Step-wise progression in human skin carcinogenesis in vitro involves mutational inactivation of p53, rasH oncogene activation and additional chromosome loss.

Two mechanisms relevant for skin carcinogenesis in man are mutational inactivation of p53 and oncogenic activation of c-rasH gene. Previously, we transfected c-rasH oncogene into human skin keratinocytes (HaCaT) with u.v.-typic mutations in both p53 alleles, which produced benign and malignant tumorigenic clones, expressing similar amounts of mutant Ras protein. Here we show that neither the ras integration site nor the karyotypic changes affects the formation of the benign or malignant tumorigenic phenotype. From the original malignant HaCaT-ras clone we took single human chromosomes, carrying the c-rasH oncogene and transferred them by microcell mediated chromosome transfer into genetically different untransfected nontumorigenic HaCaT cells. This novel approach identified the genetic background of the recipient cell as a critical determinant for the resulting tumor phenotype. Exhibiting similar oncogene expression, microcell hybrids from early passage cells remained nontumorigenic or formed benign tumors, while those with more cytogenetic aberrations (later passages) and loss of > 1 copy of chromosome 15 became malignant. Since aberrations in chromosome 15 were also detected in three of five human skin carcinoma lines this study provides evidence that p53 and c-rasH mutations are early events of human skin carcinogenesis, while loss of gene(s) on chromosome 15 is a late event.

Comparison of spectral karyotyping and conventional cytogenetics in 39 patients with acute myeloid leukemia and myelodysplastic syndrome.

Spectral karyotyping (SKY) was performed in patients with acute myeloid leukemia (AML; n = 25), secondary AML (s-AML; n = 7), myelodysplastic syndrome (MDS; n = 6) and s-MDS (n = 1) to complement conventional cytogenetic investigations. According to the results of conventional cytogenetics the patients were subdivided into three groups: group 1, normal karyotype, n = 19 cases, median age = 64 years; group 2, patients displaying either one or two single aberrations, n = 10 cases, median age = 54 years; group 3, patients with > or =3 independent aberrations, n = 10 cases, median age = 61.5 years. SKY identified no abnormal metaphases in group 1. In one patient of group 2 a hidden translocation t(7;14)(q3?1;q2?2) could be revealed with SKY. Conventional cytogenetics had only shown trisomy 8. A similar t(7;14) was also detected in one patient of group 3. SKY was helpful for the delineation of marker chromosomes and additional material. Furthermore, SKY could distinguish between partial and total monosomies or real existing and apparent deletions. The combination of G-banding, FISH and SKY was found very useful for the precise delineation of the karyotype. As a result of our study we recommend SKY investigation as an important additional tool for accurate chromosome analysis. The detected t(7;14) might represent a novel recurrent translocation in acute myeloid leukemias.

Establishment and characterization of a new, factor-independent acute myeloid leukemia line designated Ei501.

We established a factor-independent acute myeloid leukemia cell line, designated Ei501. The line has been growing in RPMI 1640 media for 18 months and can be maintained without addition of growth factors. Ei501 is positive for myeloperoxidase and negative for esterase and PAS. Cytogenetic analysis revealed the FAB M3 associated t(15;17) translocation and a translocation of the chromosomes 7 and 8: 46 XX, -7, +t(7;8)(q32;q13), t(15;17)(q22;q12). This karyotype was confirmed by fluorescence in situ hybridization. Ei501 cells express AML-associated surface markers such as CD13, CD33 and CD38. Although 42% of the patient's blast cells were CD34-positive, the line lacks surface expression of CD34. Furthermore the line has a number of characteristics which are detectable in blasts from AML patients, such as surface adhesion molecules, cytokines such as TGF-beta, cytokine receptors such as the IL-2 receptor beta and gamma chains or the IL-4 receptor and the genes for the transcription factor wt-1 (Wilms' tumor gene) and for the proto-oncogene bcl-2, both shown to be present in the majority of patients with AML. Additionally the line can be used as target in cytotoxicity assays using IL-2 activated cytotoxic lymphocytes as effector cells. In conclusion, besides a rare karyotype the Ei501 cell line has several features common in AML, and may therefore be used as a model to study pathogenetic mechanisms in acute myeloid leukemia.

Immunophenotyping is an independent factor for risk stratification in AML.

BACKGROUND: Chromosomal abnormalities are one of the most important prognostic factors in acute myeloid leukemia (AML). However, only a limited number of patients have such informative chromosomal abnormalities. The prognostic value of immunophenotyping in this disease is still unclear. METHODS: Seven hundred and eighty-three newly diagnosed AML patients treated in the German SHG-AML trials in 1991 and 1996 were analyzed with a panel of 33 antibodies. Expression was correlated to overall survival, complete remission-rate, and complete remission duration, and tested in a multivariate analysis including other clinical and biological markers. RESULTS: With a median follow-up of 4.3 years, patients with AML blasts negative for CD9, CD11b, CD13, CD34, and CD41, or positive for CD15, CD33, CD38, CD64, and MPO had superior overall survival. This effect was associated with a significantly higher complete remission rate (CD13, CD34, CD41, and CD64) or a longer complete remission duration (CD9, CD11b, and CD64). Cox-regression analysis, including cytogenetic, morphologic, and biologic parameters showed CD9, CD13, CD34, and CD64 as independent factors for overall survival. These markers were used for a prognostic score. Patients were pooled in three groups with highly significant differences of overall survival. The prognostic relevance of this score was confirmed in patients with normal karyotype and/or in younger patients

[Classic maternal phenylketonuria and sonographic evidence of fetal trisomy 21: first description]. / Klassische maternale Phenylketonurie und sonografische Hinweiszeichen auf eine fetale Trisomie 21, Erstbeschreibung.

Phenylketonuria is the best known pathology of amino acid metabolism. Presented here is the case of a 23-year-old prima gravida with phenylketonuria since birth. After delivery, her child was diagnosed with free trisomy 21. Abnormal sonographic signs such as bilateral hydrothorax, polyhydramnion, and short femura under the 10th percentile could be demonstrated in the ultrasound scan at 33 weeks of gestation. Regularly measured maternal phenylalanine levels during the complete pregnancy as well as preconceptionally were always under the embryopathic cutoff point of 1 200 micromoles/L (20 mg/L). An association seems unlikely. This is the first description of such a constellation according to a literature search (PubMed, Cochrane Library).

Preparation and karyotype analysis of mitotic chromosomes of the freshwater sponge Spongilla lacustris.

The present study documents for the first time the karyotype and mitotic chromosomes of a sponge. For the studies the freshwater sponge Spongilla lacustris (Lin. 1758) was used. Its karyotype comprises nine different chromosome pairs ranging in size from 2.1 to < or = 0.7 microns. Changes in size and shape of the chromosomes during the progression of mitosis are documented both light and electron microscopically. The data reveal that the lowest multicellular eukaryotes, the sponges, have already reached a high level of evolution of the mitotic mechanism.

Complete haematological and cytogenetic response to interferon alpha-2a of a myeloproliferative disorder with eosinophilia associated with a unique t(4;7) aberration.

A female patient with eosinophilia and cardiac symptoms was found to have a unique chromosomal aberration [t(4;7)(q11;p13)] of bone-marrow precursors. The disorder was classified as a chronic myeloproliferative syndrome with eosinophilia. Due to a significant increase in the white blood cell and eosinophil count during initial treatment with prednisone and hydroxyurea, Interferon alpha-2a was administered at a dose of 3-5 x 10(6) I.U. s.c., five times per week, and induced a long-term complete haematological and cytogenetic response. The clinical features of this case are presented and discussed in the context of the current literature.

Underestimation of inversion (16) in acute myeloid leukaemia using standard cytogenetics as compared with polymerase chain reaction: results of a prospective investigation.

In order to determine whether the polymerase chain reaction (PCR) is more suitable for the detection of inversion (16) as compared with standard cytogenetics, we prospectively investigated a total of 132 cases of de novo acute myeloid leukaemia (AML) (n = 121) and secondary AML after myelodysplastic syndromes (MDS) (n = 11) using a sensitive and nested PCR procedure to detect the fusion transcripts CBFbeta-MYH11. All patients were recruited within 10 months in an ongoing multicentre AML-trial. In addition, several cases from a retrospective molecular analysis were included. The data were compared with standard cytogenetics performed in a central laboratory. Of the 132 prospective AML cases, five patients (3.7%) harboured inv(16) upon conventional cytogenetics. In all cases fusion transcripts CBFbeta-MYH11 were detected using PCR. In addition in two patients fusion transcripts were detected, although cytogenetics revealed a normal karyotype. In the group of patients analysed retrospectively, four patients harboured fusion transcripts specific for CBFbeta-MYH11; cytogenetics were normal in one case, and could not be evaluated in two cases. These data show that PCR may be a better means to detect inv(16) in AML. Since inv(16) may have prognostic impact in AML, detection of this aberration seems important in the clinical management of AML patients.

Detection of karyotypic aberrations in acute myeloblastic leukaemia: a prospective comparison between PCR/FISH and standard cytogenetics in 140 patients with de novo AML.

In 140 patients with de novo acute myeloid leukaemia (AML) standard cytogenetics were compared with RT-PCR for the detection of t(8;21), t(15;17) and inv(16) and fluorescence in situ hybridization (FISH) for numerical aberrations of chromosomes 7, 8, X and Y. RT-PCR detected 18 cases with t(8;21), 12 with t(15;17) and seven with inv(16). In two cases with t(8;21), two with t(15;17) and four with inv(16) these aberrations had not been detected by standard cytogenetics. There were no false negative PCR results. In 12 patients with these chromosomal changes, standard cytogenetics revealed additional chromosomal aberrations. In 16 patients sole numerical aberrations of the chromosomes 7, 8, X or Y were found by FISH. In these patients the sensitivity of FISH and standard cytogenetics was comparable. In 87 patients no aberrations could be found by PCR and FISH whereas in 24 of these patients standard cytogenetics revealed an abnormal karyotype. These data recommend the combination of standard cytogenetics and molecular techniques to improve the sensitivity for the detection of genetic lesions in AML. Once chromosomal markers have been identified by combined analysis these markers could be used to monitor residual disease during/after chemotherapy, by RT-PCR and/or FISH.