Emerging evidence for the role of differential tumor microenvironment in breast cancer racial disparity: a closer look at the surroundings.

Although increased awareness leading to early detection and prevention, as well as advancements in treatment strategies, have resulted in superior clinical outcomes, African American women with breast cancer continue to have greater mortality rates, compared to Caucasian American counterparts. Moreover, African American women are more likely to have breast cancer at a younger age and be diagnosed with aggressive tumor sub-types. Such racial disparities can be attributed to socioeconomic differences, but it is increasingly being recognized that these disparities may indeed be due to certain genetic and other non-genetic biological differences. Tumor microenvironment, which provides a favorable niche for the growth of tumor cells, is comprised of several types of stromal cells and the various proteins secreted as a consequence of bi-directional tumor-stromal cross-talk. Emerging evidence suggests inherent biological differences in the tumor microenvironment of breast cancer patients from different racial backgrounds. Tumor microenvironment components, affected by the genetic make-up of the tumor cells as well as other non-tumor-associated factors, may also render patients more susceptible to the development of aggressive tumors and faster progression of disease resulting in early onset, thus adversely affecting patients' survival. This review provides an overview of breast cancer racial disparity and discusses the existence of race-associated differential tumor microenvironment and its underlying genetic and non-genetic causal factors. A better understanding of these aspects would help further research on effective cancer management and improved approaches for reducing the racial disparities gaps in breast cancer patients.

microRNA-29 negatively regulates EMT regulator N-myc interactor in breast cancer.

BACKGROUND: N-Myc Interactor is an inducible protein whose expression is compromised in advanced stage breast cancer. Downregulation of NMI, a gatekeeper of epithelial phenotype, in breast tumors promotes mesenchymal, invasive and metastatic phenotype of the cancer cells. Thus the mechanisms that regulate expression of NMI are of potential interest for understanding the etiology of breast tumor progression and metastasis. METHOD: Web based prediction algorithms were used to identify miRNAs that potentially target the NMI transcript. Luciferase reporter assays and western blot analysis were used to confirm the ability of miR-29 to target NMI. Quantitive-RT-PCRs were used to examine levels of miR29 and NMI from cell line and patient specimen derived RNA. The functional impact of miR-29 on EMT phenotype was evaluated using transwell migration as well as monitoring 3D matrigel growth morphology. Anti-miRs were used to examine effects of reducing miR-29 levels from cells. Western blots were used to examine changes in GSK3ß phosphorylation status. The impact on molecular attributes of EMT was evaluated using immunocytochemistry, qRT-PCRs as well as Western blot analyses. RESULTS: Invasive, mesenchymal-like breast cancer cell lines showed increased levels of miR-29. Introduction of miR-29 into breast cancer cells (with robust level of NMI) resulted in decreased NMI expression and increased invasion, whereas treatment of cells with high miR-29 and low NMI levels with miR-29 antagonists increased NMI expression and decreased invasion. Assessment of 2D and 3D growth morphologies revealed an EMT promoting effect of miR-29. Analysis of mRNA of NMI and miR-29 from patient derived breast cancer tumors showed a strong, inverse relationship between the expression of NMI and the miR-29. Our studies also revealed that in the absence of NMI, miR-29 expression is upregulated due to unrestricted Wnt/ß-catenin signaling resulting from inactivation of GSK3ß. CONCLUSION: Aberrant miR-29 expression may account for reduced NMI expression in breast tumors and mesenchymal phenotype of cancer cells that promotes invasive growth. Reduction in NMI levels has a feed-forward impact on miR-29 levels.

Intraoperative Fluorescence Guidance for Breast Cancer Lumpectomy Surgery.

BACKGROUND: Although lumpectomy and mastectomy provide equivalent survival for patients with breast cancer, local recurrence after lumpectomy increases breast cancer mortality. Positive lumpectomy margins, which imply incomplete tumor removal, are the strongest predictor of local recurrence and are identified days after surgery, necessitating a second surgery. METHODS: In this prospective trial, we assessed margin status with or without pegulicianine fluorescence-guided surgery (pFGS) for stages 0 to 3 breast cancers. To prevent surgeons from performing smaller than standard lumpectomies in anticipation of pFGS assistance, patients were randomly assigned 10:1 to pFGS or control groups, thus randomization was not designed to provide a control group for evaluating device performance. In patients undergoing pFGS, additional pFGS-guided cavity margins were excised at sites of pegulicianine signal. We evaluated three coprimary end points: the percentage of patients for whom pFGS-guided margins contained cancer, sensitivity, and specificity. RESULTS: Overall, 406 patients received 1.0 mg/kg intravenous pegulicianine followed by lumpectomy. Among 392 patients randomly assigned, 316 had invasive cancers, and 76 had in situ cancers. In 27 of 357 patients undergoing pFGS, pFGS-guided margins removed tumor left behind after standard lumpectomy, 22 from cavity orientations deemed negative on standard margin evaluation. Second surgeries were avoided by pFGS in 9 of 62 patients with positive margins. On per-margin analysis, pFGS specificity was 85.2%, and sensitivity was 49.3%. Pegulicianine administration was stopped for adverse events in six patients. Two patients had grade 3 serious adverse events related to pegulicianine. CONCLUSIONS: The use of pFGS in breast cancer surgery met prespecified thresholds for removal of residual tumor and specificity but did not meet the prespecified threshold for sensitivity. (Funded by Lumicell, Inc. and the National Institutes of Health; Clinicaltrials.gov number, NCT03686215.)

Micro-RNA-632 downregulates DNAJB6 in breast cancer.

DNAJB6 is a constitutively expressed member of the HSP40 family. It has been described as a negative regulator of breast tumor progression and a regulator of epithelial phenotype. Expression of DNAJB6 is reported to be compromised with tumor progression. However, factors responsible for its downregulation are still undefined. We used a knowledge-based screen for identifying miRNAs capable of targeting DNAJB6. In this work, we present our findings that hsa-miR-632 (miR-632) targets the coding region of DNAJB6. Invasive and metastatic breast cancer cells express high levels of miR-632 compared with mammary epithelial cells. Analysis of RNA from breast tumor specimens reveals inverse expression patterns of DNAJB6 transcript and miR-632. In response to exogenous miR-632 expression, DNAJB6 protein levels are downregulated and the resultant cell population shows significantly increased invasive ability. Silencing endogenous miR-632 abrogates invasive ability of breast cancer cells and promotes epithelial like characteristics noted by E-cadherin expression with concomitant decrease in mesenchymal markers such as Zeb2 and Slug. Thus, miR-632 is a potentially important epigenetic regulator of DNAJB6, which contributes to the downregulation of DNAJB6 and plays a supportive role in malignant progression.

Primary Malignant Peripheral Nerve Sheath Tumor of the Breast: A Rare Case Report and Review of Literature.

Primary breast sarcomas are uncommon and primary mammary malignant peripheral nerve sheet tumors (MPNST) are exceptionally rare. MPNSTs are malignant variants of peripheral nerve sheath tumors. These neoplasms are often associated with neurofibromatosis type I (NF-I) but can also occur sporadically. They tend to occur in the deeper soft tissues, trunk, and extremities. A 60-year-old Asian female was referred to our surgical clinic for evaluation of a left breast mass and an abnormal mammogram. The patient noticed the mass in the left breast three months earlier and was referred for mammography by her primary physician. Mammography reported partially defined masses in the superior aspect of the left breast, and ultrasound showed a solid mass measuring 5.2 X 3 cm. The mass was 11 cm on clinical exam. Subsequent core biopsy of the left breast lesion showed high-grade malignant neoplasm. Workup showed no evidence of metastatic disease, and the patient underwent modified radical mastectomy. The neoplastic cells were positive for CD99, S-100, SOX-10, neuron specific enolase, p53, vimentin, focally positive for neurofilament, D2-40, p63, and negative for epithelial, melanoma and other sarcoma markers. The tumor was triple negative estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), with Ki-67 at 61%. A diagnosis of primary high grade malignant peripheral nerve sheath tumor of the breast was rendered. The patient does not have a history of NF-1. An accurate diagnosis of this rare entity is necessary because it plays a crucial role in the therapeutic options and prognosis. In our case the patient underwent modified radical mastectomy. The purpose of presenting this unique case is to provide awareness of the existence of this entity among pathologists and clinicians for better patient care.

Clinical Impact of Intraoperative Margin Assessment in Breast-Conserving Surgery With a Novel Pegulicianine Fluorescence-Guided System: A Nonrandomized Controlled Trial.

Importance: Positive margins following breast-conserving surgery (BCS) are often identified on standard pathology evaluation. Intraoperative assessment of the lumpectomy cavity has the potential to reduce residual disease or reexcision rate following standard of care BCS in real time. Objective: To collect safety and initial efficacy data on the novel pegulicianine fluorescence-guided system (pFGS) when used to identify residual cancer in the tumor bed of female patients undergoing BCS. Design, Setting, and Participants: This prospective single-arm open-label study was conducted as a nonrandomized multicenter controlled trial at 16 academic or community breast centers across the US. Female patients 18 years and older with newly diagnosed primary invasive breast cancer or ductal carcinoma in situ DCIS undergoing BCS were included, excluding those with previous breast cancer surgery and a history of dye allergies. Of 283 consecutive eligible patients recruited, 234 received a pegulicianine injection and were included in the safety analysis; of these, 230 were included in the efficacy analysis. Patients were enrolled between February 6, 2018, and April 10, 2020, and monitored for a 30-day follow-up period. Data were analyzed from April 10, 2020, to August 5, 2021. Interventions: Participants received an injection of a novel imaging agent (pegulicianine) a mean (SD) of 3.2 (0.9) hours prior to surgery at a dose of 1 mg/kg. After completing standard of care (SOC) excision, pFGS was used to scan the lumpectomy cavity to guide the removal of additional shave margins. Main Outcomes and Measures: Adverse events and sensitivity, specificity, and reexcision rate. Results: Of 234 female patients enrolled (median [IQR] age, 62.0 [55.0-69.0] years), 230 completed the trial and 1 patient with a history of allergy to contrast agents had an anaphylactic reaction and recovered without sequelae. Correlation of pFGS with final margin status on a per-margin analysis showed a marked improvement in sensitivity over standard pathology assessment of the main lumpectomy specimen (69.4% vs 38.2%, respectively). On a per-patient level, the false-negative rate of pFGS was 23.7% (9 of 38), and sensitivity was 76.3% (29 of 38). Among 32 patients who underwent excision of pFGS-guided shaves, pFGS averted the need for reexcision in 6 (19%). Conclusions and Relevance: In this pilot feasibility study, the safety profile of pegulicianine was consistent with other imaging agents used in BCS, and was associated with a reduced need for second surgery in patients who underwent intraoperative additional excision of pFGS-guided shaves. These findings support further development and clinical performance assessment of pFGS in a prospective randomized trial. Trial Registration: ClinicalTrials.gov Identifier: NCT03321929.

A phase I trial of azacitidine and nanoparticle albumin bound paclitaxel in patients with advanced or metastatic solid tumors.

BACKGROUND: Secreted protein acidic and rich in cysteine (SPARC), an albumin-binding protein, is downregulated by hypermethylation in many cancers. Hypomethylating agents such as azacitidine can upregulate SPARC in tumors, which may enhance the accumulation of albumin-bound drugs at tumor site. The objectives of this phase I trial was to determine the safety and maximum tolerated dose and to assess any clinical activity of the combination of azacytidine and weekly nanoparticle-albumin-bound (nab®) paclitaxel. METHODS: Patients received escalating azacytidine doses daily for 5 days, followed by nab-paclitaxel at the standard 100mg/m2 weekly dose for 3 weeks in 4-week cycles. Dose-limiting toxicities (DLTs) were monitored during the first cycle. Serum was obtained at baseline, during and after treatment for correlative study. RESULTS: All sixteen total patients enrolled were evaluable for toxicity, while 13 patients were evaluable for response. Two of five patients treated with 100mg/m2 of azacytidine had DLT of prolonged grade 4 neutropenia. Therefore, the MTD of azacitidine in this regimen is 75 mg/m2. Three additional patients were treated with no grade 4 toxicity in cycle 1. Clinical activity included 1 complete response (CR) in refractory DLBCL, 2 CR in ovarian cancer, 4 partial responses (PR) in ovarian and endometrial cancer, 4 stable diseases (SD) in lung, sarcoma and pancreatic cancer, 1 unconfirmed PR in breast cancer, and 1 progression of disease in CLL/SLL. CONCLUSIONS: Priming with azacitidine 75 mg/m2 daily for 5 days, followed by weekly nab-paclitaxel 100 mg/m2 weekly was well tolerated and results in dramatic responses pre-treated cancer patients.

Resistin potentiates chemoresistance and stemness of breast cancer cells: Implications for racially disparate therapeutic outcomes.

Breast cancer (BC) continues to be the most frequently diagnosed cancer in American women, which disproportionately affects women of African-American (AA) descent. Previously, we reported greater serum levels of resistin in AA BC patients relative to Caucasian-American (CA) patients, and established its role in growth and aggressiveness of breast tumor cells. Here we have investigated the role of resistin in BC-chemoresistance. MDA-MB-231 and MDA-MB-468 BC cells of CA and AA origin, respectively, were incubated with resistin prior to doxorubicin treatment. Our data suggest that resistin conferred chemoresistance to both BC cell lines; however, the effect on AA cells was more profound. Furthermore, the resistin-induced doxorubicin-resistance was shown to occur due to suppression of apoptosis. Resistin treatment also affected the stemness of BC cells, as suggested by reduced cell surface expression of CD24, induced expression of CD44 and ALDH1, and increased capability of cells to form mammospheres. Mechanistic studies revealed that resistin-induced chemoresistance, apoptosis and stemness of BC cells were mediated through STAT3 activation. Taken together, our findings provide novel insight into the role of resistin in BC biology, and strengthen its role in racially disparate clinical outcomes.

A Phase I Study of Neoadjuvant Chemotherapy With Nab-Paclitaxel, Doxorubicin, and Cyclophosphamide in Patients With Stage II to III Breast Cancer.

BACKGROUND: The aims of this study were to assess the safety and tolerability of nanoparticle albumin bound paclitaxel (nab-paclitaxel), doxorubicin, and cyclophosphamide as combination therapy for breast cancer patients in the neoadjuvant setting and to assess the overall clinical response and pathologic complete response (pCR). PATIENTS AND METHODS: Twenty-six women with newly diagnosed stage II to III histologically or cytologically proven adenocarcinoma of the breast with negative HER2 status were enrolled. Patients were treated with nab-paclitaxel 100 mg/m2, doxorubicin 50 mg/m2, and cyclophosphamide 500 mg/m2 on day 1 and nab-paclitaxel 100 mg/m2 on day 8 in a 21-day cycle for 6 cycles total. RESULTS: Most adverse events attributed to treatment were decreased white blood cell count, neutropenia, anemia, thrombocytopenia, and lymphopenia with a median duration of 8 days. Fifteen of 23 (65.2%; 95% confidence interval [CI], 45.7%-84.6%) had a complete clinical response and 8 of 23 (34.7%; 95% CI, 15.2%-54.1%) had a partial clinical response for an overall clinical response rate of 100%. Thirteen of 23 patients (56.5%; 95% CI, 36.2%-76.7%) had a pCR. All 10 triple-negative breast cancer (TNBC) patients (100%) achieved a pCR. CONCLUSION: The regimen of nab-paclitaxel, doxorubicin, and cyclophosphamide chemotherapy was well tolerated and resulted in high clinical as well as pathologic responses, particularly in TNBC.

Resistin and interleukin-6 exhibit racially-disparate expression in breast cancer patients, display molecular association and promote growth and aggressiveness of tumor cells through STAT3 activation.

African-American (AA) women with breast cancer (BC) are diagnosed with more aggressive disease, have higher risk of recurrence and poorer prognosis as compared to Caucasian American (CA) women. Therefore, it is imperative to define the factors associated with such disparities to reduce the unequal burden of cancer. Emerging data suggest that inherent differences exist in the tumor microenvironment of AA and CA BC patients, however, its molecular bases and functional impact have remained poorly understood. Here, we conducted cytokine profiling in serum samples from AA and CA BC patients and identified resistin and IL-6 to be the most differentially-expressed cytokines with relative greater expression in AA patients. Resistin and IL-6 exhibited positive correlation in serum levels and treatment of BC cells with resistin led to enhanced production of IL-6. Moreover, resistin also enhanced the expression and phosphorylation of STAT3, and treatment of BC cells with IL-6-neutralizing antibody prior to resistin stimulation abolished STAT3 phosphorylation. In addition, resistin promoted growth and aggressiveness of BC cells, and these effects were mediated through STAT3 activation. Together, these findings suggest a crucial role of resistin, IL-6 and STAT3 in BC racial disparity.

Resveratrol modulates human mammary epithelial cell O-acetyltransferase, sulfotransferase, and kinase activation of the heterocyclic amine carcinogen N-hydroxy-PhIP.

Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural antioxidant found in plants, such as grapes, that studies suggest has cancer chemopreventive activity. We investigated the effects of resveratrol on DNA binding via esterification reactions with 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) - a metabolite of a mammary gland carcinogen present in cooked meats. Treatment of primary cultures of human mammary epithelial cells with 50 microM resveratrol led to a decrease in PhIP-DNA adducts ranging from 31 to 69%. Using substrate-specific assays and mammary gland tissue cytosols, resveratrol inhibited PhIP-DNA adduct formation by O-acetyltransferase and sulfotransferase catalysis. Cytosols from tumor tissue and breast reduction tissue were similarly affected. Resveratrol also suppressed O-acetyltransferase and sulfotransferase activities from the breast cancer cell lines MCF-7 and ZR-75-1. It was also observed that resveratrol stimulated ATP-dependent cytosolic activation of N-OH-PhIP in all human samples but not in mouse liver samples. In addition to resveratol's other preventive effects, the present data suggest that O-acetyltransferases and sulfotransferases may represent anti-oncogenic targets for resveratrol.