NPM1, FLT3 and CEBPA mutations in pediatric patients with AML from Argentina: incidence and prognostic value

Mutations in NPM1, FLT3 and CEBPA genes are found in 25-35 % of adult acute myeloblastic leukemia (AML) cases and correlate with prognosis. To date, there have been no reports about these mutations in pediatric AML from Argentina. The aims of the present study were to describe the incidence of NPM1, FLT3 and CEBPA mutations and to analyze their prognostic impact in this population. The incidences of these mutations within a population of 216 pediatric AML cases were: NPM1-mutated 4.2 %, CEBPA-mutated 1.9 %, FLT3-ITD 10.2 % and FLT3-TKD 7.9 %. Among 33 patients with normal karyotype, we found significantly higher frequencies for NPM1-mutated 24.2 % and CEBPA-mutated 12.1 %. Overall survival (pOS) for the 163 eligible non-acute promyelocytic leukemia cases was 46.2 ± 4.3 %, while leukemia-free survival probability was 51.0 ± 4.4 % (n = 135). The NPM1-mutated/FLT3-ITD-negative genotype showed better outcome than any other combined NPM1/FLT3 genotype; this difference was statistically significant within the group of high-risk patients (pOS ± SE 83.3 ± 15.2 % versus 33.1 ± 4.7 %; p = 0.0251). This is the first report of the frequencies of these mutations in Argentina. Despite the limited number of patients, a favorable prognosis of AML with genotype NPM1-mutated/FLT3-ITD-negative was confirmed. This is especially relevant within the high-risk group of patients, as it may contribute to the detection of patients with better prognosis, and thus avoid unnecessary treatment intensification.

Duplication dup(1)(q41q44) defined by fluorescence in situ hybridization: delineation of the ‘trisomy 1q42→qter syndrome’

We report on a novel case of pure partial tandem duplication 1q42q43 confirmed by fluorescence in situ hybridization (FISH). We compare the manifestations of our patient with similar cases previously reported. We conclude that the most common clinical manifestations of trisomy 1q42qter are prenatal and postnatal growth retardation, relative macrocephaly, triangular face, prominent forehead, broad nasal bridge, abnormal philtrum, micro/retrognathia, cardiac defects and mental retardation. We would like to emphasize the importance of the FISH technique in the identification of the duplicated segment.

[Focal fatty liver lesions: infrequent ultrasonographic presentation]

We present case of focal fatty liver lesions. Echography images revealed multiple hyperechogenic lesions similar to those observed in metastatic disease. Aspiration was negative and diagnosis was based on the results of liver biopsy alone, carried out during laparoscopy. The difficulty of determining the etiology of this type of lesión by echography is discussed.

Good outcome of children with acute myeloid leukemia and t(8;21)(q22;q22), even when associated with granulocytic sarcoma: a report from a single institution in Argentina

BACKGROUND

The association between t(8;21) and granulocytic sarcoma (GS) is well known, but to the authors' knowledge the prognostic significance of GS in these patients has not been defined clearly.

METHODS

Between January 1990 and July 1999 174 children with acute myeloid leukemia were admitted to the study institution. Translocation (8;21) was identified in 20 patients (11.5%). Eighteen patients were evaluable for the current study and 8 presented with GS at the time of diagnosis (GS+).

RESULTS

The authors defined two groups of patients: those who were GS+ and those who were GS-. One patient in the GS+ group and two patients in the GS- group died during the induction phase of the study. Complete remission was achieved in seven patients in the GS+ group and eight patients in the GS- group. Two patients developed a recurrence in the GS+ group as did one patient in the GS- group. The event free-survival probability (the standard error) was 58% (18%) in the GS+ group and 70% (14%) in the GS- group. Localization of GS was in only one site in seven patients and at multiple sites in one patient. Patients with an epidural mass received local radiotherapy (one patient) or surgery (two patients). Two of these patients developed paraplegia as sequelae: one patient after surgery and one patient after radiotherapy. One patient with orbital GS received local radiotherapy because of progressive proptosis. The remaining four patients had a complete resolution of the GS with chemotherapy only.

CONCLUSIONS

In the current study of patients with t(8;21)(q22;q22), the presence of granulocytic sarcoma was not found to be an adverse prognostic factor. However, careful attention should be paid, especially to patients with an epidural site, to avoid sequelae. Chemotherapy appears to be the optimum treatment for these children.

[Translocation t(9;11) in acute childhood lymphoblastic leukemia]

We report a case of a de novo acute lymphoblastic leukaemia (ALL) with t(9;11) (p21;q23) and a novel translocation t(2;8) (p15;q24). The former is characteristic of acute nonlymphoblastic leukaemia (ANLL) and has rarely been detected in ALL. The blasts showed L2 morphology by the French American British (FAB) classification and pre B ALL immunophenotype.

Tandem triplication and quadruplication of chromosome 21 in childhood acute lymphoblastic leukemia

A 5-year-old girl with ALL was shown to have a leukemic clone characterized by a triplication and quadruplication of chromosome 21, arranged in tandem, at diagnosis and relapse, respectively. To our knowledge, this is the second report of this chromosomal anomaly in ALL, which was confirmed by in situ staining. The karyotype evolution in the leukemic clone from triplication to quadruplication at relapse emphasizes the association of chromosome 21 with hematopoietic malignancies.

Regulation of amiloride-sensitive Na+ channels by endothelin-1 in distal nephron cells

We used patch-clamp methods to investigate the effects of basolateral endothelin-1 (ET-1) on the amiloride-sensitive Na+ channel in A6 distal nephron cells. One hundred picomolar ET-1 decreased channel activity via an increase in mean time closed (P < 0.01, n = 10). Channel inhibition by pM ET-1 was mimicked by an ET-B receptor agonist (P < 0.05, n = 7) and was prevented by ET-B antagonists (P = 0.14, n = 10) but not by an ET-A antagonist (P < 0.05, n = 4). With the inhibitory ET-B receptor blocked, higher doses of ET-1 (10 nM) actually increased channel activity through an increase in mean time open (P < 0.001, n = 12). The current-voltage relationship and the number of channels were not changed by basolateral ET-1 exposure. We conclude that 1) basolateral ET-1 regulates amiloride-sensitive Na+ channels; 2) binding of picomolar ET-1 to ET-B receptors inhibits, whereas the binding of nanomolar ET-1 to a different ET receptor (likely ET-A) stimulates, channel activity; and 3) these dose-dependent, distal nephron responses provide a potential mechanism for the in vivo natriuresis and antinatriuresis observed in response to "subpressor" and "pressor" concentrations of ET-1, respectively.

New variant Ph translocation in chronic myeloid leukemia: t(Y;22)(p11;q11)

A 4-year-old boy with chronic myeloid leukemia (CML) was shown to have a variant Ph t(Y;22)(p11;q11). To our knowledge, this is the first report of a variant Ph translocation involving Y. Molecular analysis showed that the breakpoint on chromosome 22 is in the breakpoint cluster region (bcr), typical of CML with the classic t(9;22), suggesting that it might be a complex Ph translocation with the involvement of 9q34.

Safety and immunogenicity of an inactivated hepatitis A vaccine in children 2 to 5 years old

The reactogenicity and immunogenicity of an inactivated hepatitis A vaccine were assessed. Seventy healthy children aged between 2 and 5 years old, who lacked antibodies against the hepatitis A virus, were enrolled in this study. With a 0-, 1-, and 6-month vaccination schedule, the children received three doses of 360 enzyme-linked immunosorbent assay (ELISA) units of hepatitis A vaccine intramuscularly (deltoid). Safety parameters were recorded in standardized diary cards by the parents on the day of injection and the three following days. Blood tests for liver enzymes and anti-hepatitis A virus antibody analyses were performed the day of screening and 1, 2, 6 and 7 months after the first dose. Anti-hepatitis A virus antibody was tested by ELISA. Titres < 20 mIU/ml were considered negative. For the three hepatitis A vaccine doses administered, 22% (46/210) of the diary cards reported any kinds of signs or symptoms. Soreness at the injection site (9%, 18/210) and malaise (6%, 12/210) were the most common local and systemic reactions reported, respectively. The seroconversion rates were 83, 99 and 100% one month after the 1st, 2nd, and 3rd doses, respectively. The corresponding geometric mean titres were 124, 352, and 2,778 mIU/ml. We conclude that this HAV vaccine is safe and immunogenic in healthy children. As the hepatitis A epidemiology pattern is rapidly changing in our country (and other regions), resulting in an increasing population of susceptible adolescents and young adults, we suggest that the routine vaccination against hepatitis A in pre-school children attending day-care centres should be seriously considered.

Primary adenocarcinoma of the terminal ileum simulating Crohn's disease

An unusual case of histologically proven ileal adenocarcinoma mimicking regional enteritis in a 22-year-old man is reported. Although in 2 previous reports the patient's age was stressed as an important factor for the differential diagnosis, this was not of diagnostic help in our case. This report emphasizes the need to include other diagnostic possibilities when regional enteritis has an anomalous evolution and responds poorly to treatment.