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Biomedical subjects

U Mittler

Publications and source records attributed to U Mittler.

At least 19 recordsLinked to original sources

[Desmoid tumors of the head and neck].

Desmoid tumors of the head and neck, also known as aggressive fibromatoses, are rare. They are soft tissue neoplasms arising from musculoaponeurotic structures and characterized of locally aggressive infiltration and recurrences. Complete surgical excision of desmoid tumors is considered to be the only effective method of cure. It is likewise important to make a function-preserving surgery. In addition to the radicality this aspect should be a primary goal to minimize morbidity. MRI is the first choice in the preoperative evaluation of neck desmoids. We describe the successful treatment of desmoid tumors in two cases (M. sternocleidomastoideus, M. levator scapulae). Intraoperative neuromonitoring was very helpful for identification and protection of the motor nerves.

Biopsy↗

Familial urticaria pigmentosa associated with thrombocytosis as the initial symptom of systemic mastocytosis and Down's syndrome.

Most cases of urticaria pigmentosa are confined to the skin, but visceral involvement and/or haematological abnormalities have been observed. It is still a matter of debate whether all forms of mastocytosis are true neoplasias or reactive hyperplasias. Familial inheritance of urticaria pigmentosa is rare. We report on a fraternal set with urticaria pigmentosa as part of a systemic mastocytosis. The first patient additionally revealed persistent thrombocytosis and splenomegaly. His brother developed urticaria pigmentosa, intermittent diarrhoea, hepatomegaly and asthma bronchiale associated with trisomy 21 (Down's syndrome). The association of mastocytosis with thrombocytosis has seldom been described. In our patient it preceded the development of systemic mastocytosis. The association with Down's syndrome has not been reported until now.

Biopsy, Needle↗

Expression of components of the IGF signalling system in childhood acute lymphoblastic leukaemia.

BACKGROUND: Alterations in the insulin-like growth factor (IGF) system have been reported for different tumours. They are of particular interest in the search for new prognostic and therapeutic approaches in cancer. In childhood acute lymphoblastic leukaemia (ALL) the amount of "tumour mass" at diagnosis can exceed 1 kg. To understand the endocrine, paracrine, and autocrine potential of the malignant transformed progenitor cells, the ability of these cells to express components of the IGF system needs to be investigated. AIM: To characterise the expression pattern of genes of the IGF system in malignant lymphoblasts of children suffering from ALL. METHODS: Reverse transcription polymerase chain reaction of Ficoll separated mononuclear cells from 142 children with ALL, 127 cord blood samples, and 55 blood samples of age matched controls were studied. RESULTS: The expression of IGF-I, IGF-II, IGF binding protein 5 (IGFBP-5), and CTGF (IGFBP-rP2) was seen in a higher proportion of mononuclear cells of patients with ALL than in controls. Patients with ALL who were in continuous remission had a lower percentage of IGFBP-2 and IGFBP-3 expressing mononuclear cells at diagnosis than did those who developed a relapse. Only malignant lymphoblasts of B cell origin showed expression of CTGF (IGFBP-rP2). Malignant lymphoblasts of T cell origin more often expressed IGFBP-2 and IGFBP-5, whereas IGF-II and IGFBP-3 expression was seen more often in lymphoblasts of B cell origin. CONCLUSIONS: Malignant lymphoblasts of patients with ALL express components of the IGF system and therefore promote their own growth in an autocrine, paracrine, or endocrine manner. Whether these components will be useful as prognostic factors in the stratification of ALL treatment in children needs to be evaluated.

Biomarkers, Tumor↗

Gliomatosis cerebri: post-mortem molecular and immunohistochemical analyses in a case treated with thalidomide.

Gliomatosis cerebri (GC) is a rare tumor of the central nervous system (CNS) characterized by widespread diffuse infiltration of the brain and spinal cord by neoplastic glial cells. We report the case of a 17-year-old boy with a bioptically diagnosed fibrillary astrocytoma. The administration of thalidomide, which was suggested to be beneficial in the treatment of human cancers, had no substantial clinical effect on our patient. Autopsy studies revealed a diffuse infiltration of the frontal and temporal lobes of the right hemisphere, brainstem, and the leptomeninges covering the whole spinal cord by an astrocytic tumor, which showed features both of low-grade astrocytoma and glioblastoma multiforme. No mutations in the p53 and PTEN tumor suppressor genes were found; immunoreactivities for p53, PTEN, and EGFR could not be detected.

Adolescent↗

Postoperative neoadjuvant chemotherapy before radiotherapy as compared to immediate radiotherapy followed by maintenance chemotherapy in the treatment of medulloblastoma in childhood: results of the German prospective randomized trial HIT '91.

PURPOSE: The German Society of Pediatric Hematology and Oncology (GPOH) conducted a randomized, prospective, multicenter trial (HIT '91) in order to improve the survival of children with medulloblastoma by using postoperative neoadjuvant chemotherapy before radiation therapy as opposed to maintenance chemotherapy after immediate postoperative radiotherapy. METHODS AND MATERIALS: Between 1991 and 1997, 158 patients were enrolled and 137 patients randomized. Seventy-two patients were allocated to receive neoadjuvant chemotherapy before radiotherapy (arm I, investigational). Chemotherapy consisted of ifosfamide, etoposide, intravenous high-dose methotrexate, cisplatin, and cytarabine given in two cycles. In arm II (standard arm), 65 patients were assigned to receive immediate postoperative radiotherapy, with concomitant vincristine followed by 8 cycles of maintenance chemotherapy consisting of cisplatin, CCNU, and vincristine ("Philadelphia protocol"). All patients received radiotherapy to the craniospinal axis (35.2 Gy total dose, 1.6 Gy fractionated dose / 5 times per week followed by a boost to posterior fossa with 20 Gy, 2.0 Gy fractionated dose). RESULTS: During chemotherapy Grade III/IV infections were predominant in arm I (40%). Peripheral neuropathy and ototoxicity were prevailing in arm II (37% and 34%, respectively). Dose modification was necessary in particular in arm II (63%). During radiotherapy acute toxicity was mild in the majority of patients and equally distributed in both arms. Myelosuppression led to a mean prolongation of treatment time of 11.5 days in arm I and 7.5 days in arm II, and interruptions in 35% of patients in arm I. Quality control of radiotherapy revealed correct treatment in more than 88% for dose prescription, more than 88% for coverage of target volume, and 98% for field matching. At a median follow-up of 30 months (range 1.4-62 months), the Kaplan-Meier estimates for relapse-free survival at 3 years for all randomized patients were 0.70+/-0.08; for patients with residual disease: 0.72+/-0.06; without residual disease: 0.68+/-0.09; M0: 0.72+/-0.04; M1: 0.65+/-0.12; and M2/3: 0.30+/-0.15. For all randomized patients without M2/3 disease: 0.65+/-0.05 (arm I) and 0.78+/-0.06 (arm II) (p < 0.03); patients between 3 and 5.9 years: 0.60+/-0.13 and 0.64+/-0.14, respectively, but patients between 6 and 18 years: 0.62+/-0.09 and 0.84+/-0.08, respectively (p < 0.03). In a univariate analysis the only negative prognostic factors were M2/3 disease (p < 0.002) and an age of less than 8 years (p < 0.03). CONCLUSIONS: Maintenance chemotherapy would seem to be more effective in low-risk medulloblastoma, especially in patients older than 6 years of age. Neoadjuvant chemotherapy was accompanied by increased myelotoxicity of the subsequent radiotherapy, causing a higher rate of interruptions and an extended overall treatment time. Delayed and/or protracted radiotherapy may therefore have a negative impact on outcome. M2/3 disease was associated with a poor survival in both arms, suggesting the need for a more intensive treatment. Young age and M2/3 stage were negative prognostic factors in medulloblastoma, but residual or M1 disease was not, suggesting a new stratification system for risk subgroups. High quality of radiotherapy may be a major contributing factor for the overall outcome.

Adolescent↗

CTGF (IGFBP-rP2) is specifically expressed in malignant lymphoblasts of patients with acute lymphoblastic leukaemia (ALL).

Connective tissue growth factor (CTGF) is a major chemotactic and mitogenic factor for connective tissue cells. The amino acid sequence shares an overall 28-38% identity to IGFBPs and contains critical conserved sequences in the amino terminus. It has been demonstrated that human CTGF specifically binds IGFs with low affinity and is considered to be a member of the IGFBP superfamily (IGFBP-rP2). In the present study, the expression of CTGF (IGFBP-rP2) in human leukaemic lymphoblasts from children with acute lymphoblastic leukaemia (ALL) was investigated. RNA samples from tumour clones enriched by ficoll separation of bone marrow or peripheral blood mononuclear cells (MNC) from 107 patients with childhood ALL at diagnosis and 57 adult patients with chronic myeloid leukaemia (CML) were studied by RT-PCR. In addition MNC samples from children with IDDM and cord blood samples from healthy newborns were investigated as control groups. Sixty-one percent of the patients with ALL (65 of 107) were positive for CTGF (IGFBP-rP2) expression. In the control groups, no expression of CTGF (IGFBP-rP2) in peripheral MNC was detected, and in the group of adult CML patients only 3.5% (2 of 57) were positive for this gene. The role of CTGF (IGFBP-rP2) in lymphoblastic leukaemogenesis requires further evaluation, as does its potential utility as a tumour marker.

Adolescent↗

Familial clustering of Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is considered a non-hereditary disorder. Evaluation of the few familial cases might provide insight into its aetiology and pathogenesis. We conducted a survey to identify familial LCH cases. Data on family history, zygosity assessment in twins, clinical and laboratory features, treatment outcome, and present status were collected. According to variable confidence for twins monozygosity assessment, we termed these pairs 'presumed monozygotic' (pMZ). Nine families had more than one affected relative: five with LCH-concordant twin pairs, four with LCH in siblings or cousins. Three twin pairs not concordant for LCH were also studied. Overall, four of five pMZ twin pairs and one of three dizygotic (DZ) pairs were concordant for LCH. The pMZ twins had simultaneous and early disease onset (mean age 5.4 months); onset was at 21 months in the DZ pair. Clinical features were similar in the pMZ pairs. One pair of DZ twins had disseminated LCH. The three healthy twins (one pMZ, two DZ) remain asymptomatic 0.3, 5.9 and 4.7 years, respectively, after disease onset in their co-twins. Of the two families with affected non-twin siblings, one had known parental consanguinity and the other possible consanguinity. Potential consanguinity was also present in one of the two families with affected first cousins. Our data support high LCH concordance rates in pMZ twins and add the finding of LCH concordance in one of three dizygotic pairs studied. Taken together with our identification of LCH in siblings and first cousins from known or possibly consanguineous families, and with prior reports of three affected parent-child pairs, the data support a role for genetic factor(s) in LCH. The work-up of newly diagnosed patients should include a careful, extensive family history and chromosome studies. When possible, constitutional and/or lesional DNA should be obtained for future study.

Child, Preschool↗

von Willebrand factor-cleaving protease in thrombotic thrombocytopenic purpura and the hemolytic-uremic syndrome.

BACKGROUND: Thrombotic thrombocytopenic purpura and the hemolytic-uremic syndrome are severe microvascular disorders of platelet clumping with similar signs and symptoms. Unusually large multimers of von Willebrand factor, capable of agglutinating circulating platelets under high shear stress, occur in the two conditions. We investigated the prevalence of von Willebrand factor-cleaving protease deficiency in patients with familial and nonfamilial forms of these disorders. METHODS: Plasma samples were obtained from 53 patients with thrombotic thrombocytopenic purpura or hemolytic-uremic syndrome. Von Willebrand factor-cleaving protease was assayed in diluted plasma samples with purified normal von Willebrand factor as the substrate. The extent of the degradation of von Willebrand factor was assessed by electrophoresis in sodium dodecyl sulfate-agarose gels and immunoblotting. To determine whether an inhibitor of von Willebrand factor-cleaving protease was present, we measured the protease activity in normal plasma after incubation with plasma from the patients. RESULTS: We examined 30 patients with thrombotic thrombocytopenic purpura and 23 patients with the hemolytic-uremic syndrome. Of 24 patients with nonfamilial thrombotic thrombocytopenic purpura, 20 had severe and 4 had moderate protease deficiency during an acute event. An inhibitor found in 20 of these patients was shown to be IgG in five of five tested plasma samples. Of 13 patients with nonfamilial hemolytic-uremic syndrome, 11 had normal levels of activity of von Willebrand factor-cleaving protease during the acute episode, whereas in 2 patients, the activity was slightly decreased. All 6 patients with familial thrombotic thrombocytopenic purpura lacked von Willebrand factor-cleaving protease activity but had no inhibitor, whereas all 10 patients with familial hemolytic-uremic syndrome had normal protease activity. In vitro proteolytic degradation of von Willebrand factor by the protease was studied in 5 patients with familial and 7 patients with nonfamilial hemolytic-uremic syndrome and was normal in all 12 patients. CONCLUSIONS: Nonfamilial thrombotic thrombocytopenic purpura is due to an inhibitor of von Willebrand factor-cleaving protease, whereas the familial form seems to be caused by a constitutional deficiency of the protease. Patients with the hemolyticuremic syndrome do not have a deficiency of von Willebrand factor-cleaving protease or a defect in von Willebrand factor that leads to its resistance to protease.

ADAM Proteins↗

p53 and ras mutations in Ewing's sarcoma.

The role of tumor suppressor genes and oncogenes in the development of Ewing's sarcoma has not yet been fully clarified. In this study, we analyzed the frequency of p53 tumor suppressor gene mutation in exons 4-8 by PCR-SSCP and direct sequencing, and the expression of p53-protein in Ewing's sarcoma (ES) by using immunohistochemistry. The overexpression of MDM2, which acts as a functional inactivator of p53, was studied by immunohistochemistry. In addition, a screening for point mutations in the hot spot regions codon 12 and 13 of exon 1 and codon 61 of exon 2 of ras-genes (H-ras, N-ras, K-ras) was performed. In one case, a p53 gene mutation could be confirmed in codon 238 of exon 7 (1/24). Overexpression of MDM2 was found in five cases; in ras-genes, no mutations were detected. Compared with other highly malignant mesenchymal pediatric tumors such as osteosarcomas, mutations of p53 and ras in Ewing's sarcomas are an extraordinarily rare event. However, their frequency is comparable to that of PNET, suggesting that the low incidence of these mutations in ES and PNET could be group-specific for tumors of neuroectodermal genesis.

Adolescent↗

Genetic instability in osteoblastic tumors of the skeletal system.

At the histological level, the differential diagnosis of osteoblastic bone tumors is characterized by several problems that cannot be solved by conventional histological methods including immunohistology. Differentiating aneurysmal bone cyst from telangiectatic osteosarcoma or giant cell tumor from giant cell-containing highly malignant osteosarcoma are only two examples reflecting the complexity of this field. To develop a new approach to these diagnostic problems, we analyzed the genetic instability in a large number of bone-forming tumor-like lesions as well as in benign and malignant osteoblastic tumors. Our research concentrated on genetic alterations in cell cycle regulator genes: mutations in the p53 gene and ras gene, loss of heterozygosity at the p53, p16 and Rb-locus, and amplification of the mdm2-gene and the c-myc-gene. In addition to cell cycle regulators, the telomerase activity has also been analyzed. The results show that the number of genetic alterations increases with the malignancy of the tumors. The highest number of genetic alterations could thus be found in conventional intraosseous osteosarcoma. In tumor-like lesions, genetic alterations have rarely been observed. The results of this study show that analyzing the genetic instability probably contributes to an improvement in the differential diagnosis of osteoblastic tumors.

Bone Neoplasms↗

Elevated serum levels of IGFBP-2 found in children suffering from acute leukaemia is accompanied by the occurrence of IGFBP-2 mRNA in the tumour clone.

Insulin-like growth factor-binding proteins (IGFBPs) are important modulators of IGF action. In 50 children suffering from acute lymphoblastic leukaemia (ALL), we studied the serum levels of IGFBP-1,-2 and-3. The mean standard deviation score (SDS) values were estimated to be 0.7, 3.1 and -1.7 for the IGFBP-1,-2 and-3, respectively, compared with the normal range defined by a SDS from -2 to +2. IGFBP-1 and-3 were normal, but for IGFBP-2 we found a significantly elevated serum level compared with control groups (P < 0.05). However, during chemotherapy this increased serum IGFBP-2 normalized. In addition, we found a correlation between higher serum levels and the detection rate of the IGFBP-2 transcript in corresponding cells. In patients with ALL, the detection rates of IGFBP-2 mRNA were estimated to be 72% and 35% at the time of diagnosis and at day 33 of chemotherapy respectively; in the control groups (healthy children and children at their initial presentation of diabetes mellitus), the values were 28% and 33% respectively. Based on the correlation between IGFBP-2 serum levels and the corresponding gene expression as well as the normalization of IGFBP-2 levels during chemotherapy, we concluded that the increased serum level mainly originated from the tumour clone itself. Furthermore, possible functional consequences of elevated IGFBP-2 were outlined.

Adolescent↗

[Genetic instability in osteoblastic tumors of the skeletal system].

In the histological differential diagnosis of osteoblastic bone tumors, several problems could not have been solved by conventional histological methods including immunohistology. Some well-known examples are the differential diagnosis between aneurysmal bone cyst and telangiectatic osteosarcoma and giant cell tumor versus giant cell-containing highly malignant osteosarcoma. As a new approach to these diagnostic problems, we analyzed the genetic instability in a larger number of bone-forming tumor-like lesions, benign and malignant osteoblastic tumors. Analysis focused on genetic alterations in cell cycle regulator genes: Mutations in the p53 gene and ras gene, loss of heterozygosity at the p53, p16 and Rb-locus, and amplification of the mdm2 gene and the c-myc-gene. In addition to cell cycle regulators, the telomerase activity has also been analyzed. The results show that the number of genetic alterations increases with the malignancy of the tumors. The highest number of genetic alterations could thus be found in conventional intraosseous osteosarcoma. In tumor-like lesions, genetic alterations have rarely been observed. The results of this study show that the analysis of genetic instability will probably contribute to an improved differential diagnosis of osteoblastic tumors.

Bone Neoplasms↗

Expression of MDR1/p-glycoprotein and multidrug resistance-associated protein in childhood solid tumours.

We evaluated the expression of MDR1/p-glycoprotein in paediatric tumours using reverse transcriptase polymerase chain reaction (RT-PCR), RNA dot blot analysis, and immunohistochemistry on formalin fixed paraffin-embedded material with JSB-1 and C-219 monoclonal antibodies, and compared these three techniques. The expression of multidrug resistance-associated protein (MRP) gene was examined by RT-PCR assay. We studied MDR1/p-glycoprotein and MRP expression in 13 samples from 10 neuroblastoma patients, 11 samples from 10 nephroblastoma patients, 2 rhabdomyosarcomas, 1 adrenocortical carcinoma and 10 benign tumours or tumour-like lesions. Eleven of 13 neuroblastomas, 7 of 11 nephroblastomas, 2 rhabdomyosarcomas, 1 adrenocortical carcinoma, and 7 of 10 benign tumours or tumour-like lesions showed MDR1 PCR products. By RNA dot blot analysis, MDR1 transcripts were detectable in 11 of 34 specimens. Immunohistochemically, we detected positive reaction products for JSB-1 in 26 of 36 samples. There was a significant correlation between the immunoreactivity for JSB-1 and the expression of MDR1 mRNA expression by RT-PCR (P = 0.0001). However, the presence of p-glycoprotein immunostaining does not correlate with the MDR1 expression shown by RT-PCR in every case. As for MRP mRNA expression, 9 of 13 neuroblastomas and 10 of 11 nephroblastomas revealed PCR products.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Final height and puberty in 40 patients after antileukaemic treatment during childhood.

UNLABELLED: Endocrine dysfunction and damage of the epiphysial growth plates have been reported as late effects of antileukaemic treatment during childhood. It is a common opinion that cranial irradiation (CI) is the most important factor for blunted growth. Accordingly, recent therapeutic strategies in acute lymphoblastic leukaemia (ALL) avoid cranial irradiation. Here we analysed longitudinal data on growth and puberty of 54 children in first complete remission, who were treated with 18 Gy CI or not submitted to radiotherapy. Two chemotherapeutic protocols were compared which were similar during the induction period but differed in the intensity of maintenance therapy. In cranial irradiated patients both in males and females the pubertal growth spurt started at a mean age of 1.2 years (SD: 0.93 years) earlier than controls. Age at diagnosis and age at pubertal growth spurt were significantly correlated (r = 0.35, P = 0.017). Similarly, menarche occurred at a mean age (n = 22) of 12.1 years and was correlated with the age at start of therapy in girls who were treated with 18 Gy CI (r = 0.61, P = 0.01). Adult height was reached spontaneously in 30 patients treated during prepubertal age and in 10 treated shortly before or during puberty. In all prepubertal patients treated for 2-3 years with intensive maintenance therapy blunted growth resulted in a significant loss of -1.85 H-SDS (median, P = 0.0051) compared to height at diagnosis. However, if continuation treatment used only methotrexate and 6-mercaptopurine (i.e. BFM protocol) final height equalled projected adult height, despite 18 Gy CI. CONCLUSIONS: (1) multiagent chemotherapy is of major impact for growth and puberty; (2) 18 Gy cranial irradiation is below the critical dosage responsible for blunted growth; (3) loss in potential growth might be prevented by current CT strategies; (4) onset of puberty depends on age when antileukaemic therapy is applied.

Adolescent↗

Expression of P-glycoprotein in high grade osteosarcomas with special emphasis on chondroblastic subtype.

The development of chemoresistance is one of the major clinical problems in the therapy of malignant bone tumors in childhood. The expression of membrane-bound P-glycoprotein turned out to be an essential factor in the evidence of resistant tumor cells. To investigate the significance of multidrug resistance in the prognosis of highly malignant osteosarcomas, the immunohistologic expression of P-glycoprotein was investigated in the tumor tissue of 52 patients under special consideration of the histologic subtype. The data were compared with the histologic regression grade in the resection specimen and correlated with clinical data. Formalin-fixed, paraffin-embedded tissue and, additionally, fresh frozen material taken from the primary biopsy were stained using monoclonal antibody JSB1. 29 (55%) of the tumors investigated were P-glycoprotein positive. Considering the response to chemotherapy, no conclusion could be drawn regarding P-glycoprotein expression, regression grade in the resection specimens, and the clinical follow-up. P-glycoprotein was detected in only 52% of the non-responders. A positive reaction was also evidenced in 59% of the patients with high chemosensitivity. A comparison of the histologic subtypes yielded a significant result in the chondroblastic osteosarcomas. 11 of 12 cases showed a strong expression of P-glycoprotein. Most of the cases were non-responders, and using Kaplan-Meier live tables, an unfavorable clinical outcome could be demonstrated. Possibly, chondroblastic tumors have a special position among osteosarcomas because of their differentiation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Serum levels of insulin-like growth factor-I, -II and insulin-like growth factor binding proteins -2 and -3 in children with acute lymphoblastic leukaemia.

UNLABELLED: The insulin-like growth factor (IGF) signaling pathway may be of importance for the proliferation of different tumours (e.g. breast cancer and Wilms tumour). The bioavailability of both IGF-I and IGF-II is regulated by specific IGF-binding proteins (IGFBPs). IGFBP-2 is the predominant binding protein during fetal life, where it is expressed in most tissues. In contrast, postnatally it is mainly released by specific cell types (hepatocytes, astroglia, kidney cells, prostate cells) and a range of tumour cell lines. Furthermore, phytohaemagglutinin stimulated normal lymphoblasts and malignant lymphoblasts express IGFBP-2. In order to investigate the IGF regulatory pathway in leukaemia serum levels of IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were determined in 28 leukaemic children. Whereas serum levels of IGF-I (mean/range: -2.7/-0.1 to -6.7 SDS), IGF-II (-3.6 SDS/-1.3 to -8.7) and IGFBP-3 (-2.0/+2.2 to -7.1 SDS) were significantly decreased comparable to levels in growth hormone deficiency, IGFBP-2 levels (+4.0/-0.45 to +7.4 SDS) were found to be markedly elevated and inversely correlated to IGF-I (r = -0.51, P = 0.013). After haematological remission upon chemotherapy all four parameters had normalized in the 16 re-investigated children. Similar findings have been observed in one boy with a relapse including CNS leukaemia. CONCLUSION: This study demonstrates that the proliferation of malignant lymphoblasts (at diagnosis vs treatment) occurs in the presence of decreased serum levels of IGF-I, IGF-II and IGFBP-3 and that diminished production of these peptides may contribute to impaired growth. It further indicates that serum levels of IGFBP-2 may be directly related to the proliferation of lymphoblasts.

Adolescent↗