BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy characterized by uncontrolled proliferation and impaired differentiation of myeloid cells in the bone marrow. The tumor suppressor gene TP53 plays a crucial role in maintaining genomic integrity and preventing the development of cancer. TP53 mutations are frequently observed in AML (∼10% of patients) and are associated with aggressive disease behavior, resistance to therapy, and poor prognosis.
CONCLUSIONS: Recent changes in classification of TP53-mutated myelodysplastic syndrome (MDS) have occurred related to the allelic status of TP53 and more importantly to harmonize MDS/AML patients as a homogeneous hematological malignancy. Current treatment regimens involve hypomethylating agents +/- venetoclax or intensive chemotherapy although unfortunately independent of treatment regimen the overall survival (OS) of this patient cohort is around 6 months with poor long-term outcomes after allogeneic stem-cell transplantation. Recent developments geared toward the treatment of TP53-mutated MDS/AML have focused on immunotherapies.
CONCLUSIONS: Notably, there is optimism surrounding these new therapies that could provide breakthroughs with improving outcomes either as monotherapy or combined with established nonimmune therapies. This paper aims to provide an overview of TP53-mutated MDS/AML, including the underlying mechanisms, clinical implications, and emerging therapeutic strategies targeting this hematologic malignancy.

BACKGROUND: Accumulating evidence suggests immunomodulatory and context-dependent effects of TP53 mutations in cancer. We performed an exploratory analysis of the transcriptional, immunobiological and prognostic associations of TP53 mutations within the gene expression-based consensus molecular subtypes (CMSs) of colorectal cancer (CRC).
METHODS: In a single-hospital series of 401 stage I-IV primary CRCs, we sequenced the whole coding region of TP53 and analysed CMS-dependent transcriptional consequences of the mutations by gene expression profiling. Immunomodulatory associations were validated by multiplex, fluorescence-based immunohistochemistry of immune cell markers. Prognostic associations of TP53 mutations were analysed in an aggregated series of 635 patients classified according to CMS, including publicly available data from a French multicentre cohort (GSE39582).
RESULTS: TP53 mutations were found in 60% of the CRCs. However, gene set enrichment analyses indicated that their transcriptional consequences varied among the CMSs and were most pronounced in CMS1-immune and CMS4-mesenchymal. Subtype specificity was primarily seen as an upregulation of gene sets reflecting cell cycle progression in CMS4 and a downregulation of T cell activity in CMS1. The subtype-dependent immunomodulatory associations were reinforced by significant depletion of several immune cell populations in mutated tumours compared with wild-type (wt) tumours exclusively in CMS1, including cytotoxic lymphocytes (adjusted p value in CMS1=0.002 and CMS2-4>0.9, Microenvironment Cell Populations (MCP)-counter algorithm). This was validated by immunohistochemistry-based quantification of tumour infiltrating CD8+ cells. Within CMS1, the immunomodulatory association of TP53 mutations was strongest among microsatellite stable (MSS) tumours, and this translated into a propensity for metastatic disease and poor prognostic value of the mutations specifically in the CMS1/MSS subtype (both series overall survival: TP53 mutation vs wt: HR 5.52, p=0.028).
CONCLUSIONS: Integration of TP53 mutation status with the CMS framework in primary CRC suggested subtype-dependent immunobiological associations with prognostic and potentially immunotherapeutic implications, warranting independent validation.