Preleukemia: the normal side of cancer.

PURPOSE OF REVIEW: In the present review, we will define the preleukemic state. We aim at increasing awareness and research in the field of preleukemia that will nurture targeted therapy for the earlier steps of leukemia evolution. RECENT FINDINGS: Emerging evidence supports the role of hematopoietic stem/progenitor cells carrying recurrent leukemia-related mutations as the cell of origin of both myeloid and lymphoid malignancies. The preleukemic stem cells can maintain at least to some extent their functionality; however, they have increased fitness endowed by the preleukemic mutations that lead to clonal expansion. SUMMARY: The latent preleukemic period before overt leukemia presents can take years, and the majority of carriers will never develop leukemia in their lifetime. The preleukemic state is not rare, with greater than 1% of individuals having acquired one or more of the recognized preleukemic lesions. The high frequency of such abnormalities in the population may be the cost of growing old; however, another view could be that in order to survive to old age, the hematopoietic system must adapt to create robust hematopoietic stem/progenitor cells with an increased fitness and clonal expansion. Hence, leukemia does not necessarily start as a disease, but rather as a need, with the normally functioning preleukemic hematopoietic stem cells trying to maintain health for years but in time succumbing to their own acquired virtues.

GATA1-mutant clones are frequent and often unsuspected in babies with Down syndrome: identification of a population at risk of leukemia.

Transient abnormal myelopoiesis (TAM), a preleukemic disorder unique to neonates with Down syndrome (DS), may transform to childhood acute myeloid leukemia (ML-DS). Acquired GATA1 mutations are present in both TAM and ML-DS. Current definitions of TAM specify neither the percentage of blasts nor the role of GATA1 mutation analysis. To define TAM, we prospectively analyzed clinical findings, blood counts and smears, and GATA1 mutation status in 200 DS neonates. All DS neonates had multiple blood count and smear abnormalities. Surprisingly, 195 of 200 (97.5%) had circulating blasts. GATA1 mutations were detected by Sanger sequencing/denaturing high performance liquid chromatography (Ss/DHPLC) in 17 of 200 (8.5%), all with blasts >10%. Furthermore low-abundance GATA1 mutant clones were detected by targeted next-generation resequencing (NGS) in 18 of 88 (20.4%; sensitivity ∼0.3%) DS neonates without Ss/DHPLC-detectable GATA1 mutations. No clinical or hematologic features distinguished these 18 neonates. We suggest the term "silent TAM" for neonates with DS with GATA1 mutations detectable only by NGS. To identify all babies at risk of ML-DS, we suggest GATA1 mutation and blood count and smear analyses should be performed in DS neonates. Ss/DPHLC can be used for initial screening, but where GATA1 mutations are undetectable by Ss/DHPLC, NGS-based methods can identify neonates with small GATA1 mutant clones.

Prognostic significance of combined MN1, ERG, BAALC, and EVI1 (MEBE) expression in patients with myelodysplastic syndromes.

Overexpression of MN1, ERG, BAALC, and EVI1 (MEBE) genes in cytogenetically normal acute myeloid leukemia (AML) patients is associated with poor prognosis, but their prognostic effect in patients with myelodysplastic syndromes (MDS) has not been studied systematically. Expression data of the four genes from 140 MDS patients were combined in an additive score, which was validated in an independent patient cohort of 110 MDS patients. A high MEBE score, defined as high expression of at least two of the four genes, predicted a significantly shorter overall survival (OS) (HR 2.29, 95 % CI 1.3-4.09, P= .005) and time to AML progression (HR 4.83, 95 % CI 2.01-11.57, P< .001) compared to a low MEBE score in multivariate analysis independent of karyotype, percentage of bone marrow blasts, transfusion dependence, ASXL1, and IDH1 mutation status. In a validation cohort of 110 MDS patients, a high MEBE score predicted shorter OS (HR 1.77; 95 % CI 1.04-3.0, P= .034) and time to AML progression (HR 3.0, 95 % CI 1.17-7.65, P= .022). A high MEBE expression score is an unfavorable prognostic marker in MDS and is associated with an increased risk for progression to AML. Expression of the MEBE genes is regulated by FLI1 and c-MYC, which are potential upstream targets of the MEBE signature.

The immunoglobulin gene repertoire of low-count chronic lymphocytic leukemia (CLL)-like monoclonal B lymphocytosis is different from CLL: diagnostic implications for clinical monitoring.

In the revised National Cancer Institute Working Group (NCI-WG)/International Workshop on Chronic Lymphocytic Leukemia (IWCLL) guidelines for CLL, CLL-like monoclonal B lymphocytosis (MBL) is defined as the presence of less than 5 x 10(9)/L B lymphocytes in the peripheral blood. However, the concentration of MBL in the blood is extremely variable. MBL in subjects with lymphocytosis require treatment at a rate of 1.1% per year and present immunoglobulin (IG) gene features and similar to good prognosis CLL. Little is known about low-count MBL cases, accidentally found in the general population. We analyzed IGHV-D-J rearrangements in 51 CLL-like MBL cases from healthy individuals, characterized by few clonal B cells. Seventy percent of the IGHV genes were mutated. The most frequent IGHV gene was IGHV4-59/61, rarely used in CLL, whereas the IGHV1-69 gene was lacking and the IGHV4-34 gene was infrequent. Only 2 of 51 (3.9%) MBL cases expressed a CLL-specific stereotyped HCDR3. Therefore, the IG gene repertoire in low-count MBL differs from both mutated and unmutated CLL, suggesting that the detection of MBL in an otherwise healthy subject is not always equivalent to a preleukemic state. Detailed IG analysis of individual MBL may help to identify cases that necessitate continuous clinical monitoring to anticipate disease progression.

Transient pancytopenia preceding acute lymphoblastic leukemia with positive Philadelphia chromosome.

Transient pancytopenia preceding acute lymphoblastic leukemia (pre-ALL) is a rare but well-known occurrence usually affecting children and adolescents. Though pre-ALL in a few adults has ever been reported, the association of this preleukemic syndrome with positive Philadelphia chromosome and P190(BCR-ABL) is extremely rare. To the best of our knowledge, this is the first report of adult B-cell type pre-ALL with positive Philadelphia chromosome and P190(BCR-ABL) published in the literature. We report the case of a 49-year-old woman who was diagnosed with B-cell type ALL associated positive Philadelphia chromosome and P190(BCR-ABL) preceded by transient pancytopenia. The clinical, morphologic, immunophenotypic and molecular features of this patient are described and the literature reviewed.

Preleukemia: one name, many meanings.

Definition of preleukemia has evolved. It was first used to describe the myelodysplastic syndrome (MDS) with a propensity to progress to acute myeloid leukemia (AML). Individuals with germline mutations of either RUNX1, CEBPA, or GATA2 can also be called as preleukemic because they have a markedly increased incidence of evolution into AML. Also, alkylating chemotherapy or radiation can cause MDS/preleukemia, which nearly always progress to AML. More recently, investigators noted that AML patients who achieved complete morphological remission after chemotherapy often have clonal hematopoiesis predominantly marked by either DNMT3A, TET2 or IDH1/2 mutations, which were also present at diagnosis of AML. This preleukemic clone represents involvement of an early hematopoietic stem cells, which is resistant to standard therapy. The same clonal hematopoietic mutations have been identified in older 'normal' individuals who have a modest increased risk of developing frank AML. These individuals have occasionally been said, probably inappropriately, to have a preleukemia clone. Our evolving understanding of the term preleukemia has occurred by advancing technology including studies of X chromosome inactivation, cytogenetics and more recently deep nucleotide sequencing.

Marrow cytogenetic and cell-culture analyses of the myelodysplastic syndromes: insights to pathophysiology and prognosis.

Marrow cytogenetic and granulocyte-macrophage colony formation (CFU-GM) studies were performed on 34 previously untreated patients with documented myelodysplastic syndromes seen between January 1978 and June 1982. All patients were managed without chemotherapy until progression to acute leukemia was observed. All 10 patients with exclusively abnormal marrow metaphases developed acute leukemia (100%) while only one (7%) of 14 patients with solely normal marrow metaphases subsequently developed leukemia (p less than 0.001). Three (42%) of the seven patients with both normal and abnormal marrow metaphases developed acute leukemia. Fifteen (86%) of the 19 patients with either large cluster or no growth patterns developed acute leukemia while only two (13%) of 15 patients with either small cluster or colony forming growth patterns developed acute leukemia (p less than 0.001). Abnormal marrow cytogenetic status correlated with abnormal marrow CFU-GM growth pattern (p less than 0.05). Analysis of CFU-GM sensitivity to inhibition by prostaglandin E was performed in 12 patients. Nine patients showed CFU-GM refractoriness to inhibition by prostaglandin E. Seven of these patients eventually developed leukemia. Three patients had CFU-GMs which were initially sensitive to prostaglandin E inhibition. In these three patients, a loss of CFU-GM sensitivity to prostaglandin E was observed prior to their progression to morphologically identifiable acute leukemia.

Diagnostic and prognostic values of in vitro culture growth patterns of marrow granulocyte-macrophage progenitors in patients with myelodysplastic syndrome.

The in vitro culture growth of marrow granulocyte-macrophage progenitors (CFU-GM assay) was studied in 102 consecutive patients with newly diagnosed primary myelodysplastic syndrome (MDS) to determine its diagnostic utility and prognostic value. There were 18 patients with refractory anemia (RA), eight RA with ringed-sideroblast (RARS), 30 RA with excess of blasts (RAEB), 18 chronic myelomonocytic leukemia (CMML), and 28 RAEB in transformation (RAEB-T). Patients with MDS had a significantly lower number of GM colonies and a significantly higher cluster to colony ratio than those of normal controls and patients with cytopenias of other causes. Six in vitro growth patterns were observed; 85% of patients with MDS showed various abnormal growth patterns, and 42% of all MDS patients exhibited a leukemic growth pattern at diagnosis. None of the 40 patients with cytopenias of other causes had a leukemic type growth. A leukemic growth pattern was rarely observed in patients with RA and RARS (4%), but was common in other subgroups (57%). The distribution of various growth patterns was not statistically different among patients with RAEB, CMML, and RAEB-T. Thirty-six patients developed acute leukemia during the follow-up period. The MDS patients with leukemic type growth were at increased risk of rapid progression to acute leukemia, and they also had a shorter survival time than patients with a non-leukemic pattern. These results showed that simply scoring the number of CFU-GM is of limited value for the diagnosis and the prediction of prognosis of MDS, whereas the in vitro marrow culture growth pattern is of prognostic significance independently of the FAB classification. It is concluded that the in vitro growth pattern of marrow CFU-GM is helpful in diagnosing patients with MDS as well as in predicting their clinical outcome.

Elevated plasma level of differentiation inhibitory factor nm23-H1 protein correlates with risk factors for myelodysplastic syndrome.

We measured plasma nm23-H1 level (nm23-H1), a differentiation inhibitory factor, by an enzyme-linked immunosorbent assay (ELISA) in patients with aplastic anemia (AA) and myelodysplastic syndrome (MDS). The nm23-H1 in AA was not significantly elevated when compared to normal subjects (6.66 +/- 1.20 ng/ml vs 5.13 +/- 0.81 ng/ml; P = 0.274). In contrast, MDS patients had significantly high levels of nm23-H1 compared not only to normal subjects (11.16 +/- 1.42 vs 5.13 +/- 0.81 ng/ml; P = 0.0004) but also to those of the AA group (11.16 +/- 1.42 ng/ml vs 6.66 +/- 1.20 ng/ml; P = 0.018). In the MDS group of patients, no significant difference was observed in the nm23-H1 levels between patients with refractory anemia (RA) and RA with excess blasts (RAEB)/RAEB in transformation (10.71 +/- 1.61 ng/ml vs 9.24 +/- 2.66 ng/ml; P = 0.672). Of the patients with RA, patients with low risk according to the International Prognostic Scoring System (IPSS) had significantly low levels of nm23-H1 compared to those of IPSS INT-1 level cases (6.40 +/- 1.36 ng/ml vs 13.05 +/- 2.50 ng/ml; P = 0.0028), suggesting that nm23-H1 may be useful as a prognostic marker for MDS, especially in low risk patients.

Acute megakaryocytic leukemia. Description of a case initially seen as preleukemia syndrome.

A 52-year-old man had aregenerative anemia unresponsive to pyridoxine hydrochloride. Acute leukemia developed, and he died four months after diagnosis. At autopsy he had acute megakaryocytic leukemia with involvement of bone marrow, liver, spleen, adrenals, kidneys, and thyroid. Chromosomal analysis revealed absence of both diploid and Ph1 chromosomes. A mode of 45 chromosomes and aneuploidy were present. This is similar to the only other case with chromosomal studies. Of the 15 acceptable documented cases, eight were men and seven were women. Their age varied from 28 to 76 (mean, 55) years. Only two were less than 40 years of age. Most had pancytopenia, and all were dead within six months of diagnosis.

Preleukemia and urticaria pigmentosa followed by acute myelomonoblastic leukemia.

A preleukemic syndrome, mast cell hyperplasia in the bone marrow, and urticaria pigmentosa simultaneously developed in a 76-year-old woman. A year later, the patient died of acute myelomonoblastic leukemia. These associations provide evidence favoring the origin of the tissue mast cell from a bone marrow stem cell.

Ocular complications in myelodysplastic syndromes as preleukemic disorders.

PURPOSE: To identify ocular complications in patients with myelodysplastic syndromes (MDS), who have a propensity to progress to acute myeloid leukemia (AML). METHODS: Forty-one patients with MDS were the subjects in this retrospective study, and 21 patients with AML were selected as controls. Reviewing their clinical records, we verified that corneal ulcer, iridocyclitis, vitreous hemorrhage, retinal hemorrhage, and optic neuritis had been evaluated using slit-lamp assessment and opthalmoscopy in all the patients. In this study, the MDS patients were classified into those with refractory anemia (RA) and those with refractory anemia with excess blasts (RAEB). RESULTS: Ocular complications were found in 19 (46.3%) of the 41 patients with MDS, comprising corneal ulcer (two cases), iridocyclitis (five), vitreous hemorrhage (one), retinal hemorrhage (ten), cotton wool spots (one), and optic neuritis (two). (Some patients had more than one ocular complication.) Ocular complications were identified in 12 of the 21 (57.1%) patients with AML. There was no significant difference in frequency of ocular complications between MDS and AML (P = 0.4892). In MDS, retinal hemorrhage was associated with significantly reduced platelet counts (P = 0.0063). The frequency of ocular complications was significantly higher in MDS-RAEB than in MDS-RA (P = 0.0478). Retinal hemorrhage was significantly more frequent in patients with MDS-RAEB than in patients with MDS-RA (P = 0.0433). CONCLUSION: Ocular complications in MDS patients should be carefully examined as prognostic factors for progression to acute leukemia.

The preleukemic syndrome (hematopoietic dysplasia).

It has been recognized for many decades that epithelial dysplasia can represent an early histological sign of epithelial neoplasia. So it is with hematopoietic tissue wherein dysplasia of bone marrow cells can be an early sign of impending acute myeloid leukemia. Although this 'preleukemic syndrome' of hematopoietic dysplasia can often be identified well in advance of the classic histological signs of acute leukemia, a wide variety of basic studies on bone marrow cells, from patients and from experimental animals with induced preleukemia, clearly indicate that the preleukemic marrow cells are members of a fully established neoplastic clone. Consequently, it is likely that the preleukemic syndrome is merely acute leukemia diagnosed earlier than usual and which, in some patients, can be very slowly progressive, and in others may not progress at all. This article reviews the evidence in support of the notion that the preleukemic syndrome is an 'early leukemia', places the preleukemic syndrome in the context of a larger group of myelodysplastic disorders, reviews the laboratory studies of value for both diagnosis and for use in the assessment of prognosis, and summarizes the therapeutic options available for the management of patients with this disorder.

Clonal lymphocytes in persons without known chronic lymphocytic leukemia (CLL): implications of recent findings in family members of CLL patients.

Several genetic abnormalities have been characterized in chronic lymphocytic leukemia (CLL) but these are predominantly secondary events and the initiating phenomena in the etiology of the disease are yet to be established. Studies of inherited susceptibility have identified the early oncogenic events in both familial and "sporadic" forms of several malignant disorders, and this may also be possible in CLL. However, the utility of linkage analysis in identifying a predisposition locus for the disease is limited because large multigenerational families segregating CLL are rare, while the more frequent small nuclear CLL families contain insufficient numbers of affected individuals. The power to detect predisposition gene(s) could be greatly increased by extending the number of affected individuals within a particular family, for example, by identifying family members with subclinical levels of disease. High-sensitivity flow cytometry techniques, developed to monitor disease in CLL patients undergoing treatment, have allowed accurate enumeration of subclinical levels of CLL cells in healthy individuals from the general population and CLL families. Emerging evidence confirms the phenotypic, genotypic, and clinical associations between the aberrant cells in healthy individuals and those in CLL patients. The data suggest that inherited factors increase the susceptibility to both indolent and aggressive CLL, and they provide unbiased demonstration that the age of onset in CLL families is younger than in the general population.

Bone marrow mast cell content in preleukemic syndrome.

Bone marrow mast cell content was evaluated by a semiquantitative method in 22 marrow specimens from 20 patients with preleukemic syndrome and was compared with 21 marrow specimens from iron-deficient control subjects. Results indicate a statistically significant increase of bone marrow mast cell content in patients with preleukemic syndrome in comparison to control subjects (p less than or equal to 0.0005). Two of 20 preleukemic patients converted to acute myeloblastic leukemia and conversion was accompanied by a significant decrease of bone marrow mast cell content. Our findings indicate that bone marrow mast cell content can be reproducibly quantitated and represents an additional morphologic criterion for diagnosis of the preleukemic syndrome.

Myelodysplastic (preleukemia) syndromes: the bone marrow factory failure problem.

The myelodysplastic syndromes are a group of hematologic disorders that adversely affect the levels of hemoglobin, platelets, erythrocytes, and leukocytes. Although the cause of this syndrome is unknown, new diagnostic techniques have facilitated identification and classification of these diseases into five categories: refractory anemia (refractory cytopenia), refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, and chronic myelomonocytic leukemia. Cytogenetic abnormalities may be present in more than 55% of the patients. Symptomatic patients should be assessed relative to life-threatening versus non-life-threatening cytopenias and age. Management consists of primarily supportive measures, although certain approaches that are currently being used or under investigation, such as concomitant administration of erythropoietin and other growth factors, show promise for the future.

The prognostic value of chromosome studies in patients with the preleukemic syndrome (hemopoietic dysplasia).

Banded chromosome studies obtained at the time of diagnosis from 42 patients with the preleukemic syndrome had clonal abnormalities in fifteen. Using Kaplan-Meier product limit survival analysis, it was found that patients with chromosome abnormalities developed acute leukemia more frequently than those without (p less than 0.05). However, we noted that in a subset of patients with complex abnormalities and in a subset previously exposed to alkylating agents, almost all developed leukemia. When either subset was excluded from the larger group analysis there were no differences in leukemia-free survival between cytogenetically abnormal and normal groups. Thus, in the prognostic evaluation of our patients with the preleukemic syndrome a chromosome abnormality per se did not predict rapid evolution to acute leukemia. However, almost all preleukemic patients with complex chromosome abnormalities and almost all alkylator-exposed preleukemic patients can be expected to develop overt leukemia within 1 yr.