Blast crisis of chronic myeloid leukemia: diagnosis prompted by T(8;9)

Comparative Gene Expression Analysis Reveals Similarities and Differences of Chronic Myeloid Leukemia Phases

Chronic myeloid leukemia (CML) is a slowly progressing blood cancer that primarily affects elderly people. Without successful treatment, CML progressively develops from the chronic phase through the accelerated phase to the blast crisis, and ultimately to death. Nowadays, the availability of targeted tyrosine kinase inhibitor (TKI) therapies has led to long-term disease control for the vast majority of patients. Nevertheless, there are still patients that do not respond well enough to TKI therapies and available targeted therapies are also less efficient for patients in accelerated phase or blast crises. Thus, a more detailed characterization of molecular alterations that distinguish the different CML phases is still very important. We performed an in-depth bioinformatics analysis of publicly available gene expression profiles of the three CML phases. Pairwise comparisons revealed many differentially expressed genes that formed a characteristic gene expression signature, which clearly distinguished the three CML phases. Signaling pathway expression patterns were very similar between the three phases but differed strongly in the number of affected genes, which increased with the phase. Still, significant alterations of MAPK, VEGF, PI3K-Akt, adherens junction and cytokine receptor interaction signaling distinguished specific phases. Our study also suggests that one can consider the phase-wise CML development as a three rather than a two-step process. This is in accordance with the phase-specific expression behavior of 24 potential major regulators that we predicted by a network-based approach. Several of these genes are known to be involved in the accumulation of additional mutations, alterations of immune responses, deregulation of signaling pathways or may have an impact on treatment response and survival. Importantly, some of these genes have already been reported in relation to CML (e.g., AURKB, AZU1, HLA-B, HLA-DMB, PF4) and others have been found to play important roles in different leukemias (e.g., CDCA3, RPL18A, PRG3, TLX3). In addition, increased expression of BCL2 in the accelerated and blast phase indicates that venetoclax could be a potential treatment option. Moreover, a characteristic signaling pathway signature with increased expression of cytokine and ECM receptor interaction pathway genes distinguished imatinib-resistant patients from each individual CML phase. Overall, our comparative analysis contributes to an in-depth molecular characterization of similarities and differences of the CML phases and provides hints for the identification of patients that may not profit from an imatinib therapy, which could support the development of additional treatment strategies.

Chronic myeloid leukemia blast crisis presented with AML of t(9;22) and t(3;14) mimicking acute lymphocytic leukemia

BACKGROUND

Clinically, 90%-95% of cases of CML have the characteristic t(9;22) (q34.1;q11.2) translocation that leads to the Philadelphia (Ph) chromosome. Rarely, patients with CML can present directly in a blast crisis (BC). While most blast crises are of myeloid origin, myeloid BC with ALL-like morphologic features and Ph-positive acute myeloid leukemia (AML) is rare, especially at the time of CML diagnosis.

CASE PRESENTATION

A 20-year-old man presented with Ph chromosome-positive AML mimicking acute lymphocytic leukemia (ALL). Bone marrow (BM) aspiration revealed AML with ALL-like morphologic features. The results of the immunophenotypic analysis suggested AML. Cytogenetic analysis of the BM cells revealed a 46,XY,t(3;14)(q21;q32),t(9;22)(q34;q11.2)[20] karyotype. Thus, we called the condition AML mimicking ALL. The patient was diagnosed with myeloid BC based on the combination of clinical, cytologic, and cytogenetic studies.

CONCLUSION

To date, no case reports of a patient diagnosed with CML BC presented with Ph chromosome-positive AML mimicking ALL have been reported. We present the case given its rarity, easy misdiagnosis, and poor prognosis. It is important to combine clinical, cytologic, and cytogenetic analyses in distinguishing CML BC from de novo AML with the t(9;22)，and further cases should be accumulated to explore how to improve the prognosis of the patients.

Clinicopathological characteristics of extramedullary acute megakaryoblastic leukemia (AMKL): report of a case with initial mastoid presentation and review of literature to compare extramedullary AMKL and non-AMKL cases

Extramedullary acute megakaryoblastic leukemia (AMKL) is a rare neoplasm with a varied clinical presentation. AMKL with initial mastoid presentation has never been reported. The extreme rarity of mastoid AMKL, together with the tendency of extramedullary AMKL to mimic other small blue cell tumors, can create a diagnostic challenge. We report a case of AMKL that initially presented as a mastoid lesion and provide a comprehensive review and analysis that compares the characteristics of extramedullary AMKL and nonmegakaryoblastic acute myeloid leukemia (AML) in reported pediatric cases over the past 30 years. We found that patients with extramedullary AMKL were not only younger than patients without megakaryocytic differentiation but were also limited to those ≤ 2 years of age. In addition, girls predominated in both AMKL and AML MLL(+) groups compared with other types of AML (P  =  0.0366 and P  =  0.0082). Furthermore, we found that extramedullary AMKL was more likely to involve bone than AML MLL(+) (P < 0.0001) or other types of AML (P  =  0.0002). These findings suggest that extramedullary AMKL should be considered in the differential diagnosis of SBCT in children, especially in patients with mastoid or other bony lesions, those ≤ 2 years of age, and female patients.