Mosquito control exposures and breast cancer risk: analysis of 1071 cases and 2096 controls from the Ghana Breast Health Study

Epidemiologic data on insecticide exposures and breast cancer risk are inconclusive and mostly from high-income countries. Using data from 1071 invasive pathologically confirmed breast cancer cases and 2096 controls from the Ghana Breast Health Study conducted from 2013 to 2015, we investigated associations with mosquito control products to reduce the spread of mosquito-borne diseases, such as malaria. These mosquito control products were insecticide-treated nets, mosquito coils, repellent room sprays, and skin creams for personal protection against mosquitos. Multivariable and polytomous logistic regression models were used to estimate odds ratios (ORadj) and 95% confidence intervals (CI) with breast cancer risk-adjusted for potential confounders and known risk factors. Among controls, the reported use of mosquito control products were mosquito coils (65%), followed by insecticide-treated nets (56%), repellent room sprays (53%), and repellent skin creams (15%). Compared to a referent group of participants unexposed to mosquito control products, there was no significant association between breast cancer risk and mosquito coils. There was an association in breast cancer risk with reported use of insecticide-treated nets; however, that association was weak and not statistically significant. Participants who reported using repellent sprays were at elevated risks compared to women who did not use any mosquito control products, even after adjustment for all other mosquito control products (OR = 1.42, 95% CI=1.15-1.75). We had limited power to detect an association with repellent skin creams. Although only a few participants reported using repellent room sprays weekly/daily or < month-monthly, no trends were evident with increased frequency of use of repellent sprays, and there was no statistical evidence of heterogeneity by estrogen receptor (ER) status (p-het > 0.25). Our analysis was limited when determining if an association existed with repellent skin creams; therefore, we cannot conclude an association. We found limited evidence of risk associations with widely used mosquito coils and insecticide-treated nets, which are reassuring given their importance for malaria prevention. Our findings regarding specific breast cancer risk associations, specifically those observed between repellent sprays, require further study.

Associations of Circulating Estrogens and Estrogen Metabolites with Fecal and Oral Microbiome in Postmenopausal Women in the Ghana Breast Health Study

The human fecal and oral microbiome may play a role in the etiology of breast cancer through modulation of endogenous estrogen metabolism. This study aimed to investigate associations of circulating estrogens and estrogen metabolites with the fecal and oral microbiome in postmenopausal African women. A total of 117 women with fecal (N = 110) and oral (N = 114) microbiome data measured by 16S rRNA gene sequencing, and estrogens and estrogen metabolites data measured by liquid chromatography tandem mass spectrometry were included. The outcomes were measures of the microbiome and the independent variables were the estrogens and estrogen metabolites. Estrogens and estrogen metabolites were associated with the fecal microbial Shannon index (global P < 0.01). In particular, higher levels of estrone (β = 0.36, P = 0.03), 2-hydroxyestradiol (β = 0.30, P = 0.02), 4-methoxyestrone (β = 0.51, P = 0.01), and estriol (β = 0.36, P = 0.04) were associated with higher levels of the Shannon index, while 16alpha-hydroxyestrone (β = -0.57, P < 0.01) was inversely associated with the Shannon index as indicated by linear regression. Conjugated 2-methoxyestrone was associated with oral microbial unweighted UniFrac as indicated by MiRKAT (P < 0.01) and PERMANOVA, where conjugated 2-methoxyestrone explained 2.67% of the oral microbial variability, but no other estrogens or estrogen metabolites were associated with any other beta diversity measures. The presence and abundance of multiple fecal and oral genera, such as fecal genera from families Lachnospiraceae and Ruminococcaceae, were associated with several estrogens and estrogen metabolites as indicated by zero-inflated negative binomial regression. Overall, we found several associations of specific estrogens and estrogen metabolites and the fecal and oral microbiome. IMPORTANCE Several epidemiologic studies have found associations of urinary estrogens and estrogen metabolites with the fecal microbiome. However, urinary estrogen concentrations are not strongly correlated with serum estrogens, a known risk factor for breast cancer. To better understand whether the human fecal and oral microbiome were associated with breast cancer risk via the regulation of estrogen metabolism, we conducted this study to investigate the associations of circulating estrogens and estrogen metabolites with the fecal and oral microbiome in postmenopausal African women. We found several associations of parent estrogens and several estrogen metabolites with the microbial communities, and multiple individual associations of estrogens and estrogen metabolites with the presence and abundance of multiple fecal and oral genera, such as fecal genera from families Lachnospiraceae and Ruminococcaceae, which have estrogen metabolizing properties. Future large, longitudinal studies to investigate the dynamic changes of the fecal and oral microbiome and estrogen relationship are needed.

Relation of circulating estrogens with hair relaxer and skin lightener use among postmenopausal women in Ghana

BACKGROUND

Hair relaxers and skin lighteners have been commonly used by African women, with suggestions that they may have hormonal activity.

OBJECTIVES

To investigate the relationship of hair relaxer and skin lightener use to serum estrogen/estrogen metabolite levels.

METHODS

We utilized the postmenopausal population-based controls of the Ghana Breast Health Study to estimate adjusted geometric means (GM) and 95% confidence intervals of individual circulating estrogen levels by hair relaxer/skin lightener exposure categories.

RESULTS

Of the 585 postmenopausal women included in our analysis, 80.2% reported hair relaxer use and 29.4% skin lightener use. Ever hair relaxer use was positively associated with estriol (adjusted GM 95.4 pmol/L vs. never 74.5, p value = 0.02) and 16-epiestriol (20.4 vs. 16.8, p value = 0.05) particularly among users of lye-based hair relaxers. Positive associations between scalp burns and unconjugated estrogens were observed (e.g., unconjugated estrone: 5+ scalp burns 76.9 [59.6-99.2] vs. no burns 64.0 [53.7-76.3], p-trend = 0.03). No association was observed between use of skin lighteners and circulating estrogens.

SIGNIFICANCE

This study presents evidence that circulating 16-pathway estrogens (i.e., estriol and 16-epiestriol) may be increased in users of lye-based hair relaxer products. Among hair relaxer users, unconjugated estrogen levels were elevated in women with a greater number of scalp burns.

IMPACT STATEMENT

In this population-based study of hair relaxer and skin lightener use among postmenopausal women in Ghana, altered estrogen metabolism was observed with hair relaxer use, particularly among women using lye-based products or with a greater number of scalp burns. In contrast, skin lightener use was not associated with differences in estrogen metabolism in this population. Continued investigation of the potential biological impact on breast cancer risk of hair relaxer use is warranted.

The oral microbiome and breast cancer and nonmalignant breast disease, and its relationship with the fecal microbiome in the Ghana Breast Health Study

The oral microbiome, like the fecal microbiome, may be related to breast cancer risk. Therefore, we investigated whether the oral microbiome was associated with breast cancer and nonmalignant breast disease, and its relationship with the fecal microbiome in a case-control study in Ghana. A total of 881 women were included (369 breast cancers, 93 nonmalignant cases and 419 population-based controls). The V4 region of the 16S rRNA gene was sequenced from oral and fecal samples. Alpha-diversity (observed amplicon sequence variants [ASVs], Shannon index and Faith's Phylogenetic Diversity) and beta-diversity (Bray-Curtis, Jaccard and weighted and unweighted UniFrac) metrics were computed. MiRKAT and logistic regression models were used to investigate the case-control associations. Oral sample alpha-diversity was inversely associated with breast cancer and nonmalignant breast disease with odds ratios (95% CIs) per every 10 observed ASVs of 0.86 (0.83-0.89) and 0.79 (0.73-0.85), respectively, compared to controls. Beta-diversity was also associated with breast cancer and nonmalignant breast disease compared to controls (P ≤ .001). The relative abundances of Porphyromonas and Fusobacterium were lower for breast cancer cases compared to controls. Alpha-diversity and presence/relative abundance of specific genera from the oral and fecal microbiome were strongly correlated among breast cancer cases, but weakly correlated among controls. Particularly, the relative abundance of oral Porphyromonas was strongly, inversely correlated with fecal Bacteroides among breast cancer cases (r = -.37, P ≤ .001). Many oral microbial metrics were strongly associated with breast cancer and nonmalignant breast disease, and strongly correlated with fecal microbiome among breast cancer cases, but not controls.

Breast Cancer Risk in Women from Ghana Carrying Rare Germline Pathogenic Mutations

BACKGROUND

Risk estimates for women carrying germline mutations in breast cancer susceptibility genes are mainly based on studies of European ancestry women.

METHODS

We investigated associations between pathogenic variants (PV) in 34 genes with breast cancer risk in 871 cases [307 estrogen receptor (ER)-positive, 321 ER-negative, and 243 ER-unknown] and 1,563 controls in the Ghana Breast Health Study (GBHS), and estimated lifetime risk for carriers. We compared results with those for European, Asian, and African American ancestry women.

RESULTS

The frequency of PV in GBHS for nine breast cancer genes was 8.38% in cases and 1.22% in controls. Relative risk estimates for overall breast cancer were: (OR, 13.70; 95% confidence interval (CI), 4.03-46.51) for BRCA1, (OR, 7.02; 95% CI, 3.17-15.54) for BRCA2, (OR, 17.25; 95% CI, 2.15-138.13) for PALB2, 5 cases and no controls carried TP53 PVs, and 2.10, (0.72-6.14) for moderate-risk genes combined (ATM, BARD1, CHEK2, RAD51C, RAD52D). These estimates were similar to those previously reported in other populations and were modified by ER status. No other genes evaluated had mutations associated at P &lt; 0.05 with overall risk. The estimated lifetime risks for mutation carriers in BRCA1, BRCA2, and PALB2 and moderate-risk genes were 18.4%, 9.8%, 22.4%, and 3.1%, respectively, markedly lower than in Western populations with higher baseline risks.

CONCLUSIONS

We confirmed associations between PV and breast cancer risk in Ghanaian women and provide absolute risk estimates that could inform counseling in Ghana and other West African countries.

IMPACT

These findings have direct relevance for breast cancer genetic counseling for women in West Africa.

Measured body size and serum estrogen metabolism in postmenopausal women: the Ghana Breast Health Study

Background

Several anthropometric measures have been associated with hormone-related cancers, and it has been shown that estrogen metabolism in postmenopausal women plays an important role in these relationships. However, little is known about circulating estrogen levels in African women, and the relevance to breast cancer or breast cancer risk factors. To shed further light on the relationship of anthropometric factors and estrogen levels in African women, we examined whether measured body mass index (BMI), waist-to-hip ratio (WHR), height, and self-reported body size were associated with serum estrogens/estrogen metabolites in a cross-sectional analysis among postmenopausal population-based controls of the Ghana Breast Health Study.

Methods

Fifteen estrogens/estrogen metabolites were quantified using liquid chromatography-tandem mass spectrometry in serum samples collected from postmenopausal female controls enrolled in the Ghana Breast Health Study, a population-based case–control study conducted in Accra and Kumasi. Geometric means (GMs) of estrogens/estrogen metabolites were estimated using linear regression, adjusting for potential confounders.

Results

Measured BMI (≥ 30 vs. 18.5–24.9 kg/m2) was positively associated with parent estrogens (multivariable adjusted GM for unconjugated estrone: 78.90 (66.57–93.53) vs. 50.89 (43.47–59.59), p-value < 0.0001; and unconjugated estradiol: 27.83 (21.47–36.07) vs. 13.26 (10.37–16.95), p-value < 0.0001). Independent of unconjugated estradiol, measured BMI was associated with lower levels of 2-pathway metabolites and higher levels of 16-ketoestradriol. Similar patterns of association were found with WHR; however, the associations were not entirely independent of BMI. Height was not associated with postmenopausal estrogens/estrogen metabolite levels in African women.

Conclusions

We observed strong associations between measured BMI and parent estrogens and estrogen metabolite patterns that largely mirrored relations that have previously been associated with higher breast cancer risk in postmenopausal White women. The consistency of the BMI-estrogen metabolism associations in our study with those previously noted among White women suggests that estrogens likely explain part of the BMI-postmenopausal breast cancer risk in both groups. These findings merit evaluation in Black women, including prospective studies.

Circulating tumor DNA is readily detectable among Ghanaian breast cancer patients supporting non-invasive cancer genomic studies in Africa

Circulating tumor DNA (ctDNA) sequencing studies could provide novel insights into the molecular pathology of cancer in sub-Saharan Africa. In 15 patient plasma samples collected at the time of diagnosis as part of the Ghana Breast Health Study and unselected for tumor grade and subtype, ctDNA was detected in a majority of patients based on whole- genome sequencing at high (30×) and low (0.1×) depths. Breast cancer driver copy number alterations were observed in the majority of patients.

Abstract 81: Studying Ghanian Cancer Genomes Using Cell-free DNA

Purpose: Analysis of cell free DNA could provide a rapid and non-invasive approach to detect cancer and provide new molecular insights in many African countries where expert pathology is lacking. Hence, we tested whether whole-genome sequencing of cfDNA (WGS-cfDNA) could identify somatic alterations that drive breast cancer.

Methods: We conducted a pilot on 15 Ghanaian women (median age 49.5 years) recruited as part of the Ghana Breast Health Study. cfDNA was extracted and subjected to WGS at 30x and 0.1x. ichorCNA software was used to predict copy number alterations and ctDNA fractions.

Results: We found extensive amplification and deletion of multiple chromosomal regions including those with oncogenes and tumor suppressor genes associated with breast cancer. Similar copy number alterations for selected breast cancer genes were observed with 0.1x and 30x cfDNA-WGS with increasing concordance between the two instruments as the ctDNA fraction increases. We observed a high frequency (&gt;50%) of copy number gain in 3/5 regions and potential target genes for the amplification (chr8p11-12 [ZNF703] n=8, 53.3%; chr8q24.2 [MYC] n=9, 60%; chr19q12 [CCNE1] n=9, 60%), which were in agreement to previous observations among African-American (AA) ancestry compared to European-American (EA) ancestry in TCGA datasets.

Conclusion: Our data provided evidence that ctDNA-based genomic studies are possible and ctDNA analysis could be a tool for future molecular oncology studies in Africa for cancer etiology, surveillance and clinical trials.

Citation Format: Samuel Ahuno, Anna-Lisa Doebley, Thomas Ahearn, Joel Yarney, Nicholas Titiloye, Nancy Hamel, Ernest Adjei, Joe-Nat Clegg-Lamptey, Lawrence Edusei, Baffour Awuah, Xiaoyu Song, Verne Vanderpuye, Mustapha Abubakar, Maire Duggan, Daniel Stover, Kofi Nyarko, John Bartlet, Francis Aitpillah, Daniel Ansong, Kevin Gardner, Anne Bowcock, Carlos Caldas, William Foulkes, Seth Wiafe, Wiafe-Addai, Montserrat Garcia-Closas, Alexander Kwarteng, Gavin Ha, Jonine Figueroa, Paz Polak, On Behalf Of Ghana Breast Health Study Team. Studying Ghanian Cancer Genomes Using Cell-free DNA [abstract]. In: Proceedings of the 9th Annual Symposium on Global Cancer Research; Global Cancer Research and Control: Looking Back and Charting a Path Forward; 2021 Mar 10-11. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2021;30(7 Suppl):Abstract nr 81.

The Analysis of bcl-2 in Association with p53 and Ki-67 in Triple Negative Breast Cancer and Other Molecular Subtypes in Ghana

BACKGROUND

Little is known about the role of apoptosis in the tumorigenesis and prognosis of breast cancer in Ghana. Chemotherapeutic drug efficacy partially relates to apoptosis induction, rendering it a vital target in cancer therapy with unique biomarker opportunities that have not been exploited. Aberrations in this pathway are central to tumorigenesis, tumor progression, overall tumor growth, and regression during treatment therapies. Antiapoptotic bcl-2 (gene) and p53 are known to play roles in apoptosis while Ki-67 is a proliferative marker. The aim of our study is to determine the association of bcl-2 (protein) with p53 and Ki-67 in 203 consecutive breast cancer cases over a 10-year period.

METHOD

A retrospective cross-sectional study on archival FFPE tissue blocks over a 9-year period with abstraction of clinicopathologic data. Two hundred and three consecutive and suitable FFPE blocks were selected for tissue microarray (TMA) construction, and IHC (bcl-2 (protein), Ki-67, p53, cyclin D, pan cytokeratins A and E, ER, PR, and HER2/neu) was done. Expressions of bcl-2 (protein), p53, and Ki-67 were related to histological grade, lymphovascular invasion, and molecular subtypes. SPSS version 23 was used to analyze results.

RESULTS

Most of our cases were in the fifth decade of life (31%); invasive carcinoma of no special type (NST) was predominant (87%); histological grade III (38%) was the highest; and Luminal A (19.8%), Luminal B (9.9%), HER2 (16%), and TNBC (54.3%) constituted the molecular classes. bcl-2 expression was found in 38% of the cases. Our cases also showed mutation in p53 (36.7%) and ki-67 expression (62.5%). bcl-2 (protein) and p53 significantly correlated with Luminal B and TNBC (p < 0.01). Ki-67 also correlated significantly with Luminal A and B and HER2 overexpression (p < 0.01). Premenopausal age (40-49) and histological grade inversely correlated with bcl-2 (protein) expression. p53 statistically correlated with Ki-67 (p < 0.05).

CONCLUSION

Our results show high expression of bcl-2 (protein) suggesting an important role of apoptosis in Ghanaian breast cancer cases. bcl-2 (protein), p53, and Ki-67 expressions emerged interdependently from this research and can thus be manipulated in prediction and prognosis of breast cancers in our setting.

Reproductive factors and risk of breast cancer by tumor subtypes among Ghanaian women: A population-based case-control study

Higher proportions of early-onset and estrogen receptor (ER) negative cancers are observed in women of African ancestry than in women of European ancestry. Differences in risk factor distributions and associations by age at diagnosis and ER status may explain this disparity. We analyzed data from 1,126 cases (aged 18-74 years) with invasive breast cancer and 2,106 controls recruited from a population-based case-control study in Ghana. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for menstrual and reproductive factors using polytomous logistic regression models adjusted for potential confounders. Among controls, medians for age at menarche, parity, age at first birth, and breastfeeding/pregnancy were 15 years, 4 births, 20 years and 18 months, respectively. For women ≥50 years, parity and extended breastfeeding were associated with decreased risks: >5 births vs. nulliparous, OR 0.40 (95% CI 0.20-0.83) and 0.71 (95% CI 0.51-0.98) for ≥19 vs. <13 breastfeeding months/pregnancy, which did not differ by ER. In contrast, for earlier onset cases (<50 years) parity was associated with increased risk for ER-negative tumors (p-heterogeneity by ER = 0.02), which was offset by extended breastfeeding. Similar associations were observed by intrinsic-like subtypes. Less consistent relationships were observed with ages at menarche and first birth. Reproductive risk factor distributions are different from European populations but exhibited etiologic heterogeneity by age at diagnosis and ER status similar to other populations. Differences in reproductive patterns and subtype heterogeneity are consistent with racial disparities in subtype distributions.

Histopathological Pattern of Prostate Cancer in a Tertiary Hospital in Ghana

Objectives

Prostate adenocarcinoma (PCa) accounts for considerable morbidity in aging men in Africa. With fewer studies reporting on PCa within the subregion, this study was set out to analyze various clinicopathological patterns in PCa lesions, providing additional data for comparison with reported PCa cases in other parts of the globe.

Methods

The study included prostatic adenocarcinoma tissues received in the Department of Pathology, Komfo Anokye Teaching Hospital, over a period of 6 years (from 2008 to 2013). Relevant clinical data including age, histopathological diagnosis, and Gleason’s microscopic grading were extracted from the surgical day book of the department. In a consecutive order, archived tissue blocks and slides of the selected cases were also retrieved for review and confirmation of diagnosis.

Results

Mean age at presentation was 71.7 ± 8.72 years (age ranged from 53 to 96 years) with a peak in the seventh decade of life (n = 41, 52.6%). Majority of the cases were poorly differentiated (n = 43, 55.1%), followed by moderately differentiated (n = 20, 25.6%) and well-differentiated samples (n = 15, 19.2%). Highest occurrence of prostate adenocarcinoma was recorded in the year 2009 (n = 46), followed by 2008 and 2009 (n = 16 and 13, respectively), together accounting for 96.2% of the cases reported.

Conclusion

Histopathological evaluation of prostatic biopsies remains the mainstay of diagnosing prostate adenocarcinoma in Ghana. The pattern of incidence in the population is in line with several reported studies, with majority of the cases diagnosed at the late stage of the disease and thus portending worse prognosis.

Skin lighteners and hair relaxers as risk factors for breast cancer: results from the Ghana breast health study

Skin lighteners and hair relaxers, both common among women of African descent, have been suggested as possibly affecting breast cancer risk. In Accra and Kumasi, Ghana, we collected detailed information on usage patterns of both exposures among 1131 invasive breast cancer cases and 2106 population controls. Multivariate analyses estimated odds ratios (ORs) and 95% confidence intervals (CIs) after adjustment for breast cancer risk factors. Control usage was 25.8% for ever use of skin lighteners and 90.0% for use of hair relaxers for >1 year. The OR for skin lighteners was 1.10 (95% CI 0.93-1.32), with higher risks for former (1.21, 0.98-1.50) than current (0.96, 0.74-1.24) users. No significant dose-response relations were seen by duration, age at first use or frequency of use. In contrast, an OR of 1.58 (95% CI 1.15-2.18) was associated with use of hair relaxers, with higher risks for former (2.22, 1.56-3.16) than current (1.39, 1.00-1.93) users. Although numbers of burns were inconsistently related to risk, associations increased with duration of use, restricted to women who predominately used non-lye products (P for trend < 0.01). This was most pronounced among women with few children and those with smaller tumors, suggesting a possible role for other unmeasured lifestyle factors. This study does not implicate a substantial role for skin lighteners as breast cancer risk factors, but the findings regarding hair relaxers were less reassuring. The effects of skin lighteners and hair relaxers on breast cancer should continue to be monitored, especially given some biologic plausibility for their affecting risk.

Assessment of Wound-Healing Properties of Medicinal Plants: The Case of Phyllanthus muellerianus

Phyllanthus muellerianus (Family Euphorbiaceae) is a shrub, which is widely distributed in West Africa and employed traditionally as a wound-healing agent especially in Ghana. The aim of the study was to determine the in vivo wound-healing activity of aqueous aerial part extract of P. muellerianus (PLE) and its major isolate, geraniin. Excision and incision wound models were used to determine the wound-healing activity. Wounds were treated with PLE (0.25, 0.5, and 1% w/w) and geraniin (0.1, 0.2, and 0.4% w/w) aqueous creams. PLE and geraniin significantly (p < 0.001) increased wound contraction rate and hydroxyproline production compared to untreated wounds. Histological studies of wound tissues showed high levels of fibroblasts and increased collagen content and cross-linking in PLE and geraniin-treated wound tissues. Immuno-histochemical investigations revealed high levels of TGF-β₁ in PLE and geraniin-treated wound tissues compared to the untreated wound tissues. Tensile strength of incised wounds was significantly (p < 0.05) high in PLE and geraniin-treated wounds. PLE (0.1–100 μg/mL) significantly (p < 0.001) reduce LDH release from HaCaT-keratinocytes compared to the untreated cells. PLE and geraniin possess wound healing and cytoprotective effect.

Abstract 5044: Molecular analysis of HBV in histologically confirmed hepatocellular carcinoma in a tertiary hospital in Ghana

Background: Hepatocellular carcinoma (HCC) is a leading cause of death in Africa. Viral hepatitis B is a leading cause of hepatocellular cancer in Ghana and most African countries except Egypt where hepatitis C virus is more prevalent. This study aims at reviewing the histopathological patterns of HCC and its association with hepatitis B virus in our environment.

Method: Demographics and histological diagnosis were retrieved from the surgical daybook and archival FFPE tissue samples with histopathologically confirmed HCC were used for this study. Sections (10µm) were taken from the tissues and digested to obtain DNA lysates. The DNA lysates were used in polymerase chain reaction (PCR) to determine the prevalence of HBV in the biopsies.

Result: Of the 24 confirmed cases of HCC seen in the 5 year period, there were 17 males and 7 females with M:F ratio of 2.4:1. The mean age of our patients was 39.92 ± 1.98 years with age range 13-85 years. 50% of the cases were moderately differentiated while 25% each were well and poorly differentiated. Out of the 24 archival HCC biopsies screened, HBV DNA PCR amplification was achieved in 11 after the restriction fragment length polymorphism PCR reaction. Out of the 24 archival HCC biopsies screened, HBV DNA PCR amplification was achieved in 11 (45.83%) after the restriction fragment length polymorphism PCR reaction. Eight of the 11 cases were found in the male and 3 in females. Of the 11 (45.83%) samples that were positive for HBV DNA, 3 were above 40 years and 8 were 40 years and below.

Conclusion: The overall prevalence of HBV DNA in our study was 45.83% and a greater proportion seen in less than 40 years. This suggests that most of our patients are infected with HBV early in life in our environment.

Citation Format: Babatunde M. Duduyemi, Du-bois Asante, Nicholas Titiloye, Mary Afihene. Molecular analysis of HBV in histologically confirmed hepatocellular carcinoma in a tertiary hospital in Ghana [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5044.

Design considerations for identifying breast cancer risk factors in a population-based study in Africa

Although breast cancer is becoming more prevalent in Africa, few epidemiologic studies have been undertaken and appropriate methodologic approaches remain uncertain. We therefore conducted a population-based case-control study in Accra and Kumasi, Ghana, enrolling 2,202 women with lesions suspicious for breast cancer and 2,161 population controls. Biopsy tissue for cases prior to neoadjuvant therapy (if given), blood, saliva and fecal samples were sought for study subjects. Response rates, risk factor prevalences and odds ratios for established breast cancer risk factors were calculated. A total of 54.5% of the recruited cases were diagnosed with malignancies, 36.0% with benign conditions and 9.5% with indeterminate diagnoses. Response rates to interviews were 99.2% in cases and 91.9% in controls, with the vast majority of interviewed subjects providing saliva (97.9% in cases vs. 98.8% in controls) and blood (91.8% vs. 82.5%) samples; lower proportions (58.1% vs. 46.1%) provided fecal samples. While risk factor prevalences were unique as compared to women in other countries (e.g., less education, higher parity), cancer risk factors resembled patterns identified elsewhere (elevated risks associated with higher levels of education, familial histories of breast cancer, low parity and larger body sizes). Subjects with benign conditions were younger and exhibited higher socioeconomic profiles (e.g., higher education and lower parity) than those with malignancies, suggesting selective referral influences. While further defining breast cancer risk factors in Africa, this study showed that successful population-based interdisciplinary studies of cancer in Africa are possible but require close attention to diagnostic referral biases and standardized and documented approaches for high-quality data collection, including biospecimens.

Abstract C11: Impact of pathologic specimen quality on classifying molecular subtypes of breast cancer: A pilot study from three hospitals in Ghana, Africa

Background: Breast cancer is a heterogeneous disease with clinically, molecularly and pathologically defined subtypes that have different etiologies, clinical presentations and outcomes. African women reportedly have especially high rates of breast cancers that are estrogen receptor (ER) or progesterone receptor (PR) negative, or triple negative [ER, PR and human epidermal growth factor receptor-2 (HER-2) negative], with the proportion reported for triple negative breast cancers ranging from 28-82%, compared to 11-20% among Caucasian populations. However, it is unclear to what extent pathology and specimen handling affect receptor measurements in Africa. Here we sought to determine pathology specimen quality of breast tumor tissues from three hospitals in Ghana where we are conducting a molecular epidemiologic study of breast cancer.

Methods: We acquired 15 formalin-fixed paraffin-embedded (FFPE) archived breast cancer tissue blocks with specimens obtained at biopsy (N=5) or surgery (N=10) from three hospitals in Ghana. Blocks were re-embedded and four 0.5um whole sections were cut for hematoxylin and eosin stains, and immunohistochemistry (IHC) using previously validated protocols for ER (clone 1D5), PR (clone PgR1294) and HER2 (polyclonal), all obtained from Dako (Carpinteria CA). Specimens were considered ER or PR positive if 10% or more cells stained positive, while HER2 was considered positive if intensity of staining was 3+.

Results: Specimens were noted to be embedded in high-melting temperature paraffin. To perform ER, PR, and HER2 IHC staining, deparaffinization procedures were optimized for hard paraffin. Zonal and gradient staining patterns were noted in surgical specimens, features that are likely due to delayed/prolonged fixation. Zonal/gradient staining issues were not identified in the needle biopsies, which were smaller compared to specimens collected at surgery and generally placed in buffered formalin immediately after collection. IHC assays of the tumor specimens revealed that 67% were ER-positive, 20% PR-positive, and 66% HER2 positive. The proportion negative for all three markers was 13%.

Conclusion: In contrast to previous reports for African breast cancer patients, within our sample of FFPE breast cancers from Ghana we found a higher prevalence of ER positive tumors and a lower prevalence of tumors negative for all three markers. These results suggest that the high rates of hormone receptor negativity previously reported in African populations may be inaccurate due to various sources of error, particularly fixation time and IHC staining protocols. Future studies focusing on proper documentation of sample collection procedures and optimization of IHC methods are required to determine the true prevalence of molecular subtypes of breast cancer among African women. Such efforts are essential for breast cancer surveillance, identifying etiologic factors for prevention efforts and developing more effective treatment programs.

Citation Format: Jonine D. Figueroa, Lawrence Edusei, Ernest Adjei, Nicholas Titiloye, Kris Ylaya, Beatrice Addai, Joe Nat Clegg-Lamptey, Baffour Awuah, Kofi Nyarko, Daniel Ansong, Seth Wiafe, Louise A. Brinton, Stephen Hewitt. Impact of pathologic specimen quality on classifying molecular subtypes of breast cancer: A pilot study from three hospitals in Ghana, Africa. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C11. doi:10.1158/1538-7755.DISP13-C11