Giuseppe Basso

Role of cranial radiotherapy for childhood T-cell acute lymphoblastic leukemia with high WBC count and good response to prednisone. Associazione Italiana Ematologia Oncologia Pediatrica and the Berlin-Frankfurt-Münster groups.

PURPOSEnThe ALL-BFM 90 and AIEOP-ALL 91 studies share the same treatment backbone and have 5-year event-free survival (EFS) rates close to 75%. This study evaluated the impact of differing presymptomatic CNS therapies in T-cell acute lymphoblastic leukemia (T-ALL) patients with a good response to prednisone (PGR) according to WBC count and Berlin-Frankfurt-Münster (BFM) risk factor (RF).nnnPATIENTSnA total of 192 patients (141 boys; median age, 7.5 years) with T-ALL, PGR, RF less than 1.7, and no CNS leukemia diagnosed between 1990 and 1995 were enrolled onto the ALL-BFM 90 (n = 123) or AIEOP-ALL 91 (n = 69) study. Presymptomatic CNS therapy consisted of cranial radiation (CRT) and intrathecal methotrexate (I.T. MTX) (11 doses) in the BFM study and of extended triple intrathecal therapy (T.I.T.) (17 doses) in the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) study. Patients were divided into a low-WBC group (WBC count < 100,000/microL) and a high-WBC group (WBC count > 100,000/microL). EFS was compared using the log-rank test.nnnRESULTSnFor patients treated with CRT and I.T. MTX (BFM group), the 3-year EFS rate was 89.8% (SE = 3.5) for 99 patients in the low-WBC group versus 81.9% (SE = 8.2) in the high-WBC group (difference not significant). Conversely, for patients treated with T.I.T. alone (AIEOP group), the EFS rate was 80.6% (SE = 5.6) in 55 patients with a low WBC count versus 17.9% (SE = 11.0) in 14 patients with a high WBC count (P < .001).nnnCONCLUSIONnThese data suggest that CRT may not be necessary in PGR T-ALL patients with a WBC count less than 100,000/microL; on the contrary, in patients with a high count, extended T.I.T. may be inferior to CRT and I.T. MTX.

Analysis of cyclin-dependent kinase inhibitor genes (CDKN2A, CDKN2B, and CDKN2C) in childhood rhabdomyosarcoma.

p16INK4A, p15INK4B, and p18 proteins are highly specific inhibitors of cyclin‐dependent serine/threonine kinase (CDK) activities required for G1‐S transition in the eukaryotic cell division cycle. Mutations, mainly homozygous deletions, of the CDKN2A (p16INK4A/MTSI) gene have been recently found in tumor cell lines and in many primary tumors. We looked for homozygous deletions of CDKN2A, CDKN2B (p15INK4B), and CDKN2C (p18) in 12 primary rhabdomyosarcoma (RMS) specimens and in five cell lines established from this cancer type. By means of polymerase chain reaction (PCR) and PCR‐single strand conformation polymorphism (PCR‐SSCP), we analyzed the presence of biallelic gene deletion or point mutation causing gene function loss. All the examined tumor cell lines (100%) and three of 12 (25%) primary tumors showed homozygous deletion of CDKN2A. Furthermore, no aberrant bands in primary tumors were detected via SSCP, suggesting the absence of mutations in the coding region. In all cases the deleted area at 9p21 also involved the CDKN2B gene. Conversely, no homozygous deletion or point mutations were detected when CDKN2C was analyzed. Our results strongly indicate that the p16INK4A (and/or p15INK4B) protein plays a key role in the development and/or progression of childhood rhabdomyosarcoma and suggest that this CDK‐inhibitor protein might control proliferation and/or differentiation of human muscle cells. Moreover, alteration of CDKN2C does not appear to be involved in the genesis of rhabdomyosarcoma. Genes Chromosom Cancer 15:217–222 (1996).

Cytogenetic analysis of hepatoblastoma: Hypothesis of cytogenetic evolution in such tumors and results of a multicentric study

Hepatoblastoma is a rare pediatric malignant tumor of the liver. Previous cytogenetic reports are sporadic. We karyotyped nine consecutive hepatoblastomas from the Italian centers participating in a multicentric study on hepatic tumors (SIOPEL 1). Six cases showed abnormal karyotypes. The most common abnormalities were trisomies of chromosomes 2 and 20. Four cases showed abnormalities of chromosome 1. On the basis of findings, we speculate the possibility of a cytogenetic evolutive pattern of hepatoblastomas.

Cell adhesion molecule expression in cord blood CD34+ cells.

Self‐renewal, proliferation, differentiation, homing, and mobilization of hematopoietic progenitor cells (HPCs) are regulated by a complex mechanism that involves the bone marrow (BM) microenvironment. Cell adhesion molecules (CAMs) expressed on HPCs and on endothelial and stromal cells play a pivotal role in this process. In this study, we have used three‐color cytofluorometric analysis to compare CAM expression in the subsets of cord blood (CB) and BM HPCs and examined the effect of a short exposure to various cytokines on L‐selectin expression. The study was carried out on unseparated samples to avoid any possible bias from positive CD34 selection. CAMs were highly expressed in both CB and BM CD34+CD38+ cells. In this population, L‐selectin, H‐CAM, and LFA‐1 were significantly more expressed in BM than in CB.

Outcome and lineage involvement in t(12;21) childhood acute lymphoblastic leukaemia

The t(12;21)(p13;q22) translocation has been described recently as the most recurrent genetic lesion in paediatric acute lymphoblastic leukaemias (ALLs). It has also been associated with B‐precursor lineage involvement and good outcome.

Cytogenetics of pediatric central nervous system tumors.

A cytogenetic analysis was performed on short-term cultures of 43 previously untreated childhood central nervous system neoplasms of various histology. The cells were obtained from pediatric patients, none of whom had received therapy before karyotypic evaluation. Successful chromosome studies were performed on 24 tumors. The most commonly detected structural abnormalities involved chromosomes 1 and 17. Other structural chromosome abnormalities involved chromosomes 3, 6, 8, 9, 11, 12, and 20.

Lack of p73 expression in mature B-ALL and identification of three new splicing variants restricted to pre B and C-ALL indicate a role of p73 in B cell ALL differentiation.

Lack of p 73 expression in mature B-ALL and identification of three new splicing variants restricted to pre B and C-ALL indicate a role of p 73 in B cell ALL differentiation

Clinical relevance of DNA ploidy and proliferative activity in childhood rhabdomyosarcoma: a retrospective analysis of patients enrolled onto the Italian Cooperative Rhabdomyosarcoma Study RMS88.

PURPOSEnEvaluation of the possible clinical relevance of DNA ploidy and proliferative activity assessed as S-phase fraction (SPF) in childhood rhabdomyosarcoma (RMS).nnnPATIENTS AND METHODSnWe conducted a retrospective study on 59 RMS patients enrolled onto the ICS-RMS88 protocol (seven botryoid, 35 embryonal, and 17 alveolar RMS), for which formalin-fixed paraffin-embedded (FFPE) tissue was available. Nuclear suspensions for cytometric investigation were obtained using a mechanical disaggregation. Tumors were distinguished according to their DNA index (DI) value as follows: diploid (0.9 < DI < 1.1), hyperdiploid (1.1 < or = DI < 1.8 or DI > or = 2.2), and tetraploid (1.8 < or = DI < 2.2); for analysis of SPF, a cutoff value of 14% was used.nnnRESULTSnDNA histograms were diploid in 19 (33%) cases, hyperdiploid in 29 (49%), and tetraploid in 10 (32%). One patient showed both a hyperdiploid and a tetraploid peak. The 5-year overall survival (OS) rate by ploidy status was 73% in hyperdiploid patients as compared with 33% and 25% in diploid and tetraploid patients, respectively (P = .0012). A striking difference emerged when the 5-year OS for the combined diploid and tetraploid RMS groups was compared with survival of the hyperdiploid RMS group: 30% versus 73%, respectively (P = .0006). In addition, the SPF was prognostically relevant: 5-year OS by SPF less than or greater than 14% was 70% and 36%, respectively (P = .009). Multivariate analysis confirmed the importance of DNA content (P = .0006) and SPF (P = .034) in predicting survival.nnnCONCLUSIONnThese findings confirm that ploidy and SPF are important new prognostic factors that are able to identify selected groups of patients at high risk of treatment failure, even if the tumors presentation is favorable according to standard criteria.

Persistence of E2A/PBX1 transcripts in t(1;19) childhood acute lymphoblastic leukemia: Correlation with chemotherapy intensity and clinical outcome

The occurrence of t(1;19) translocation was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) for the E2A/PBX1 hybrid message in a panel of 37 consecutive childhood acute lymphoblastic leukemias (ALLs). Three patients with B-precursor ALL were found to be positive at diagnosis and were re-tested during follow-up to assess the presence of minimal residual disease (MRD). Two of them became PCR-negative during treatment, whereas one remains positive 3 years after diagnosis. Since all three patients are presently in clinical and hematological complete remission, PCR detection of persistent E2A/ PBX1 transcript does not seem to affect significantly the DFS at 3 years. However, the predictivity for an eventual late relapse still remains to be assessed.

Frequent clonal loss of heterozygosity (LOH) in the chromosomal region 1p32 occurs in childhood T cell acute lymphoblastic leukemia (T-ALL) carrying rearrangements of the TAL1 gene.

Deletions and chromosomal translocations involving the 1p32 region, are frequently observed in T cell acute lymphoblastic leukemia (T-ALL). One of the most common genetic changes is the breakage of the TAL1 gene, which was originally described to be involved in the T-ALL carrying the t(1;14)(p32;q11) translocation. Site-specific deletions in the TAL1 gene are reported to occur in 12–26% of T-ALL with apparently normal karyotype. In order to investigate the presence of other subkaryotypic abnormalities involving the 1p32 chromosomal region, where TAL1 gene is mapped, we assessed losses of heterozygosity (LOH) for microsatellite markers, in a series of 22 children with T-ALL. Microsatellite polymorphic markers flanking the TAL1 gene (D1S211, D1S197, D1S200 and D1S220) were analyzed to detect LOH. Eight patients displayed LOH for at least one of the markers, suggesting the existence of hot spot regions at the short arm of chromosome 1. Two out of 11 with no molecular evidences of TAL1 gene involvement, compared to six out of 11 in the group of TAL1 rearranged gene, showed LOH at 1p32. TAL1 gene rearrangements and clonal LOH may represent two independent events, but could be related to the same causes. For the first time this study provides evidences that LOH at 1p32 region, occurs in T-ALL in the same region known to be involved in chromosomal deletions and translocations. LOH mapping may help to define the location of a new putative tumor-suppressor gene implicated in the trasformation and progression of children T-ALL.