Detection of oncogenic mutations in cervical carcinoma using method High Resolution Melting (HRM).

Oncogenic mutations in proto-oncogenes and tumor suppressor genes represent one of key events in cancerogenesis. In this study, we analysed mutation status in PIK3CA, KRAS and EGFR proto-oncogenes and TP53 tumor suppressor gene in a cohort of twenty-four patients diagnosed with squamous cell carcinoma or adenocarcinoma using the screening method "High Resolution Melting" (HRM). Positive findings were confirmed and identified by Sanger sequencing. Totally, we detected DNA sequence changes in targeted regions in seven patients (7/24, 29.2%). In PIK3CA gene, we found six sequence changes in four patients (4/24, 16.7%) and four of them were confirmed as oncogenic mutations. In KRAS gene, we detected sequence changes in four patients (4/24, 16.7%). Conversely, we identified pathogenic or potentially pathogenic sequence changes neither in EGFR nor TP53 genes. Our results suggest that sequence changes are specific neither for a certain histological subtype, clinical stage nor lymph node involvement and they appear independently on the presence of HPV (human papillomavirus) infection since early clinical stages. We observed the correlation between the presence of DNA sequence changes and hTERC gene amplification, but we did not find a significant relationship between the identified DNA sequence changes and detected copy-number alterations using the technique of array-CGH (array-based comparative genomic hybridization). Regardless our results confirmed an important role of oncogenic mutations in PIK3CA and KRAS genes in the neoplastic transformation process in the cervical carcinoma pathogenesis. Their identification in the early clinical stages should encourage further studies to better understand these mutations and exploit them for more detailed diagnostics.

[Identification of a Family with SUFU Germline Deletion Based on a Case of Desmoplastic Medulloblastoma in an Infant]. / Identifikace rodiny s nosicstvím germinální delece genu SUFU na podklade dia-gnózy desmoplastického meduloblastomu u batolete.

BACKGROUND: Medulloblastoma, an embryonal neuroectodermal tumor of the cerebellum, is the most common malignant brain tumor in children. There are approximately 15 cases diagnosed in the Czech Republic each year. The recent World Health Organization classification recognizes several histopathological subtypes of medulloblastoma: classical, desmoplastic/ nodular with its extensive-nodularity variant, and anaplastic/ large-cell variant. Further molecular analysis identified four basic subgroups of medulloblastoma: WNT, SHH, Group 3, and Group 4. The subgroup of SHH meduloblastoma is associated with somatic mutations of SHH, PTCH1, SUFU, SMO and TP53, while the most common mutations found in infants up to three years of age were PTCH1 and SUFU. The majority of medulloblastomas are sporadic diseases, whereas only about 5- 10% of all cases occur in connection with hereditary genetic syndromes. CASE: We present a case of a 21-months old girl diagnosed with a localized posterior fossa tumor. The histopathological examination revealed a desmoplastic/ nodular medulloblastoma. The treatment comprised a radical exstirpation of the tumor followed by adjuvant chemotherapy. With the use of array-CGH, a partial biallelic deletion of the SUFU gene (locus 10q24.32) was detected in the tumor DNA, whereas a monoallelic deletion was found in the peripheral lymphocyte DNA of the patient. These findings were confirmed by an independent qPCR method. Monoallelic germline deletion of SUFU was also identified in the patients mother, who was a healthy carrier. Pedigree of the family suggested a transition of the germline deletion of SUFU, since another brain tumors (including one case diagnosed before the age of three years) were identified in previous generations. CONCLUSION: Germline mutations in SUFU gene are believed to predispose to infant desmoplastic/ nodular medulloblastomas, basal cell carcinomas and meningiomas. The susceptibility gene shows autosomal dominant inheritance with an incomplete penetrance. There is no evidence-based surveillance strategy suggested for the carriers of germline SUFU mutations/ deletions so far. Our recommendation is based both on a family history of our patient and similar cases described in the literature. Since the germinal mutations in SUFU are responsible for up to 50% of all desmoplastic medulloblastomas in children under three years of age, genetic testing of SUFU should be encouraged in this population of patients.

Molecular cytogenetic analyses of hTERC (3q26) and MYC (8q24) genes amplifications in correlation with oncogenic human papillomavirus infection in Czech patients with cervical intraepithelial neoplasia and cervical carcinomas.

UNLABELLED: It is known that cervical cancer develop from precancerous intraepithelial neoplasia (CIN) which is characterized by series of genetic abnormalities. The progression of CIN to cervical carcinoma has been associated especially with the genomic integration of oncogenic human papilloma virus (HPV) and gain of the human telomerase RNA gene hTERC (3q26) and MYC (8q24). In this study, cytology specimens of cervical intraepithelial neoplasia and cervical carcinoma from 74 Czech women were analyzed using the triple-color Cervical FISH Probe Kit designed for identification of HPV infected cells and copy number aberration of the hTERC and MYC genes. HPV-positivity exhibited 70% of patients with premalignant lesions (CIN I - CIN III, carcinoma in situ), chromosomal changes were found in 53.3% of cases - MYC amplification had 33.3% of women with CIN I - CIN III and 50% with carcinoma in situ. Amplification of hTERC was detected in 16.7% of patient with CIN I, in 50% with CIN II, in 58.3% with CIN III and in 66.7% with carcinoma in situ. Based on HPV-positivity and the occurrence of chromosomal aberrations, patients were divided into high-, intermediate- and low-risk group. Among women with cervical carcinomas, HPV infection was detected in 90.1% of specimens and chromosomal aberrations were found in 87.5% of samples. Amplification of MYC gene was detected in 25% and hTERC gene in 62.5% of patients. According to the histopathological grade of tumors, MYC gene amplification occurred more frequently in specimens of spinocellular carcinoma than adenocarcinoma (p=0.029). We found no association between the frequency of cytogenetic lesions and the incidence of lymphangiogenesis or lymph node metastases in cervical carcinoma patients. Simultaneous hTERC and MYC genes amplification was significantly more frequent in samples of cervical carcinomas than in premalignant lesions (p=0.008).In a cohort of 26 patients with cervical carcinoma we used oligo-based GGH+SNP microarray technique for the high resolution mapping of copy number changes of hTERC and MYC genes. We found that recurrent gain of genetic material in chromosome 3q26 area carrying hTERC gene of size 43.6 Mb between 3q25.1-3qter and duplication of 3q were the most common genomic identifications of amplified gene. In MYC locus array-CGH profiling identified duplication of 8q and trisomy 8 as frequent genomic changes.Our work confirmed that in cervical carcinoma gains of hTERC and MYC genes are specific genomic changes associated with developing of malignant phenotype. We also showed that in premalignant stages HPV-FISH assay can be used as an effective diagnostic procedure to identify patients carrying highly risking HPV infection and chromosomal aberrations associated with this malignancy. KEYWORDS: cervical cancer, cervical dysplasia, HPV infection, hTERC amplification, MYC amplification, FISH, array-CGH.

Incidence of cytogenetic aberrations in two B lineage subpopulations in multiple myeloma patients analyzed by combination of whole-genome profiling and FISH.

Multiple myeloma (MM) is an incurable malignant disease of the terminal developmental stage of B-lymphocytes. While genetic heterogeneity of MM is widely described, little is known about its genetic basis as well as primary damage during plasma cells (PC) development. In this study, we focused on genome-wide screening of DNA copy number changes using oligonucleotide-based array-CGH together with I-FISH of the IgH locus rearrangements in pair samples of bone marrow B-cells (CD19+) and CD138+ PC from newly diagnosed MM patients. The IgH disruption was found in 8.9% (4/45) of CD19+ samples and in 57.8% (26/45) of CD138+ samples. The genomic profiling using array-CGH identified copy number alterations (CNAs) in 10% (2/20) of CD19+ samples in regions known to be important for MM pathogenesis. In contrast, we found CNAs in 100% (16/16) of CD138+ samples. Most common chromosomal abnormalities were trisomies of odd-numbered chromosomes (3, 5, 7, 9, 11, 15, 19 and 21), gain 1q, gain Xq and monosomy of chromosome 13. We did not find any correlation between incidence of CNAs in CD19+ and CD138+ cells. In conclusion, effective utilization of FISH and array-CGH can identify genetic lesions in premalignant stages leading to better understanding and characterization of MM.

[Chromosome banding analysis of peripheral blood lymphocytes stimulated with IL2 and CpG oligonucleotide DSP30 in patients with chronic lymphocytic leukemia]. / Cytogenetické vysetrení lymfocytu periferní krve po stimulaci IL2 a CpG oligonukleotidem DSP30 u pacientu s chronickou lymfocytární leukemií

BACKGROUND: Chromosomal aberrations play an important role as prognostic factors in chronic lymphocytic leukemia (CLL). These aberrations are mostly detected by fluorescent in situ hybridization (FISH), as chromosomal banding analysis has been scarce due to low proliferative activity of malignant B-lymphocytes in vitro. In 2006, a new method using stimulation with IL-2 and CpG oligonucleotide DSP30 for metaphase generation in CLL was published [1]. The objective of our study was to verify the efficacy of stimulation and to evaluate if the method is suitable for routine diagnostics. PATIENTS AND METHODS: In total, peripheral blood samples of 369 CLL patients were analyzed in parallel by chromosomal banding analysis and by FISH probes for 13q14, 11q22-23, CEP12 and 17p13. RESULTS: Out of 369 patients, 307 (83%) were successfully stimulated for metaphase generation. Chromosomal aberrations were detected in 243 (79%) out of 307 patients evaluated by chromosomal banding analysis. Other aberrations that are not included into standard FISH panel were detected in patients karyotypes, e.g. del(6q), del(14q), t(14;18)(q32;q21), t(11;14)(q13;q32) and t(18;22)(q21;q11). One hundred and three (42%) patients showed complex aberrant karyotype not detected by FISH analysis. CONCLUSION: Stimulation with IL-2 and oligonucleotide DSP30 is an efficient method how to induce proliferation of malignant B-lymphocytes and allows detection of a substantial number of chromosomal aberrations in addition to those detected by standard FISH panel. Using this method in routine diagnostics is helpful particularly in identification of patients with complex aberrant karyotype.

Unique Combination of 22q11 and 14qter Microdeletion Syndromes Detected Using Oligonucleotide Array-CGH.

We report an infant with a unique combination of 22q11 deletion syndrome and 14q terminal deletion syndrome. The proband had clinical symptoms compatible with diagnosis of 22q11 deletion syndrome: microcephaly, micrognathia, high-arched palate, hypertelorism, short palpebral fissures, square nasal root, prominent tubular nose, hypoplastic nasal alae, bulbous nasal tip, dysplastic low-set ears, short philtrum, and heart defect, but no cell-mediated immunodeficiency typical for the syndrome. G-banding and fluorescence in situ hybridization analyses revealed a karyotype 45,XY,der(14)t(14;22)(q32.3;q11.2),-22.ish del(14)(q32.33)(D14S1420-),del(22)(q11.2q11.2)(N25-). Subsequent analyses disclosed a translocation between chromosomes 14 and 22 in the proband's mother with a deleted 14q telomere. Using comparative genome hybridization on oligonucleotide-based microarray (array-CGH), the deletion at 22q11.21 in the size of ∼4.25 Mb was revealed in the proband as well as the deletion of the telomeric area at 14q32.33qter (∼3.24 Mb) in the proband and his mother. However, both the proband and his mother showed mild symptoms (microcephaly, thin lips, carp-shaped mouth) typical for patients with the described terminal 14q deletion syndrome.

Analysis of chromosomal aberrations in patients with mental retardation using the array-CGH technique: a single Czech centre experience.

Submicroscopic structural chromosomal aberrations (microduplications and microdeletions) are believed to be common causes of mental retardation. These so-called copy number variations can now be routinely detected using various platforms for array-based comparative genomic hybridization (array-CGH), which allow genome-wide identification of pathogenic genomic imbalances. In this study, oligonucleotide-based array-CGH was used to investigate a panel of 23 patients with mental retardation and developmental delay, dysmorphic features or congenital anomalies. Array-CGH confirmed or revealed 16 chromosomal aberrations in a total of 12 patients. Analysis of parental samples showed that five aberrations had occurred de novo: del(1)(p36.33p36.23), del(4)(p16.3p16.2) joined with dup(8)(p23.3p23.1), del(6)(q14.1q15), del(11)(q13.1q13.4). Three aberrations appeared to be inherited from an unaffected parent: dup(3)(q29), del(6)(q12), dup(16)(p13.11). Six aberrations appeared to be inherited from a parental carrier: del(1)(p36.33) joined with dup(12)(q24.32), del(21)(q22.2q22.3) joined with dup(11)(q24.2q25), del(X)(q22.3) and del(1)(q21.1). In two cases, parents were not available for testing: del(17)(q11.2q12) and del(2)(q24.3q31.1). Our results show that the use of oligonucleotide-based array- CGH in a clinical diagnostic laboratory increases the detection rate of pathogenic submicroscopic chromosomal aberrations in patients with mental retardation and congenital abnormalities, but it also presents challenges for clinical interpretation of the results (i.e., distinguishing between pathogenic and benign variants). Difficulties with analysis notwithstanding, the array-CGH is shown to be a sensitive, fast and reliable method for genome-wide screening of chromosomal aberrations in patients with mental retardation and congenital abnormalities.

Oligonucleotide-based array CGH as a diagnostic tool in multiple myeloma patients.

Multiple myeloma (MM) is a hematological disease caused by malignant proliferation of clonal plasma cells (PCs) known for its clinical and biological heterogeneity. Identification of chromosomal changes in genome of PCs plays a key role in MM pathogenesis and is supposed to have important prognostic significance for MM patients. There are two major genetic entities in MM. Hyperdiploid tumors (H-MM), which include about 50% of MM tumors, often have multiple trisomies involving chromosomes 3, 5, 7, 9, 11, 15, 19, and 21 and a substantially lower prevalence of IgH translocations. Nearly half of tumors are non-hyperdiploid (NH-MM), and mostly have one of five recurrent IgH translocations: 11ql13 (CCND1), 6p21 (CCND3), 16q23 (MAF), 20q12 (MAFB), and 4p16 (FGFR3 and MMSET). The development and expanded use of new technologies, such as genome-wide array-based comparative genomic hybridization (aCGH) has accelerated genomic research in MM. This technique is a powerful tool to globally analyze recurrent copy number changes in tumor genome in a single reaction and to study cancer biology and clinical behaviors. It widely overcame routinely used cytogenetic techniques (G-banding, FISH) both in minimal resolution of chromosomal changes and amount of obtained genomic data important for further analyses and clinical applications. Array CGH technique is now used to better understanding of molecular phenotypes, sensitivity to particular chemotherapeutic agents, and prognosis of these diseases. This paper brings brief literature and methodic overview of oligonucleotide-based array-CGH technique in MM diagnosis.

Visualization of numerical centrosomal abnormalities by immunofluorescent staining.

The presence of multiple centrosomes in tumor cells is associated with the formation of multipolar mitotic spindles and results in aneuploidy of both daughter cells. Centrosome amplification is a feature of all cancer cells. We have previously described centrosome amplification in abnormal B cells. Further studies of centrosome amplification in different stages of B lineage development could provide important information about multiple myeloma pathogenesis.

Coincidence of chronic lymphocytic leukaemia with Merkel cell carcinoma: deletion of the RB1 gene in both tumors.

The authors report a case of a 64-year-old man with chronic lymphocytic leukaemia (CLL) diagnosed 5 years ago. Recently, the patient was admitted with a tumour of the skin in the left lumbar region. Histological and immunohistochemical examinations established the diagnosis of Merkel cell carcinoma (MCC). Electron-microscopic examination revealed the formation of spherical aggregates of intermediate-sized filaments in the perinuclear region. The coincidence of MCC and CLl is rather rare and in published cases, no cytogenetic examinations were performed. We examined the RB1 gene using the interphase FISH method. A biallelic deletion in CLL tumour cells was detected; in MCC tumour cells, biallelic deletion was found in 33% of the cells and monoallelic deletion in 57% of the cells. In addition, chromosome 6 trisomy and 1p36 deletion were detected. Examination of non-neoplastic cells of the patient's skin showed a biallelic presence of the RB1 gene. According to the relevant literature, examination of the RB1 gene in CLL has informational value as a prognostic factor. The relationship between deletion of the RB1 gene and prognosis in MCC has not yet been determined and needs more research.

TP53 mutation profile in chronic lymphocytic leukemia: evidence for a disease specific profile from a comprehensive analysis of 268 mutations.

The TP53 mutation profile in chronic lymphocytic leukemia (CLL) and the correlation of TP53 mutations with allele status or associated molecular genetics are currently unknown. We performed a large mutation analysis of TP53 at four centers and characterized the pattern of TP53 mutations in CLL. We report on 268 mutations in 254 patients with CLL. Missense mutations appeared in 74% of cases compared with deletions and insertions (20%), nonsense (4%) and splice site (2%) mutations. The majority (243 of 268) of mutations were located in the DNA-binding domain. Transitions were found in 131 of 268 mutations, with only 41 occurring at methylated CpG sites (15%), suggesting that transitions at CpGs are uncommon. The codons most frequently mutated were at positions 175, 179, 248 and 273; in addition, we detected a common 2-nt deletion in the codon 209. Most mutations (199 of 259) were accompanied by deletion of the other allele (17p-). Interestingly, trisomy 12 (without 17p-) was only found in one of 60 cases with TP53 mutation (without 17p-) compared with 60 of 16 in the cohort without mutation (P=0.006). The mutational profile was not different in the cohorts with and without previous therapy, suggesting that the mechanism underlying the development of mutations may be similar, independent of treatment.

Centrosome amplification as a possible marker of mitotic disruptions and cellular carcinogenesis in multiple myeloma.

Centrosome amplification (CA) as a potential marker of mitotic disruptions in multiple myeloma (MM) was investigated in two populations of B-cell lineage: B-cells and plasma cells (PCs). Using immunofluorescent staining, it was shown that CA in B-cells is present in 3.2+/-2.5% in healthy donors versus 9.9+/-7.9% in MM patients (p<0.0001). Based on the calculated threshold value of CA in B-cells, 37% (14/38) of MM patients were positive. There was no significant correlation between CA-positive MM cases (based on PC samples evaluation) and the occurrence of cytogenetic abnormalities in PCs, including del(13)(q14), del(17)(p13), gain(1)(q21) and hyperdiploidy.

Negative prognostic significance of two or more cytogenetic abnormalities in multiple myeloma patients treated with autologous stem cell transplantation.

Malignant plasma cells in multiple myeloma (MM) are frequently characterized by complex karyotypes and chromosome instability. These cytogenetic changes are considered important prognostic indicators in MM patients. We have studied samples from 68 patients with newly diagnosed MM who were treated with high-dose chemotherapy and autologous stem cell transplantation. G-banding revealed abnormal karyotypes in 14 of 55 patients (25%) who had informative conventional cytogenetics. The combination of cytoplasmic immunoglobulin light chain labeling and interphase fluorescent in situ hybridization (cIg-FISH) revealed the presence of genetic aberrations in 53 of 68 patients (78%). Chromosome 13 abnormalities were found in 33 patients (50%) and IgH rearrangements in 36 patients (56.25%). In IgH positive patients we performed subsequent examinations of IgH affecting translocations t(4;14) and t(11;14) and we found translocation t(11;14) in 8 patients (12.5%) and t(4;14) in 10 patients (15.5%). The occurrences of others chromosomal abnormalities with known prognostic impact in MM were as follows: del(17)(p13) was present in 5 patients (9.8%) and gain 1q21 in 14 patients (36%). Analysis of survival of patients with different cytogenetic abnormalities revealed shorter overall survival (OS) in patients with IgH rearrangements (p=0.020) and trend to shorter OS in patients with gain 1q21 (p=0.064), respectively. Remarkably, patients with two or more aberrations had significantly shorter overall survival (p=0.001), time to progression (p=0.036) and progression free survival (p=0.008). Our results show a high incidence of chromosomal abnormalities in MM patients and confirm the prognostic impact of selected chromosomal aberrations as well as cumulative effect of multiple cytogenetic changes occurring simultaneously.

[The origin and formation of chromosomal translocations in multiple myeloma]. / Uloha chromozomových translokací pri vzniku a výoji mnohocetného myelomu.

Multiple myeloma is a malignant disease of terminal developmental stages of B-lymphocytes, i.e. plasma cells. During the progress of the disease genetic changes are cumulated in these cells which are the cause of their fully malignant phenotype. The affection of plasma cells is characterized by the presence of various numerical and structural chromosomal aberrations. A frequent cytogenetic finding is the presence of reciprocal translocations originating within the process of the so-called illegitimate switch recombination, affecting the gene for heavy chains of immunoglobulins (IgH) in the 14q32 chromosome area. As a result of this recombination the oncogenes on derived chromosomes get under control of the molecular enhancers of the IgH locus. This paper summarizes the current knowledge concerning the formation mechanism of chromosomal translocations in multiple myeloma and the areas of their formation; it also mentions the way of their detection. The paper presents the most frequent types of chromosomal translocations affecting the area of chromosome 14q32 in the karyotype of people diseased with multiple myeloma, including the frequency of their detection and the prognostic significance for the patients.

Efficacy of high-resolution comparative genomic hybridization (HR-CGH) in detection of chromosomal abnormalities in children with acute leukaemia.

The efficient detection of chromosomal aberrations in childhood acute leukaemias presents a significant component in the diagnostics of this frequent malignant disease. We used comparative genomic hybridization (CGH) and high-resolution comparative genomic hybridization (HR-CGH) to determine the frequency of chromosomal changes in 33 children with acute leukaemia (AL). The yields of chromosomal abnormalities were compared with the results obtained using conventional cytogenetics (G-banding) and fluorescence in situ hybridization (FISH). Conventional cytogenetics revealed chromosomal changes in 17 (52 %) of studied patients. The employment of FISH together with G-banding analysis identified chromosomal changes in 27 (82 %) of the AL patients investigated. CGH detected changes in DNA copy numbers in 24 (73 %) patients, 40 losses and 67 gains were found in total. HR-CGH disclosed 98 losses and 97 gains in 26 (79 %) patients. In comparison with CGH, HR-CGH analyses unveiled 88 new chromosomal aberrations: 58 losses and 30 gains. The most commonly gained chromosomes were 21 (22.5 %), X (15 %), 18 (12,5 %) and 17 (10 %). The most common losses involved sub-regions or arms of chromosomes 7 (15 %), 9 (12.5 %), 16, 19 and 1 (10 % each). Cytogenetic and molecular cytogenetic analyses of 33 childhood acute leukaemias revealed chromosomal changes in total 31 (94 %) patients. The evaluation of HR-CGH sensitivity proved that the minimal cell population of malignant cells in which a certain chromosomal change could be found was close to the 20 - 30 % level. Our results confirm the benefits of HR-CGH in detecting chromosomal changes in childhood AL. Supplementing G-banding and FISH with the HR-CGH diagnostic method increases the detection of unbalanced structural chromosomal rearrangements and can reveal small cell clones with gains and losses of whole chromosomes in hyperdiploid AL.

Incidence of the main genetic markers in glioblastoma multiforme is independent of tumor topology.

Glioblastoma multiforme (GBM) is the most common as well as the most aggressive type of primary brain tumor of astrocytic origin in adults. GBM is characterized by a high degree of intratumoral heterogeneity both in histomorphology and genetic changes. Trisomy/polysomy of chromosome 7, monosomy of chromosome 10, EGFR gene amplification and p53 deletion have been described as the typical genetic markers for tumor classification and prediction of possible response to therapy. Our work was based on detection of these four main genetic changes both in central and peripheral parts of the tumors to evaluate possible differences in the topological incidence of these genetic markers. Chromosomal abnormalities in tumor samples from a group of 21 patients surgically treated for GBM were characterized by means of the interphase-fluorescence in situ hybridization (I-FISH) technique using sets of centromere and locus-specific DNA probes. In addition, we performed a detailed analysis of one selected tumor sample using a genomic microarray system (GenoSensor Array 300) to characterize copy number changes of specific sequences and refine results obtained by I-FISH. However, the data show no significant differences in occurrence of the described genetic markers in either part of the tumor.

The optimization of sample treatment for spectral karyotyping with applications for human tumour cells.

Spectral karyotyping (SKY) represents an important tool for the investigation of the complex chromosomal rearrangements (CCRs) in many human malignancies which may be difficult to characterize by conventional banding techniques. The main goal of our work was to optimize the most important steps in the preparation of molecular cytogenetic slides for a SKY protocol. This approach consisted of optimization of both the aging procedure and protease pretreatment of the slides, with special regard given to the preservation of chromosome structure and shape, as well as to the intensity of hybridization signals. The best results were obtained with a chemical aging procedure using SSC or ethanol in combination with trypsin pretreatment applied at a higher concentration for a shorter period of pretreatment. A resulting protocol for SKY also applicable to human solid tumour cells was subsequently proposed. The practical potential of the SKY technique was demonstrated on examples of two types of human embryonal tumours--neuroblastoma and Wilms' tumour, in which some kinds of chromosomal aberrations were not detectable by means of classic cytogenetic methods.

Malignant fibrous histiocytoma of the parotid gland.

We described a rare malignant fibrous histiocytoma of the parotid gland (MFH) in a 63-year-old woman. During six months the tumour size became 10 cm in diameter with skin ulceration. The tumour was examined morphologically, by immunohistochemistry and molecular biology methods - FASAY and CGH. The histology revealed a storiform-pleomorphic type of MFH with high mitotic rate. The FASAY method identified a non-mutated p53 gene. The chromosomal changes were identified by the CGH method and 6 cytogenetic changes were found in the tumour cells (deletions at 8p12-p22, 13q32-qter, 14q24-qter, and gains of chromosomal material at 5p, 8q12-q23, and Xq25-qter). The patient died shortly after the beginning of chemotherapy. Autopsy revealed brain and cerebellar haemorrhage. No other tumour foci were proved. In view of short course of disease we lack the data about the influence of the non-mutated p53 gene on the prognosis and therapy.

[The significance and current diagnostic options of cytogenetic changes in multiple myeloma]. / Význam a soucasné moznosti diagnostiky cytogenetických zmen u mnohocetného myelomu.

Multiple myeloma is a malignant disease caused by malign transformation of B-cells, their clonal proliferation and the accumulation of myeloma cells in the bone marrow. These cells are set apart by a pronounced genetic instability. Chromosomal abnormalities are probably the most important prognostic factors in myeloma which influence the division of the patients into individual sub-groups each with a different developmental process of the disease and thus a different approach during treatment. The study summarizes the methodological approaches and current options in classical and molecular cytogenetics during the examination of cytogenetic changes in multiple myeloma. It presents the most common types of numerical and structural chromosomal changes found in the karyotype of multiple myeloma patients, and their prognostic importance.