Molecular and cellular aspects of extramedullary manifestations of acute myeloid leukemia

Abstract

The myeloid extramedullary tumor is a solid tumor formed by infiltration of immature myeloid cells in various tissues of the body. This tumor is also identified as chloroma or myeloid sarcoma (MS). MS is a manifestation of acute myeloid leukemia (AML) occurring at presentation or during treatment or relapse. MS is associated with multiple chromosomal abnormalities and molecular mutations since patients with these disorders bear a high potential for MS manifestation. There is a high incidence of extramedullary infiltration (EMI) in AML. AML patients with EMI have a worse prognosis than patients without it. Hematopoietic stem cells and leukemic stem cells reside in a special bone marrow microenvironment called niche, which is essential for their normal functions. Cancers are exploited dysfunctional cell-cell and matrix-cell interactions, which convert a normal niche into a neoplastic niche. This study summarizes the current knowledge on the molecular and cellular characteristics of AML with EMI and extramedullary niches in AML patients.

Association of Leukemia Cutis With Survival in Acute Myeloid Leukemia

“…The predilection of patients with AML and LC to have additional sites of extramedullary involvement may reflect distinctive biological characteristics of these leukemic cells. Although the pathogenesis remains unclear, a variety of cytogenetic and molecular genetic features have been linked with LC or other extramedullary involvement . In the present study, the patients with LC had greater odds of an additional chromosome 8 (OR, 2.13), although differences between the remaining cytogenetic and molecular features did not reach statistical significance.…”

“…Although the pathogenesis remains unclear, a variety of cytogenetic and mo-lecular genetic features have been linked with LC or other extramedullary involvement. [24][25][26] In the present study, the patients with LC had greater odds of an additional chromosome 8 (OR, 2.13), although differences between the remaining cytogenetic and molecular features did not reach statistical significance. It remains undetermined which genes affected by aneuploidy of chromosome 8 may predispose patients to LC.…”

Circular RNA regulatory network reveals cell–cell crosstalk in acute myeloid leukemia extramedullary infiltration

“…Based on the circRNA/miRNA/mRNA regulatory network, the functions of circRNA in EMI were assessed, which primarily involved cell adhesion, migration, signal transduction and cell–cell communication. Previous reports on EMI have also considered cell–cell communication to play an important role in EMI, with leukemic cells subverting normal interactions and converting a normal niche into a neoplastic niche [31]. circRNAs responsible for multiple processes were thought to play an even more important role.…”

Extramedullary involvement in pediatric myeloid leukemia: challenges of diagnosis and treatment. Clinical cases and a literature review

“…КЛИНИЧЕСКИЕ НАБЛЮДЕНИЯ Х отя экстрамедуллярные поражения (ЭМП) при остром миелобластном лейкозе (ОМЛ) встре чаются достаточно часто, их прогностическое значение не определено и они представляют суще ственные трудности при выборе терапевтической тактики. ЭМП характеризуются присутствием агре гированных бластных клеток за пределами костного мозга (КМ) и их основными вариантами являются миелоидная саркома (МС; миелосаркома, гранулоцитарная саркома, хлорома) различной локализации, поражение центральной нервной системы (ЦНС) и кожи [1][2][3].…”

“…Частота случаев ЭМП у детей варьирует от 7 до 49%, по опубликованным данным наиболее крупных исследовательских групп, при этом причинами таких отличий могут быть как неверная трактовка ЭМП (например, включение пациентов с диффузным поражением кроветворных органов), так и различные подходы к интерпретации поражения ЦНС [2,[9][10][11][12][13]. Кроме того, высокая доля ЭМП в отдельных исследо ваниях может наблюдаться при непропорционально высокой представленности определенных подтипов заболевания, например ОМЛ с t (8;21), при котором частота ЭМП достигает 18-24% [3]. Первичные изоли рованные МС без морфологического поражения КМ и МС при низком содержании бластов в КМ составляют не более 2-4% всех случаев [14].…”