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The clinical impact of therapy-related acute leukemias is increasing with the extension of cancer-related survival; however, the origins remain largely unknown. Acute erythroleukemia (AEL), a rare unfavorable type of myeloid neoplasia, may also develop secondary to cytotoxic therapy. The disorder is featured by specific genetic alterations, most importantly multi-allelic mutations of the TP53 gene. While AEL might appear as a part of the therapy-related MDS/AML, spectrum information regarding the genetic complexity and progression is largely missing. We present two AEL cases arising after cytotoxic therapy and melphalan-based myeloablation/autologous peripheral stem cell transplantation due to multiple myeloma (MM). As stated, multiple pathogenic TP53 variants were present unrelated to preexisting MM, in parallel with uninvolved/wild-type hemopoiesis. Potential mechanisms of leukemic transformation are discussed, which include (1) preexisting preneoplastic hemopoietic stem cells (HSC) serving as the common origin for both MM and AEL, (2) the generation and intramedullary survival of p53-deficient post-chemotherapy HSCs, (3) reinoculation of mobilized autologous TP53 mutated HSCs, and (4) melphalan treatment-related late-onset myelodysplasia/leukemia with newly acquired TP53 mutations.

Background: Mutation of the TP53 gene is one of the major drivers of myelodysplastic neoplasias (MDS) and acute myeloid leukemia with myelodysplasia-related changes (AML-MR). TP53 mutations present in these hematopoietic malignancies form a distinct molecular genetic cluster with a worse prognosis than without the alteration. However, besides well-characterized hot-spot variants, a significant proportion of TP53 alterations are of uncertain clinical significance. Methods: To enlighten so far unknown aspects, bone-marrow samples from altogether 77 patients are analyzed retrospectively with the diagnosis of AML-MR (26 cases), MDS-IB (12 cases), and MDS-LB (39 cases) according to WHO 2022 guidelines. Next-generation sequencing results are correlated with histological, cytogenetic, and survival data. Results: Twenty out of the 30 TP53 mutation types detected by NGS are not categorized in current public databases; thus, their clinical significance remained mysterious. Because of the interpretation difficulties and the absence of clinical correlations, pathogenicity is established based on in silico approaches. The 12 pathogenicity classification systems, as well as protein stability, protein–DNA, protein–protein interaction, and post-translational modification analyses are applied. We found statistically significant differences between AML/MDS groups considering p53 pathogenicity, protein structural changes, and overall survival. The largest number of abnormalities with the most severe consequences are found in AML-MR cases. Conclusions: These molecular and in silico protein data further support that MDS with increased-blast (MDS-IB) is an intermediate group between AML-MR and MDS with low-blast (MDS-LB) patients, which frequently progresses to AML and is therefore considered a pre-leukemic condition.

Upregulation of carbonic anhydrase IX (CAIX) was found to be associated with unfavorable prognosis and resistance to treatment in a broad spectrum of malignancies, recently also in classical Hodgkin’s lymphoma (cHL). As demonstrated, variable CAIX expression in a significant number of cHL cases was associated with poor treatment response. The current study focused on the quantification CAIX immunopositivity and its relative expression compared to the total CD30+ neoplastic pool using digital image analysis. One hundred and one lymph node samples featuring cHL histology were analyzed for both CD30 and CAIX by immunohistochemistry. Whole histological slides were scanned and immunopositivity was determined as the histoscore (H-score) using the DensitoQuant software module (3DHistech Kft., Budapest, Hungary). CAIX positivity was observed in the HRS-cells of 56/101 cases (55.44%) and frequently observed in the proximity of necrotic foci. CAIX H-scores were highly variable (range: 2.16−90.36, mean 18.7 ± 18.8). Individual CAIX values were independent of the much higher CD30 values (range 3.46−151.3, mean 52.37 ± 30.74). The CAIX/CD30 index proved to be the highest in the aggressive lymphocyte-depleted (LD) subtype (CAIX/CD30: 0.876). The CAIX expression and the CAIX/CD30 relative index can be precisely determined by image analysis, and values reflect the extent of a tumor mass undergoing hypoxic-stress-related adaptation in the most aggressive forms of cHL.