Targeted therapeutics in treatment of children and young adults with solid tumors: an expert survey and review of the literature

Although prognosis of children with solid tumors is steadily improving, long-term survival is not achievable in all patients, especially in patients with recurrent or refractory disease. Despite the increasing number of targeted therapeutics (TT), only very few TT have been introduced into clinical protocols. Accordingly, clinical experience concerning the efficacy and safety of these drugs is limited. This may possibly discourage oncologists from administering TT to children.We performed a comprehensive review of the literature to identify TT that may be considered for treatment of children and young adults with solid tumors. Moreover, we interviewed an expert panel of the Society for Pediatric Oncology and Hematology (GPOH) using questionnaires in a modified Delphi process in order to describe the experts' experiences in the use of these TT.Among 30 TT identified to be possibly useful in children and young adults, imatinib, bevacizumab and rapamycin were most widely used. These drugs were reported as having mostly little to no severe adverse events and seem to induce at least partial responses in a subset of patients. In addition, our study confirms and expands the present knowledge about adverse events and the potential efficacy of 5 other commonly used TT in this population.This information may be useful for oncologists when administering these TT to children and young adults with solid tumors. Controlled clinical trials are urgently needed to test their safety and efficacy.

DNA methylation pattern of brain stem pilocytic astrocytomas in children

10021

Background: Pilocytic astrocytoma (WHO grade I) comprises the most frequent brain tumor in childhood. We were recently able to identify BRAF as a centrally important oncogene in these tumors showing duplication or activation in a majority of cases. Although histologically indistinguishable, tumors with brain stem location have a particularly poor prognosis. It is not well established, whether this is due to their close proximity to pivotal anatomic sites or due to distinct biological characteristics. Methods: To identify novel genes involved in astrocytoma pathogenesis, we performed a genome-wide DNA methylation analysis of 78 pilocytic astrocytoma samples from different tumor locations (diencephalic, cerebral, cerebellar, brain stem). BeadChip methylation technology was used to identify genes showing differential promoter methylation among tumors. Two CpG sites were analyzed for each of a total of 14.000 promoters per sample. Clinical and molecular subgroups were compared using Significance Analysis of Microarrays (SAM). Results: In this genome-wide approach, we identified an 11-gene signature that was able to correctly separate all brain stem tumors (n = 8) from the majority of tumors from other locations (56/70). Moreover, from 14 tumors clustering together with the brain stem tumors, 5 patients experienced disease recurrence (38%) as opposed to 20% in the remaining group. Genes contained in the signature most interestingly included three homeobox family genes (HOXB1, HOXD3, and HOXD4), and NES, a tumor stem cell marker. Conclusions: These data suggest that brain stem pilocytic astrocytomas display biologic features different from most tumors of other locations and share a methylation signature with tumors prone to disease recurrence from other locations. We provide first evidence for a role of differentially methylated homeobox family genes in the pathogenesis of pilocytic astrocytoma.

No significant financial relationships to disclose.

Use of CDK6 oncogene amplification and 17q gain to predict poor clinical risk groups in adult medulloblastoma

2030

Background: While in children medulloblastoma comprises the most common malignant brain tumor, it accounts for only 1% of intracranial malignancies in adults. The infrequent appearance of MB in adults poses the question, whether these tumors are the same in adults and children in terms of biological and clinical peculiarities. Methods: Array-CGH was performed for a total 34 adult medulloblastoma samples (>18 years) and results were compared with data from 101 pediatric patients. Selected genomic regions were further investigated by FISH analysis in an independent cohort of 415 samples (112 adult and 303 pediatric). All 146 adult patients received a standard treatment regimen consisting of tumor resection, irradiation of the neuroaxis with 36 Gy, a boost of 20–23 Gy to the posterior fossa, and eight cycles of vincristin, lomustine, and cisplatin. To identify novel prognostic markers, DNA copy-number information was correlated with survival data using log rank and chi-square tests. Results: Copy-number gains of chromosome 17q as well as high-level amplifications of CDK6 were identified as significant adverse prognostic markers in adult medulloblastoma. Apart from one exception, CDK6 amplifications were only observed in adult patients (9% in adults versus 0.2 % in children), whereas amplifications of MYC or MYCN were significantly overrepresented in the pediatric cohort, but when present were also associated with dismal prognosis in adults. Monosomy of chromosome 6, in contrast to the pediatric cohort, was not significantly associated with good prognosis, although nuclear ß-catenin accumulation was detected in most cases (r = 0.68). Based on these results, we propose a molecular staging system for adult medulloblastoma: i) cases with oncogene amplification (10% of cases, 5-year OS = 0%); ii) cases with chromosome 17q gain without oncogene amplification (25% of cases, 5-year-OS = 35%); and iii) cases without oncogene amplification or 17q gain (65% of cases, 5-year OS = 92%). Conclusions: We report on the largest cohort of adult medulloblastoma investigated for genomic imbalances to date. We propose a model for the molecular risk stratification of adult medulloblastoma comprising three distinct genomic risk groups with significantly different survival and tumor biology.

No significant financial relationships to disclose.

Molecular risk stratification in pediatric medulloblastoma

9506

Background: Medulloblastoma is the most common malignant brain tumor and a significant cause of cancer mortality in children. Despite considerable therapeutic advances, prognosis remains poor, with a five-year-survival rate of about 60% emphasizing the urgent need for markers to allow for a more accurate tailoring of treatment intensity. Methods: We performed genome-wide analysis of DNA-copy number in 112 medulloblastomas using array-CGH. All patients had received craniospinal irradiation after surgery. Standard adjuvant chemotherapy with lomustine, cisplatin and vincristine or a regimen with equal potency had been administered to 73 patients. To identify novel prognostic markers, DNA copy number information was correlated with survival data using log rank and chi-square tests. For selected candidate genes identified by array-CGH, mRNA and protein expression were analyzed by real-time quantitative PCR, and immunohistochemically on tissue microarrays consisting of medulloblastomas from 189 patients. Results: Copy-number gains of chromosomes 6 and 17q, high-level amplifications of MYC and MYCN, and loss of 9p21.3 (CDKN2A locus) were identified as significant adverse prognostic markers; monosomy 6 was associated with good prognosis. Monosomy 6 and gain of 17q were mutually exclusive, whereas trisomy 6 almost always occurred in conjunction with 17q gain. Tumors with trisomy 6 and 17q gains exhibit strong up-regulation of MAP3K7 (chr. 6) and NLK (17q) mRNA, two key-enzymes of the non-canonical calcium-dependent Wnt-signaling pathway. Furthermore, this subgroup exclusively shows high mRNA-expression of several cancer-retina antigens (e.g. GNGT1, GNGT2, PDE6, RCV1, RDS and NRL). Tumors with monosomy 6, in contrast, display highly activated canonical Wnt signaling as indicated by nuclear protein expression of beta-catenin. Conclusions: We propose a model for the molecular risk stratification of medulloblastoma comprising five risk groups with significantly different survival using copy-number status of MYC, MYCN, and chromosomes 6 and 17q. Furthermore, we give evidence for a role of noncanonical calcium-dependent Wnt-signalling in medulloblastoma metastasis in a subset of tumors. Cancer-retina antigens could be used to facilitate the diagnosis and follow-up of this molecular subgroup.

No significant financial relationships to disclose.

Further evidence for a somatic KRAS mutation in a pilocytic astrocytoma

Astrocytomas are the most common brain tumors of childhood. However, knowledge of the molecular etiology of astrocytomas WHO grade I and II is limited. Germline mutations in the Ras-guanosine triphosphatase-activating protein, neurofibromin, in individuals with neurofibromatosis type I predispose to pilocytic astrocytomas. This association suggests that constitutive activation of the Ras signaling pathway plays a fundamental role in astrocytoma development. We screened 25 WHO I and II astrocytomas for mutations of PTPN11, NRAS, KRAS, and HRAS genes and identified the somatic G12A KRAS mutation in one pilocytic astrocytoma. These data suggest that Ras is rarely mutated in these tumors. Analyzed astrocytomas without mutations in Ras or neurofibromin may harbor mutations in other proteins of this pathway leading to hyperactive Ras signaling.

Screening molekularbiologischer Marker zur Risikostratifizierung bei Medulloblastomen

BACKGROUND

The present study evaluates molecular markers for patients at risk of poor or no response to medulloblastoma. The aim of the study is to optimize therapy stratification.

PATIENTS AND METHODS

69 snap-frozen medulloblastoma samples were examined. C-MYC amplification was determined by fluorescence in situ hybridisation (FISH) analysis. Methylation specific PCR revealed the level of promoter methylation status of the tumor suppressor genes CASP8 (Caspase 8), TIMP3, CDH1 (E-Cadherin), CDKN2A (p16) and MGMT. Expression of GAS7 was evaluated by RT-PCR.

RESULTS

C-MYC amplification: 4/69 tumors displayed high level amplification; 53/69 tumors displayed low level (< 4 copies) or no amplification; 12/69 samples were not predictive. In patients with c-MYC amplification a tendency towards unfavorable outcome was observed (p = 0.3). Promoter methylation status: CASP8: in 36/40 tumors methylated; TIMP3: 1/38 methylated; MGMT 0/44 methylated; CDKN2A: 1/46 methylated; E-cadherin 3/36 methylated; no association between methylation status and clinical outcome. GAS7: Detection of specific RNA in 20/29 medulloblastoma samples.

CONCLUSION

No significant association between amplification of c-MYC and clinical outcome was observed. Promoter methylation of tumor suppressor genes is non-randomly distributed with a high level of methylation of CASP8. Recent studies show that silencing of CASP8 by methylation could be overcome by interferon gamma providing a possible therapeutic mechanism. GAS7 was shown to be a marker of mature neuronal cells with potential antitumorigenic capacity in neuronal tumors. In medulloblastoma 20/29 of the tumors examined express GAS7. Therefore a tumor suppressing function of GAS7 is improbable.

Neonatal mastocytosis with pachydermic bullous skin without c-Kit 816 mutation

BACKGROUND

Bullous mastocytosis is an unusual variant of mast cell disease with widespread bullae as the main cutaneous feature induced by mast cell proteases that cause dermoepidermal separation.

CASE REPORT

A rare case of diffuse cutaneous bullous mastocytosis with pachydermia and unusually extensive skin folding is described in a 3-week-old girl. The diagnosis was confirmed by immunohistochemistry with Giemsa stain, the naphthol ASD chloroacetate esterase reaction and elevated blood levels for tryptase, histamine in serum and histamine and 1.4-methylimidazol acetic acid in the 24-hour urine. Blood cell count was normal, as were thrombocytosis and leukocytosis. FACS analysis of the bone marrow aspiration material showed 1% mast cells. No c-Kit 816 [Asp-->Val] somatic mutation was found. Systemic involvement of other organs was excluded.

DISCUSSION

The prognosis of c-Kit-negative diffuse bullous mastocytosis is not known. Regular blood controls are mandatory, and screening for germ cell ovarian cancer and bone marrow controls should be performed as well.

No aberrant methylation of neurofibromatosis 1 gene (NF1) promoter in pilocytic astrocytoma in childhood

Tumors of the central nervous system are the most frequent solid tumors in childhood. With 30-40% of this heterogenous group, low-grade astrocytomas represent the most common subtype. Neurofibromatosis type 1 (NF1) is strongly associated with the development of pilocytic astrocytoma (PA), frequently appearing as optic glioma. Neurofibromatosis 1 gene (NF1 ) fulfills the criteria of a tumor suppressor gene and is deleted or mutated heterozygously in patients with NF1. This suggests an involvement in the development of PA. To clarify whether silencing of NF1 by promoter methylation plays a role in PA and especially in optic glioma, the authors investigated the methylation status in 30 PA, 6 of which had optic glioma. However, no methylation was found at the NF1 promoter region in PA. To rule out that silencing of NF1 by promoter methylation is restricted to higher-grade astrocytomas, 15 pediatric WHO II degree and IV degree astrocytomas were analyzed: 12 astrocytomas II and 3 glioblastomas displayed no NF1 promoter methylation. The authors conclude that NF1 silencing by methylation plays no role in low-grade astrocytoma.

Mycoplasma pneumoniae associated organising pneumonia in a 10 year old boy

We describe a 10 year old boy with organising pneumonia associated with acute Mycoplasma pneumoniae infection. The diagnosis of organising pneumonia was made by open lung biopsy and the M pneumoniae infection was proven serologically. Antibiotic and long term corticosteroid treatment resulted in steadily improving pulmonary function monitored by spirometry. The introduction of anti-inflammatory treatment with NSAIDs/immunosuppressive agents in order to spare steroids was well tolerated and resulted in further improvement of the pulmonary function. To our knowledge this is the first documented case of Mycoplasma pneumoniae associated organising pneumonia to be reported in a child.

Isochromosome 1q as an early genetic event in a child with intracranial ependymoma characterized by molecular cytogenetics

Data concerning cytogenetic features of childhood ependymoma are rare. In this article, a gain of 1q was identified as the sole alteration in a primary childhood infratentorial ependymoma by comparative genomic hybridization (CGH). A recurrence of this brain tumor was studied using multiplex-fluorescence in situ hybridization (M-FISH) in addition to CGH and G-banding analysis. In accordance with the primary tumor, a gain of 1q corresponding to an isochromosome 1q was observed indicating an early event in the tumor development. Furthermore, M-FISH classified several other rearranged chromosomes including 6q and 17p that have previously been found to be involved in the development and progression of childhood ependymoma.

Identification of seven novel mutations including the first two genomic rearrangements in SLC26A3 mutated in congenital chloride diarrhea

Congenital chloride diarrhea (CLD) is an autosomal recessive disorder characterized by defective intestinal electrolyte absorption, resulting in voluminous osmotic diarrhea with high chloride content. A variety of mutations in the solute carrier family 26, member 3 gene (SLC26A3, previously known as CLD or DRA) are responsible for the disease. Since the identification of the SLC26A3 gene and the determination of its genomic structure, altogether three founder and 17 private mutations have been characterized within miscellaneous ethnic groups. We screened for mutations in seven unrelated families with CLD. The diagnoses were confirmed by fecal chloride measurements. The combined PCR-SSCP and sequencing analyses revealed altogether seven novel mutations including two missense mutations (S206P, D468V), two splicing defects (IVS12-1G>C, IVS13-2delA), one nonsense mutation (Q436X), one insertion/deletion mutation (2104-2105delGGins29-bp), and an intragenic deletion of SLC26A3 exons 7 and 8. Two previously identified mutations were also found. This is the first report of rearrangement mutations in SLC26A3. Molecular features predisposing SLC26A3 for the two rearrangements may include repetitive elements and palindromic-like sequences. The increasingly wide diversity of SLC26A3 mutations suggests that mutations in the SLC26A3 gene may not be rare events.

Detection of chromosomal imbalances in leiomyosarcoma by comparative genomic hybridization and interphase cytogenetics

Leiomyosarcomas comprise a group of malignant soft-tissue tumors with smooth-muscle differentiation. In this study, 14 cases of leiomyosarcoma were screened for changes in relative chromosome copy number by comparative genomic hybridization. A high number of imbalances (mean, 16.3; range, 6-26) was detected, with chromosomal gains occurring about twice as much as losses. The most frequent gains were found in 5p15, 8q24, 15q25-->q26, 17p, and Xp (43% to 50%), whereas the most frequent losses were found in 10q and 13q (50% and 78%, respectively). Twenty high-level amplifications affecting 15 different chromosomal subregions were detected in nine different tumors. In three leiomyosarcomas, sequences on chromosome arm 17p were found to be highly amplified, with a minimal overlapping region on subbands 17p12-->p11. We further discovered that the Smith-Magenis syndrome critical region on 17p11.2 is included in the 17p amplicons of two leiomyosarcoma cases. Using probes flanking this genetically unstable region, a mean of 14 and 22 signals per nucleus, respectively, was detected in both leiomyosarcomas by fluorescence in situ hybridization. In conclusion, this analysis identifies a number of characteristic chromosomal imbalances in leiomyosarcomas and provides evidence for the localization of potential oncogenes and tumor suppressor genes active in leiomyosarcoma genomes.

Chronic autoimmune thrombopenia/neutropenia in a boy with persistent parvovirus B19 infection

OBJECTIVE

We report an 11-year-old boy presenting with splenomegaly, chronic thrombocytopenia and concordant neutropenia.

RESULTS

In contrast to autoantibodies against platelets, there were no detectable neutrophil-specific autoantibodies present in this patient. Extensive serologic investigations revealed increased IgM- and IgG-antibody titers against parvovirus B19. A nested polymerase chain reaction (PCR) showed parvovirus B19-specific sequences in the patient's bone-marrow cells but not in the serum. Specific antibodies against the structural proteins VP1 and VP2 in addition to those against non-structural protein NS1 of parvovirus B19 were detected by Western blot analysis. Thrombocytopenia and neutropenia responded to immunosuppressive therapy and subsequent splenectomy, the latter being necessary due to severe side-effects of steroid medication.

CONCLUSION

Autoimmune thrombocytopenia/neutropenia may have been triggered and/or sustained by a chronic parvovirus B19 infection. Patients with this very rare disorder should be screened for this virus.

Preradiation chemotherapy of children and young adults with malignant brain tumors: results of the German pilot trial HIT'88/'89

BACKGROUND

Preradiation chemotherapy could be beneficial in malignant brain tumors, because the blood-brain tumor-barrier is disrupted after surgery, bone marrow recovery--essential for intense chemotherapy--is still intact, and CNS toxicity and ototoxicity of active drugs are lower before irradiation of a child's brain.

PATIENTS AND METHODS

A neoadjuvant phase 2 and a single arm pilot trial were initiated to investigate the efficacy and toxicity of an intense multidrug regimen before radiotherapy in 147 patients aged between 3 and 29; 9 years with medulloblastoma (94), malignant glioma (22), ependymoma (21), and stPNET (10). They were treated with one or two cycles consisting of procarbazine, ifosfamide/mesna with etoposide, high dose methotrexate/CF, and cisplatin with cytarabine.

RESULTS

Radiation therapy was delayed for 17-30 weeks (median 23 weeks) in 112 patients who received two cycles. Chemotherapy was well tolerated. Serious infections were observed in 20 patients, with one fatal fungal septicemia. In 69 high risk patients with a residual tumor and/or solid CNS metastases an objective response (CR plus PR) was achieved in 67% medulloblastoma, 57% stPNET, 55% anaplastic ependymoma and 25% malignant glioma. Progression-free survival (PFS) at 5 years was 57% in 14 high risk patients with medulloblastoma, who achieved a complete response (CR). After a less than CR the PFS was 20% (p = 0.01). Overall survival at 5 years was 57% in medulloblastoma, 62% in ependymoma, 36% in malignant glioma and 30% in stPNET.

CONCLUSION

The HIT'88/'89 regimen was well tolerated and efficacious in regard to response rates and early PSF particularly in medulloblastoma and anaplastic ependymoma. Based on these results the prospectively randomized trial HIT'91 was designed to investigate the optimal timing of chemotherapy. Preradiation chemotherapy according to the HIT'88/'89 regimen was compared with the standard regimen using CCNU, cisplatin, and vincristine after radiation therapy. Additionally, strict quality control of the three treatment modalities was instituted to help improve the survival rates in both trial arms.

Current diagnostic and therapeutic management of CNS metastasis in childhood primitive neuroectodermal tumors and ependymomas

Metastatic disease is a major problem in the management of the most frequent childhood brain tumors, in ependymoma and primitive neuroectodermal tumors (PNET). Today, contrast enhanced craniospinal MRI and careful analysis of craniospinal fluid are a prerequisite for correct staging of both tumors and imply therapeutic consequences. So far metastatic spread of medulloblastoma and some ependymomas is prevented by conventional chemotherapy and radiotherapy. However, some forms of diffuse metastatic dissemination in medulloblastoma are resistant to conventional therapeutic regimens and require new experimental strategies.

Bilateral zonular cataract associated with the mitochondrial cytopathy of Pearson syndrome

PURPOSE

To report a child with the mitochondrial cytopathy of Pearson syndrome and zonular cataract.

METHOD

Case report. We describe a 6-year-old boy with Pearson syndrome.

RESULTS

At age 3 years, the boy developed secondary strabismus caused by bilateral zonular cataract. Subsequently, he underwent successful bilateral cataract extraction with intraocular lens implantation. Postoperative visual acuity with best correction was RE, 20/25 and LE, 20/40.

CONCLUSIONS

Children with Pearson syndrome should be examined ophthalmologically to rule out zonular cataract and possible amblyopia. Mitochondrial cytopathies such as Pearson syndrome should be included in the differential diagnosis of congenital and early juvenile cataract.

Foamy virus vectors for suicide gene therapy

To improve the delivery of so-called suicide genes into tumors, recombinant retroviruses were constructed by inserting the herpes virus type 1 (HSV-1) thymidine kinase (tk), the E. coli cytosine deaminase (cd) and polynucleoside phosphorylase (pnp), or the jellyfish gene for the green fluorescent protein (gfp) into a foamy virus (FV)-derived replication-competent vector (pFOV-7). Expression and stability of the inserted foreign gene was analyzed by immunoblot and polymerase chain reaction (PCR). The functionality of the suicide genes was determined by a metabolic assay on virus vector infected cells and treatment with the respective prodrugs. In terms of vector stability and effectiveness of specific cell killing a virus transducing the pnp gene (FOV-7/pnp) was superior to those using the other two suicide genes. FOV-7/pnp is a candidate virus for suicide gene delivery into solid tumors.

DMBT1, a new member of the SRCR superfamily, on chromosome 10q25.3-26.1 is deleted in malignant brain tumours

Loss of sequences from human chromosome 10q has been associated with the progression of human cancer. Medulloblastoma and glioblastoma multiforme are the most common malignant brain tumours in children and adults, respectively. In glioblastoma multiforme, the most aggressive form, 80% of the tumours show loss of 10q. We have used representational difference analysis to identify a homozygous deletion at 10q25.3-26.1 in a medulloblastoma cell line and have cloned a novel gene, DMBT1, spanning this deletion. DMBT1 shows homology to the scavenger receptor cysteine-rich (SRCR) superfamily. Intragenic homozygous deletions has been detected in 2/20 medulloblastomas and in 9/39 glioblastomas multiformes. Lack of DMBT1 expression has been demonstrated in 4/5 brain-tumour cell lines. We suggest that DMBT1 is a putative tumour-suppressor gene implicated in the carcinogenesis of medulloblastoma and glibolastoma multiforme.

Molecular analysis of medulloblastomas occurring simultaneously in monozygotic twins

We report male monocygotic twins with concordant desmoplastic medulloblastoma diagnosed at the age of 20 months. Both tumours were completely removed. As chromosomal loci 17p13 and 9q31 are frequently altered in medulloblastoma these regions were analysed in both tumours in detail using restriction fragment length polymorphism and microsatellite analysis. No common aberration was found. The c-myc gene on chromosome 8q21 was not amplified.

CONCLUSION

Although a common genetic defect has not been found in our patients' tumours the clinical presentation supports the assumption of an inherited genetic predisposition to develop medulloblastoma in at least some cases.

Mapping of chromosomal gains and losses in primitive neuroectodermal tumors by comparative genomic hybridization

A series of 18 primitive neuroectodermal tumors (PNETs), the most common malignant central nervous system tumors of childhood, were analyzed with the recently developed approach of comparative genomic hybridization (CGH). In five cases, in which only small amounts of DNA were available, universal polymerase chain reaction was successfully applied to generate adequate probe material. In 15 tumors, chromosomal imbalances were elicited, most frequently involving chromosome 17 (loss of 17p and gain of 17q). Further recurrent imbalances included gains of the distal regions of 4p, 5p, 5q, 7q, 8q, and 9p. High-level amplifications were found on 2p24 (one case) and 8q24 (three cases), suggesting involvement of the protooncogenes MYCN and MYC, respectively. In one of these cases, Southern blot analysis could be performed, proving high-copy-number amplification of MYC. Interestingly, none of the three patients with high-copy-number amplifications of MYC responded to therapy.

Severe low-titer cold-hemagglutinin disease responsive to steroid pulse therapy

We report the case of a 12-year-old boy suffering from severe low-titer cold-hemagglutinin disease with excruciating colicky abdominal pain, jaundice, and acute hemolytic anemia requiring transfusion. Cold hemagglutinins of the IgM type and a positive direct antiglobulin test, predominantly against C3d, were found. Steroid pulse therapy with 20 mg/kg body wt. methylprednisolone for 3 consecutive days was given. Abdominal pain disappeared within 12 h of the first steroid infusion and hemolysis was halted. We conclude that a therapeutic trial with steroid pulse therapy in severe low-titer cold-hemagglutinin disease is warranted.

Spontaneous hematological remission in a boy with myelodysplastic syndrome and monosomy 7

We report the case of a 14-month-old boy with myelodysplastic syndrome (refractory anemia with blast excess) and bone marrow monosomy 7. Within 2 years after presentation hematological remission gradually occurred without any chemotherapy. After the patient had received three transfusions within the first 4 months, red cell production normalized. However it took 18 more months for neutropenia to resolve. The patient is well 34 months after the first presentation. Molecular analysis of the bone marrow blasts showed no mutations of the ras genes or of the FLR-exon of the NF-1 gene. To our knowledge this is the first report of monosomy 7 syndrome with spontaneous hematological remission.

Polymerase chain reaction-amplification of urease genes: rapid screening for ureaplasma urealyticum infection in endotracheal aspirates of ventilated newborns

Ureaplasma urealyticum infection has been considered to play an important role in the development of bronchopulmonary dysplasia (BPD) in premature infants. Since standard culture methods of U. urealyticum are difficult to perform, new rapid and sensitive methods are needed to detect lung infection of ventilated newborns. Here we describe the polymerase chain reaction as a rapid method to screen endotracheal aspirates for ureaplasma infection. Urease-specific sequences could only be detected in 1 out of 36 ventilated newborns. The procedure described in this paper may facilitate further studies to determine the role of U. urealyticum in development of BPD.

[Tumor suppressor genes: occurrence, significance and function]

Tumor-suppressor-genes were detected by DNA-analysis of childhood tumors. A homozygous deletion or mutation of these genes is closely associated with different malignant tumors. Tumor-suppressor-genes seem to play an important role in cellular development and differentiation. The understanding of this pathomechanism in cancerogenesis is most important for calculating a genetic risk for tumor development.

[Diagnosis of monozygosity in multiple births by DNA fingerprinting]

The incidence of monozygotic twins is one in 250 pregnancies. Triplets are estimated to occur in 1 of 86(2) pregnancies. Determination of zygosity may be done by comparison of physical characteristics, blood group or tissue typing, chromosome studies, or examination of various other polymorphic protein markers. Here we describe the differentiation between monozygotic and dizygotic twins and triplets by DNA-fingerprinting. This is a fast, non-invasive and reliable (error probability 0.003%) method to determine monozygosity of twins or triplets. It is also a reliable paternity test.

Rearranged HPV 16 molecules in an anal and in a laryngeal carcinoma

By hybridization under stringent conditions, one out of two anal carcinomas and one out of 36 laryngeal carcinomas were shown to harbor HPV 16 DNA in high copy number. Further analysis of both tumor DNAs indicated a rearrangement of the viral DNA in the tumor cells. HPV 16 DNA in the anal carcinoma could chiefly be found episomally in two different forms: a minority as 7.9-kb oligomeric episomes with no apparent modifications; as 10.7-kb rear-ranged oligomeric episomes with a duplication of the part of the viral genome encoding the open reading frames (ORF) E7, E1 and parts of E6 and E2. In the laryngeal carcinoma, integrated and episomal HPV 16 DNA molecules of 7.9 kb were present, together with rearranged molecules of approximately 18 kb with multiple duplications of the ORF E4 and parts of the ORFs E2, E5, L1 and L2. Possible consequences for transcription of the modified viral genomes are discussed.

Molecular cloning of two new HPV types (HPV 37 and HPV 38) from a keratoacanthoma and a malignant melanoma

Several benign and malignant skin tumors were analyzed for the presence of human papillomavirus (HPV) DNA. By hybridization with different HPV DNA probes under non-stringent conditions (Tm -40 degrees C), two tumors were found to contain HPV-specific DNA sequences in high copy numbers: (1) a keratoacanthoma from a patient who also suffered from a basalioma; (2) a superficial spreading malignant melanoma of an immunosuppressed patient. For further analysis of these DNA sequences genomic libraries from both tumor DNAs were constructed and, out of these, 4 different HPV DNA types have been cloned. By cross-hybridization experiments and restriction map analysis HPV 9 DNA was identified in the keratoacanthoma whereas HPV 17a DNA could be cloned from the malignant melanoma. From each tumor one additional HPV-type not identical to other known HPV-types was cloned. These isolates are closely related to HPV 9, 15, 17, 22 and 23. A physical map of both HPV DNAs was constructed. Size (7.8 kbp), co-linear alignment to HPV 16, cross-hybridization with other HPV-types under conditions of low stringency and monomeric episomal state of the HPV molecules indicate that these two DNA probes represent new HPV types that have been tentatively designated as HPV 37 (keratoacanthoma) and HPV 38 (malignant melanoma). None of these two HPV types could be found in any other of 231 tumor DNAs originating from different tissues.

A new type of papillomavirus DNA, its presence in genital cancer biopsies and in cell lines derived from cervical cancer

DNA of a new papillomavirus type was cloned from a cervical carcinoma biopsy. Two EcoRI clones of 7.8 and 6.9 kb in length were obtained, the latter contained a 900-bp deletion. The BamHI fragments of both clones were used to characterize the DNA. It represents a distinct type of papillomavirus as determined by its size, its cross-hybridization with DNA of other papillomavirus types under conditions of low stringency only, the co-linear alignment of its genome with HPV 6 and HPV 16 prototypes and its occasional occurrence as oligomeric episomes. We tentatively propose to designate it as HPV 18. DNA hybridizing with HPV 18 under stringent conditions was detected in 9/36 cervical carcinomas from Africa and Brazil, in 2/13 cervical tumors from Germany and 1/10 penile carcinomas. Benign tumors (17 cervical dysplasias, 29 genital warts), eight carcinomata in situ and 15 biopsies of normal cervical tissue were devoid of detectable HPV 18 DNA. HPV 18-related DNA was found, however, in cells of the HeLa, KB and C4-1 lines all derived from cervical cancer. The state of the viral DNA was investigated in four cervical cancer biopsies. The data reveal that the DNA might be integrated into the host cell genome. One tumor provided evidence for head to tail tandem repeats some of which persisted as circular episomes.