Multiparameter characterization of L3 leukemia cell populations

Survival analyses in cardiovascular research, part I: the essentials

This review provides a practical guide to the essentials of survival analysis and their reporting in cardiovascular studies, although most of its key content can be extrapolated to other medical fields. This is the first in a series of 2 educational articles laying the groundwork to address the most relevant statistical issues in survival analyses, which will smoothly drive the reader from the most basic analyses to the most complex situations. The focus will be on the type and shape of survival data, and the most common statistical methods, such as nonparametric, parametric and semiparametric models. Their adequacy, interpretation, advantages and disadvantages are illustrated by examples from the field of cardiovascular research. This article ends with a set of recommendations to guide the strategy of survival analyses for a randomized clinical trial and observational studies. Other topics, such as competing risks, multistate models and recurrent-event methods will be addressed in the second article.

Immunophenotyping of leukemia

Modern immunophenotyping of hematological malignancies by flow cytometry is assisted by a wide array of easily accessible monoclonal antibodies, by antibodies conjugated to diverse fluorochromes, and by reliable techniques for cell membrane permeabilization. Simultaneous assessment of multiple surface and intracellular markers at diagnosis reduces the number of cells required, helps the identification of the malignant cells and determines the degree of immunophenotypic heterogeneity of the malignant cell population. A few critical markers are sufficient to establish the lineage association in the majority of cases of acute and chronic leukemias and lymphomas. More extensive immunophenotyping can provide information about the cells' stage of differentiation, assess the expression of prognostically important features, and determine clonality. The identification of leukemia-associated immunophenotypes can be used for monitoring minimal residual disease during therapy. The presence of cells expressing these phenotypes in patients who are in clinical remission is associated with an increased risk of relapse.

Survival analysis in public health research

This paper reviews the common statistical techniques employed to analyze survival data in public health research. Due to the presence of censoring, the data are not amenable to the usual method of analysis. The improvement in statistical computing and wide accessibility of personal computers led to the rapid development and popularity of nonparametric over parametric procedures. The former required less stringent conditions. But, if the assumptions for parametric methods hold, the resulting estimates have smaller standard errors and are easier to interpret. Nonparametric techniques include the Kaplan-Meier method for estimating the survival function and the Cox proportional hazards model to identify risk factors and to obtain adjusted risk ratios. In cases where the assumption of proportional hazards is not tenable, the data can be stratified and a model fitted with different baseline functions in each stratum. Parametric modeling such as the accelerated failure time model also may be used. Hazard functions for the exponential, Weibull, gamma, Gompertz, lognormal, and log-logistic distributions are described. Examples from published literature are given to illustrate the various methods. The paper is intended for public health professionals who are interested in survival data analysis.

Refractory anemia with excess of blasts and isochromosome 12p in a patient with primary mediastinal germ-cell tumor

Isochromosome(12p), a cytogenetic abnormality characteristic of germ-cell tumors, is exceedingly rare in hematologic disorders. The cytogenetic analysis of a patient diagnosed as refractory anemia with excess of blasts with an associated i(12p), who previously had a teratocarcinoma of the mediastinum, is presented. The cytogenetic analysis was performed at diagnosis of the hematologic malignancy, with all 30 metaphases in the bone marrow culture showing a 47,X, -Y, +8, +i(12)(p10) karyotype. The cytogenetic findings in this patient are compared with those published concerning the association of mediastinal germ-cell tumors and malignant hematologic disorders.

Isochromosome 1q in acute monocytic leukemia: a new nonrandom association

We report a case of de novo acute monocytic leukemia in a 25-year-old man in whom the sole clonal cytogenetic abnormality was an additional isochromosome 1q. Cytogenetic polymorphisms indicate that, in addition to the formation of the isochromosome, a duplication of the remaining normal chromosome 1 had taken place. Other reported cases suggest an association between acute monocytic leukemia and i(1q).

Morphologic characteristics of acute lymphoblastic leukemia (ALL) with abnormalities of chromosome 8, band q24

The CALGB prospectively studied 140 adult acute lymphoblastic leukemia (ALL) patients for cytogenetic abnormalities. Seven (5%) patients with adequate cytogenetic preparations had t(8;14)(q24;q32) or t(8;22)(q24;q11). Patients were compared with non-8q24 patients for clinical and laboratory characteristics, response to therapy, and survival. The median age of patients with translocations involving 8q24 (71% males) was 40 years. Forty-three percent had lymphadenopathy, 29% splenomegaly, and 29% hepatomegaly. None exhibited central nervous system (CNS), skin, or gum involvement. These features did not differ significantly from non-8q24 ALLs. Patients with 8q24 translocations had higher hemoglobins (11.5 vs. 9.8 g/dl; P = 0.04) and lower percentage of blasts in the peripheral blood (8.5% vs. 69%; P = 0.007). Although all seven were finally categorized as ALL-L3, a marked variation in the proportion of typical L3 blasts was observed that initially resulted in the diagnoses of ALL-L2 in three cases and prolymphocytic leukemia in one. In five of five patients, the blasts typed as B cells (SIg+ and CD19+). Complete remission rates for patients with 8q24 translocations were 43%, whereas they were 68% for non-8q24 ALLS (P = 0.22). Furthermore, patients with 8q24 abnormalities exhibited significantly shorter survival (4.8 vs. 18.4 mo; P less than 0.001). We conclude that ALL with translocations of 8q24 in adults shows a mature B-cell immunophenotype (SIg+), poor prognosis and morphology ranging from classical ALL-L3 to ALL with a subpopulation of L3 cells. Thus, the diagnosis of ALL-L3 should be made when blastic cells possess a mature B-cell immunophenotype (SIg+) and an 8q24 translocation, even though the number of L3 cells is low.

Conversion of high grade lymphoma tumor cell line to intermediate grade with TPA and bryostatin 1 as determined by polypeptide analysis on 2D gel electrophoresis

A high-resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used for total cellular polypeptide mapping of two established lymphoma cell lines; MANCA, a Burkitt's line representing a high grade lymphoma (HGL) and WSU-NHL (nodular histiocytic lymphoma) representing an intermediate grade lymphoma (IGL). Gels were digitized and analysed with an image scanning computer using the Elsie 4 system. Polypeptide mapping revealed striking similarities in 1100 polypeptide spots in both types. However, three polypeptides were unique to HGL (Molecular mass/isoelectric point (Mr/PI): 39/4.4, 35/5.6, 33/4.8), and one to IGL (95/4.7). In order to investigate the kinetics of expression of these polypeptides, the two cell lines were treated with two protein kinase C (PKC) activators, tumour promoting 12-O tetradecanoylphorbol 13-acetate (TPA) and bryostatin 1. 2D-PAGE of the treated cells revealed that the HGL line loses its unique polypeptides and expresses a new one. The new polypeptide has the same Mr and PI as that unique to the untreated IGL (95/4.7). TPA or bryostatin 1 treatment of the IGL line for 72 h induced no significant changes. Our data show a unidirectional change from HGL to IGL, supporting the clinical notion that HGL is less differentiated than IGL. It also shows the similarity in the mode of action of bryostatin 1 and TPA in inducing these polypeptide changes.