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1.
J Neurooncol ; 160(3): 659-668, 2022 Dec.
Article En | MEDLINE | ID: mdl-36369416

PURPOSE: Our aim was to determine the main risk factors related to the occurrence of permanent alopecia in childhood medulloblastoma (MB) survivors. METHODS: We retrospectively analyzed the clinical features of all consecutive MB survivors treated at our institute. We divided the patients into 3 groups depending on the craniospinal irradiation (CSI) dose received and defined permanent alopecia first in terms of the skin region affected (whole scalp and nape region), then on the basis of the toxicity degree (G). Any relationship between permanent alopecia and other characteristics was investigated by a univariate and multivariate analysis and Odds ratio (OR) with confidence interval (CI) was reported. RESULTS: We included 41 patients with a mean10-year follow-up. High dose CSI resulted as an independent factor leading to permanent hair loss in both groups: alopecia of the whole scalp (G1 p-value 0.030, G2 p-value 0.003) and of the nape region (G1 p-value 0.038, G2 p-value 0.006). The posterior cranial fossa (PCF) boost volume and dose were not significant factors at multivariate analysis neither in permanent hair loss of the whole scalp nor only in the nuchal region. CONCLUSION: In pediatric patients with MB, the development of permanent alopecia seems to depend only on the CSI dose ≥ 36 Gy. Acute damage to the hair follicle is dose dependent, but in terms of late side effects, constant and homogeneous daily irradiation of a large volume may have a stronger effect than a higher but focal dose of radiotherapy.


Cerebellar Neoplasms , Craniospinal Irradiation , Medulloblastoma , Humans , Child , Craniospinal Irradiation/adverse effects , Medulloblastoma/radiotherapy , Medulloblastoma/complications , Cerebellar Neoplasms/complications , Cohort Studies , Retrospective Studies , Alopecia/etiology , Risk Factors , Survivors , Radiotherapy Dosage , Cranial Irradiation/adverse effects , Cranial Irradiation/methods
2.
NPJ Precis Oncol ; 5(1): 64, 2021 Jul 14.
Article En | MEDLINE | ID: mdl-34262104

In children with cancer, the heterogeneity in ototoxicity occurrence after similar treatment suggests a role for genetic susceptibility. Using a genome-wide association study (GWAS) approach, we identified a genetic variant in TCERG1L (rs893507) to be associated with hearing loss in 390 non-cranial irradiated, cisplatin-treated children with cancer. These results were replicated in two independent, similarly treated cohorts (n = 192 and 188, respectively) (combined cohort: P = 5.3 × 10-10, OR 3.11, 95% CI 2.2-4.5). Modulating TCERG1L expression in cultured human cells revealed significantly altered cellular responses to cisplatin-induced cytokine secretion and toxicity. These results contribute to insights into the genetic and pathophysiological basis of cisplatin-induced ototoxicity.

3.
J Clin Immunol ; 34(8): 922-7, 2014 Nov.
Article En | MEDLINE | ID: mdl-25216720

Interferon-γ receptor 1 (IFN-γR1) deficiency is one of the primary immunodeficiencies conferring Mendelian Susceptibility to Mycobacterial Disease (MSMD). Some cases of neoplasms have been recently reported in patients with MSMD, underlying the already known link between immunodeficiency and carcinogenesis. We report the first case of intracranial tumour, i.e. pineal germinoma, in a 11-year-old patient with complete IFN-γR1 deficiency. The first clinical presentation of the genetic immunodeficiency dates back to when the child was aged 2 y and 10 mo, when he presented a multi-focal osteomyelitis caused by Mycobacterium scrofulaceum. The diagnosis of IFN-γR1 deficiency (523delT/523delT in IFNGR1 gene) was subsequently made. The child responded to antibiotic therapy and remained in stable clinical condition until the age of 11 years, when he started complaining of frontal, chronic headache. MRI revealed a solid pineal region mass lesion measuring 20 × 29 × 36 mm. Histological findings revealed a diagnosis of pineal germinoma. The patient received chemotherapy followed by local whole ventricular irradiation with boost on pineal site, experiencing complete remission, and to date he is tumor-free at four years follow-up. Four other cases of tumors have been reported in patients affected by MSMD in our knowledge: a case of Kaposi sarcoma, a case of B-cell lymphoma, a case of cutaneous squamous cell carcinoma and a case of oesophageal squamous cell carcinoma. In conclusion, in patients with MSMD, not only the surveillance of infectious diseases, but also that of tumors is important.


Antineoplastic Agents/therapeutic use , Germinoma/complications , Germinoma/therapy , Immunologic Deficiency Syndromes/complications , Immunologic Deficiency Syndromes/genetics , Radiotherapy , Receptors, Interferon/genetics , Age of Onset , Child , Germinoma/physiopathology , Humans , Male , Pineal Gland/pathology , Receptors, Interferon/deficiency , Treatment Outcome , Interferon gamma Receptor
4.
Pathologica ; 104(6): 428-31, 2012 Dec.
Article En | MEDLINE | ID: mdl-23547428

Glioneuronal tumours are a group of primary brain neoplasms of relatively recent acquisition in the World Health Organization (WHO) Classification of the Central Nervous System tumours. In diagnostic practice it is still possible to encounter glioneuronal tumours that cannot be placed into any of the well-defined WHO categories despite a growing list of entities. We have recently published four paediatric cases of diffuse leptomeningeal tumours that cannot be easily classified in the currently used CNS WHO classification, but which have histological and immunohistochemical criteria to be considered as glioneuronal tumours. The clinical, neuroradiological and pathological long-term follow-up of an unusual diffuse leptomeningeal glioneuronal tumour is presented herein.


Central Nervous System/pathology , Meningeal Neoplasms/pathology , Neoplasms, Neuroepithelial/pathology , Adolescent , Humans , Male
5.
Am J Med Genet A ; 149A(7): 1539-43, 2009 Jul.
Article En | MEDLINE | ID: mdl-19533801

Gorlin syndrome (GS) is inherited in an autosomal dominant pattern with high-penetrance and is characterized by a range of developmental anomalies and increased risk of developing basal cell carcinoma and medulloblastoma. Between 50% and 85% of patients with GS harbor germ line mutations in the only susceptibility gene identified to date, PTCH1, a key component in the Sonic Hedgehog signaling pathway. Another component in this pathway, SUFU, is known to be involved in susceptibility to medulloblastoma but has never been reported in GS patients to date. We have identified the known c.1022 + 1G>A SUFU germ line splicing mutation in a family that was PTCH1-negative and who had signs and symptoms of GS, including medulloblastoma. This is the first report of a germ line SUFU mutation associated with GS.


Basal Cell Nevus Syndrome/genetics , Germ-Line Mutation , Repressor Proteins/genetics , Adult , Basal Cell Nevus Syndrome/diagnosis , Base Sequence , Child, Preschool , Family , Female , Humans , Patched Receptors , Patched-1 Receptor , Receptors, Cell Surface/genetics
7.
Neuropathol Appl Neurobiol ; 34(3): 306-15, 2008 Jun.
Article En | MEDLINE | ID: mdl-17995922

AIMS: Herein we report on the successful isolation and establishment of a novel, long-term, primary, neurosphere-like cell line called 1603-MED from a 5-year-old boy affected by a highly aggressive anaplastic medulloblastoma. METHODS: Elaboration of the new protocol for neurosphere assay is extensively discussed, together with a complete immuno-histochemical and cytogenetic characterization of 1603-MED. RESULTS: Clinical course and histopathology are briefly discussed. The 1603-MED possesses a high capacity for proliferation, CD133 expression, self-renewal and differentiation, thus indicating that anaplastic medulloblastoma contains a subpopulation of cancer stem cells as observed in classic medulloblastoma. CONCLUSIONS: 1603-MED provides us with the first in vitro model of anaplastic medulloblastoma that may be suitable for studying both tumour progression and the genetic mechanisms related to therapy resistance, and may lead to the development and testing of chemosensitivity and new therapeutic targets.


Cell Culture Techniques/methods , Cell Line, Tumor/cytology , Cerebellar Neoplasms/pathology , Medulloblastoma/pathology , Neurons/cytology , Stem Cells/cytology , Cell Differentiation , Child, Preschool , Flow Cytometry , Humans , Immunohistochemistry , Male
8.
Childs Nerv Syst ; 23(2): 219-23, 2007 Feb.
Article En | MEDLINE | ID: mdl-17058088

OBJECTS: Genetic syndromes associated with ependymoma are uncommon, with the exception of NF2. We describe two cases of ependymoma presenting with Klinefelter's Syndrome (KS) as co-morbid condition. MATERIALS AND METHODS: The first patient was diagnosed for KS during pregnancy; he also presented a thyroid agenesis and a deficit of methyltetrahydrofolate reductase (MTHFR); at 30 months of age he was operated on for a grade II ependymoma of IV ventricle; after a multiple-stage surgery, he underwent oral chemotherapy and stereotactic radiotherapy, but after 15 months he presented a local recurrence and died. The second patient was diagnosed for KS at the age of 16 months; at 10 years of age, due to back pain, he underwent an MRI, which showed a cauda equine tumor. He underwent surgery and radiotherapy. Histology was of mixopapillary ependymoma. CONCLUSION: In a review of literature, various neoplasms have been described in association with KS. To our knowledge, these are the first two cases reported of ependymoma associated to KS. A retrospective study of 44 monoinstitutional ependymoma cases demonstrated association with genetic syndromes in 22%.


Central Nervous System Neoplasms/genetics , Ependymoma/genetics , Klinefelter Syndrome/genetics , Methylenetetrahydrofolate Reductase (NADPH2)/deficiency , Central Nervous System Neoplasms/complications , Child , Child, Preschool , Ependymoma/complications , Glial Fibrillary Acidic Protein/metabolism , Humans , Klinefelter Syndrome/complications , Male
9.
J Neurooncol ; 77(1): 89-94, 2006 Mar.
Article En | MEDLINE | ID: mdl-16292488

PURPOSE: The objective of the study was to evaluate the efficacy and toxicity of Temozolomide (TMZ) administered for 5 consecutive days in three daily dosing in children with recurrent or refractory high-grade glioma. PATIENTS AND METHODS: Twenty-four patients with a median age of 10.5 years were enrolled onto this open-label, multicenter, phase II study. The patients were previously treated with surgical resection (17 of 24), radiotherapy (19 of 24) and chemotherapy (18 of 24). Therapy was administered orally three times a day for 5 consecutive days at the dose of 200 mg/m(2)/dx5 for chemotherapy naive patients. In patients heavily pretreated with chemotherapy the starting dose was of 150 mg/m(2)/dx5. RESULTS: A total of 95 cycles were administered. The median progression free-survival (PFS) was 3 months for the entire group while disease stabilization was obtained in 7 patients (29.1%), all with supratentorial tumors. No CR or PR was observed. TMZ treatment showed a limited toxicity. Thrombocytopenia was the most common hematological adverse effect. Our data suggest a marginal activity of TMZ in children with recurrent high-grade glioma.


Antineoplastic Agents, Alkylating/therapeutic use , Brain Neoplasms/drug therapy , Dacarbazine/analogs & derivatives , Glioma/drug therapy , Neoplasm Recurrence, Local/drug therapy , Adolescent , Antineoplastic Agents, Alkylating/adverse effects , Bone Marrow/drug effects , Child , Child, Preschool , Dacarbazine/adverse effects , Dacarbazine/therapeutic use , Disease-Free Survival , Drug Administration Schedule , Female , Humans , Male , Neutropenia/chemically induced , Temozolomide , Thrombocytopenia/chemically induced , Treatment Outcome
10.
Bone Marrow Transplant ; 35 Suppl 1: S31-4, 2005 Mar.
Article En | MEDLINE | ID: mdl-15812527

Primary brain tumours, a heterogeneous group of cancer that constitute the second most common cancer in childhood, were historically treated with neurosurgical resection and radiation therapy. Chemotherapy has proven to be beneficial for some histological types, which has since led to exploration of the role of high-dose chemotherapy and haematopoietic stem cell rescue. Patients with high-grade glial tumours, primitive neuroectodermal tumours and high-risk medulloblastoma usually fare poorly. The indicators of bad prognosis are metastatic status, extent of resection and age. Children <3 years at diagnosis carry worse prognosis. Rare cancers such as ependymoblastoma, atypical teratoid rhabdoid tumour and choroid plexus carcinoma have a dismal prognosis regardless of the above-mentioned indicators. The use of myeloablative therapy (MAT) has been investigated to improve the rate of long-term DFS, as well as to reduce and delay in the youngest children the use of the craniospinal irradiation associated with unacceptable late effects. We will overview the literature regarding patients with 'good and uncertain indications' to MAT. Ependymoma and brain stem tumours, for which the available data discourage the use of MAT, are excluded. Finally, we will summarize a single Institution experience (Giannina Gaslini Children's Hospital, Genoa) with MAT in the period 1997-2003.


Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Cerebellar Neoplasms/drug therapy , Antineoplastic Agents , Cerebellar Neoplasms/pathology , Child , Child, Preschool , Female , Humans , Male , Prognosis , Treatment Outcome
11.
J Neurosurg ; 91(6): 971-7, 1999 Dec.
Article En | MEDLINE | ID: mdl-10584843

OBJECT: Some medulloblastomas (MBs) are characterized by extreme nodularity and intranodular nuclear uniformity in a fine fibrillary background. These lesions have also been designated as "cerebellar neuroblastoma." Although numerous reports have been published in which their morphological features have been investigated, only a few studies have been focused on their neuroradiological appearance, biological behavior, and response to therapy. The goal of this study was to gather more information about these lesions. METHODS: The authors present 11 cases of MB with extensive nodularity. Five patients were boys and six were girls; all but one were 24 months of age or younger at diagnosis. Magnetic resonance imaging disclosed a peculiar grapelike architecture in eight cases. Surgical tumor removal was complete in nine cases and partial in one. In the other case a biopsy sample of the tumor was obtained after a preoperative course of chemotherapy. After surgery, two children were treated with radiotherapy alone and one with craniospinal irradiation followed by systemic chemotherapy. Eight patients were treated with chemotherapy only. All the patients in the study are presently alive with a median follow up of 66 months. Eight patients (73%) are in complete remission at 35 to 156 months. Three patients treated with chemotherapy alone postsurgery relapsed; however, all underwent successful retreatment (two with craniospinal irradiation and one with further surgery plus high-dose chemotherapy) and are in complete remission. A review of the literature revealed that patients in 11 of 12 reported cases were younger than 3 years of age and that seven of eight in whom follow-up information was available were alive and well, with survival times ranging from 6 to 84 months. CONCLUSIONS: Medulloblastomas with extensive nodularity represent a variant that is characterized by: 1) occurrence in very young children; 2) a peculiar grapelike appearance on neuroimaging; and 3) an apparently favorable outcome.


Cerebellar Neoplasms/pathology , Medulloblastoma/pathology , Cerebellar Neoplasms/drug therapy , Cerebellar Neoplasms/radiotherapy , Cerebellar Neoplasms/surgery , Cerebellum/pathology , Cerebellum/surgery , Chemotherapy, Adjuvant , Child, Preschool , Combined Modality Therapy , Cranial Irradiation , Female , Follow-Up Studies , Humans , Infant , Magnetic Resonance Imaging , Male , Medulloblastoma/drug therapy , Medulloblastoma/radiotherapy , Medulloblastoma/surgery , Prognosis , Radiotherapy, Adjuvant
12.
Klin Padiatr ; 209(4): 222-7, 1997.
Article En | MEDLINE | ID: mdl-9293454

BACKGROUND: Secreting germ cell tumors are an invariably fatal subgroup within the malignant pediatric brain tumors. Thus in 1993, an international working group was initiated to establish a cooperative study for diagnostic and treatment of intracranial secreting germ cell tumors of the CNS. To pilot this protocol, since 1994 German and Italian patients are treated in accordance with the established guidelines. METHODS: Regarding to the achieved consensus within the international protocol committee a characteristical diagnostic imaging (CT/MRI scan) of head and spine and a significant increase of tumor markers beta-HCG (> 50 IU/l) and/or AFP (> 25 ng/ml) are defined as sufficient diagnostic criteria. Additionally staging procedures include an initial CSF cytology. Treatment consists of 4 courses PEI: platinum (20 mg/m2 day 1-5), VP16 (100 mg/ m2 day 1-3), and ifosfamide (1.5 g/m2 day 1-5). Surgery of the residual tumor is administered after chemotherapy, if resection is possible, followed by craniospinal irradiation (30 Gy with tumor boost 24 Gy). RESULTS: Until September 96, 19 patients (16 boys and 3 girls) aged 8 to 19 years are registered and have finished their treatment. Seven children are diagnosed by elevated tumor markers. Six of 7 children with stereotactic fine needle biopsy and histology of germinoma have a significant marker increase as a specific characteristic for secreting non-germinomatous germ cell tumors. In 6 patients, the tumor is primarily resected, 2 children are biopsied. In 2 children spinal metastases are diagnosed initially. Tumor marker response is evaluated in 16 children. Thirteen of 16 patients show a clear marker normalization after 2 courses of PEI. One boy with a slight increase of the tumor marker after the 4th course developed an early spinal relapse and died. One girl showed a spinal recurrence during focal radiotherapy. She is still under relapse treatment. A significant decrease of tumor volume after chemotherapy is documented in 10/13 children, who have a definite signal tumor at start of therapy. In 3 children tumor volume does not change despite of marker normalization. Histology of these tumors is teratoma. One of these children died postoperatively because of tumor bleeding. 17/19 patients are alive, 16 of them are in complete remission with a median follow-up of 11 months. CONCLUSION: These results show a further significant increase of event-free survival (EFS 81%). The piloted chemotherapy is proven to be effective and the protocol is now open as an international SIOP CNS GCT study that is started in October 1996.


Central Nervous System Neoplasms/therapy , Hormones, Ectopic/metabolism , Neoplasms, Germ Cell and Embryonal/therapy , Adolescent , Central Nervous System Neoplasms/metabolism , Central Nervous System Neoplasms/pathology , Chemotherapy, Adjuvant , Child , Chorionic Gonadotropin, beta Subunit, Human/metabolism , Combined Modality Therapy , Female , Follow-Up Studies , Germany , Germinoma/metabolism , Germinoma/pathology , Germinoma/therapy , Humans , Male , Neoplasm Staging , Neoplasms, Germ Cell and Embryonal/metabolism , Neoplasms, Germ Cell and Embryonal/pathology , Pilot Projects , Radiotherapy, Adjuvant , Treatment Outcome , alpha-Fetoproteins/metabolism
13.
J Pediatr Endocrinol Metab ; 10(1): 41-9, 1997.
Article En | MEDLINE | ID: mdl-9364341

We assessed the efficacy of GH treatment in 25 GH deficient patients irradiated for brain tumors (eight with glioma cranio-irradiated, eleven with medulloblastoma and six with ependymoma craniospinal-irradiated). We administered GH at doses of 0.6-0.9 IU/kg/week for one to three years at least two years after diagnosis of the tumor. We assessed the efficacy of the treatment each year by comparing the values of height velocity over bone age and change in the ratios progression of chronological age/progression of bone age and progression of statural age/progression of bone age. The treatment promoted satisfactory growth; better results were obtained in patients with glioma, who received cranial irradiation only, than in those with medulloblastoma or ependymoma, who received spinal irradiation as well. Moreover, the growth prognosis improved, especially in the cranio-irradiated patients. In our series of patients four presented tumor recurrence; these results did not differ significantly from those in irradiated patients with cerebral tumors who were not treated with GH.


Brain Neoplasms/radiotherapy , Human Growth Hormone/deficiency , Human Growth Hormone/therapeutic use , Radiotherapy/adverse effects , Adolescent , Age Determination by Skeleton , Body Height , Cerebellar Neoplasms/radiotherapy , Child , Child, Preschool , Ependymoma/radiotherapy , Female , Glioma/radiotherapy , Human Growth Hormone/administration & dosage , Humans , Male , Medulloblastoma/radiotherapy , Neoplasm Recurrence, Local
16.
Pediatr Radiol ; 26(10): 731-3, 1996 Oct.
Article En | MEDLINE | ID: mdl-8805608

The subject of this paper is a 2-year-old child with progressive paraparesis. MRI showed a large lumbosacral intradural-extramedullary mass and the histological diagnosis was Langerhans cell histiocytosis. The histopathological and neuroradiological findings are discussed.


Histiocytosis, Langerhans-Cell/diagnosis , Spinal Cord Diseases/diagnosis , Child, Preschool , Female , Histiocytosis, Langerhans-Cell/pathology , Humans , Magnetic Resonance Imaging , Spinal Cord Diseases/pathology
17.
Neuroradiology ; 38 Suppl 1: S196-9, 1996 May.
Article En | MEDLINE | ID: mdl-8811715

We report a child aged 2 years presenting with delayed motor development. A thoracolumbar subcutaneous mass was noticed in the first months of life. MRI showed a low conus medullaris, confirmed the presence of the mass and detected a second solid lesion in the intradural space. Surgery confirmed that the two lesions were distinct, as on MRI. The histopathological features were in common with fibrous hamartoma of infancy, giant cell angioblastoma and the "diffuse type" of infantile fibromatosis. The presence of a low conus medullaris associated with a congenital clinical presentation suggested a disontogenetic aetiology.


Fibroma/diagnosis , Magnetic Resonance Imaging , Spinal Cord/abnormalities , Spinal Cord/pathology , Spinal Neoplasms/diagnosis , Child, Preschool , Fibroma/etiology , Humans , Male , Spinal Neoplasms/etiology
18.
Neuroradiology ; 38(4): 352-9, 1996 May.
Article En | MEDLINE | ID: mdl-8738095

Our purpose was to determine whether medulloblastoma (MB) shows specific neuroradiological features which may be employed in differential diagnosis from other common posterior cranial fossa tumours in childhood. Preoperative MRI was performed on 20 children with MB, and preoperative CT in 17 of them. All underwent surgery and histopathological diagnosis. There was a constant relationship between high density on CT and low signal on T1-weighted images. Signal behaviour on T2-weighted images and the degree of contrast enhancement were more variable. Most tumours arose in the midline, from the cerebellar vermis, involving the fourth ventricle, but hemisphere and extra-axial neoplasms were also seen. The combination of high density on CT and low signal on T1-weighted images is highly suggestive of MB and may assist preoperative differential diagnosis from other posterior cranial fossa tumours.


Cerebellar Neoplasms/diagnosis , Magnetic Resonance Imaging , Medulloblastoma/diagnosis , Tomography, X-Ray Computed , Adolescent , Cerebellar Neoplasms/pathology , Cerebellar Neoplasms/surgery , Cerebellum/pathology , Cerebral Ventricles/pathology , Child , Child, Preschool , Diagnosis, Differential , Female , Humans , Male , Medulloblastoma/pathology , Medulloblastoma/surgery
19.
Cancer ; 77(5): 977-82, 1996 Mar 01.
Article En | MEDLINE | ID: mdl-8608493

BACKGROUND: Intracranial immature teratomas (IT) are very rare germ cell tumors (GCT). The value of chemotherapy in their treatment has not been defined. METHODS: A child was referred to our hospital for consultation regarding the need for adjuvant treatment after being operated upon twice (at the age of 7 months and 11 months) for a large supratentorial intracerebral mass. The patient was staged and the tumor specimens reviewed. Histology was that of an IT with no other type of malignant GCT. RESULTS: Considering the age, lack of any sign of residual tumor by computed tomography and magnetic resonance imaging, absence of tumor cells in the spinal fluid or elevation of tumor markers, and based on the reported poor response of such tumors to chemotherapy, a policy of "wait and see" was adopted. One month later, the child presented with a rapidly growing intracranial mass invading the cranial bones on the left side. Chemotherapy consisting of 4 cycles of carboplatin, etoposide, and bleomycin followed by another 4 cycles of ifosfamide, vincristine, and dactinomycin alternating with carboplatin and etoposide, achieved complete remission, and 24 months after discontinuation of treatment, the patient continued free of disease. CONCLUSIONS: This report indicates that chemotherapy may be effective therapy for intracranial IT. In our patient, chemotherapy modified the natural aggressive behavior of this disease and achieved a persistent, complete remission. Given the minimal information available in the literature concerning the response of IT to chemotherapy, this case addresses the issue of whether chemotherapy alone is adequate to treat intracranial germ cell tumors.


Brain Neoplasms/drug therapy , Teratoma/drug therapy , Brain Neoplasms/surgery , Chemotherapy, Adjuvant , Combined Modality Therapy , Humans , Infant , Male , Teratoma/surgery
20.
Genes Chromosomes Cancer ; 15(1): 18-25, 1996 Jan.
Article En | MEDLINE | ID: mdl-8824721

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.


Chromosome Deletion , Hamartoma/genetics , Heterozygote , Repressor Proteins/genetics , Tuberous Sclerosis/genetics , Genes, Tumor Suppressor , Humans , Polymorphism, Genetic , Tuberous Sclerosis Complex 2 Protein , Tumor Suppressor Proteins
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