Julia Tchou

Comparison of Triple-negative and Estrogen Receptor- positive/Progesterone Receptor-positive/HER2-negative Breast Carcinoma Using Quantitative Fluorine-18 Fluorodeoxyglucose/Positron Emission Tomography Imaging Parameters A Potentially Useful Method for Disease Characterization

This study was designed to investigate the fluorine‐18 fluorodeoxyglucose (FDG)‐positron emission tomography (PET) imaging characteristics of triple‐negative (estrogen receptor‐negative [ER−]/progesterone receptor‐negative [PR−]/HER2‐negative [HER2−]) breast carcinoma and compare the results with characteristics of ER+/PR+/HER2− breast carcinomas, which usually carry a favorable prognosis.

Differentiation of benign and malignant breast tumors by in-vivo three-dimensional parallel-plate diffuse optical tomography

We have developed a novel parallel-plate diffuse optical tomography (DOT) system for three-dimensional in vivo imaging of human breast tumor based on large optical data sets. Images of oxy-, deoxy-, and total hemoglobin concentration as well as blood oxygen saturation and tissue scattering were reconstructed. Tumor margins were derived using the optical data with guidance from radiology reports and magnetic resonance imaging. Tumor-to-normal ratios of these endogenous physiological parameters and an optical index were computed for 51 biopsy-proven lesions from 47 subjects. Malignant cancers (N=41) showed statistically significant higher total hemoglobin, oxy-hemoglobin concentration, and scattering compared to normal tissue. Furthermore, malignant lesions exhibited a twofold average increase in optical index. The influence of core biopsy on DOT results was also explored; the difference between the malignant group measured before core biopsy and the group measured more than 1 week after core biopsy was not significant. Benign tumors (N=10) did not exhibit statistical significance in the tumor-to-normal ratios of any parameter. Optical index and tumor-to-normal ratios of total hemoglobin, oxy-hemoglobin concentration, and scattering exhibited high area under the receiver operating characteristic curve values from 0.90 to 0.99, suggesting good discriminatory power. The data demonstrate that benign and malignant lesions can be distinguished by quantitative three-dimensional DOT.

Comparison of triple-negative and estrogen receptor-positive/progesterone receptor-positive/HER2-negative breast carcinoma using quantitative fluorine-18 fluorodeoxyglucose/positron emission tomography imaging parameters: a potentially useful method for disease characterization.

This study was designed to investigate the fluorine‐18 fluorodeoxyglucose (FDG)‐positron emission tomography (PET) imaging characteristics of triple‐negative (estrogen receptor‐negative [ER−]/progesterone receptor‐negative [PR−]/HER2‐negative [HER2−]) breast carcinoma and compare the results with characteristics of ER+/PR+/HER2− breast carcinomas, which usually carry a favorable prognosis.

Diffuse optical measurement of blood flow in breast tumors

Blood flow contrast between tumor and normal tissues in patients with malignant and benign breast cancer was measured by diffuse optical correlation methods. The measurements were carried out with a hand-held optical probe that was manually scanned over the tumor-bearing breast. Increased blood flow was observed in tumor regions relative to healthy tissue, and control subjects did not exhibit significant blood flow heterogeneity. The measurements introduce a new optical contrast for diffuse optical mammography.

Microbially Driven TLR5-Dependent Signaling Governs Distal Malignant Progression through Tumor-Promoting Inflammation

The dominant TLR5(R392X) polymorphism abrogates flagellin responses in >7% of humans. We report that TLR5-dependent commensal bacteria drive malignant progression at extramucosal locations by increasing systemic IL-6, which drives mobilization of myeloid-derived suppressor cells (MDSCs). Mechanistically, expanded granulocytic MDSCs cause γδ lymphocytes in TLR5-responsive tumors to secrete galectin-1, dampening antitumor immunity and accelerating malignant progression. In contrast, IL-17 is consistently upregulated in TLR5-unresponsive tumor-bearing mice but only accelerates malignant progression in IL-6-unresponsive tumors. Importantly, depletion of commensal bacteria abrogates TLR5-dependent differences in tumor growth. Contrasting differences in inflammatory cytokines and malignant evolution are recapitulated in TLR5-responsive/unresponsive ovarian and breast cancer patients. Therefore, inflammation, antitumor immunity, and the clinical outcome of cancer patients are influenced by a common TLR5 polymorphism.

Identification of a long non-coding RNA-associated RNP complex regulating metastasis at the translational step

Long non‐coding RNAs (lncRNAs) are a novel class of regulatory genes that play critical roles in various processes ranging from normal development to human diseases such as cancer progression. Recent studies have shown that lncRNAs regulate the gene expression by chromatin remodelling, transcription, splicing and RNA decay control, enhancer function, and epigenetic regulation. However, little is known about translation regulation by lncRNAs. We identified a translational regulatory lncRNA (treRNA) through genome‐wide computational analysis. We found that treRNA is upregulated in paired clinical breast cancer primary and lymph‐node metastasis samples, and that its expression stimulates tumour invasion in vitro and metastasis in vivo. Interestingly, we found that treRNA downregulates the expression of the epithelial marker E‐cadherin by suppressing the translation of its mRNA. We identified a novel ribonucleoprotein (RNP) complex, consisting of RNA‐binding proteins (hnRNP K, FXR1, and FXR2), PUF60 and SF3B3, that is required for this treRNA functions. Translational suppression by treRNA is dependent on the 3′UTR of the E‐cadherin mRNA. Taken together, our study indicates a novel mechanism of gene regulation by lncRNAs in cancer progression.

Degree of Tumor FDG Uptake Correlates with Proliferation Index in Triple Negative Breast Cancer

Purpose2-Deoxy-2-[F-18]fluoro-D-glucose (FDG) uptake may be a useful surrogate marker for proliferation index, but the correlation has not always been clear-cut. Previous research by our group suggests that FDG-positron emission tomography (PET) is sensitive in detecting triple negative breast cancer. We therefore performed a pilot study to test if FDG uptake correlated with proliferation index in women with triple negative cancer.ProceduresTo determine whether proliferation index correlates with metabolic uptake of FDG in women with triple negative breast cancer, we performed a retrospective analysis correlating %Ki67 nuclear stain with tumor maximum standardized uptake values (SUVmax) in a group of 41 women, 22 with triple negative and 19 with non-triple negative breast cancer.ResultsAs expected, [18F]-PET imaging was significantly more sensitive in detecting triple negative breast cancer than non-triple negative breast cancer, 95.5% vs 68.4% (p = 0.036). In general, SUVmax and %Ki67 nuclear stain values rise as histologic grade worsens. Histologic grade of triple negative breast cancer was more often poorly differentiated than non-triple negative cancer (p = 0.001). SUVmax correlated with %Ki67 nuclear staining in our entire cohort (spearman correlation = 0.485, p = 0.002). Moreover, this significant correlation appeared to be driven primarily by a subset of women with triple negative cancer (spearman correlation = 0.497, p = 0.019).ConclusionsDegree of tumor FDG uptake correlated significantly with proliferation index in women with triple negative breast cancer suggesting a potential role of FDG-PET in treatment response monitoring for this group of women. Future studies are necessary to define the role of PET imaging as a non-invasive means to monitor breast cancer treatment response in the neoadjuvant setting.

Transforming Growth Factor β-Mediated Suppression of Antitumor T Cells Requires FoxP1 Transcription Factor Expression

Tumor-reactive T cells become unresponsive in advanced tumors. Here we have characterized a common mechanism of T cell unresponsiveness in cancer driven by the upregulation of the transcription factor Forkhead box protein P1 (Foxp1), which prevents CD8⁺ T cells from proliferating and upregulating Granzyme-B and interferon-γ in response to tumor antigens. Accordingly, Foxp1-deficient lymphocytes induced rejection of incurable tumors and promoted protection against tumor rechallenge. Mechanistically, Foxp1 interacted with the transcription factors Smad2 and Smad3 in preactivated CD8⁺ T cells in response to microenvironmental transforming growth factor-β (TGF-β), and was essential for its suppressive activity. Therefore, Smad2 and Smad3-mediated c-Myc repression requires Foxp1 expression in T cells. Furthermore, Foxp1 directly mediated TGF-β-induced c-Jun transcriptional repression, which abrogated T cell activity. Our results unveil a fundamental mechanism of T cell unresponsiveness different from anergy or exhaustion, driven by TGF-β signaling on tumor-associated lymphocytes undergoing Foxp1-dependent transcriptional regulation.

Human breast cancer associated fibroblasts exhibit subtype specific gene expression profiles

BackgroundBreast cancer is a heterogeneous disease for which prognosis and treatment strategies are largely governed by the receptor status (estrogen, progesterone and Her2) of the tumor cells. Gene expression profiling of whole breast tumors further stratifies breast cancer into several molecular subtypes which also co-segregate with the receptor status of the tumor cells. We postulated that cancer associated fibroblasts (CAFs) within the tumor stroma may exhibit subtype specific gene expression profiles and thus contribute to the biology of the disease in a subtype specific manner. Several studies have reported gene expression profile differences between CAFs and normal breast fibroblasts but in none of these studies were the results stratified based on tumor subtypes.MethodsTo address whether gene expression in breast cancer associated fibroblasts varies between breast cancer subtypes, we compared the gene expression profiles of early passage primary CAFs isolated from twenty human breast cancer samples representing three main subtypes; seven ER+, seven triple negative (TNBC) and six Her2+.ResultsWe observed significant expression differences between CAFs derived from Her2+ breast cancer and CAFs from TNBC and ER + cancers, particularly in pathways associated with cytoskeleton and integrin signaling. In the case of Her2+ breast cancer, the signaling pathways found to be selectively up regulated in CAFs likely contribute to the enhanced migration of breast cancer cells in transwell assays and may contribute to the unfavorable prognosis of Her2+ breast cancer.ConclusionsThese data demonstrate that in addition to the distinct molecular profiles that characterize the neoplastic cells, CAF gene expression is also differentially regulated in distinct subtypes of breast cancer.

Fibroblast activation protein expression by stromal cells and tumor-associated macrophages in human breast cancer

Fibroblast activation protein (FAP) has long been known to be expressed in the stroma of breast cancer. However, very little is known if the magnitude of FAP expression within the stroma may have a prognostic value and reflect the heterogeneous biology of the tumor cell. An earlier study had suggested that stromal FAP expression in breast cancer was inversely proportional to prognosis. We, therefore, hypothesized that stromal FAP expression may correlate with clinicopathologic variables and may serve as an adjunct prognostic factor in breast cancer. We evaluated the expression of FAP in a panel of breast cancer tissues (n = 52) using a combination of immunostain analyses at the tissue and single-cell level using freshly frozen or freshly digested human breast tumor samples, respectively. Our results showed that FAP expression was abundantly expressed in the stroma across all breast cancer subtypes without significant correlation with clinicopathologic factors. We further identified a subset of FAP-positive (or FAP(+)) stromal cells that also expressed CD45, a pan-leukocyte marker. Using freshly dissociated human breast tumor specimens (n = 5), we demonstrated that some of these FAP(+)CD45(+) cells were CD11b(+)CD14(+)MHC-II(+), indicating that they were likely tumor-associated macrophages (TAMs). Although FAP(+)CD45(+) cells have been demonstrated in the mouse tumor stroma, our results demonstrating that human breast TAMs expressed FAP were novel and suggested that existing and future FAP-directed therapy may have dual-therapeutic benefits targeting both stromal mesenchymal cells and immune cells such as TAMs. More work is needed to explore the role of FAP as a potential targetable molecule in breast cancer treatment.