The molecular analyses of hematological malignancies--lineage specific classification and its clinical implications

Cells from 203 children with leukemia/lymphoma were analyzed by the FAB (French-American-British) system using a broad panel of markers such as immunological marker studies, Southern blot and Northern blot analyses to establish a lineage specific classification of childhood leukemia. Phenotypically, they were divided into B-lineage (62.6%), T-lineage (9.8%), non-lymphoid (14.3%) and uncertain lineage (13.3%). Two B-lineage ALL cells and two T-lineage ALL cells studied did not show immunoglobulin (Ig) or T-cell receptor (TCR) gene rearrangements, respectively. Therefore, those four cases were excluded from the final classification. The uncertain lineage leukemia, which includes undifferentiated leukemia and mixed lineage leukemia, were further subclassified at the DNA and RNA levels. The definitions of B-lineage and T-lineage cells, incidence of dual genotypes or spillover, heterogeneity of undifferentiated leukemia, and a new classification for mixed lineage leukemia were discussed.     

Malignant Cutaneous Adnexal Tumors and Role of SLNB

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Rearrangement of the T cell receptor gamma-chain gene in childhood acute lymphoblastic leukemia

We analyzed rearrangements of the T cell receptor gamma-chain (T gamma) gene as well as rearrangements of the T cell receptor beta-chain (T beta) gene and immunoglobulin heavy-chain (IgH) gene in 68 children with acute lymphoblastic leukemia (ALL). All 15 patients with T cell ALL showed rearrangements of both T beta and T gamma genes. Twenty-four of 53 non-T, non-B ALL patients (45%) showed T gamma gene rearrangements and only 14 of these also showed T beta gene rearrangements. Only a single patient rearranged the T beta gene in the absence of T gamma gene rearrangement. The rearrangement patterns of the T gamma gene in non-T, non-B ALL were quite different from those observed in T cell ALL, as 20 of 23 patients retained at least one germline band of the T gamma gene. In contrast, all T cell ALL patients showed no retention of germline bands. These data indicate that rearrangement of the T gamma gene is not specific for T cell ALL. Further, the results also suggest that T gamma gene rearrangement precedes T beta gene rearrangement. The combined analysis of rearrangement patterns of IgH, T beta, and T gamma genes provides new criteria for defining the cellular origin of leukemic cells and for further delineation of leukemia cell heterogeneity.     

Duality of n-3 Polyunsaturated Fatty Acids on Mcp-1 Expression in Vascular Smooth Muscle: A Potential Role of 4-Hydroxy Hexenal

N-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have protective effects against atherosclerosis. Monocyte chemotactic protein (MCP)-1 is a major inflammatory mediator in the progression of atherosclerosis. However, little is known about the regulation of Mcp-1 by DHA and EPA in vessels and vascular smooth muscle cells (VSMCs). In this study, we compared the effect of DHA and EPA on the expression of Mcp-1 in rat arterial strips and rat VSMCs. DHA, but not EPA, suppressed Mcp-1 expression in arterial strips. Furthermore, DHA generated 4-hydroxy hexenal (4-HHE), an end product of n-3 polyunsaturated fatty acids (PUFAs), in arterial strips as measured by liquid chromatography-tandem mass spectrometry. In addition, 4-HHE treatment suppressed Mcp-1 expression in arterial strips, suggesting 4-HHE derived from DHA may be involved in the mechanism of this phenomenon. In contrast, Mcp-1 expression was stimulated by DHA, EPA and 4-HHE through p38 kinase and the Keap1-Nuclear factor erythroid-derived 2-like 2 (Nrf2) pathway in VSMCs. In conclusion, there is a dual effect of n-3 PUFAs on the regulation of Mcp-1 expression. Further study is necessary to elucidate the pathological role of this phenomenon.     

Prognostic factors in childhood acute lymphoblastic leukemia in Japan. Japan Association of Childhood Leukemia Study

A retrospective analysis of children with acute lymphoblastic leukemia (ALL) was performed to evaluate the current status of diagnosis and treatment of ALL in Japanese children. Clinical records of 670 children with ALL were collected and analyzed; these children had been diagnosed between 1991 and 1995 at the 53 institutions in 4 areas participating in the Japan Association of Childhood Leukemia Study. It was found that T-cell ALL was significantly less frequent in Tokai and Hokkaido than in Kansai and Chu-Shikoku. The overall induction rate was 92.4%. The estimated 7-year overall survival rate and event-free survival (EFS) rate were 76.0% +/- 1.9% and 61.4% +/- 2.1%, respectively. EFS rates were significantly different among the geographic areas. In female patients with B-cell precursor (B-pre) ALL and white blood cell counts at diagnosis (WBCsdiag) below 50.0 x 10(9)/L, favorable outcomes were significant. Favorable outcomes were not significant in B-pre ALL patients with a WBCdiag above 50.0 x 10(9)/L or in T-cell ALL patients. The EFS rate for infants was significantly worse than that for patients over 1 year of age. In B-pre ALL, but not in T-cell ALL, it was found that the higher the WBCdiag, the worse the EFS rate. Multivariate analysis showed that the following factors were significantly unfavorable for EFS: the Philadelphia chromosome, an translocations associated with chromosome 11q23, an acute unclassified leukemia, mixed-lineage leukemia, a WBCdiag above 100.0 x 10(9)/L, and male gender. Hyperdiploidy (> 50 chromosomes) was significantly favorable for EFS. For further tailoring of treatment and to improve the outcome in childhood ALL, a prospective large-scale study should be undertaken in Japan.     

Acute myeloid leukaemia with myelodysplastic features in children: a report of Japanese Paediatric Leukaemia/Lymphoma Study Group

The clinical characteristics and prognostic relevance of acute myeloid leukaemia (AML) with myelodysplastic features remains to be clarified in children. We prospectively examined 443 newly diagnosed patients in a multicentre clinical trial for paediatric de novo AML, and found ‘AML with myelodysplasia‐related changes’ (AML‐MRC) according to the 2008 World Health Organization classification in 93 (21·0%), in whom 59 were diagnosed from myelodysplasia‐related cytogenetics alone, 28 from multilineage dysplasia alone and six from a combination of both. Compared with 111 patients with ‘AML, not otherwise specified’ (AML‐NOS), patients with ‘AML‐MRC’ presented at a younger age, with a lower white blood cell count, higher incidence of 20–30% bone marrow blasts, unfavourable cytogenetics and a lower frequency of Fms‐like tyrosine kinase 3 internal tandem duplication (FLT3‐ITD), NPM1 and CEBPA mutations. Complete remission rate and 3‐year probability of event‐free survival were significantly worse in ‘AML‐MRC’ patients (67·7 vs. 85·6%, P < 0·01, 37·1% vs. 53·8%, P = 0·02, respectively), but 3‐year overall survival and relapse‐free survival were comparable with ‘AML‐NOS’ patients. By multivariate analysis, FLT3‐ITD was solely associated with worse overall survival. These results support the distinctive features of the category ‘AML‐MRC’ even in children.     

High WT1 mRNA expression after induction chemotherapy and FLT3-ITD have prognostic impact in pediatric acute myeloid leukemia: a study of the Japanese Childhood AML Cooperative Study Group

The prognostic value of WT1 mRNA expression in pediatric acute myeloid leukemia (AML) remains controversial. A sample of newly diagnosed (n?=?158) AML patients from the Japanese Childhood AML Cooperative Treatment Protocol, AML 99, were simultaneously analyzed for WT1 expression, cytogenetic abnormalities and gene alterations (FLT3, KIT, MLL, and RAS). WT1 expression (including more than 2,500 copies/??gRNA) was detected in 122 of the 158 (77.8?%) initial diagnostic AML bone marrow samples (median 45,500 copies/??gRNA). Higher WT1 expression was detected in French American British (FAB)-M0, M3, M7 and lower expression in M4 and M5. Higher WT1 expression was detected in AML with inv(16), t(15;17) and Down syndrome and lower in AML with 11q23 abnormalities. Multivariate analyses demonstrated that FLT3-internal tandem duplication (ITD), KIT mutation, MLL-partial tandem duplication were correlated with poor prognosis; however, higher WT1 expression was not. FLT3-ITD was correlated with WT1 expression and prognosis. Furthermore, 74 WT1 expression after induction chemotherapy was analyzed. Higher WT1 expression after induction chemotherapy was significantly correlated with M1 or M2/M3 marrow, FLT3-ITD and poor prognosis. Multivariate analyses in 74 AML patients revealed that FLT3-ITD, MLL-PTD, and KIT mutations were associated with poor prognosis; however, NRAS Mutation, KRAS mutation and high WT1 expression (>10,000 copies/??gRNA) did not show poor prognosis. Our findings suggest that higher WT1 expression at diagnosis does not correlate with poor prognosis, but that WT1 expression after induction chemotherapy is considered to be a useful predictor of clinical outcome in pediatric AML.     

Magnetic resonance imaging of skeletal muscle in patients with Duchenne muscular dystrophy--serial axial and sagittal section studies

Magnetic resonance imaging of skeletal muscles in thirteen patients with Duchenne muscular dystrophy was performed to estimate pathological changes. Serial axial and sagittal sections of the right lower extremity were recorded. In the early stage, the T1 values of gastrocnemius and soleus muscles were slightly lower than the control values, and in the late stage, the values were much lower in all muscles examined. In sagittal sections, the gastrocnemius muscles in the early stage showed a high density area at the distal region adjacent to soleus muscle, and the soleus muscle showed a high density area adjacent to the gestrocnemius muscle. In serial axial sections, high density areas of the anterior and posterior tibialis muscles appeared first at their proximal and peripheral regions. It was concluded that the sequence of appearance of pathological changes was different not only among individual muscles but also among various regions of each muscle; the high density changes appeared first at myotendon junctions.