B-cell and T-cell lymphomas and leukemias often have distinct genetic mutations that are diagnostically defining or prognostically significant. A subset of these mutations consists of specific point mutations, which can be evaluated using genetic sequencing approaches or point mutation specific antibodies. Here, we describe genes harboring point mutations relevant to B-cell and T-cell malignancies and discuss the current availability of these targeted point mutation specific antibodies. We also evaluate the possibility of generating novel antibodies against known point mutations by computationally assessing for chemical and structural features as well as epitope antigenicity of these targets. Our results not only summarize several genetic mutations and identify existing point mutation specific antibodies relevant to hematologic malignancies, but also reveal potential underdeveloped targets which merit further study.

Context.—: Evidence of T-cell clonality is often critical in supporting the diagnosis of a T-cell lymphoma. Objectives.—: To retrospectively explore the significance of copy number losses at the 14q11.2 T-cell receptor α locus in relation to the presence of a T-cell neoplasm and proportion of T cells by targeted next-generation sequencing. Design.—: Targeted next-generation sequencing data from 139 tissue biopsies, including T-cell lymphomas, B-cell lymphomas, classic Hodgkin lymphomas, nonhematopoietic malignancies, and normal samples, were reviewed for copy number losses involving the T-cell receptor α gene segments at chr14q11.2. Results.—: We found that biallelic or homozygous deletion of 14q11.2 was found in most (28 of 33, 84.8%) T-cell lymphomas. The magnitude of 14q11.2 loss showed a statistically significant correlation with the proportion of T cells in lymphoma tissue samples. Copy number losses could also be detected in other lymphomas with high numbers of T cells (8 of 32, 25% of B-cell lymphomas, 4 of 4 classical Hodgkin lymphomas), though biallelic/homozygous deletion of 14q11.2 was not significantly observed outside of T-cell lymphomas. Most nonhematopoietic neoplasms and normal tissues (59 of 64, 92.2%) showed no significant copy number losses involving the T-cell receptor α locus at chr14q11.2. Conclusions.—: Analysis of copy number losses at the T-cell receptor α locus chr14q11.2 with targeted next-generation sequencing can potentially be used to estimate the proportion of T cells and detect T-cell neoplasms.

Background/Objectives: There remains a need for additional prognostic markers in classic follicular lymphoma (cFL) to identify aggressive disease. Immunohistochemical stains such as Ki-67, MYC, and p53 have shown variable associations with histologic grade and adverse outcomes. In this study, we aimed to assess intrafollicular Ki-67, MYC, and p53 expression in cFL via immunohistochemistry, quantified by both manual and digital methods, and evaluate their relation to histologic grade and clinical outcomes. Methods: We evaluated 37 cases of cFL from 2000 to 2019 and performed immunohistochemistry for Ki-67, MYC, and p53 on tumor microarray tissue. Stains were assessed within follicles by digital pathology means on QuPath software and via manual low-power estimates. Results:MYC expression was greater in FL3A compared to FL1–2 across all digital and manual scoring methods (all p < 0.05). Ki-67 and p53 expression did not differ by histologic grade group. No biomarker showed a significant association with adverse clinicopathologic features or outcomes, including FLIPI risk group, bulky disease, clinical stage, event-free survival, or overall survival. Manual and digital scores demonstrated strong correlations for all markers (ρ = 0.71–0.89, all p < 0.001). Conclusions: In our cohort, MYC expression was increased in FL3A compared to FL1–2, while no intrafollicular biomarker measurement was associated with adverse clinicopathologic features or clinical outcomes in exploratory analyses. These findings should be interpreted with caution in light of our limited cohort size. Strong concordance between manual and digital scoring supports the feasibility of digital IHC quantification in cFL.