and lipid-soluble plasma antioxidants between the low- and high-breakage group. In agreement with previous findings, the clastogenic effects of plasma ultrafiltrates in the test cultures were reduced by the antioxidant enzyme superoxide dismutase. The presence of clastogenic factors in the plasma of HIV patients is further evidence for a prooxidant state in these persons. Since clastogenic factor formation appears to occur at an early stage of the disease, it may be significant for virus release or activation, because of the superoxide anion stimulating effects of clastogenic factors. From a practical standpoint, clastogenic factors may be useful for evaluation of promising drugs.     

Posters

Introduction  Fine needle aspiration (FNA) cytology of the thyroid is a well-established test in the clinical work-up of patients with solitary nodules of the thyroid. Thyroid FNA does however have limitations and audit of diagnostic performance is important.
Methods  The histopathology archives of the Royal Victoria Hospital were searched for all thyroid resections and the histopathological diagnosis was correlated with the pre-operative cytological diagnosis, where available. Special emphasis was placed on the accuracy of tumour diagnosis.
Results  A total of 173 cases were identified during the 2-year period, of these 93 had available pre-operative FNA. A total of 57 tumours were identified. A small number (six of 57) of significant discrepancies were identified. These included a malignant lymphoma diagnosed as Hashimoto's thyroiditis, a metastasis which the FNA had suggested was a medullary carcinoma and an insular carcinoma diagnosed as medullary carcinoma on FNA. False positives included a colloid cyst diagnosed as suspicious of malignancy and a cytological diagnosis of papillary carcinoma not confirmed on histology.
Discussion  At present, the majority of thyroid FNAs in our clinics are performed by surgeons and material is not routinely available for immunocytochemistry. In spite of these limitations, there were few major discrepancies. These might be reduced if pathologist aspirators were able to perform FNAs and collect material for further studies, where necessary. This would allow identification of medullary carcinomas and malignant lymphomas.
Conclusion  FNA of thyroid lesions is a useful investigation in our clinical setting, however, some areas of potential for improvement have been identified.     

Variation of superoxide dismutase levels in fetal calf serum

The results of cytogenetic studies and of other experiments based on tissue-culture systems may be influenced by various components of tissue-culture medium and by variations among batches of fetal calf serum used for supplementation of the media. Negative results may be obtained in breakage studies as a consequence of medium components with a protective effect [6]. Attention has been drawn to differences in growth pattern [8] and mitotic indices [11] in lymphocyte cultures set up with different culture media. Variations in the incidence of sister-chromatid exchanges according to differences in media [7] and sera [5] have also been observed. It has been suggested [9] that the failure of some laboratories to detect increases in sister-chromatid exchanges after treatment with the tumor promoter phorbol-myristate-acetate (PMA) may be due to high concentrations of the free-radical-scavenging enzyme superoxide dismutase (SOD) in the sera used and that heat inactivation of the sera may be responsible for these differences. In the following, we report that considerable variation in the SOD content exists between batches of fetal calf serum, up to levels with anticlastogenic effect.