Regression of a congenital mesoblastic nephroma

Histologically, the cellular variant of congenital mesoblastic nephroma (CMN) is very similar to another rare tumor of infancy, infantile fibrosarcoma (IFS). In addition to the histologic similarities, these tumor types share cytogenetic abnormalities including translocation t(12;15)(p13;q25). We describe herein the case of a child who did not have immediate surgical resection of a CMN and whose tumor was untreated for 8 months. During that time, the tumor demonstrated a significant degree of regression. The shared translocation with IFS, a tumor with well‐documented potential for spontaneous regression, suggests that this genetic abnormality may have contributed to the favorable clinical course. Pediatr Blood Cancer. 2010;55:364–368. © 2010 Wiley–Liss, Inc.     

Differences in HLA class II alleles of isolated South American Indian populations from Brazil and Argentina

We have studied the HLA class II alleles in 277 South American Indians, which included Argentinian tribes from the Gran Chaco: Toba (n = 135), Toba-Pilaga (n = 19), Mataco-Wichi (n = 49), and Xavantes, a tribe from Central Brazil (n = 74). In the Brazilian tribe, only four DR groups were found: DRB1^*1602 (gf = 0.303), DRB1^*04 including DRB1^*0404 (gf = 0.070) and DRB1^*0407 (gf = 0.077), DRB1^*0802 fgf = 0.265), and DRB1^*1402 (gf = 0.303). The HLA class II allele frequencies were similar among the different Argentinian tribes, and 90% of DRB1 alleles belonged to three families: DRB1^*04 (including DRB1^*0403, DRB1^*0404, DRB1^*0407, DRB1^*0411, and DRB1^*0417), DRB1^*0802, and DRB1^*14 (including DRB1^*1402 and DRB1^*1406). At the DPB1 locus, we found only seven alleles, the most frequent being DPB1^*0402. Comparison of HLA class II alleles with those of North American Indians that we have previously studied shows that the frequency of some HLA class II alleles in Brazilian Xavantes resembles that of North American Indians more than that of the Argentinian Indian tribes. The allele DRB1^*0417 was found exclusively in this population.     

Low-dose oral etoposide-based induction regimen for children with acute lymphoblastic leukemia in first bone marrow relapse.

We evaluated the clinical response to low-dose etoposide in relapsed acute lymphoblastic leukemia (ALL). Of the 45 patients with ALL in first bone marrow relapse enrolled on the ALL R15 protocol, 44 had received epipodophyllotoxins during frontline therapy. In the first week of remission induction therapy, patients received etoposide (50 mg/m(2) per day) administered orally as a single agent once or twice daily. On Day 8, patients started to receive dexamethasone, vincristine, and L-asparaginase. Etoposide was administered until Day 22. Two courses of consolidation therapy were followed by continuation therapy or hematopoietic stem cell transplantation. After 7 days of single-agent etoposide treatment, peripheral blast cell counts (P=0.013) and percentages of bone marrow blasts (P=0.016) were significantly reduced. In all, 38 (84.4%) attained second remission. Only time to relapse was significantly associated with outcome (P=0.025): the 5-year event-free survival estimates (+/-se) were 52.0+/-9.6% for those with late relapse and 20.0+/-8.0% for those with early relapse. We conclude that low-dose etoposide administered orally has a cytoreductive effect in relapsed ALL.     

Translocation t(9;11)(p21;q23) in pediatric de novo and secondary acute myeloblastic leukemia.

The t(9;11)(p21;q23) has been associated with characteristic clinical features and a superior treatment outcome in previously untreated pediatric acute myeloblastic leukemia (AML), but has not been well studied in children with secondary AML. This translocation was detected in 6.7% of de novo and 46% of secondary AML patients treated at St Jude Children's Research Hospital over an 11-year period. Clinical, immunophenotypic, and morphologic characteristics were examined for the cases of t(9;11) secondary AML (n = 12) and compared with findings for children with t(9;11) de novo AML (n = 12). Patients with t(9;11) secondary AML were older at diagnosis, had higher hemoglobin levels, and central nervous system leukemia or hepatosplenomegaly was less frequent. These differences probably reflect survival of the first malignancy and close clinical scrutiny during post-treatment follow-up. Whereas the t(9;11)(p21;q23) occurred exclusively in the French-American-British (FAB) M5 subtype in de novo AML, the FAB M0 and M4 subtypes were also represented in secondary cases. The complete remission rate was somewhat higher for the de novo AML group (91 vs 58%; p = 0.16); their event-free survival was clearly superior to that for children with t(9;11) secondary AML (p = 0.003). Host differences related to the previous malignancy or its treatment could explain the poorer clinical outcome for patients with t(9;11) secondary AML. Alternatively, there could be critical differences at the translocation site or additional, hidden molecular events, that explain the different outcomes.