Allelic loss of selected tumor suppressor genes in acute lymphoblastic leukemia in children.

Defect in function of tumor suppressor genes may lead to initiation/progression of leukemias. RB1, CDKN2A and TP53 gene alterations are found in acute lymphoblastic leukemia (ALL) in children. Data showing a contribution of these alterations to the pathomechanism of leukemias are contradictory and their impact on a disease course still remains undefined. The main aim of the study was to identify and the characterize of RB1, CDKN2A and TP53 allele loss in ALL children patients at diagnosis. 46 children with de novo ALL were examined. Fluorescent in situ hybridization was performed on bone marrow smear preparations. We demonstrated that at least one of three investigated deletions occurred statistically more frequently in T-lineage leukemia patients (p = 0.044); this was the most frequent in respect to RB1 gene (p = 0.054). Additionally, at least one of the examined deletions was observed statistically more frequently in patients with WBC above 20 000/µl (p = 0.043), this was the most frequent for CDKN2A gene (p = 0.066). Presented results seem to give an evidence that deletions of RB1 and CDKN2A genes may contribute to the development of hyperleukocytic type of T-lineage ALL in children, nevertheless this observation needs further investigations.

A common variant of CDKN2A (p16) predisposes to breast cancer.

BACKGROUND: A common missense variant of the CDKN2A gene (A148T) predisposes to malignant melanoma in Poland. An association between malignant melanoma and breast cancer has been reported in several families with CDKN2A mutations, OBJECTIVE: To determine whether this variant also predisposes to breast cancer. METHODS: Genotyping was undertaken in 4209 cases of breast cancer, unselected for family history, from 18 hospitals throughout Poland and in 3000 controls. RESULTS: The odds ratio (OR) associated with the CDKN2A allele for women diagnosed with breast cancer before the age of 50 was 1.5 (p = 0.002) and after age 50 it was 1.3 (p = 0.2). The effect was particularly strong for patients diagnosed at or before the age of 30 (OR = 3.8; p = 0.0002). CONCLUSIONS: CDKN2A appears to be a low penetrance breast cancer susceptibility gene in Poland. The association should be confirmed in other populations.

Myelodysplastic syndromes according to FAB and WHO classification. Single center experience.

The results of clinical and laboratory observations of 119 MDS patients divided acc. to FAB, and - after excluding RAEB-t and CMML groups -- of 95 patients divided accordingly to WHO classification are presented. The diagnosis of MDS was based on medical interview, physical examination, blood biochemistry, peripheral blood (PB) and bone marrow (BM) cytomorphology and cytochemistry, trephine biopsy and cytogenetic examination. All hematologic examinations were done according to routine methods. Cytogenetic analyses were carried out on BM cells from 24-48 h cultures in standard conditions. At least 15-20 GTG-banded metaphases were analyzed in every patient. The survival time (ST) of patients differed significantly between the FAB or WHO groups, with p=0.0004 for FAB and p=0.02 for WHO. The progression to AML was more common in less favorable groups, with p=0.0001 for FAB and p=0.00016 for WHO. The distribution of IPSS prognostic index among the groups showed statistically significant difference (p=0.0004 for FAB, and p=0.0001 for WHO), whereas the distribution of karyotypic abnormalities did not. However, in univariate analysis statistically significant influence on ST showed, beside the both classification systems: cytogenetics, the presence of blasts in PB, age and IPSS index. In multivariate analysis the sole independent prognostic factors were: PB blasts and cytogenetics. The authors conclude that the WHO classification offers a good prognostic tool for MDS patients. However, the karyotype and the presence of blasts in PB should always be taken into account.

Addition of cladribine to daunorubicin and cytarabine increases complete remission rate after a single course of induction treatment in acute myeloid leukemia. Multicenter, phase III study.

To assess the efficacy of an original DAC-7 regimen: daunorubicine (DNR) 60 mg/m2/day, days 1-3; cytarabine (AraC) 200 mg/m2/day, days 1-7; cladribine (2-CdA) 5 mg/m2/day, days 1-5, 400 untreated adult acute myeloid leukemia patients (including 63 with preceding myelodysplastic syndrome), aged 45 (16-60) years were randomized to either DAC-7 (n=200) or DA-7 (without 2-CdA, n=200). The overall CR rate equaled 72% for DAC-7 and 69% for DA-7 arm (P=NS). After a single course of DAC-7 induction, the CR rate equaled 64% and was significantly higher compared to 47% in the DA-7 arm (P=0.0009). Median hospitalization time during the induction was 7 days shorter for DAC-7 compared to the DA-7 group (33 vs 40 days, P=0.002). Toxicity was comparable in both groups. The probability of 3-year leukemia-free survival (LFS) for DAC-7 and DA-7 group equaled 43 and 34%, respectively (P=NS). There was a trend toward higher LFS rate for patients aged >40 years receiving DAC-7 compared with DA-7 regimen (44 vs 28%, P=0.05). This study proves that addition of 2-CdA increases antileukemic potency of DNR+AraC regimen, thus resulting in a higher CR rate after one induction cycle when compared to DA-7, without additional toxicity. It shortens hospitalization time and may improve long-term survival in patients aged >40 years.

Novel RB1 gene constitutional mutations found in Polish patients with familial and/or bilateral retinoblastoma.

Retinoblastoma is the most common intraocular malignancy in children. It is estimated that 60 percent of cases are nonhereditary and unilateral, 15% are hereditary and unilateral, and 25 percent are hereditary and bilateral. Hereditary predisposition for retinoblastoma is caused by germline mutations in the RB1 gene and is transmitted in an autosomal dominant manner. Most of the reported mutations are unique to one family, but there are sites where mutations are recurrent. We have performed RB1 gene mutation analysis in eight patients with familial and/or bilateral retinoblastoma by DNA/RNA sequencing. Constitutional mutations were found in five out of eight patients. Three mutations were novel: g.IVS7+5G>A, g.156709T>A, and g.IVS21+1G>A (p.G203-E240del, p.Y659X, and p.I703-E737del).

Karyotype and FISH analysis of a newly established cell line derived from a human bladder carcinoma.

A new human malignant urologic cell line was established in vitro from a moderately differentiated transitional cell carcinoma of the bladder and cytogenetically characterized. Repeated chromosome analyses of the cell line using conventional RHG and GTG banding and non-radioactive in situ hybridization showed a stable karyotype with a modal number of 48 and chromosomal rearrangements, some of which have not been previously described. Numerical deviation included three trisomies (+7, +8, +9) and one nullisomy (-19, -19). Structural changes involved a balanced translocation (1;5)(q12;q12), an isochromosome 3q, a 14p+, and two markers. Fluorescence in situ hybridization (FISH), using biotin-labeled alpha satellite probes for chromosome 9 or painting for chromosomes 1 and 8, applied to interphase nuclei or metaphases showed similar results to those found by conventional cytogenetic study. This cell line may be an interesting model for fuller characterization by molecular biology studies and for testing anti-cancer drugs in vitro.

The genes of interferons and interferon-related factors: localization and relationships with chromosome aberrations in cancer.

The paper presents a review of data on the localization of interferons (IFNs) and IFN system genes and their relationship with human diseases, mainly cancer. Genes of interferon system proteins are located at the sites of breakpoints of the structural chromosome aberrations in cancer. Thus, any of them are rearranged or translocated in various tumor types. As the activity of these genes plays a role in cancer development, their rearrangements may be one of the crucial points in the pathogenesis of some cancer types. Besides, they also take part in organism immunity against viral infections. Transfection experiments with IFN system genes have proved the influence of these genes on cancer behavior and may serve as a basis for clinical gene therapy. IFN-alpha and IFN-beta genes are located at 9p21-22, the site of frequent homozygotic deletions in cancer. Their loss sensitizes cells to the growth inhibitory actions of exogenous IFNs. The IFN-gamma gene, a representative of class II genes, is located at 12q24.1. Transfection of class II IFNs genes to cancer cell lines causes cell proliferation arrest and augments the expression of HLA antigens, which may be clinically useful in stimulating the immune destruction of tumor cells. The interferon regulatory factor 1 (IRF-1) gene is located at 5q31, the site of common deletions in myelodysplastic syndromes (MDS) and secondary leukemias. The loss of heterozygosity of this gene was found in MDS, which proves that IRF-1 may be a tumor suppressor. A transfection of its gene causes neoplastic transformation arrest. The double-stranded RNA-activated protein kinase (PKR) gene is located at 2p21-22, a region which is frequently rearranged in leukemia. Transfection of a wild type PKR gene reverses neoplastic transformation caused by transfection of a mutated PKR gene, proving that PKR acts as a dominant negative cancer suppressor.

[Cytogenetic analysis in couples with spontaneous abortions]. / Badania cytogenetyczne u malzenstw z poronieniami samoistnymi.

Cytogenetic studies were performed in 129 couples with the history of recurrent spontaneous miscarriages. In 8 couples (6.2%) chromosome aberrations were found The most frequent aberrations were reciprocal translocations (in 6 couples). Pericentric inversion of chromosome 9 was detected in 3 couples (2.3%) while the chromosome polymorphism was observed in 20% of analyzed cases.

[Chromosome aberrations in chronic myeloid leukemia]. / Aberracje chromosomów w przewleklej bialaczce szpikowej.

Chromosome Philadelphia is a cytogenetic marker of chronic myeloid leukemia. It results from a translocation t(9;22) or other, more complex, translocations. Before the onset of blastic crisis, secondary aberrations occur, the most often--trisomy 8, isochromosome 17q and extra Ph chromosome. Their presence has a prognostic significance. Particular aberrations may occur in association with determined haematological and clinical features.

[Chromosome localization of cytokine genes. Correlation with cytogenetic changes in hematologic neoplasms]. / Chromosomowa lokalizacja genów dla cytokin. Korelacje ze zmianami cytogenetycznymi w nowotworach ukladu krwiotwórczego.

Localization of genes coding for cytokines and their receptors correlates frequently with breakpoints of chromosome aberrations in leukemogenesis and particular clinical and hematologic symptoms. In some cases a rearrangement of these genes and its relationship with disease course were proved.

[Chronic myeloid leukemia without Philadelphia chromosome (Ph-negative CML)]. / Przewlekla bialaczka szpikowa bez obecnosci chromosmu Filadelfia (Ph-ujemna pbs).

Ph-negative chronic myeloid leukemia [Ph(-)CML] is a heterogenous group of conditions characterized by similar cytogenetic pattern but variable changes at the molecular level. All cases with BCR gene rearrangement in this group have clinical and haematological course similar to Ph(+)CML. However, CML without rearrangements of ABL and BCR genes, called "atypical CML", forms a separate entity showing clinical and morphological features different from classical CML.

[Lymph node involvement as a primary localization of extramedullary blast crisis of chronic granulocytic leukemia (PBS)]. / Zajecie wezlów chlonnych jako pierwotna, pozaszpikowa lokalizacja przelomu blastycznego przewleklej bialaczki szpikowej (PBS).

Among 28 patients with blastic crisis of chronic granulocytic leukemia (CGL) its primary symptom in four persons was lymph nodes enlargement. In two of them histopathologic examination confirmed myeloblastic infiltration. Lymph nodes involvement appeared 1-7 months before the onset of blastic transformation in peripheral blood and bone marrow: myeloblastic in two patients, promyelocytic in one and lymphoblastic myeloblastic (bi-phenotypic) in one. Survival time from nodal infiltration was 8-16 months and from the diagnosis of CGL 16-105 months. Remission of the disease after first blastic crisis was achieved in three patients. Cytogenetic examinations disclosed double Ph chromosome in three and single Ph chromosome in one patient.