Vitamin D receptor polymorphisms and associated miRNAs in the development of breast cancer in African American women.

Breast cancer (BCa) is a prevalent form of cancer in women, exhibiting varying rates and distribution across different ethnic groups. Among these groups, African American (AA) women have the highest incidence of BCa and the lowest levels of Vitamin D (VD). Numerous studies have explored the connection between variations in the VDR gene and BCa risk, particularly in different populations, but research on the AA population remains limited. Epigenetic modifications, including specific microRNAs (miRNAs), can influence gene expression without altering the genetic code and have been implicated in cancer initiation and progression. Our hypothesis suggests that VDR gene variations may increase BCa risk in AA women and that changes in miRNA expression profiles could contribute to BCa development. Using data from the 1000 Genome Project, we identified five VDR gene variants with significant frequency differences between AA and European-American (EA) populations. We genotyped 404 African American BCa cases and controls for five variants using TaqMan® assays. SNPstats assessed their association with BCa risk. The rs1544410 variant's recessive model (A/A) showed a decreased BCa risk in AA (odds ratio 0.33, 95% CI: 0.15-0.73, p-value 0.0041). Conversely, the rs2853563 variant's recessive model (A/A) was linked to an increased BCa risk (odds ratio 4.04, 95% CI: 1.49-10.95, p-value 0.0022). We investigated miRNA expression influenced by VD in HCC1806 Triple-Negative Breast Cancer (TNBC) cell lines with the A/A allele for rs2853563. nCounter® Nanostring technology assessed miRNA profiles after calcitriol treatment. Our results indicated that calcitriol treatment led to reduced expression of six miRNAs, four of which are associated with tumor suppression in the presence of the AA genotype in TNBC cell lines. These findings suggest that specific VDR genotypes could have a potential effect on the miRNAs expression which could potentially serve as markers for cell proliferation in TNBC.

Characterization of GATA3 and Mammaglobin in breast tumors from African American Women.

GATA3 and Mammaglobin are often used in the clinic to identify metastases of mammary origin due to their robust and diffuse expression in mammary tissue. However, the expression of these markers has not been well characterized in tumors from African American women. The goal of this study was to characterize and evaluate the expression of GATA3 and mammaglobin in breast tumors from African American women and determine their association with clinicopathological outcomes including breast cancer subtypes. Tissue microarrays (TMAs) were constructed from well preserved, morphologically representative tumors in archived formalin-fixed, paraffin-embedded (FFPE) surgical blocks from 202 patients with primary invasive ductal carcinoma. Mammaglobin and GATA3 expression was assessed using immunohistochemistry (IHC). Univariate analysis was carried out to determine the association between expression of GATA3, mammaglobin and clinicopathological characteristics. Kaplan-Meier estimates of overall survival and disease-free survival were also plotted and a log-rank test performed to compare estimates among groups. GATA3 expression showed statistically significant association with lower grade (p<0.001), ER-positivity (p<0.001), PR-positivity (p<0.001), and the luminal subtype (p<0.001). Mammaglobin expression was also significantly associated with lower grade (p=0.031), ER-positivity (p=0.007), and PR-positivity (p=0.022). There was no association with recurrence-free or overall survival. Our results confirm that GATA3 and mammaglobin demonstrate expression predominantly in luminal breast cancers from African American women. Additional markers with improved specificity and sensitivity are warranted for triple negative breast tumors given the high prevalence in women of African descent.

Cyclin A2 and Ki-67 proliferation markers could be used to identify tumors with poor prognosis in African American women with breast cancer.

Background: Diagnosed invasive breast carcinomas in African American patients are more aggressive compared with those in Caucasian patients and diagnosed at later stages of the disease with higher grade tumors. Despite advances in breast cancer systemic treatment, new prognostic and predictive biomarkers are still needed. Therefore, potential biomarkers were chosen to correlate with different subtypes, recurrence, and survival of invasive breast cancer in a cohort of African American women. Methods: Eight protein biomarkers (ER, PR, HER2, Cyclin A2, Cytokeratin 5, Vimentin, Bcl2, and Ki-67) were evaluated using tissue microarrays (TMAs) and immunohistochemistry (IHC). The IHC results from TMAs were analyzed by both supervised and unsupervised clustering methods. The predictive clusters for the supervised and unsupervised methods were compared for agreement with the empirical classification. Kappa values were used to determine the overall percent correct clusters and agreement between specific clusters. Chi-square statistics was used to examine the association between hierarchical and multinomial logistic clustering methods. Results: Five subtypes of breast tumors with distinct protein expression patterns were identified among the studied 166 breast tumors. Luminal B tumors have been distinguished from luminal A tumors by staining for cell cycle proteins Cyclin A2 and Ki-67, which promote cell proliferation. Forty-nine percent were stained positive for Cyclin A2, 39.2% positive for Ki-67, and 37% positive for both Cyclin A2 and Ki-67. The age of patients did not show any significant effect whether five (p-value= 0.576) or eight (p-value= 0.605) biomarkers were used, which indicating that age did not have any influence on the classification of the subtypes. Ninety percent of the thirty triple negative tumors were positive for Cyclin A2 or Ki-67 or both. Six-year overall survival was better for luminal A tumors (76%) than luminal B tumors (71%). Likewise, six-year relapse-free survival was better for luminal A tumors (76%) than luminal B tumors (29%). Conclusion: Discovery of molecular markers such as Cyclin A2 and Ki-67, and subtypes that are most prevalent in African Americans could lead to a better understanding of the factors contributing to higher morbidity and mortality in this group and to aid in decision-making to offer earlier treatment.

Characterization of GATA3 and Mammaglobin in breast tumors from African American women.

GATA3 and Mammaglobin are often used in the clinic to identify metastases of mammary origin due to their robust and diffuse expression in mammary tissue. However, the expression of these markers has not been well characterized in tumors from African American women. The goal of this study was to characterize and evaluate the expression of GATA3 and mammaglobin breast tumors from African American women and determine their association with clinicopathological outcomes including breast cancer subtypes. Tissue microarrays (TMAs) were constructed from well preserved, morphologically representative tumors in archived formalin-fixed, paraffin-embedded (FFPE) surgical blocks from 202 patients with primary invasive ductal carcinoma. Mammaglobin, and GATA3 expression was assessed using immunohistochemistry (IHC). Univariate analysis was carried out to determine the association between expression of GATA3, mammaglobin and clinicopathological characteristics. Kaplan-Meier estimates of overall survival and disease-free survival were also plotted and a log-rank test performed to compare estimates among groups. GATA3 expression showed statistically significant association with lower grade (p<0.001), ER-positivity (p<0.001), PR-positivity (p<0.001), and the luminal subtype (p<0.001). Mammaglobin expression was also significantly associated with lower grade (p=0.031), ER-positivity (p=0.007), and PR-positivity (p=0.022). There was no association with recurrence-free or overall survival. Our results confirm that GATA3 and mammaglobin demonstrate expression predominantly in luminal breast cancers from African American women. Markers with improved specificity and sensitivity are warranted given the high prevalence of triple negative breast cancer in the group.

Review of genetic and pharmacogenetic differences in cytotoxic and targeted therapies for pancreatic cancer in African Americans.

Pancreatic ductal adenocarcinoma (PDAC) is currently the third leading cause of cancer mortality and the incidence is projected to increase by 2030. Despite recent advances in its treatment, African Americans have a 50-60% higher incidence and 30% higher mortality rate when compared to European Americans possibly resulting from differences in socioeconomic status, access to healthcare, and genetics. Genetics plays a role in cancer predisposition, response to cancer therapeutics (pharmacogenetics), and in tumor behavior, making some genes targets for oncologic therapeutics. We hypothesize that the germline genetic differences in predisposition, drug response, and targeted therapies also impact PDAC disparities. To demonstrate the impact of genetics and pharmacogenetics on PDAC disparities, a review of the literature was performed using PubMed with variations of the following keywords: pharmacogenetics, pancreatic cancer, race, ethnicity, African, Black, toxicity, and the FDA-approved drug names: Fluoropyrimidines, Topoisomerase inhibitors, Gemcitabine, Nab-Paclitaxel, Platinum agents, Pembrolizumab, PARP-inhibitors, and NTRK fusion inhibitors. Our findings suggest that the genetic profiles of African Americans may contribute to disparities related to FDA approved chemotherapeutic response for patients with PDAC. We recommend a strong focus on improving genetic testing and participation in biobank sample donations for African Americans. In this way, we can improve our current understanding of genes that influence drug response for patients with PDAC.

Hereditary variants of unknown significance in African American women with breast cancer.

Expanded implementation of genetic sequencing has precipitously increased the discovery of germline and somatic variants. The direct benefit of identifying variants in actionable genes may lead to risk reduction strategies such as increased surveillance, prophylactic surgery, as well as lifestyle modifications to reduce morbidity and mortality. However, patients with African ancestry are more likely to receive inconclusive genetic testing results due to an increased number of variants of unknown significance decreasing the utility and impact on disease management and prevention. This study examines whole exome sequencing results from germline DNA samples in African American women with a family history of cancer including 37 cases that were diagnosed with breast cancer and 51 family members. Self-identified ancestry was validated and compared to the 1000 genomes population. The analysis of sequencing results was limited to 85 genes from three clinically available common genetic screening platforms. This target region had a total of 993 variants of which 6 (<1%) were pathogenic or likely pathogenic, 736 (74.1%) were benign, and 170 (17.1%) were classified as a variant of unknown significance. There was an average of 3.4±1.8 variants with an unknown significance per individual and 85 of 88 individuals (96.6%) harbored at least one of these in the targeted genes. Pathogenic or likely pathogenic variants were only found in 6 individuals for the BRCA1 (p.R1726fs, rs80357867), BRCA2 (p.K589fs, rs397507606 & p.L2805fs, rs397507402), RAD50 (p.E995fs, rs587780154), ATM (p.V2424G, rs28904921), or MUTYH (p.G396D, rs36053993) genes. Strategies to functionally validate the remaining variants of unknown significance, especially in understudied and hereditary cancer populations, are greatly needed to increase the clinical utility and utilization of clinical genetic screening platforms to reduce cancer incidence and mortality.

Inverse Correlation of KISS1 and KISS1R Expression in Triple-negative Breast Carcinomas from African American Women.

BACKGROUND/AIM: The kisspeptin 1 (KISS1) gene encodes a precursor polypeptide which after proteolysis forms the kisspeptin-10 (KISS1) protein. KISS1, retains maximum physiological activity when it binds to its receptor (KISS1R), allowing KISS1 to effectively function as a suppressor of metastasis in melanomas and other types of cancer. The goal of this study was to evaluate the expression of KISS1 and KISS1R in breast carcinomas from African American (AA) women and correlate their association with clinicopathological features, including breast cancer subtypes, and outcomes. MATERIALS AND METHODS: Tissue microarrays were constructed from formalin-fixed, paraffin-embedded surgical blocks from 216 AA patients. KISS1 and KISS1R expression was assessed using immunohistochemistry. Univariate analysis was used to determine the association between the expression of KISS1 and KISS1R, and clinicopathological characteristics. Pearson correlation was also determined between immunohistochemical H-scores, tumor size, and the number of positive lymph nodes. Kaplan-Meier estimates of overall and disease-free survival were plotted, and log-rank tests were performed to compare estimates among groups. RESULTS: KISS1 protein expression was found to be higher in receptor-negative and triple-negative breast cancer (TNBC) compared to other subtypes (p<0.001). However, KISS1R expression was higher in non-TNBC tumors compared to other subtypes (p<0.001). Higher KISS1R expression was marginally negatively correlated with tumor size (p=0.077), and positively correlated with lymph-node positivity (p=0.056), and disease-free survival (p=0.092). CONCLUSION: Our study showed a significant inverse correlation between KISS1 and KISS1R in TNBC. This investigation implicates a role for KISS1 and KISS1R in the pathogenesis of TNBCs in AA women.

Challenges and Strategies of Successful Mentoring: The Perspective of LEADS Scholars and Mentors from Minority Serving Institutions.

Mentoring continues to be a salient conversation in academia among junior and senior faculty and administrators. Mentors provide guidance and structure to junior faculty so that they can meet their academic and professional goals. Mentors also convey skills in balancing life and academic pursuits. Therefore, the purpose of this descriptive study was to provide additional insight from a training program called Leading Emerging and Diverse Scientists to Success (LEADS) regarding successful strategies and challenges of mentoring relating to lessons learned from the scholars and mentees' perspective. The LEADS program provided multiple training platforms to increase skills and knowledge regarding research to promote expertise in grant writing and submission for funding opportunities among diverse scientists. These findings reinforce the knowledge about the value of a mentor in helping define the research pathway of their mentee and underscoring the importance of mentoring.

Lessons Learned from the Medical University of South Carolina Transdisciplinary Collaborative Center (TCC) in Precision Medicine and Minority Men's Health.

The Transdisciplinary Collaborative Center (TCC) in Precision Medicine for Minority Men's Health was established at the Medical University of South Carolina (MUSC) in 2015 to address disparities in the translation of precision medicine approaches among racial minority groups. This regional consortium focuses on three primary areas: (1) the development of a consortium of regional and national partners, (2) conducting transdisciplinary research examining synergistic effects of biological, social, physiological, and clinical determinants of chronic disease risks and outcomes, and (3) dissemination and implementation of precision medicine approaches, with an emphasis on reducing disparities in health care and outcomes among minority men. Given consistent calls to better translate precision medicine approaches and the focus of this consortium on addressing disparities among minority men, we provide an overview of our experience in developing the MUSC TCC, including barriers and facilitators to conducting translational research on minority men's health issues in the context of precision medicine. Lessons learned and areas for improvement include providing enough time to create consistent partnerships and community engagement to improve recruitment and retention, identifying unique ways to engage diverse partners from across the region and nation, and better approaches to dissemination and communication for large partnerships focusing on precision medicine.

Corrigendum to "Annexin 2 protein expression is associated with breast cancer subtypes in African American women" [Heliyon Volume 6, Issue 2, February 2020, e03241].

[This corrects the article DOI: 10.1016/j.heliyon.2020.e03241.].

Annexin 2 protein expression is associated with breast cancer subtypes in African American women.

BACKGROUND: A review of literature on the expression of Annexin 2 in cancer has shown that there is very limited research work on the association of this protein with breast cancer aggressiveness in African Americans. In the present study, TMA breast tissues from African American women were stained with Annexin 2 antibody to determine the association between the molecular subtypes and Annexin 2 protein expression. METHOD: An annotated case series of 135 breast cancer tissues archived from 2000 to 2010 was acquired from the Howard University Tumor Registry. The association between ANX2 expression and survival by molecular subtypes Luminal A, Luminal B, HER2, and Triple Negative (TN) was assessed using Multinomial regression, chi-square analysis, and Kaplan-Meir graphs (Stata 11). RESULTS: Our findings show a marked association between ANX2 protein expression in Luminal B and HER2 subtypes unadjusted and when adjusted for age. Borderline differences in tumor grade were found in TN only.Univariately, age (<50, 50 + years) and metastases were highly significant for overall survival, disease-free survival and recurrence-free survival. Stage, tumor size, and nodal involvement were of borderline or greater significance for overall and disease-free survival. ANX2 expression was not significant. Kaplan Meier tests of ANX2 showed significant separation of overall survival by ANX2 protein expression in all breast tumor subtypes. In multivariate analyses comparing TN to Luminal A, ANX2 was not important while controlling for age and grade. CONCLUSION: ANX2 might be a biomarker of aggressiveness and a relevant candidate biomarker in high risk African American women with Luminal B and HER2 breast cancer.

Genetic Polymorphisms in IL-10 Promoter Are Associated With Smoking and Prostate Cancer Risk in African Americans.

BACKGROUND/AIM: Even though prostate cancer (PCa) has good prognosis, there is a discrepancy in the risk among ethnic groups, with high morbidity in African American men. Single nucleotide polymorphisms (SNPs) in interleukin 10 (IL-10) have been associated with inflammation and cancer risk. We investigated the association of five SNPs in the IL-10 promoter with clinical features such as Gleason score and smoking. MATERIALS AND METHODS: A total of 413 DNA samples were obtained from a nested case-control study of African American males who were genotyped for 5 SNPs utilizing pyrosequencing. Multiple and binary logistic regression models were applied to analyze the clinical and genotypic data. RESULTS: rs12122923 and rs1800871 were associated with PCa risk. Smoking was also found to increase the risk of PCa by 1.6-fold. rs1800893 was found to be associated with lower grades for prostate cancer. CONCLUSION: IL-10 promoter polymorphisms might be a risk factor for PCa development in smoking subjects and PCa progression.

Reporting of race in genome and exome sequencing studies of cancer: a scoping review of the literature.

PURPOSE: Minorities are often underrepresented in clinical cancer research yet the frequency of reporting of race in genomic sequencing studies of cancer is unknown. This scoping review determines the rate at which race is reported as a demographic variable, the factors associated with reporting of race, and the participation rates of minority populations. METHODS: PubMed was systematically searched from 1 January 2010 through 15 November 2018 and 11,014 studies were assessed for eligibility. Publications reporting genome or exome sequencing data for patients with one of the ten most common cancers in the United States were included. RESULTS: A total of 231 publications containing sequencing data from 15,721 unique patients met inclusion criteria. Race was reported in 37% of studies compared with 84% of studies reporting age and 85% reporting gender. Reporting of race was associated with cohort size, sequencing method, familial cancer, cancers with disparities, and reporting of age and gender. Minority populations were significantly underpowered to detect recurrent pathogenic variants in most cancers. CONCLUSION: Race is underreported as a demographic variable in genomic sequencing studies of cancer. Substantially increased efforts are needed to sequence patients from underrepresented populations to reduce health disparities in patients of non-European ancestry.

Factors associated with willingness to provide biospecimens for genetics research among African American cancer survivors.

This study evaluated factors associated with willingness to provide biospecimens for cancer genetic research among African American cancer survivors. A total of 200 African American adults diagnosed with breast, colon, and/or prostate cancers completed a self-administered survey. Family history information, beliefs about cancer research, cancer genetics and disparities knowledge, willingness to provide a biospecimen, and demographics were obtained. Chi-square, independent samples t tests, and logistic regression analyses were performed. Overall, 79% of this sample was willing to provide a biospecimen for cancer genetics research. Independent associations of willingness to provide a biospecimen existed among demographics (males (p = 0.041)), those who believed in the importance of genetic causes of cancer (p < 0.001), individuals who believe it is important to participate in genetics research (p < 0.001), and those who indicated they would participate in genetics research to help future generations (p = 0.026). Overall, 12.5-56% of participants demonstrated some level of genetics and cancer disparities. This study identified factors that may be incorporated into future research interventions to engage the African American cancer population in cancer genetics biobanking research.

Radiogenomic Predictors of Adverse Effects following Charged Particle Therapy.

Radiogenomics is the study of genomic factors that are associated with response to radiation therapy. In recent years, progress has been made toward identifying genetic risk factors linked with late radiation-induced adverse effects. These advances have been underpinned by the establishment of an international Radiogenomics Consortium with collaborative studies that expand cohort sizes to increase statistical power and efforts to improve methodologic approaches for radiogenomic research. Published studies have predominantly reported the results of research involving patients treated with photons using external beam radiation therapy. These studies demonstrate our ability to pool international cohorts to identify common single nucleotide polymorphisms associated with risk for developing normal tissue toxicities. Progress has also been achieved toward the discovery of genetic variants associated with radiation therapy-related subsequent malignancies. With the increasing use of charged particle therapy (CPT), there is a need to establish cohorts for patients treated with these advanced technology forms of radiation therapy and to create biorepositories with linked clinical data. While some genetic variants are likely to impact toxicity and second malignancy risks for both photons and charged particles, it is plausible that others may be specific to the radiation modality due to differences in their biological effects, including the complexity of DNA damage produced. In recognition that the formation of patient cohorts treated with CPT for radiogenomic studies is a high priority, efforts are underway to establish collaborations involving institutions treating cancer patients with protons and/or carbon ions as well as consortia, including the Proton Collaborative Group, the Particle Therapy Cooperative Group, and the Pediatric Proton Consortium Registry. These important radiogenomic CPT initiatives need to be expanded internationally to build on experience gained from the Radiogenomics Consortium and epidemiologists investigating normal tissue toxicities and second cancer risk.

Correction: Comparative oncology DNA sequencing of canine T cell lymphoma via human hotspot panel.

[This corrects the article DOI: 10.18632/oncotarget.25209.].

Comparative oncology DNA sequencing of canine T cell lymphoma via human hotspot panel.

T-cell lymphoma (TCL) is an uncommon and aggressive form of human cancer. Lymphoma is the most common hematopoietic tumor in canines (companion animals), with TCL representing approximately 30% of diagnoses. Collectively, the canine is an appealing model for cancer research given the spontaneous occurrence of cancer, intact immune system, and phytogenetic proximity to humans. We sought to establish mutational congruence of the canine with known human TCL mutations in order to identify potential actionable oncogenic pathways. Following pathologic confirmation, DNA was sequenced in 16 canine TCL (cTCL) cases using a custom Human Cancer Hotspot Panel of 68 genes commonly mutated in human TCL. Sequencing identified 4,527,638 total reads with average length of 229 bases containing 346 unique variants and 1,474 total variants; each sample had an average of 92 variants. Among these, there were 258 germline and 32 somatic variants. Among the 32 somatic variants there were 8 missense variants, 1 splice junction variant and the remaining were intron or synonymous variants. A frequency of 4 somatic mutations per sample were noted with >7 mutations detected in MET, KDR, STK11 and BRAF. Expression of these associated proteins were also detected via Western blot analyses. In addition, Sanger sequencing confirmed three variants of high quality (MYC, MET, and TP53 missense mutation). Taken together, the mutational spectrum and protein analyses showed mutations in signaling pathways similar to human TCL and also identified novel mutations that may serve as drug targets as well as potential biomarkers.

Expression of p27 and c-Myc by immunohistochemistry in breast ductal cancers in African American women.

OBJECTIVES: Proteins p27 and c-Myc are both key players in the cell cycle. While p27, a tumor suppressor, inhibits progression from G1 to S phase, c-Myc, a proto-oncogene, plays a key role in cell cycle regulation and apoptosis. The objective of our study was to determine the association between expression of c-Myc and the loss of p27 by immunohistochemistry (IHC) in the four major subtypes of breast cancer (BC) (Luminal A, Luminal B, HER2, and Triple Negative) and with other clinicopathological factors in a population of 202 African-American (AA) women. MATERIALS AND METHODS: Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 AA women. Five micrometer sections were stained with a mouse monoclonal antibody against p27 and a rabbit monoclonal antibody against c-Myc. The sections were evaluated for intensity of nuclear reactivity (1-3) and percentage of reactive cells; an H-score was derived from the product of these measurements. RESULTS: Loss of p27 expression and c-Myc overexpression showed statistical significance with ER negative (p < 0.0001), PR negative (p < 0.0001), triple negative (TN) (p < 0.0001), grade 3 (p = 0.038), and overall survival (p = 0.047). There was no statistical significant association between c-Myc expression/p27 loss and luminal A/B and Her2 overexpressing subtypes. CONCLUSION: In our study, a statistically significant association between c-Myc expression and p27 loss and the triple negative breast cancers (TNBC) was found in AA women. A recent study found that constitutive c-Myc expression is associated with inactivation of the axin 1 tumor suppressor gene. p27 inhibits cyclin dependent kinase2/cyclin A/E complex formation. Axin 1 and CDK inhibitors may represent possible therapeutic targets for TNBC.

Admixture Mapping Links RACGAP1 Regulation to Prostate Cancer in African Americans.

BACKGROUND/AIM: Prostate cancer is the most common malignancy in US males. African American men have higher incidence and mortality rates than European Americans. Five single nucleotide polymorphisms are associated with PCa. We hypothesized haplotypes inferred from these SNPs are also associated with PCa. PATIENTS AND METHODS: We genotyped SNPs in a case-control admixture mapping study. SNP haplotypes inferred for 157 PCa cases and 150 controls were used in the regression analysis. RESULTS: We found an association between "GTCCC", "ATTCT", and "ACCCC" haplotypes and PCa after ancestry adjustment (OR=3.62, 95%CI=1.42-9.21, p=0.0070; OR=7.89, 95%CI=2.36-26.31, p=0.0008; OR=4.34, 95%CI=1.75-10.78, p=0.0016). The rs615382 variant disrupts the recombination signal binding protein with immunoglobulin kappa J binding site in Rac GTPase activating protein 1 (RACGAP1). CONCLUSION: Disruption of notch 1 mediated-repression of RACGAP1 may contribute to PCa in African Americans.

Loss of PTEN in high grade advanced stage triple negative breast ductal cancers in African American women.

INTRODUCTION: PTEN is a tumor suppressor gene that inhibits cell proliferation by inhibiting the phosphoinositide 3-kinase (PI3 K) signaling pathway. The significance of PTEN mutations resulting in variable PTEN expression and their impact on prognosis of breast cancer is not well established. The objective of our study was to correlate the immunohistochemical expression of PTEN in the four major subtypes of breast carcinoma (Luminal A, Luminal B, HER2 positive, and Triple Negative) in a population of 202 African-American (AA) females with other clinicopathological factors. MATERIALS AND METHODS: Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 African-American females. Five micrometer sections were stained with a mouse monoclonal antibody against PTEN. The sections were evaluated for the intensity of cytoplasmic and nuclear reactivity. Bivariate analysis was done via χ2 analysis and survivability data was calculated via the generation of Kaplan-Meier curves (SPSS v19). RESULTS: Loss of PTEN expression was associated with ER negative (p = 0.021), PR negative (p = 0.024) and triple negative (p = 0.0024) breast ductal cancers. It was marginally associated with distant metastasis (p = 0.074). There was no association between PTEN loss and recurrence-free survival or overall survival. CONCLUSION: In our study, a statistically significant association between PTEN loss and the triple negative breast cancers (TNBC) was found in AA women. PTEN inhibits PI3 K resulting in decreased activation of downstream effector, mammalian target of rapamycin (mTOR). Loss of PTEN results in cell proliferation through activation of mTOR. Targeted therapy with mTOR inhibitors might be useful in the treatment of TNBC.