BackgroundPancreatic cancer stem cells (CSCs) represent a small subpopulation of pancreatic cancer cells that have the capacity to initiate and propagate tumor formation. However, the mechanisms by which pancreatic CSCs are maintained are not well understood or characterized.MethodsExpression of Notch receptors, ligands, and Notch signaling target genes was quantitated in the CSC and non-CSC populations from 8 primary human pancreatic xenografts. A gamma secretase inhibitor (GSI) that inhibits the Notch pathway and a shRNA targeting the Notch target gene Hes1 were used to assess the role of the Notch pathway in CSC population maintenance and pancreatic tumor growth.ResultsNotch pathway components were found to be upregulated in pancreatic CSCs. Inhibition of the Notch pathway using either a gamma secretase inhibitor or Hes1 shRNA in pancreatic cancer cells reduced the percentage of CSCs and tumorsphere formation. Conversely, activation of the Notch pathway with an exogenous Notch peptide ligand increased the percentage of CSCs as well as tumorsphere formation. In vivo treatment of orthotopic pancreatic tumors in NOD/SCID mice with GSI blocked tumor growth and reduced the CSC population.ConclusionThe Notch signaling pathway is important in maintaining the pancreatic CSC population and is a potential therapeutic target in pancreatic cancer.

This study confirms an association between TNBC and West African ancestry; TNBC frequency among AA patients is intermediate between WA and Ghanaian/West Africans consistent with genetic admixture following the west Africa-based trans-Atlantic slave trade. TNBC frequency was low among Ethiopians/East Africans; this may reflect less shared ancestry between AA and Ethiopians.

BackgroundBmi1 is an integral component of the Polycomb Repressive Complex 1 (PRC1) and is involved in the pathogenesis of multiple cancers. It also plays a key role in the functioning of endogenous stem cells and cancer stem cells. Previous work implicated a role for cancer stem cells in the pathogenesis of pancreatic cancer. We hypothesized that Bmi1 plays an integral role in enhancing pancreatic tumorigenicity and the function of cancer stem cells in pancreatic ductal adenocarcinoma.MethodsWe measured endogenous Bmi1 levels in primary human pancreatic ductal adenocarcinomas, pancreatic intraepithelial neoplasias (PanINs) and normal pancreas by immunohistochemistry and Western blotting. The function of Bmi1 in pancreatic cancer was assessed by alteration of Bmi1 expression in several cell model systems by measuring cell proliferation, cell apoptosis, in vitro invasion, chemotherapy resistance, and in vivo growth and metastasis in an orthotopic model of pancreatic cancer. We also assessed the cancer stem cell frequency, tumorsphere formation, and in vivo growth of human pancreatic cancer xenografts after Bmi1 silencing.ResultsBmi1 was overexpressed in human PanINs, pancreatic cancers, and in several pancreatic cancer cell lines. Overexpression of Bmi1 in MiaPaCa2 cells resulted in increased proliferation, in vitro invasion, larger in vivo tumors, more metastases, and gemcitabine resistance while opposite results were seen when Bmi1 was silenced in Panc-1 cells. Bmi1 was overexpressed in the cancer stem cell compartment of primary human pancreatic cancer xenografts. Pancreatic tumorspheres also demonstrated high levels of Bmi1. Silencing of Bmi1 inhibited secondary and tertiary tumorsphere formation, decreased primary pancreatic xenograft growth, and lowered the proportion of cancer stem cells in the xenograft tissue.ConclusionsOur results implicate Bmi1 in the invasiveness and growth of pancreatic cancer and demonstrate its key role in the regulation of pancreatic cancer stem cells.

Objective: To investigate subtype-specific risk of germline alleles associated with triple negative breast cancer (TNBC) in African ancestry populations. Background: Breast cancer (BC) mortality is higher in African American (AA) compared to White American (WA) women; this disparity is partly explained by 2-fold higher TNBC incidence. Methods: We used a surgically maintained biospecimen cohort of 2884 BC cases. Subsets of the total (760 AA; 962 WA; 910 West African/Ghanaian; 252 East African/Ethiopian) were analyzed for genotypes of candidate alleles. A subset of 417 healthy controls were also genotyped, to measure associations with overall BC risk and TNBC. Results: TNBC frequency was highest in Ghanaian and AA cases (49% and 44% respectively; P < 0.0001) and lowest in Ethiopian and WA cases (17% and 24% respectively; P < 0.0001). TNBC cases had higher West African ancestry than non-TNBC (P < 0.0001). Frequency of the Duffy-null allele (rs2814778; an African ancestral variant adopted under selective pressure as protection against malaria) was associated with TNBC-specific risk (P < 0.0001), quantified West African Ancestry (P < 0.0001) and was more common in AA, Ghanaians, and TNBC cases. Additionally, rs4849887 was significantly associated with overall BC risk, and both rs2363956 and rs13000023 were associated with TNBC-specific risk, although none as strongly as the Duffy-null variant. Conclusions: West African ancestry is strongly correlated with TNBC status, as well as germline variants related to BC risk. The Duffy-null allele was associated with TNBC risk in our cohort.

Women of sub-Saharan African descent have disproportionately higher incidence of Triple Negative Breast Cancer (TNBC), and TNBC-specific mortality. Population comparative studies show racial differences in TNBC biology, including higher prevalence of basal-like and Quadruple-Negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily United States (US) populations. Due to heterogenous genetic admixture, and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNAseq on an international cohort of AAs, west and east Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed tumor-associated immunological profiles are distinct in patients of African descent.

Introduction Androgen Receptor (AR) is the most commonly-expressed nuclear hormone receptor in breast cancer and may be a marker of response to targeted anti-androgen therapy, a particularly attractive option in the setting of triple negative breast cancer (TNBC). Gene expression studies suggest that AR-positivity may distinguish a luminal/AR TNBC subtype from mesenchymal, stem cell-like, and basal-like subtypes. Furthermore, frequency of TNBC is 2–3-times higher in African American and African compared to White American and European breast cancer pts, yet little is known regarding the distribution of TNBC subtypes in the high-risk African-ancestry populations. We sought to characterize AR expression and TNBC patterns among a series of breast cancers from Ghana, Africa. Methods Formalin-fixed, paraffin-embedded invasive breast cancer specimens from 147 pts treated at a single teaching hospital in Ghana were studied at a comprehensive cancer center in the United States and analyzed for estrogen receptor (ER), progesterone receptor (PR), HER2/neu, ALDH1 and AR expression via immunohistochemistry. Results Median patient age was 45 (range, 28–76yrs). Only 31 cases (21%) were ER-positive, and 14 (10%) were HER2-positive; 89 tumors (61%) were TNBC. For the entire group, 44% were AR-positive and 45% were ALDH1-positive. ER/PR-positive tumors were more likely to be AR-positive compared to ER/PR-negative tumors (87% versus 26%; p<0.0001) but there was no association between ALDH1 and AR expression. Among the TNBC cases, 45% were ALDH1-positive and 24% were AR-positive. ALDH1-positivity versus negativity was associated with AR-positivity within the subset of TNBC tumors (36% versus 14%; p=0.019). Conclusions We confirmed the results of others showing that the majority of African breast cancers are triple-negative. We also found that AR expression is lower than that reported in other populations. Surprisingly, a marker of mammary stem cell expression was found to correlate with AR expression among triple negative tumors in this series, suggesting that novel TNBC subtypes may be identified by studying TNBC patterns among more diverse international populations.

INTRODUCTION: The optimal structure for survivorship care plan (SCP) programs and methodology for generating treatment summaries (TSs) has not yet been defined, but the Commission on Cancer and the National Accreditation Program for Breast Centers both mandate that participating oncology programs implement SCP-TS processes for patients that have completed treatment. METHODS: We used the Institute for Healthcare Improvement’s Plan-Do-Study-Act model for conducting a quality improvement project evaluating two different SCP-TS programs implemented at the Henry Ford Health System/Henry Ford Cancer Institute’s Breast Oncology Program in Detroit, Michigan. System I involved TSs drafted by nonspecialist breast clinic staff; System II involved TSs vetted through a multidisciplinary breast specialist conference approach. Accuracy of basic documentation entries related to dates and components of treatment were compared for the two approaches. RESULTS: Seventy-one System I and 93 System II documents were reviewed. Documentation was accurate in at least 90% of documents for both systems regarding delivery of chemotherapy and/or endocrine therapy and for documenting the identity of the various members of the cancer treatment team. Both systems had notable inaccuracies in documenting type of surgery performed, but System II had fewer inaccuracies than System I (33.78% v 51.67%, respectively; P = .05). System II, compared with System I, had fewer inaccuracies in documenting date of diagnosis (9.68% v 25.35%, respectively; P = .01) and had less missing information for dose of radiation delivered (9.33% v 33.9%, respectively; P < .01). CONCLUSION: A multidisciplinary team approach to drafting and reviewing SCP-TS documents improved content accuracy for our program, but ongoing education regarding documentation of various surgical procedures is warranted.

Importance African American (AA) women have a two-fold higher incidence of breast cancers that are negative for estrogen receptor, progesterone receptor and HER2/neu (triple negative breast cancer, TNBC) compared with White/Caucasian Americans (WA). TNBC likely arises from different pathogenetic pathways compared to non-TNBC, and benign breast disease (BBD) predicts for future non-TNBC. Objective To determine whether AA identity remained associated with TNBC among women with a prior diagnosis of BBD. Design Retrospective analysis; January 1, 1994-December 31, 2005; mean follow-up 10.2 years. Setting Henry Ford Health System in metropolitan Detroit, Michigan; an integrated multihospital, multispecialty health care system. Participants 2,588 AA and 3,566 WA patients age 40-70 years with biopsy-proven BBD diagnosed 1/1/1994 to 12/31/2005. Main Outcome Measures Subsequent breast cancer, stratified by phenotype. Results BBD detection and management were similar for the AA and WA patients. Subsequent breast cancers developed in approximately 4% of AA patients (mean 6.8 years following BBD diagnosis) and WA patients (mean 6.1 years). More than three-quarters of subsequent cancers in each subset were DCIS or Stage I. The 10-year probability estimate for developing TNBC was 0.56% (95% confidence interval 0.32-1.0) for AA versus 0.25% for WA (95% confidence interval 0.12-0.53). Among the 73 AA patients that developed subsequent invasive breast cancer, 24.2% were TNBC compared to 7.4% of the 111 subsequent invasive BC cases (p=0.0125) among the WA patients. Conclusion and Relevance AA identity persisted as a significant risk factor for TNBC in our study, the largest analysis to date of BBD and subsequent breast cancer phenotypes in a diverse patient population managed equitably. This suggests that AA identity is associated with inherent susceptibility for TNBC pathogenetic pathways.