Regional Variation in the Tumor Microenvironment, Immune Escape and Prognostic Factors in Breast Cancer in Sub-Saharan Africa

The low overall survival rates of patients with breast cancer in sub-Saharan Africa (SSA) are driven by regionally differing tumor biology, advanced tumor stages at diagnosis, and limited access to therapy. However, it is not known whether regional differences in the composition of the tumor microenvironment (TME) exist and affect patients' prognosis. In this international, multicentre cohort study, 1,237 formalin-fixed, paraffin-embedded breast cancer samples, including samples of the "African Breast Cancer-Disparities in Outcomes (ABC-DO) Study," were analyzed. The immune cell phenotypes, their spatial distribution in the TME, and immune escape mechanisms of breast cancer samples from SSA and Germany (n = 117) were investigated using histomorphology, conventional and multiplex IHC, and RNA expression analysis. The data revealed no regional differences in the number of tumor-infiltrating lymphocytes (TIL) in the 1,237 SSA breast cancer samples, while the distribution of TILs in different breast cancer IHC subtypes showed regional diversity, particularly when compared with German samples. Higher TIL densities were associated with better survival in the SSA cohort (n = 400), but regional differences concerning the predictive value of TILs existed. High numbers of CD163+ macrophages and CD3+CD8+ T cells accompanied by reduced cytotoxicity, altered IL10 and IFNγ levels and downregulation of MHC class I components were predominantly detected in breast cancer samples from Western SSA. Features of nonimmunogenic breast cancer phenotypes were associated with reduced patient survival (n = 131). We therefore conclude that regional diversity in the distribution of breast cancer subtypes, TME composition, and immune escape mechanisms should be considered for therapy decisions in SSA and the design of personalized therapies. See related Spotlight by Bergin et al., p. 705.

Analysis of the genomic landscapes of Barbadian and Nigerian women with triple negative breast cancer

PURPOSE

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype that disproportionately affects women of African ancestry (WAA) and is often associated with poor survival. Although there is a high prevalence of TNBC across West Africa and in women of the African diaspora, there has been no comprehensive genomics study to investigate the mutational profile of ancestrally related women across the Caribbean and West Africa.

METHODS

This multisite cross-sectional study used 31 formalin-fixed paraffin-embedded (FFPE) samples from Barbadian and Nigerian TNBC participants. High-resolution whole exome sequencing (WES) was performed on the Barbadian and Nigerian TNBC samples to identify their mutational profiles and comparisons were made to African American, European American and Asian American sequencing data obtained from The Cancer Genome Atlas (TCGA). Whole exome sequencing was conducted on tumors with an average of 382 × coverage and 4335 × coverage for pooled germline non-tumor samples.

RESULTS

Variants detected at high frequency in our WAA cohorts were found in the following genes NBPF12, PLIN4, TP53 and BRCA1. In the TCGA TNBC cases, these genes had a lower mutation rate, except for TP53 (32% in our cohort; 63% in TCGA-African American; 67% in TCGA-European American; 63% in TCGA-Asian). For all altered genes, there were no differences in frequency of mutations between WAA TNBC groups including the TCGA-African American cohort. For copy number variants, high frequency alterations were observed in PIK3CA, TP53, FGFR2 and HIF1AN genes.

CONCLUSION

This study provides novel insights into the underlying genomic alterations in WAA TNBC samples and shines light on the importance of inclusion of under-represented populations in cancer genomics and biomarker studies.

Abstract PO-142: Analysis of the genomic landscapes of Barbadian and Nigerian women with triple negative breast cancer

Women of African ancestry (WAA) are disproportionately affected by the aggressive triple negative breast cancer (TNBC) subtype that is often associated with high recurrence rates and metastasis. Although there is a high prevalence of TNBC across West Africa and in women of the African diaspora, there has been no comprehensive genomics study to investigate the mutational profile of ancestrally related women across the Caribbean and West Africa. To shed more light on this phenomenon, whole exome sequencing (WES) was performed on 31 formalin-fixed paraffin-embedded TNBC tissues from ancestrally related Barbadian and Nigerian women. We compared these genomics profiles with data from The Cancer Genome Atlas (TCGA) for African American (TCGA-AA), European American (TCGA-EA) women with TNBC. With an average coverage of 382x for tumour samples (n= 31) and 4335x for pooled germline (n=22) non-tumor samples, the most mutated genes in our cohorts include NBPF12, PLIN4, TP53 and BRCA1. For TCGA TNBC cases, these genes had a lower mutation rate, except for TP53 (32% in our cohort; 63% in TCGA-AA; 67% in TCGA-EA). For all altered genes, there were no differences in frequency of mutations between WAA TNBC groups including the TCGA-AA cohort. Additionally, we observed a high frequency of copy number variant alterations in PIK3CA, TP53, FGFR2 and HIF1AN genes. This study provides in-depth insights into the underlying genomic alterations in WAA-TNBC samples and shines light on the importance of inclusion of non-European populations in cancer genomics and biomarker studies.

Citation Format: Shawn M. Hercules, Xiyu Liu, Blessing I. Bassey-Archibong, Desiree H.A. Skeete, Suzanne Smith Connell, Adetola Daramola, Adekunbiola A.F. Banjo, Godwin Ebughe, Thomas Agan, Ima-Obong Ekanem, Joe E. Udosen, Christopher Obiorah, Aaron C. Ojule, Michael A. Misauno, Ayuba M. Dauda, Ejike C. Egbujo, Jevon C. Hercules, Amna Ansari, Ian Brain, Christine MacColl, Yili Xu, Yuxin Jin, Sharon Chang, John D. Carpten, André Bédard, Gregory R. Pond, Kim R.M. Blenman, Zarko Manojlovic, Juliet M. Daniel. Analysis of the genomic landscapes of Barbadian and Nigerian women with triple negative breast cancer [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-142.

Breast cancer pathology services in sub-Saharan Africa: a survey within population-based cancer registries

BACKGROUND

Pathologists face major challenges in breast cancer diagnostics in sub-Saharan Africa (SSA). The major problems identified as impairing the quality of pathology reports are shortcomings of equipment, organization and insufficiently qualified personnel. In addition, in the context of breast cancer, immunohistochemistry (IHC) needs to be available for the evaluation of biomarkers. In the study presented, we aim to describe the current state of breast cancer pathology in order to highlight the unmet needs.

METHODS

We obtained information on breast cancer pathology services within population-based cancer registries in SSA. A survey of 20 participating pathology centres was carried out. These centres represent large, rather well-equipped pathologies. The data obtained were related to the known population and breast cancer incidence of the registry areas.

RESULTS

The responding pathologists served populations of between 30,000 and 1.8 million and the centres surveyed dealt with 10-386 breast cancer cases per year. Time to fixation and formalin fixation time varied from overnight to more than 72 h. Only five centres processed core needle biopsies as a daily routine. Technical problems were common, with 14 centres reporting temporary power outages and 18 centres claiming to own faulty equipment with no access to technical support. Only half of the centres carried out IHC in their own laboratory. For three centres, IHC was only accessible outside of the country and one centre could not obtain any IHC results. A tumour board was established in 13 centres.

CONCLUSIONS

We conclude that breast cancer pathology services ensuring state-of-the-art therapy are only available in a small fraction of centres in SSA. To overcome these limitations, many of the centres require larger numbers of experienced pathologists and technical staff. Furthermore, equipment maintenance, standardization of processing guidelines and establishment of an IHC service are needed to comply with international standards of breast cancer pathology.

Clinicopathologic Features of Uterine Fibroids in a Private Gynecologic Setting in Calabar, Nigeria

Introduction

Uterine fibroid is a common gynecologic problem among adult females in Nigeria with variable clinical presentations. Unfortunately, these patients often seek medical attention very late after having consulted nonorthodox and/or traditional health practitioners.

Objectives

To assess the clinical outcome of patients diagnosed with uterine fibroids and review the pathologic features of specimens obtained from such patients managed over a 48-months period at Davis Medical Centre, a specialist gynecologic private health facility in Calabar, Nigeria.

Methods

This retrospective study was conducted at Davis Medical Centre, located in a semirural community in Calabar Municipality. It involved the extraction of data from case notes of patients and review of laboratory reports and H&E-stained histopathologic slides of surgical specimens removed from patients who presented with abdominal mass/swelling, heavy menstrual bleeding, abdominal pain, and inability to get pregnant having excluded other causes of infertility and ultrasonographic features suggestive of leiomyoma.

Results

A total of 82 patients aged between 26 and 54 years (mean age 36 ± 2 SD) were seen, giving an annual rate of about 20 cases yearly in the 4-year period (2015-2018) studied. Forty-eight (58.5%) had giant uterine fibroids with uterine size between 16 and 28 weeks. Myomectomy was the mainstay of treatment in 93.9% while 6.1% had abdominal hysterectomy. Histologically, the number of fibroid nodules ranged from 1 to 60 nodules with the largest weighing 4,097 g. All had the typical whorled grayish-tan gross appearance of leiomyoma uteri with a large proportion histologically showing degenerative changes of the hyaline type (39%) and few having features suggestive of adenomyosis.

Conclusion

Despite the grotesque, unusual macroscopic and characteristic microscopic findings, timely and careful surgical intervention can remedy the reproductive outcome and save lives of the affected patients when seen and managed by an experienced specialist gynecologist.

Neonatal Deaths and Autopsy Rates in a Nigerian Tertiary Hospital: A 10-Year Trend Analysis in University of Calabar Teaching Hospital, Calabar, Nigeria

The pains and challenges of pregnancy and delivery are made worse when the resultant neonate dies. Fortunately, many of these neonatal deaths can be prevented if autopsies are routinely conducted to ascertain the immediate and remote causes of death toward subsequent prevention. Unfortunately, there is paucity of studies on neonatal autopsy rates (NARs) in many developing countries, with few reports indicating unacceptably low rates. This study was therefore aimed at assessing the trend in neonatal deaths and autopsy rates in Calabar, Nigeria. Trend analysis of retrospective data obtained from medical records of neonatal deaths and deliveries was conducted. Neonatal mortality rate (NMR) and NAR were obtained for each of the years within 2004-2013. Ethical approval was obtained from the ethical committee of University of Calabar Teaching Hospital (UCTH), Calabar, Nigeria. In the 10-year study period, there were 22,916 deliveries with a male:female ratio of 1:0.95. There were 1136 neonatal deaths, yielding a total NMR of 49.6 per 1000 live births (ranging from 26.7 in 2011 to 93.7 in 2004). Bimodal peak in NMR was found at 2008 and 2012. Eighty six neonatal autopsies were conducted within the study period yielding a mean autopsy rate of 7.57%, ranging from 0% in 2008 to 25.0% in 2013. This study found unacceptably high NMR and low NAR in the study setting. There was, however, gradual decrease in mortality and increase in autopsy rates through the study period. It is essential to redouble the efforts at improving public health education and awareness on the relevance of autopsy toward improved health service delivery. Similar studies are recommended in other similar and dissimilar settings.

Cancers Attributable to Infectious Agents in Nigeria: 2012-2014

Abstract 60

Background:

Infections by certain viruses, bacteria, and parasites have been identified as risk factors for some cancers. In 2008, there were 12.7 million new cancer cases worldwide. About 2 million of these new cases were attributable to infections, which represent 16.1% of new cancer cases. The majority of these cancers occurred in less-developed regions of the world, where the Population Attributable Fraction (PAF) was estimated to be 23%. We carried out this study to evaluate the numbers of cancers in Nigeria from 2012-2014 that are attributable to infections using data from Population Based Cancer Registries (PBCR) in Nigeria.

Methods:

We considered cancers associated with Epstein-Barr virus (EBV), Human Papilloma Virus (HPV), Hepatitis B and C Virus (HBV/HCV), Human Immunodeficiency Virus and Human Herpes Virus 8 (HIV/HHV8), Helicobacter pylori, and Schistosoma haematobium that have been classified as oncogenic by IARC. We obtained data on the infection-associated cancers from registry databases of 3 PBCRs in Nigeria: Abuja, Enugu, and Calabar cancer registries. We used PAF for infectious agents associated cancers in developing countries, which were calculated using prevalence data and relative risk estimates in previous studies: EBV and Nasopharyngeal (90%), and Hodgkin's Lymphoma (80%); HPV and Cervical (100%), Vulval and Vaginal (40%), Anal (90%) and Oropharyngeal cancer (12%) in women; Penile (40%), Anal (90%) and Oropharyngeal cancer (12%) in men; HBV/HCV and Liver (92%), HIV/HHV8 and Kaposi sarcoma (100%), Non Hodgkin Lymphoma (100%); H. pylori and stomach (74%) and S. haematobium and Bladder cancer (56.6%).

Results:

The 3 PBCRs reported 4,861 cancer cases from 2012-2014: 1,875 male cases and 2,986 female cases. There were 412 infection-associated cancers in males accounting for 22% of total cancers in males, and 351 (85%) of these were attributable to infections. In females, there were 727 infection-associated cancers accounting for 24% of total cancers in females, and 674 (93%) of these were attributable to infections. Cancers of the Cervix (n=430), Liver (n=152), and Non-Hodgkin's Lymphoma (n=129) were the most common infection-associated cancers in both sexes. The most common infectious agents associated with cancers were HPV (n=453), HIV/HHV8 (n=199), HBV/HCV (n=143) and EBV (n=125).

Conclusion:

Our findings suggest that 85% of infection-associated cancers in males and 93% infection-associated cancers in females in Nigeria can be prevented with vaccination, safer risk behaviors, or anti-infective treatments.

AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST:

Michael Kolawole Odutola No relationship to disclose Elima Jedy-Agba No relationship to disclose Emmanuel Oga No relationship to disclose Festus Igbinoba Travel, Accommodations, Expenses: AstraZeneca Theresa Otu No relationship to disclose Emmanuel Ezeome Honoraria: Roche Travel, Accommodations, Expenses: Roche Ima-Obong Ekanem No relationship to disclose Ramatu Hassan No relationship to disclose Clement Adebamowo Speakers' Bureau: Merck

Developing National Cancer Registration in Developing Countries - Case Study of the Nigerian National System of Cancer Registries

The epidemiological transition in sub-Saharan Africa (SSA) has given rise to a concomitant increase in the incidence of non-communicable diseases including cancers. Worldwide, cancer registries have been shown to be critical for the determination of cancer burden, conduct of research, and in the planning and implementation of cancer control measures. Cancer registration though vital is often neglected in SSA owing to competing demands for resources for healthcare. We report the implementation of a system for representative nation-wide cancer registration in Nigeria - the Nigerian National System of Cancer Registries (NSCR). The NSCR coordinates the activities of cancer registries in Nigeria, strengthens existing registries, establishes new registries, complies and analyses data, and makes these freely available to researchers and policy makers. We highlight the key challenges encountered in implementing this strategy and how they were overcome. This report serves as a guide for other low- and middle-income countries (LMIC) wishing to expand cancer registration coverage in their countries and highlights the training, mentoring, scientific and logistic support, and advocacy that are crucial to sustaining cancer registration programs in LMIC.

Some deep mycoses diagnosed by histopathology in South Eastern Nigeria

Twenty-three cases of deep mycoses were histologically diagnosed in 6500 surgical biopsy specimens examined during a three year period (1985-1988) in the Department of Pathology, University of Calabar Teaching Hospital, Calabar, Nigeria. These included 12 cases of African histoplasmosis, four of mycetoma, four of actinomycetoma, two of paranasal aspergilloma, and one of zygomycosis due to Conidiobolus coronatus (rhinoentomophthoromycosis). Involvement of tooth gum and colon in one case each of African histoplasmosis, and of maxillary sinus in two cases of paranasal aspergilloma were unusual clinical manifestations. The need for greater awareness of deep mycoses and for provision of adequate laboratory facilities in Nigeria is emphasized.

Characterization of breast cancer subgroups in an African population

A detailed prospective study of 58 consecutive breast cancer patients and contemporaneous controls, using age, duration of tumour and presence or absence of poor prognostic signs as clinical parameters, clearly showed that the patients fell into three distinct groups. Group A accounted for 30 per cent of cancers and consisted of young women (21-45 years) with advanced cancers, a short history (3 months or less) and poor prognostic signs; these patients had fast-growing tumours. Group B, to which nearly 60 per cent of patients belonged, was made up of menopausal women (46-50 years) with advanced disease, a history of from 3 months to 1 year and poor prognostic signs; their tumour growth rate was intermediate. Group C made up slightly more than 10 per cent of cases and consisted of postmenopausal women (50 years and above) who gave a long history (1 year or more), and had resectable tumours without poor prognostic signs. Thus, although advanced breast cancer in tropical Africa is due to late presentation in the majority of cases, a small but significant proportion of women have advanced disease in spite of early presentation, attributable to fast tumour growth rate.

Cytologic diagnosis of seminoma metastatic to the central nervous system. A case report

Seminoma cells detected in the cerebrospinal fluid of a patient who had a seminoma of the testis with widespread metastases are described.