The Cancer Prevention Project of Philadelphia: preliminary findings examining diversity among the African diaspora

Lack of racial and ethnic diversity in lung cancer cell lines contributes to lung cancer health disparities

Lung cancer is the leading cause of cancer death in the United States and worldwide, and a major source of cancer health disparities. Lung cancer cell lines provide key in vitro models for molecular studies of lung cancer development and progression, and for pre-clinical drug testing. To ensure health equity, it is imperative that cell lines representing different lung cancer histological types, carrying different cancer driver genes, and representing different genders, races, and ethnicities should be available. This is particularly relevant for cell lines from Black men, who experience the highest lung cancer mortality in the United States. Here, we undertook a review of the available lung cancer cell lines and their racial and ethnic origin. We noted a marked imbalance in the availability of cell lines from different races and ethnicities. Cell lines from Black patients were strongly underrepresented, and we identified no cell lines from Hispanic/Latin(x) (H/L), American Indian/American Native (AI/AN), or Native Hawaiian or other Pacific Islander (NHOPI) patients. The majority of cell lines were derived from White and Asian patients. Also missing are cell lines representing the cells-of-origin of the major lung cancer histological types, which can be used to model lung cancer development and to study the effects of environmental exposures on lung tissues. To our knowledge, the few available immortalized alveolar epithelial cell lines are all derived from White subjects, and the race and ethnicity of a handful of cell lines derived from bronchial epithelial cells are unknown. The lack of an appropriately diverse collection of lung cancer cell lines and lung cancer cell-of-origin lines severely limits racially and ethnically inclusive lung cancer research. It impedes the ability to develop inclusive models, screen comprehensively for effective compounds, pre-clinically test new drugs, and optimize precision medicine. It thereby hinders the development of therapies that can increase the survival of minority and underserved patients. The noted lack of cell lines from underrepresented groups should constitute a call to action to establish additional cell lines and ensure adequate representation of all population groups in this critical pre-clinical research resource.

Extensive set of African ancestry-informative markers (AIMs) to study ancestry and population health

Introduction: Human populations are often highly structured due to differences in genetic ancestry among groups, posing difficulties in associating genes with diseases. Ancestry-informative markers (AIMs) aid in the detection of population stratification and provide an alternative approach to map population-specific alleles to disease. Here, we identify and characterize a novel set of African AIMs that separate populations of African ancestry from other global populations including those of European ancestry. Methods: Using data from the 1000 Genomes Project, highly informative SNP markers from five African subpopulations were selected based on estimates of informativeness (In) and compared against the European population to generate a final set of 46,737 African ancestry-informative markers (AIMs). The AIMs identified were validated using an independent set and functionally annotated using tools like SIFT, PolyPhen. They were also investigated for representation of commonly used SNP arrays. Results: This set of African AIMs effectively separates populations of African ancestry from other global populations and further identifies substructure between populations of African ancestry. When a subset of these AIMs was studied in an independent dataset, they differentiated people who self-identify as African American or Black from those who identify their ancestry as primarily European. Most of the AIMs were found to be in their intergenic and intronic regions with only 0.6% in the coding regions of the genome. Most of the commonly used SNP array investigated contained less than 10% of the AIMs. Discussion: While several functional annotations of both coding and non-coding African AIMs are supported by the literature and linked these high-frequency African alleles to diseases in African populations, more effort is needed to map genes to diseases in these genetically diverse subpopulations. The relative dearth of these African AIMs on current genotyping platforms (the array with the highest fraction, llumina's Omni 5, harbors less than a quarter of AIMs), further demonstrates a greater need to better represent historically understudied populations.

Variation in Cancer Incidence Rates Among Non-Hispanic Black Individuals Disaggregated by Nativity and Birthplace, 2005-2017: A Population-Based Cancer Registry Analysis

Objectives

Compared to other racial and ethnic groups, little to no disaggregated cancer incidence data exist for subgroups of non-Hispanic Blacks (NHBs), despite heterogeneity in sociodemographic characteristics and cancer risk factors within this group. Our objective was to examine age-adjusted cancer incidence by nativity and birthplace among NHB cancer cases diagnosed in New Jersey.

Methods

Race, ethnicity, and birthplace data from the New Jersey State Cancer Registry were used to classify NHB cancer cases diagnosed between 2005-2017. Thirteen waves of population estimates (by county, nativity, gender, age-group) were derived from the American Community Survey using Integrated Public-Use Microdata to approximate yearly demographics. Age-adjusted cancer incidence rates (overall and by site) by birthplace were generated using SEER*Stat 8.3.8. Bivariate associations were assessed using chi-square and Fisher’s exact tests. Trend analyses were performed using Joinpoint 4.7.

Results

Birthplace was available for 62.3% of the 71,019 NHB cancer cases. Immigrants represented 12.3%, with African-born, Haitian-born, Jamaican-born, ‘other-Caribbean-born’, and ‘other-non-American-born’ accounting for 18.5%, 17.7%, 16.5%, 10.6%, and 36.8%, respectively. Overall, age-adjusted cancer incidence rates were lower for NHB immigrants for all sites combined and for several of the top five cancers, relative to American-born NHBs. Age-adjusted cancer incidence was lower among immigrant than American-born males (271.6 vs. 406.8 per 100,000) and females (191.9 vs. 299.2 per 100,000). Age-adjusted cancer incidence was lower for Jamaican-born (114.6 per 100,000) and other-Caribbean-born females (128.8 per 100,000) than African-born (139.4 per 100,000) and Haitian-born females (149.9 per 100,000). No significant differences in age-adjusted cancer incidence were observed by birthplace among NHB males. Age-adjusted cancer incidence decreased for all sites combined from 2005-2017 among American-born males, immigrant males, and American-born females, while NHB immigrant female rates remained relatively stable.

Conclusions

There is variation in age-adjusted cancer incidence rates across NHB subgroups, highlighting the need for more complete birthplace information in population-based registries to facilitate generating disaggregated cancer surveillance statistics by birthplace. This study fills a knowledge gap of critical importance for understanding and ultimately addressing cancer inequities.

Disparities in Lung Cancer Treatment

PURPOSE OF REVIEW

Despite an overall reduction in lung cancer incidence and mortality rates worldwide, Blacks still have higher mortality rates compared to Whites. There are many factors that contribute to this difference. This review seeks to highlight racial disparities in treatment and the possible reasons for these disparities.

RECENT FINDINGS

Factors attributing to racial disparities in lung cancer treatment include social determinants of health, differences in the administration of guideline-concordant therapy as well as molecular testing that is essential for most NSCLC patients. One way to circumvent disparities in lung cancer survivorship is to ensure equal representation of race in research at all levels that will provide insight on interventions that will address social determinants of health, differences in treatment patterns, molecular testing, and clinical trial involvement.

Is Response to Genotoxic Stress Similar in Populations of African and European Ancestry? A Study of Dose-Response After in vitro Irradiation

Background: Exposure to genotoxic stress such as radiation is an important public health issue affecting a large population. The necessity of analyzing cytogenetic effects of such exposure is related to the need to estimate the associated risk. Cytogenetic biological dosimetry is based on the relationship between the absorbed dose and the frequency of scored chromosomal aberrations. The influence of confounding factors on radiation response is a topical issue. The role of ethnicity is unclear. Here, we compared the dose-response curves obtained after irradiation of circulating lymphocytes from healthy donors of African and European ancestry.

Materials and Methods: Blood samples from six Africans living in Africa, five Africans living in Europe, and five Caucasians living in Europe were exposed to various doses (0–4 Gy) of X-rays at a dose-rate of 0.1 Gy/min using an X-RAD320 irradiator. A validated cohort composed of 14 healthy Africans living in three African countries was included and blood samples were irradiated using the same protocols. Blood lymphocytes were cultured for 48 h and chromosomal aberrations scored during the first mitosis by telomere and centromere staining. The distribution of dicentric chromosomes was determined and the Kruskal-Wallis test was used to compare the dose-response curves of the two populations.

Results: No spontaneous dicentric chromosomes were detected in African donors, thus establishing a very low background of unstable chromosomal aberrations relative to the European population. There was a significant difference in the dose response curves between native African and European donors. At 4 Gy, African donors showed a significantly lower frequency of dicentric chromosomes (p = 8.65 10^–17), centric rings (p = 4.0310^–14), and resulting double-strand-breaks (DSB) (p = 1.32 10^–18) than European donors. In addition, a significant difference was found between African donors living in Europe and Africans living in Africa.

Conclusion: This is the first study to demonstrate the important role of ethnic and environmental factors that may epigenetically influence the response to irradiation. It will be necessary to establish country-of-origen-specific dose response curves to practice precise and adequate biological dosimetry. This work opens new perspective for the comparison of treatments based on genotoxic agents, such as irradiation.

Colorectal Cancer Screening Prevalence and Adherence for the Cancer Prevention Project of Philadelphia (CAP3) Participants Who Self-Identify as Black

Introduction

Colorectal cancer is the third leading cause of cancer-related deaths among Black men and women. While colorectal cancer screening (CRCS) reduces mortality, research assessing within race CRCS differences is lacking. This study assessed CRCS prevalence and adherence to national screening recommendations and the association of region of birth with CRCS adherence, within a diverse Black population.

Methods

Data from age-eligible adults, 50–75 years, (N = 357) participating in an ongoing, cross-sectional study, was used to measure CRCS prevalence and adherence and region of birth (e.g., Caribbean-, African-, US-born). Prevalence and adherence were based on contemporaneous US Preventive Services Task Force guidelines. Descriptive statistics were calculated and adjusted prevalence and adherence proportions were calculated by region of birth. Adjusted logistic regression models were performed to assess the association between region of birth and overall CRCS and modality-specific adherence.

Results

Respondents were 69.5% female, 43.3% married/living with partner, and 38.4% had <$25,000 annual income. Overall, 78.2% reported past CRCS; however, stool test had the lowest prevalence overall (34.6%). Caribbean (95.0%) and African immigrants (90.2%) had higher prevalence of overall CRCS compared to US-born Blacks (59.2%) (p-value <0.001). African immigrants were five times more likely to be adherent to overall CRCS compared to US-born Blacks (OR = 5.25, 95% CI 1.34–20.6). Immigrants had higher odds of being adherent to colonoscopy (Caribbean OR = 6.84, 95% CI 1.49–31.5; African OR = 7.14, 95% CI 1.27–40.3) compared to US-born Blacks.

Conclusions

While Caribbean and African immigrants have higher prevalence and adherence of CRCS when compared US-born Blacks, CRCS is still sub-optimal in the Black population. Efforts to increase CRCS, specifically stool testing, within the Black population are warranted, with targeted interventions geared towards US-born Blacks.

Emerging genomic biomarkers for improving kidney, prostate, and bladder cancer health disparities outcomes

BACKGROUND

Recent advances in genomic and genetic technologies have facilitated better health outcomes for urologic cancer patients. Genomic and genetic heterogeneity may contribute to differences in tumor biology and urologic cancer burden across various populations.

OBJECTIVE

To examine how emerging genomic and genetic biomarkers, self-reported race, and ancestry-informative markers are associated with kidney, prostate, and bladder cancer outcomes.

RESULTS

Genomic and genetic alterations found in African American kidney cancer patients included distinct somatic mutations, somatic copy number alterations, chromosomal instability, germ-line risk alleles, and germ-line genetic variants. These changes correlated with improved risk prediction, prognosis, and survival; and a predicted decrease in response to targeted therapies. SNP risk alleles and ancestry-informative markers were associated with improved risk prediction in prostate cancer patients of both African and European descent. AKT activation suggest differential response to AKT-targeted therapies in African American, Asian American, and Tunisian bladder cancer patients. Both self-reported race and genetic ancestry predicted urologic cancer risk prediction.

CONCLUSION

Precision medicine approaches that integrate population-specific genomic and genetic information with other known urologic cancer-specific characteristics can improve outcomes and be leveraged to reduce cancer health disparities. Further investigations are necessary to identify novel genomic biomarkers with clinical utility.