HIV-associated DLBCL: Clinicopathological factors including dual-colour chromogenic in situ hybridisation to assess MYC gene copies.

Sugeshnee Pather, Moosa Patel

Annals of diagnostic pathology 2022 Jun

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Diffuse large B-cell lymphoma (DLBCL) comprises up to 43% of non-Hodgkin lymphomas in South Africa due to the high seroprevalence of human immunodeficiency virus (HIV) infection in the southern African region. We explored the prognostic influence of an array of clinicopathological factors, including MYC gene copy numbers, within HIV-associated DLBCL. The retrospective inclusion of 123 tumours was followed by c-MYC immunohistochemistry and dual-colour MYC and centromere 8 (CEN8) chromogenic in situ hybridisation on formalin-fixed paraffin-embedded sections. Clinicopathological data were collected, interpreted and analysed. HIV seropositive patients comprised 81% (93/115), mean age 42 (SD 10.8) years, with 55% males, HIV negative patients comprised 19% (22/115), mean age 57 (SD 16.7) years (p = 0.001), with 59% males and the HIV status was unknown for 8 patients. The median CD4 count was 162 (IQR 215) cells/mm3, 33% of patients presented with CD4 counts <100 cells/mm3 and the median viral load was 217 (IQR 182 981) copies/mL. There was advanced stage at presentation (i.e., III-IV, 87%), with Ki-67 proliferation indices ≥90% in 85%- and c-MYC expression (i.e., ≥40%) in 58% of tumours. Double expression of c-MYC and BCL2 was associated with a non-germinal center immunophenotype (p < 0.01). Low-level increase of MYC gene copy numbers and MYC rearrangements occurred in 57% and 12%, respectively. C8 polysomy, MYC gene clusters and concurrent MYC rearrangement/increased MYC gene copies were also detected. Inferior median overall survival (OS) occurred when the CD4 counts were <100 cells/mm3 (149 days 95% CI 44-254, p 0,04) and when IPI scores were 3-5 [155 days (95% CI 37-273), p = 0.01]. Concomitant infections negatively impacted the survival outcome, multivariate regression analysis (HR 4.01, 95% CI 1.86-12.20, p = 0.02). c-MYC protein expression, low-level increase in MYC gene copy numbers, rearrangement, C8 polysomy, MYC gene clusters and concurrent MYC rearrangement/low-level gains are present in HIV+ DLBCL. CD4 counts < 100 cells/mm3, IPI scores 3-5 and concomitant infections negatively impact the survival outcome. Copyright © 2022 Elsevier Inc. All rights reserved.

Citation

Sugeshnee Pather, Moosa Patel. HIV-associated DLBCL: Clinicopathological factors including dual-colour chromogenic in situ hybridisation to assess MYC gene copies. Annals of diagnostic pathology. 2022 Jun;58:151913