Racial/ethnic disparities in breast cancer mortality continue to widen but genomic studies rarely interrogate breast cancer in diverse populations. Through genome, exome, and RNA sequencing, we examined the molecular features of breast cancers using 194 patients from Nigeria and 1037 patients from The Cancer Genome Atlas (TCGA). Relative to Black and White cohorts in TCGA, Nigerian HR + /HER2 − tumors are characterized by increased homologous recombination deficiency signature, pervasive TP53 mutations, and greater structural variation—indicating aggressive biology. GATA3 mutations are also more frequent in Nigerians regardless of subtype. Higher proportions of APOBEC-mediated substitutions strongly associate with PIK3CA and CDH1 mutations, which are underrepresented in Nigerians and Blacks. PLK2, KDM6A, and B2M are also identified as previously unreported significantly mutated genes in breast cancer. This dataset provides novel insights into potential molecular mechanisms underlying outcome disparities and lay a foundation for deployment of precision therapeutics in underserved populations.
Our study suggests a high rate of associated depression among patients with breast cancer in our environment. Clinicians should be encouraged and empowered to probe for symptoms of depression in these patient while larger hypothesis-driven studies are needed.
Background
The incidence of cancer continues to rise all over the world and current projections show that there will be 1.27 million new cases and almost 1 million deaths by 2030. In view of the rising incidence of cancer in sub-Saharan Africa, urgent steps are needed to guide appropriate policy, health sector investment and resource allocation. We posit that hospital based cancer registries (HBCR) are fundamental sources of information on the frequent cancer sites in limited resource regions where population level data is often unavailable. In regions where population based cancer registries are not in existence, HBCR are beneficial for policy and planning.
Materials and Methods
Nineteen of twenty-one cancer registries in Nigeria met the definition of HBCR, and from these registries, we requested data on cancer cases recorded from January 2009 to December 2010. 16 of the 19 registries (84%) responded. Data on year hospital was established; year cancer registry was established, no of pathologists and types of oncology services available in each tertiary health facility were shown. Analysis of relative frequency of cancers in each HBCR, the basis of diagnosis recorded in the HBCR and the total number of cases recorded by gender was carried out.
Results
The total number of cancers registered in these 11 hospital based cancer registries in 2009 and 2010 was 6484. The number of new cancer cases recorded annually in these hospital based cancer registries on average were 117 cases in males and I77 cases in females. Breast and cervical cancer were the most common cancers seen in women while prostate cancer was the commonest among men seen in these tertiary hospitals.
Conclusion
Information provided by HBCR is beneficial and can be utilized for the improvement of cancer care delivery systems in low and middle income countries where there are no population based 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.
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