Targetable subsets of non-Hodgkin lymphoma in Malawi define therapeutic opportunities

Precision Medicine in Low- and Middle-Income Countries

Most cancer cases occur in low- and middle-income countries (LMICs). The sophisticated technical and human infrastructure needed for optimal diagnosis, treatment, and monitoring of cancers is difficult enough in affluent countries; it is especially challenging in LMICs. In Western, educated, industrial, rich, democratic countries, there is a growing emphasis on and success with precision medicine, whereby targeted therapy is directed at cancers based on the specific genetic lesions in the cancer. Can such precision approaches be delivered in LMICs? We offer some examples of novel partnerships and creative solutions that suggest that precision medicine may be possible in LMICs given heavy doses of will, creativity, and persistence and a little luck.

Clinicopathologic Features of Peripheral T-Cell Lymphoma in Sub-Saharan Africa

OBJECTIVES

Peripheral T-cell lymphomas (PTCLs) are heterogeneous, clinically aggressive, and rare. Subtype distribution varies by geographic location; however, data from sub-Saharan Africa (SSA) are lacking. We sought to elucidate clinicopathologic features of PTCL in SSA.

METHODS

We reviewed PTCL consultation cases from three SSA countries. PTCL subtype was determined per 2017 World Health Organization classification. Cases with sufficient material were evaluated by polymerase chain reaction for human T-cell leukemia virus type 1 (HTLV-1) and T-cell receptor γ (TCRG) rearrangement.

RESULTS

Among 32 cases, median age was 45 years and male-to-female ratio was 1.7. Thirty (94%) of 32 cases required additional workup for subclassification. PTCL, not otherwise specified (PTCL-NOS) was the most common subtype (13/32, 41%), followed by PTCL with T-follicular helper phenotype (6/32, 19%) and systemic anaplastic large cell lymphoma (6/32, 19%). Four (16%) of 25 cases were Epstein-Barr virus positive (EBV+) (2/2 extranodal natural killer/T-cell lymphoma, 1/13 PTCL-NOS, and 1/4 angioimmunoblastic T-cell lymphoma with EBV+ immunoblasts). Two (15%) of 13 patients with PTCL-NOS were human immunodeficiency virus positive. No cases with evaluable DNA (0/15) were HTLV-1 positive, and 9 of 10 showed clonal TCRG rearrangements.

CONCLUSIONS

In comparison to Western studies, PTCLs from SSA show similar subtype distribution and male predominance but a younger age at diagnosis. Appropriate diagnosis of PTCL requires extensive ancillary testing not readily available in low-income countries, including much of SSA.

Distinct pattern of lymphoid neoplasms characterizations according to the WHO classification (2016) and prevalence of associated Epstein-Barr virus infection in Nigeria population

Background

The present study aimed to classify lymphoid neoplasms according to the latest World Health Organization (WHO) classification and outlining the distribution in Nigeria of different entities. Additionally, the study describes the prevalence of lymphoid neoplasms associated with Epstein-Barr virus (EBV) infection in the Nigerian population.

Methods

We collected 152 formalin-fixed paraffin-embedded (FFPE) tissues diagnosed as lymphoma from 2008 to 2018, coming from three different institutions located within three geopolitical zone in Nigeria. These institutions included the University College Hospital (UCH), Ibadan, Oyo State, the Enugu State University of Science and Technology Teaching Hospital (ESUTH), Enugu, Enugu State, and the Meena Histopathology and Cytology Laboratory (MHCL), Jos, Plateau State.

Results

From the total 152 cases retrieved, 50 were excluded due to insufficient tissue materials or inconclusive antigen reactivity. We confirmed 66 (64.7%) cases as lymphomas out of the remaining 102 FFPE with a male to female ratio of 2:1 and a mean age of 44.4 years. Ten entities were identified, and of these, chronic lymphocytic leukemia (CLL) was the most prevalent category (34.8%). For the diffuse large B-cell lymphomas not otherwise specified (DLBCL, NOS), the germinal centre B–cell type was the most common (71.4%). Ten lymphoma cases (15.2%) were positive for Epstein-Barr virus (EBV), most of which were Hodgkin lymphoma (HL). CLL was common in the Hausa ethnic group, HL in the Yoruba ethnic group, while the Igbo ethnic group had an equal distribution of CLL, HL, and DLBCL diagnosis.

Conclusion

Although the distribution of lymphomas in Nigeria shares some similarities with those of other countries, we described distinct features of some subtypes of lymphomas. Also, the study underscores the need for a more precise diagnosis and classification of lymphoid neoplasms in Nigeria using the latest WHO classification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13027-021-00378-z.

Identifying transcriptional profiles and evaluating prognostic biomarkers of HIV-associated diffuse large B-cell lymphoma from Malawi

Lymphoma incidence in sub-Saharan Africa (SSA) is increasing due to HIV and population aging. Diffuse Large B-cell lymphoma (DLBCL), the most common lymphoma in SSA and worldwide, is highly associated with HIV, but molecular studies of HIV-associated DLBCL are scarce globally. We describe profiling of DLBCL from Malawi, aiming to elucidate tumor biology and identify clinically meaningful biomarkers specifically for SSA. Between June 1, 2013 and June 1, 2016, 59 cases of DLBCL (32 HIV+/27 HIV-) enrolled in the Kamuzu Central Hospital Lymphoma Study were characterized, of which 54 (92%) were negative for Epstein-Barr virus. Gene expression profiling (GEP) by whole transcriptome sequencing was performed on the first 36 cases (22 HIV+/14 HIV-). Immunohistochemistry (IHC) and GEP results were compared with published data and correlated to clinical outcome and pathologic features. Unsupervised clustering strongly segregated DLBCL by HIV status (p = 0.0003, Chi-squared test), indicating a marked contribution of HIV to expression phenotype. Pathway analysis identified that HIV-associated tumors were enriched in hypoxia, oxidative stress, and metabolism related gene expression patterns. Cell-of-origin subtype, determined by sequencing and IHC, did not associate with differences in overall survival (OS), while Ki-67 proliferation index ≥80% was associated with inferior OS in HIV+ DLBCL only (p = 0.03) and cMYC/BCL2 co-expression by IHC was negatively prognostic across the entire cohort (p = 0.01). This study provides among the first molecular characterizations of DLBCL from SSA, demonstrates marked gene expression differences by HIV status, and identifies genomic and immunophenotypic characteristics that can inform future basic and clinical investigations.

Lymphoma and Pathology in Sub-Saharan Africa: Current Approaches and Future Directions

The care of patients with lymphoma relies heavily on accurate tissue diagnosis and classification. In sub-Saharan Africa, where lymphoma burden is increasing because of population growth, aging, and continued epidemic levels of human immunodeficiency virus infection, diagnostic pathology services are limited. This article summarizes lymphoma epidemiology, current diagnostic capacity, and obstacles and opportunities for improving practice in the region.