Seniha Hacihanefioglu

HER-2, TOP2A and chromosome 17 alterations in breast cancer

HER-2 amplification is a biomarker for identifying patients who respond to trastuzumab and has been evaluated as a factor predicting the response to anthracyclines. The relationship between HER-2 and response to anthracycline therapy may also be the result of the close localization of TOP2A on 17q. It has been a matter of debate whether these two genes, HER-2 and TOP2A, behave separately on different amplicons or act together thus making it possible to predict the TOP2A status from the HER-2 status. In this study TOP2A, HER-2 and chromosome 17 aneusomy were investigated by fluorescent in situ hybridization (FISH) in 50 consecutive breast cancer patients. HER-2 amplification was detected in 11 patients (22%) and TOP2A changes were seen in 6 patients (12%); two amplifications and two deletions were observed in HER-2-amplified cases and two deletions in HER-2-nonamplified cases. Three of the TOP2A-deleted cases had polysomy 17. HER-2 copy number was higher than the TOP2A copy number in one patient with co-amplification. Polysomy was observed in 9 cases (18%) and monosomy in 6 cases (12%). Aneusomy was the sole anomaly in 11 patients (22%). We conclude that the TOP2A status cannot be predicted from the HER-2 status and evaluation of the TOP2A status only in patients with HER-2 overexpression may lead to missing cases with TOP2A deletion with possible resistance to therapy. Other factors modulating topo IIα activity may also affect the response to therapy. Studies evaluating different parameters that can modulate topo IIα activity and the response to the drugs targeting the enzyme are necessary.

Anophthalmia-Waardenburg syndrome: a report of three cases.

We report on 2 Turkish families with children who had bilateral anophthalmia, upper and lower limb abnormalities, mental retardation and consanguineous parents. We have evaluated the 2 cases in the first family and the only case in the second as anophthalmia-Waardenburg syndrome. This is an extremely rare autosomal recessive syndrome.

Neuroblastoma in a dysmorphic girl with a partial duplication of 2p caused by an unbalanced translocation.

A 1-year-old female child with multiple dysmorphic features including microcephaly, hypertelorism, a short philtrum, low set ears, a narrow high arched palate, micrognathia and growth retardation was found to have a de novo chromosome abnormality including a partial duplication of the short arm of chromosome 2 and a partial deletion of the long arm of chromosome 17. The clinical features of the case shared many similarities to previous reports of trisomy 2p. Three years later, ecchymotic spots appeared around the left ocular region. Further clinical and pathological examination confirmed the diagnosis of a neuroblastoma. This is the first case of an unbalanced translocation, 46, XX, der (17), t (2; 17) (p23; q25), showing the development of a neuroblastoma in addition to the dysmorphic features. We suggest that trisomy 2p including the N-myc proto-oncogene may have predisposed the patient to the development of a neuroblastoma.

A small supernumerary marker chromosome X identified by in situ hybridization

Cytogenetic analysis of a girl with moderate mental retardation and dysmorphic features revealed a 46,XX/47,XX,+mar karyotype. Fluorescence in situ hybridization using chromosome specific alpha satellite probes showed that the supernumerary marker originated from the X chromosome. To our knowledge, this is the first reported case of a female patient mosaic for a supernumerary small marker chromosome derived from X, and hence mosaic for trisomy of the pericentric region of the X chromosome.

Enhanced Sensitivity to Oxidant-Induced Micronucleus Frequency in Elderly Individuals Is Not Associated with Glutathione S- Transferase M1 (GSTM1) Null Genotype in Lymphocytes

Background: A large number of studies have demonstrated that various kinds of DNA damage accumulate during aging and that oxidative stress possibly contributes to this process. Glutathione S-transferase M1 (GSTM1) can prevent their possible effects on DNA via detoxification of reactive substances that induced oxidative stress. Objective: To investigate the relationship between GSTM1 polymorphism and DNA sensitivity to oxidative stress with age, we used micronucleus (MN) frequency as a marker of DNA damage in lymphocytes from young and elderly subjects. Methods: This study was performed in 30 young (age range 20–36 years) and 30 elderly (age range 66–87 years) healthy individuals who were chosen on the basis of their GSTM1 genotype (15 GSTM1 null and 15 GSTM1 positive for each group). Lymphocytes were cultured after Ficoll isolation and treated for 48 h with a 30-µM dose of cumene hydroperoxide (CumOOH), a dose that does not decrease cell viability. Results: There was no significant difference in the MN frequency observed in control cultures from young and elderly individuals. However, the MN frequency in CumOOH-treated cultures was significantly higher in the elderly group than the young group (p < 0.001). No association was found between the GSTM1 phenotype and CumOOH-induced MN frequency. Conclusions: The results suggest that lymphocytes of elderly individuals are more susceptible to in vitro MN induction by CumOOH. However, this difference in susceptibility is not explained by the lack of GSTM1.

CYTOGENETIC CLONAL EVOLUTION IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA

ABSTRACT Chronic myeloid leukaemia (CML) is a clonal haematological disease characterised by t(9;22)(q34;q11) which is called Philadelphia (Ph) chromosome. Highly improved haematological and cytogenetic results were obtained in chronic phase CML with the introduction of imatinib. Occurrence of additional cytogenetic abnormalities in Ph(+) cells is defined as clonal evolution (CE) and considered to be a preceding sign for acceleration. The most common additional chromosomal changes are +8, +Ph, i(17q), +19, -Y, +21, +17 and-7. The aims of this study were to delineate the occurrence pattern of cytogenetic clonal evolution in our cohort of CML patients and to investigate the impact on the course and prognosis of CML. Additional clonal chromosomal changes in Ph(+) cells were observed in 20 cases (19%). The abnormalities seen were monosomy 21 (%35), -17 (%30), -19 and +8 in (%25), -7, -8, -13, -15, -22, +Ph, and different marker chromosomes (%20), -Y, -12, -14, -16, -20 (%15), +Y, -10, -18 (%10), and -X, -3, -9, +20, der(7;17)(q10;q10), der3?, der12? (%5). The findings of-Y, -7, -8, +8, -14, -15, -17, -18, -21, +Ph, der(7;17)(q10;q10) and del(7)(q11) have been recorded in more than one samples in at least one case. The clinical data of the 20 cases with CE were compared to 7 cases with no or minor cytogenetic response without CE and no statistically significant differences found. Considering their high frequency and persistence in successive samples, we recommend to trace -21 and -17 with FISH in addition to classical cytogenetics in CML cases.

Variant Philadelphia translocations with different breakpoints in six chronic myeloid leukemia patients.

OBJECTIVE The Philadelphia (Ph) chromosome, consisting of the t(9;22)(q34;q11) translocation, is observed in ~90% of patients with chronic myeloid leukemia (CML). Variant Ph translocations are observed in 5%-10% of CML patients. In variant translocations 3 and possibly more chromosomes are involved. Herein we report 6 CML patients with variant Ph translocations. METHODS Bone marrow samples were examined using conventional cytogenetic meth ods. Fluorescence in situ hybridization (FISH) with whole-chromosome paints and BCR-ABL 1D probes were used to confirm and/or complement the findings, and identify rearrangements beyond the resolution of conventional cytogenetic methods. RESULTS Variant Ph translocations in the 6 patients were as follows: t(7;22)(p22;q11), t(9;22;15)(q34;q11;q22), t(15;22)(p11;q11), t(1;9;22;3)(q24;q34;q11;q21), t(12;22)(p13;q11), and t(4;8;9;22)(q11;q13;q34;q11). CONCLUSION Among the patients, 3 had simple and 3 had complex variant Ph translocations. Two of the presented cases had variant Ph chromosomes not previously described, 1 of which had a new complex Ph translocation involving chromosomes 1, 3, 9, 22, and t(1;9;22;3)(q24;q34;q11;q21) apart from a clone with a classical Ph, and the other case had variant Ph translocation with chromosomes 4, 8, 9, and 22, and t(4;8;9;22)(q11;q13;q34;q11) full complex translocation. Number of studies reported that some patients with variant Ph translocation were poor responders to imatinib. All of our patients with variant Ph translocations had suboptimal responses to imatinib, denoting a poor prognosis also. Variant Ph translocations may be important as they are associated with prognosis and therapy for CML patients.

Glutathione and Related Enzymes in Rat Liver Treated with Methyl Nitrosourea

In vivo effects of methyl nitrosourea (MNU) on rat liver glutathione, glutathione S transferase and glutathione reductase have been studied. MNU was injected (20 mg per kg i.r.) weekly for 10 weeks. The animals were killed by decapitation 6 months later, livers were removed, homogenized and the enzymes were studied. Twenty-five animals were treated with MNU. Physiological salt solution was given to ten control animals. It was shown that the cytotoxic effects of MNU cause a decrease of glutathione levels. There was no difference in activity of glutathione reductase in the MNU treated group when compared to control, but glutathione S-transferase activity of the MNU treated group was found to be increased. Glutathione protects the cells against alkylating agents, which may cause cell damage due to depletion of glutathione levels. Increased levels of glutathione S-transferase may be a reaction of the organism to the alkylating agents. Because of depletion of glutathione levels, glutathione reductase levels may be unaffected.

Expression of aphidicolin, FUdR and caffeine-induced fragile sites in lymphocytes of healthy Turkish individuals.

The expression of common fragile sites (c‐fra) and frequency of chromosomal aberrations were studied in peripheral lymphocytes of 50 healthy Turkish individuals (26 males and 24 females from 1 to 87 years of age) after induction with aphidicolin (APC), 5′‐fluorodeoxyuridine (FUdR), and caffeine. A correlation was seen between age and the frequency of chromosomal aberrations in APC and caffeine treated cultures, but there were no significant differences in the frequencies of chromosomal aberrations between males and females in any of the treatments. The mean frequency of aberrations induced by FUdR was significantly higher than that induced by APC and caffeine. A chromosome aberration is defined as a fragile site when present in 1% of the cells analyzed from each culture and in at least 50% of the individuals studied. Using these criteria, 12 c‐fra were observed in the three treatments: 1p21, 1q21, 2p11‐q11, 3p14, 4q31, 6q26, 7q22, 7q32, 8q24, 11q23, 16q23, and Xp22. Sites 3p14, 16q23, and Xp22 were the most frequently observed c‐fra, with only the frequency of Xp22 being significantly increased in females in APC treated cultures. The results of these studies are important as a base against which the effects of other clastogenic and environmental agents, as well as genetic background, can be compared.

Recurrent Monosomies Confirmed by Interphase FISH in Three Chronic Myeloid Leukemia Cases

Although chronic myeloid leukemia (CML) is characterized by the Philadelphia (Ph) chromosome, which is the result of t(9;22) (q34;q11) or its variants, 10%-20% of cases have additional cytogenetic abnormalities. The most common additional abnormalities are loss of the Y chromosome, +8, +Ph, and i(17q). Since these additional chromosome abnormalities are signs of disease progression, it is important to perform cytogenetic analyses periodically in patients with CML [1].