The emergence of a functionally inactive protein p53 in the analyzed group of patients with DLBCL was caused by one of missense mutations—p.L130F, p.T155I, p.R196Q, p.G244S, p.V272E, or p.A276V—together with mutation p.A189Pfs, leading to frameshift mutations, nonsense substitution p.R213Х, or splicing mutation IVS6-36G > C. This evidence concerns the gene TP53 and diffuse large B-cell lymphoma.