The aim of the current study was to comprehensively explore TP53 gene variability resulting from somatic mutations, promoter methylation, and allelic imbalance in tumorous tissue of diffuse large B-cell lymphoma (DLBCL).
In vitro experiments performed using the DLBCL cell lines OCI-ly1 (LY1; mutant TP53), OCI-ly10 (LY10; wild-type TP53) and OCI-ly19 (LY19, wild-type TP53) demonstrated that chidamide is more potent against cells with mutant TP53 mutant than those with wild-type TP53.
We identified 122 patients diagnosed as having large B-cell lymphoma (44, MYC-negative; 29, MYC-EC; 23, MYC rearrangement; 22, MYC and BCL2 rearrangements; 4, MYC, BCL2, and BCL6 rearrangements). p53 expression significantly correlated with DLBCL with abnormal MYC status (MYC-EC, MYC rearrangement, and MYC overexpression), but adverse p53 prognostic effect was only seen with MYC-rearranged lymphoma.
Increased interleukin-17A levels promote rituximab resistance by suppressing p53 expression and predict an unfavorable prognosis in patients with diffuse large B cell lymphoma.
In addition to clinical prognostic features such lactate dehydrogenase level, platelet count, and performance status, important predictors of poor outcome in RT are TP53 disruption and clonal relationship of DLBCL to underlying CLL.
Despite advances in deciphering the molecular pathogenesis of diffuse large B-cell lymphoma (DLBCL), patients with relapsed/refractory disease, particularly those with adverse genetic features (e.g., mutated p53 or double hit lymphoma (DHL)) have very poor prognoses, and effective therapies are lacking.
The results also provide insights into the regulation and function of p50 in diffuse large B-cell lymphoma and its cross talk with the p53 pathway with important therapeutic implications.
The tumor suppressors B-lymphocyte-induced maturation protein-1 (BLIMP-1) and p53 play a crucial role in B-cell lymphomas, and their inactivation contributes to the pathogenesis of a wide spectrum of lymphoid malignancies, including diffuse large B-cell lymphomas (DLBCLs).
We found that CD37 loss (CD37<sup>-</sup>) in ∼60% of DLBCL patients showed significantly decreased survival after R-CHOP treatment, independent of the International Prognostic Index (IPI), germinal center B-cell-like (GCB)/activated B-cell-like (ABC) cell of origin, nodal/extranodal primary origin, and the prognostic factors associated with CD37<sup>-</sup>, including TP53 mutation, NF-κB<sup>high</sup>, Myc<sup>high</sup>, phosphorylated STAT3<sup>high</sup>, survivin<sup>high</sup>, p63<sup>-</sup>, and BCL6 translocation.
Of those with the morphology of diffuse large B-cell lymphoma, the EBV-negative cases were more frequently TP53-mutated (P<0.001), p53 positive by immunohistochemistry (P<0.001), CD30 negative (P<0.01), and of germinal center immunophenotype (P=0.01) compared with EBV-positive cases.
The remaining 2 DLBCL models were germinal B-cell type, with characteristic alterations of GNA13, CREBBP, and EZH2, and chromosomal translocations involving IgH and either BCL2 or MYC Only 25% of the DLBCL PDX models harbored inactivating TP53 mutations, whereas 75% exhibited copy number alterations of TP53 or its upstream modifier, CDKN2A, consistent with the reported incidence and type of p53 pathway alterations in primary DLBCL.
Loss-of-function mutations and copy number alterations in the tumor suppressors TP53 (diffuse large B-cell and follicular lymphoma), CDKN2A (diffuse large B-cell and marginal zone lymphoma), PTEN (diffuse large B-cell lymphoma), ATM (diffuse large B-cell lymphoma), and NF1 (diffuse large B-cell lymphoma), and gain-of-function mutations in the oncogenes HRAS (follicular lymphoma) and NRAS (diffuse large B-cell lymphoma) were also observed.