Determinants of COVID-19 vaccination intention in Central and Eastern Europe: A cross-sectional study in Poland, Romania, and Slovenia.

BACKGROUND: Identifying predictors of vaccination intention is critical to developing appropriate programs and campaigns targeting groups reluctant to be vaccinated. This study aimed to identify the determinants of vaccination intention at the beginning of the COVID-19 pandemic in three Central and Eastern European (CEE) countries: Poland, Romania, and Slovenia. METHODS: In this cross-sectional study, a sample of unvaccinated 1723 Poles, Romanians, and Slovenians completed an online survey (April 2021). Questions included measures of vaccination intention, attitudes towards vaccines, conspiracy mindset, preference for a type of vaccine, and trust in information sources. RESULTS: The results showed that mistrust of vaccine benefits and concerns about commercial profiteering negatively predicted vaccination intention. Conversely, trust in information from medical professionals and scientists, official sources, and traditional media was positively related to vaccination intention, while trust in digital media was negatively related to vaccination intention. In addition, preference for mRNA vaccine type was a positive significant predictor of vaccination intention. The differences between countries are discussed. CONCLUSIONS: The study results deliver suggestions for developing appropriate vaccine uptake programs and campaigns that should consider presenting the positive outcomes of vaccines via official sources and traditional media based on scientific evidence and medical professionals' knowledge.

Sperm concentration, hyaluronic acid-binding capacity, aneuploidy and persistent histones in testicular cancer.

STUDY QUESTION: Are the quantitative and qualitative characteristics of semen samples of patients with testicular cancer (TC), prior to anticancer therapy, different from infertile oligozoospermic (IO) and normozoospermic (NZ) age-matched men? SUMMARY ANSWER: Sperm concentration in TC patients was significantly decreased with no difference in estimated numerical chromosome aberrations and nuclear decondensation compared with NZ men, while the infertile, oligozoospermic men had significantly poorer sperm qualitative characteristics versus the TC group overall and oligozoospermic patients with TC. WHAT IS KNOWN ALREADY: Spermatogenesis is altered in TC patients at the time of diagnosis. However, the mechanism responsible for the decreased semen quantity in patients with TC is not well understood. Anticancer treatment may have gonadotoxic side effects and post-treatment fertility cannot be predicted. Before commencing anticancer treatment, cryopreservation may be suggested to preserve fertility but there are no data regarding the risk of genetic aberrations in these sperms. STUDY DESIGN, SIZE, DURATION: This is a cross-sectional study examining semen from 28 patients with TC, 20 IO and 20 NZ age-matched men attending the Andrology Center and the Sperm Cryopreservation Laboratory of the Medical and Health Science Center, University of Debrecen. Semen samples from patients with TC were collected after orchidectomy, but prior to anticancer treatment. Semen samples from TC patients recruited over a period of 4 years were studied. Based on their sperm concentration, TC patients were subgrouped into an oligozoospermic TC (TCO) and a normozoospermic TC group. For statistical analysis, the normal group (NZ + IO) comprised non-tumorous NZ and IO men. PARTICIPANTS/MATERIALS/SETTING, METHOD: The ejaculates were assessed as per World Health Organization guidelines. Hyaluronic acid (HA)-binding capacity was the functional test. To determine the numerical chromosome aberrations, we used multi-color fluorescence in situ hybridization. Aniline blue (AB) staining was performed as a nuclear decondensation marker test. MAIN RESULTS AND THE ROLE OF CHANCE: The results did not reveal any significant difference in disomy of sex chromosomes and chromosome 17, diploidy and estimated numerical chromosome aberrations and AB staining results upon comparing the NZ and TC groups, although the sperm concentration (P < 0.001) and HA-binding capacity (P < 0.001) were lower in the TC group. Estimated numerical chromosome aberrations (P < 0.001), AB staining (P < 0.001) and HA-binding capacity (P = 0.019) were lower in the infertile, oligozoospermic group when compared with the patients with TC. The TCO group had significantly better results in every examined parameter than the infertile, oligozoospermic group. In the non-tumorous control group (NZ + IO), a significant (P < 0.001) correlation (Spearman's rho = r) was found between sperm concentration and aneuploidy rate (r = -0.642), AB staining (r = -0.876) and HA binding (r = 0.842); the HA-binding capacity was related to the aneuploidy rate (r = -0.678) and the AB staining (r = -0.811); and there was significant correlation between aneuploidy and AB staining (r = 0.559). In the TC group, apart from the negative correlation between sperm concentration and estimated chromosomal aberrations (r = -0.642), no other correlations were observed. LIMITATIONS, REASONS FOR CAUTION: Data on confounders influencing sperm characteristics, such as smoking, occupational or environmental hazards, alcoholism, co-morbidities and other andrological conditions, were not collected. WIDER IMPLICATIONS OF THE FINDINGS: This is the first study to demonstrate that sperm qualitative characteristics in anticancer therapy naïve oligozoospermic TC patients differ significantly from those in IO men and do not differ from those in NZ men. Our results need to be validated in similar groups of men and in other patient groups with cancer where cryopreservation is advisable. STUDY FUNDING/COMPETING INTERESTS: This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP-4.2.4.A/2-11/1-2012-0001 'National Excellence Program'. The authors have no conflict of interest to declare.

Anti-cytokine autoantibodies preceding onset of autoimmune polyendocrine syndrome type I features in early childhood.

PURPOSE: Almost all patients with autoimmune polyendocrine syndrome (APS)-I have high titer neutralizing autoantibodies to type I interferons (IFN), especially IFN-ω and IFN-α2, whatever their clinical features and onset-ages. About 90 % also have antibodies to interleukin (IL)-17A, IL-17F and/or IL-22; they correlate with the chronic mucocutaneous candidiasis (CMC) that affects ~90 % of patients. Our aim was to explore how early the manifestations and endocrine and cytokine autoantibodies appear in young APS-I patients. That may hold clues to very early events in the autoimmunization process in these patients. METHODS: Clinical investigations and autoantibody measurements in 13 APS-I patients sampled before age 7 years, and 3 pre-symptomatic siblings with AIRE-mutations in both alleles. RESULTS: Antibody titers were already high against IFN-α2 and IFN-ω at age 6 months in one sibling-8 months before onset of APS-I-and also against IL-22 at 7 months in another (still unaffected at age 5 years). In 12 of the 13 APS-I patients, antibody levels were high against IFN-ω and/or IL-22 when first tested, but only modestly positive against IFN-ω in one patient who had only hypo-parathyroidism. Endocrine organ-specific antibodies were present at age 6 months in one sibling, and as early as 36 and 48 months in two of the six informative subjects. CONCLUSION: This is the first study to collate the onset of clinical features, cytokine and endocrine autoantibodies in APS-I infants and siblings. The highly restricted early autoantibody responses and clinical features they show are not easily explained by mere loss of broad-specific self-tolerance inducing mechanisms, but hint at some more sharply focused early event(s) in autoimmunization.

Determination of ng/mL levetiracetam using ultra-high-performance liquid chromatography-photodiode absorbance.

This paper demonstrates the analysis of levetiracetam, a new chiral antiepileptic drug, at ng/mL levels using an ultra-high-performance liquid chromatography (UHPLC)-photodiode absorbance (PDA) method. Three different sample preparation methods, liquid-liquid extraction with Extrelut, solid phase extraction (SPE) with Oasis HLB and Oasis MAX SPE cartridges, and protein precipitation with organic solvents were carried out. The last preparatory method is the simplest and provides the best recoveries: between 97.1% and 100.4% with RSD value below 5%. The column for separation is BEH C18 column (1.7 µm particle size and 100 × 2.1 mm i.d.) and acetonitrile-phosphate buffer (pH = 6.6; 0.01 M) (10/90 v/v) is the mobile phase. The results obtained are compared to analysis conducted by the HPLC method. The UHPLC method was validated in the range of 2-100 µg/mL levetiracetam concentration (R(2) = 0.9997). LOD and LOQ are 10 ng/mL and 33 ng/mL, respectively. The developed UHPLC method was applied to plasma samples of patient with epilepsy.

The future of primary paediatric care in Europe: reflections and Report of the EPA/UNEPSA Committee.

BACKGROUND: Changes in the scope of the field of paediatrics and the variability in primary paediatric care (PPC) and practice throughout Europe motivated the European Paediatric Association and Union of National European Paediatric Societies and Associations (EPA/UNEPSA) to establish a working group to discuss definitions of paediatric coverage in terms of age limits, find common denominators in the provision of PPC and examine the challenges and goals of 21st century paediatrics relevant to the continent. These issues were presented at the 2008 Europaediatrics in Istanbul, where a consensus declaration was drawn up and accepted by the EPA/UNEPSA Executive Committee. AIM: To present an outline of the essential elements of the 2008 EPA/UNEPSA Executive Committee consensus declaration. CONCLUSION: The definition of basic characteristics and the establishment of requirements for optimal PPC and practice are important steps in overcoming the differences among European countries and pave the way for an acceptable formulation of standardized high-quality paediatric medical care in Europe.

The BOADICEA model of genetic susceptibility to breast and ovarian cancers: updates and extensions.

Multiple genetic loci confer susceptibility to breast and ovarian cancers. We have previously developed a model (BOADICEA) under which susceptibility to breast cancer is explained by mutations in BRCA1 and BRCA2, as well as by the joint multiplicative effects of many genes (polygenic component). We have now updated BOADICEA using additional family data from two UK population-based studies of breast cancer and family data from BRCA1 and BRCA2 carriers identified by 22 population-based studies of breast or ovarian cancer. The combined data set includes 2785 families (301 BRCA1 positive and 236 BRCA2 positive). Incidences were smoothed using locally weighted regression techniques to avoid large variations between adjacent intervals. A birth cohort effect on the cancer risks was implemented, whereby each individual was assumed to develop cancer according to calendar period-specific incidences. The fitted model predicts that the average breast cancer risks in carriers increase in more recent birth cohorts. For example, the average cumulative breast cancer risk to age 70 years among BRCA1 carriers is 50% for women born in 1920-1929 and 58% among women born after 1950. The model was further extended to take into account the risks of male breast, prostate and pancreatic cancer, and to allow for the risk of multiple cancers. BOADICEA can be used to predict carrier probabilities and cancer risks to individuals with any family history, and has been implemented in a user-friendly Web-based program (http://www.srl.cam.ac.uk/genepi/boadicea/boadicea_home.html).

Diagnostic significance of HLA-DQ typing in patients with previous coeliac disease diagnosis based on histology alone.

BACKGROUND: Coeliac disease is strongly associated with human leukocyte antigen (HLA)-DQ2 or DQ8 genotypes. The diagnosis is based on demonstrating crypt-hyperplastic villous atrophy, endomysial or transglutaminase antibodies and correlation of disease activity with gluten intake. AIM: To evaluate the clinical utility of HLA-DQ typing, when coeliac disease diagnosis had previously been established solely by histology. METHODS: HLA-DQ alleles, endomysial and transglutaminase antibodies were investigated and histology slides reviewed in 70 patients diagnosed 2-25 years earlier by small-intestinal biopsy but without measuring endomysial or transglutaminase antibodies. Patients without DQ2 or DQ8 or without unequivocal villous atrophy were followed-up on free diet by using serology and biopsies. RESULTS: All 40 endomysial/transglutaminase antibodies positive patients carried DQ2 or DQ8, and 39 of them had severe villous atrophy. Only 56% of patients without endomysial or transglutaminase antibodies positivity had DQ2 or DQ8 (P < 0.001). Seropositivity and relapse developed in 4 of 11 DQ2 positive but in none of 15 DQ2 and DQ8 negative patients on long-term gluten exposure. CONCLUSIONS: Coeliac disease diagnosis based solely on histology is not always reliable. HLA-DQ typing is important in identifying DQ2 and DQ8 negative subjects who need revision of their diagnosis, but it does not have additive diagnostic value if endomysial positivity is already known.

Breast and ovarian cancer risks to carriers of the BRCA1 5382insC and 185delAG and BRCA2 6174delT mutations: a combined analysis of 22 population based studies.

A recent report estimated the breast cancer risks in carriers of the three Ashkenazi founder mutations to be higher than previously published estimates derived from population based studies. In an attempt to confirm this, the breast and ovarian cancer risks associated with the three Ashkenazi founder mutations were estimated using families included in a previous meta-analysis of populatrion based studies. The estimated breast cancer risks for each of the founder BRCA1 and BRCA2 mutations were similar to the corresponding estimates based on all BRCA1 or BRCA2 mutations in the meta-analysis. These estimates appear to be consistent with the observed prevalence of the mutations in the Ashkenazi Jewish population.

Cerebral actinomycosis before adolescence.

In a 10-year-old boy presenting with focal seizures and 6 months later with acute right-sided hemiparesis, the diagnosis of a cerebral abscess due to Actinomyces israelii was established. The immunocompetent child suffered from a complex congenital heart disease with pulmonary arteriovenous shunts and pulmonary hypertension causing mild cyanosis. His parents had been reluctant to agree to neuroimaging investigations resulting in a delayed diagnosis. Despite the long interval between first symptoms and commencement of treatment including neurosurgical excision of the abscess followed by a 4-week course of ceftriaxone, a complete recovery of the hemiparesis was observed. This patient is the first case with cerebral actinomycosis before adolescence reported so far.

Somatic mutations of KIT in familial testicular germ cell tumours.

Somatic mutations of the KIT gene have been reported in mast cell diseases and gastrointestinal stromal tumours. Recently, they have also been found in mediastinal and testicular germ cell tumours (TGCTs), particularly in cases with bilateral disease. We screened the KIT coding sequence (except exon 1) for germline mutations in 240 pedigrees with two or more cases of TGCT. No germline mutations were found. Exons 10, 11 and 17 of KIT were examined for somatic mutations in 123 TGCT from 93 multiple-case testicular cancer families. Five somatic mutations were identified; four were missense amino-acid substitutions in exon 17 and one was a 12 bp in-frame deletion in exon 11. Two of seven TGCT from cases with bilateral disease carried KIT mutations compared with three out of 116 unilateral cases (P=0.026). The results indicate that somatic KIT mutations are implicated in the development of a minority of familial as well as sporadic TGCT. They also lend support to the hypothesis that KIT mutations primarily take place during embryogenesis such that primordial germ cells with KIT mutations are distributed to both testes.

Frequent methylation of p16INK4A and p14ARF genes implicated in the evolution of chronic myeloid leukaemia from its chronic to accelerated phase.

The frequency and mechanism of p16(INK4A) and p14(ARF) gene alterations were studied in cell samples from 30 patients with Philadelphia (Ph) chromosome-positive chronic myeloid leukaemia (CML), both at diagnosis and at the onset of the accelerated phase (AP) of the disease. No alterations in the p16(INK4A) or p14(ARF) genes were found in any of the chronic phase (CP) samples. DNA sequencing analyses detected p16(INK4A) or p14(ARF) mutations in 17 AP samples. All mutations were heterozygous without loss of the other allele. Aberrant methylation of the p16(INK4A) or p14(ARF) promoters was found in 14 of 30 AP samples. The most common situation was the simultaneous methylation of both promoters. Our data indicate that p16(INK4A) and p14(ARF) are primary targets for inactivation by promoter methylation in the acceleration of CML. Transcriptional silencing of the p16(INK4A) and p14(ARF) genes may be important in the conversion of CML from the CP to the AP.

Emerging roles of BRCA1 alternative splicing.

Germline mutations of the BRCA1 gene predispose individuals mainly to the development of breast and/or ovarian cancer. However, the exact function of the gene is still unclear, although the encoded proteins are involved in various cellular processes, including transcriptional regulation and DNA repair pathways. Several BRCA1 splice variants are found in different tissues, but in spite of intense investigations, their regulation and possible functions are poorly understood at the moment. This review summarises current knowledge on the roles of these splice variants and the mechanisms responsible for their formation. Because alternative splicing is now widely accepted as an important source of genetic diversity, elucidating the functions of the BRCA1 splice variants would help in the understanding of the exact role(s) of this tumour suppressor. This should help to resolve the current paradox that, despite its seemingly vital cellular functions, mutations of this gene are associated with tissue specific tumour formation predominantly in the breast and the ovary.

Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case Series unselected for family history: a combined analysis of 22 studies.

Germline mutations in BRCA1 and BRCA2 confer high risks of breast and ovarian cancer, but the average magnitude of these risks is uncertain and may depend on the context. Estimates based on multiple-case families may be enriched for mutations of higher risk and/or other familial risk factors, whereas risk estimates from studies based on cases unselected for family history have been imprecise. We pooled pedigree data from 22 studies involving 8,139 index case patients unselected for family history with female (86%) or male (2%) breast cancer or epithelial ovarian cancer (12%), 500 of whom had been found to carry a germline mutation in BRCA1 or BRCA2. Breast and ovarian cancer incidence rates for mutation carriers were estimated using a modified segregation analysis, based on the occurrence of these cancers in the relatives of mutation-carrying index case patients. The average cumulative risks in BRCA1-mutation carriers by age 70 years were 65% (95% confidence interval 44%-78%) for breast cancer and 39% (18%-54%) for ovarian cancer. The corresponding estimates for BRCA2 were 45% (31%-56%) and 11% (2.4%-19%). Relative risks of breast cancer declined significantly with age for BRCA1-mutation carriers (P trend.0012) but not for BRCA2-mutation carriers. Risks in carriers were higher when based on index breast cancer cases diagnosed at <35 years of age. We found some evidence for a reduction in risk in women from earlier birth cohorts and for variation in risk by mutation position for both genes. The pattern of cancer risks was similar to those found in multiple-case families, but their absolute magnitudes were lower, particularly for BRCA2. The variation in risk by age at diagnosis of index case is consistent with the effects of other genes modifying cancer risk in carriers.

[Genetics of renal tumors]. / Vesedaganatok genetikája.

The quintessence of malignant transformation is the genetic alteration of the tumor progenitor cell, i.e. somatic mutation. The genetic change appearing at chromosome and/or gene level results in the disturbance of the balance of cell proliferation and differentiation. In solid tumors, including renal tumors, the basic genetic mechanism proved to be the loss of function of a specific gene pair caused by loss of the particular chromosome or chromosomal region (monosomy, deletion) or by mutation of the gene. In the well studied Wilms' tumor-aniridia-syndrome the distal part of 11p13 region is deleted. The responsible gene is the WT-1 tumor suppressor gene, a Zn finger type transcription factor. In the majority of cases the mutation of this gene leads to the tumor formation without cytogenetically detectable deletion. For manifestation of the tumor the functional damage of both alleles is needed. In other histological types of renal tumors a great variation of chromosome losses and gains, as well as translocations can be identified. In Wilms tumor of embryonic origin, tumor suppressor genes located on the short arms of chromosomes 16 and 17 play a role in the pathogenesis. Besides, the significance of abnormal genomic imprinting of IGF2 and H19 genes located on 11p15 has also been confirmed. If a part of the embryonic cells do not regress, they may develop to papillary carcinoma together with the appearance of trisomies of chromosomes 7 and 17 and loss of Y. In the transformation process from papillary adenoma to carcinoma, duplication of several chromosomal regions is involved (3q+, +8, +12, +16, +20). The origin of renal carcinoma developing from normal nephron cells is associated with a deletion of 3p and 5q+, while during the progression of the disease further variable chromosome losses appear (6q-, 8p-, 14q-, -9). Tumor-specific cytogenetic and molecular genetic changes confirm the morphological classification of epithelial renal tumors pointing at the relation of the various entities or their independence. Based on cytogenetic alterations, a sequential predictive model of renal tumors can be developed. Individual types, together with joining and sequential appearance of aberrations are in line with the multistep mechanism of carcinogenesis. At the same time, the specific cytogenetic and molecular genetic changes confirm the diagnosis, provide further information about the histological type and progression of the disease. In hereditary cases, the members of the family at risk can be identified by recognizing the possibly associating clinical symptoms and/or by detecting the constitutional mutation of the gene using molecular genetic methods. Consequently, the genetic study of renal tumors plays important role not only in diagnosis and choosing adequate therapy but also in prevention of the disease.

Effect of myelopoietic and pleiotropic cytokines on colony formation by blast cells of children with acute lymphoblastic leukemia.

The aim of this study was to see whether pleiotropic or myeloid hematopoietic growth factors, which do not stimulate normal lymphoid cells, can induce proliferation of blast cells of the acute lymphoid leukemia (ALL) of childhood. Bone marrow cells of 13 children with untreated ALL (nine common ALL, two myeloid antigen positive ALL and two early T-cell ALL) formed colonies of leukemic blast cells in primary methylcellulose cultures. Spontaneous growth was observed in three of 13 cases, whereas phytohemagglutinin-stimulated leukocyte conditioned medium (PHA-LCM), a conventional source of various natural human cytokines, induced colony formation in ten of 13 cases. A similar rate of responsiveness was seen with recombinant human granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF); a combination of these three cytokines induced colony formation in all cases studied. The effect of these growth factors on colony formation seemed to be dose-dependent in some cases. Of the stimuli studied, GM-CSF induced the smallest number of colonies, whereas the effects of G-CSF, SCF and PHA-LCM were similar in this respect. Combination of cytokines proved to be even more efficient in inducing clonal proliferation of leukemic lymphoblasts. In double combinations, G-CSF and GM-CSF as well as G-CSF and SCF were able to potentiate each other's effects. Triple combination of these cytokines mediated the most potent growth stimulus. Our results demonstrate that myeloid and pleiotropic cytokines are able to stimulate clonal proliferation of pediatric leukemic lymphoblasts. This may present a potential hazard to children with ALL while on adjuvant therapy with hematopoietic growth factors. In vitro colony assays performed prior to or in parallel with the administration of hematopoietic growth factors to ALL patients may help to forecast their possible effects on leukemic cells in vivo.

Molecular genetic abnormalities in the pathogenesis of human lung cancer.

In the past few years our knowledge of the molecular pathogenesis of lung cancer has significantly increased. There are several molecular mechanisms involved in the multistage carcinogenesis through which respiratory epithelial cells become preneoplastic and then invasive cancer. In this review we summarize some of these changes including, genomic alterations such as loss of heterozygosity and microsatellite alterations, autocrine-paracrine loops, alterations in oncogenes and tumor suppressor genes, tumor angiogenesis, aberrant promoter methylation and inherited predisposition to lung cancer. Translation of these findings to the clinic is also discussed.

Allelic imbalance and microsatellite instability in BRCA1 associated breast and ovarian tumors.

We have investigated the involvement of microsatellite instability (MSI) and allelic imbalance (AI) at chromosome 13q and 17 in 41 breast and 41 ovarian carcinomas and their association with BRCA1 and BRCA2 gene mutations. MSI was detected in 20% of ovarian and 7% of breast tumors. AI at the BRCA1 locus was detected in 59% and 32% of ovarian and breast tumors, respectively. At the BRCA2 locus, AI rates were 49% and 44% for ovarian and breast tumors, respectively. Germline BRCA1 mutations, identified in 5 (12%) ovarian tumors and in one (2%) breast tumor were not associated with MSI. In only 2/5 BRCA1 positive tumors loss of the wild-type allele was observed. We conclude that BRCA1 mutation status is not associated with MSI and that MSI found in a fraction of ovarian tumors may reflect possible mutations in one of the DNA mismatch repair genes.

Constitutive intracellular expression and activation-induced cell surface up-regulation of CD44v3 in human T lymphocytes.

The cell adhesion molecule CD44 exists in multiple isoforms generated by alternative RNA splicing. Increased expression of CD44 isoforms containing exon v6 and v9 has been reported to be associated with the activated state of T lymphocytes. Using monoclonal antibodies against variant exon products we studied the expression of another variant exon, v3 on resting and in vitro activated human peripheral blood T cells. We found that CD44v3, in parallel with CD44v6, is up-regulated at the surface of normal T cells stimulated by anti-CD3 antibody or by the phorbol ester PMA, as well as on PMA-stimulated T cell leukemia lines CCRF-CEM and MOLT-4. Beside the cell surface, we demonstrated CD44v3 intracellularly in both resting and activated T cells by flow cytometry and immunomorphology. Reverse transcription-PCR and Western blot analyses confirmed the constitutive expression of CD44v3 in these cells. The increase in the cell surface expression of CD44v3 on stimulated T lymphocytes was inhibited by cycloheximide and brefeldin A, indicating the requirement of de novo protein synthesis and endoplasmic reticulum Golgi transport. Our studies establish CD44v3 as an additional activation marker for human T cells, with a yet unidentified function.

Expression profiles of BRCA1 splice variants in asynchronous and in G1/S synchronized tumor cell lines.

Disrupting the function of the BRCA1 gene by mechanisms other than germline mutations is suspected to occur in cases of sporadic breast/ovarian cancers. Using ribonuclease protection assay and multiplex RT-PCR, we examined the change of the total BRCA1 mRNA pool and the expression profile of four predominant BRCA1 splice variants in asynchronous and in G1/S synchronized tumor cell populations compared to normal breast cells. Experiments were carried out on MCF-7 and MDA-MB-231 breast cancer, OVCAR-5 ovarian cancer, and K562 leukemia cell lines. The ratio of the full length, the delta(11q), the delta(9,10), and the delta(9,10,11q) BRCA1 isoforms showed different expression patterns in the examined breast and ovarian tumor cell lines as compared to the leukemia cell line. This observation raises the possibility that the dysregulation of alternative splicing of the BRCA1 gene could be involved in tumor formation in the breast and the ovary, even in the absence of germline mutations.