ctDNA and residual cancer burden are prognostic in triple-negative breast cancer patients with residual disease.

Triple-negative breast cancer (TNBC) patients with residual disease (RD) after neoadjuvant systemic therapy (NAST) are at high risk for recurrence. Biomarkers to risk-stratify patients with RD could help individualize adjuvant therapy and inform future adjuvant therapy trials. We aim to investigate the impact of circulating tumor DNA (ctDNA) status and residual cancer burden (RCB) class on outcomes in TNBC patients with RD. We analyze end-of-treatment ctDNA status in 80 TNBC patients with residual disease who are enrolled in a prospective multisite registry. Among 80 patients, 33% are ctDNA positive (ctDNA+) and RCB class distribution is RCB-I = 26%, RCB-II = 49%, RCB-III = 18% and 7% unknown. ctDNA status is associated with RCB status, with 14%, 31%, and 57% of patients within RCB-I, -II, and -III classes demonstrating ctDNA+ status (P = 0.028). ctDNA+ status is associated with inferior 3-year EFS (48% vs. 82%, P < 0.001) and OS (50% vs. 86%, P = 0.002). ctDNA+ status predicts inferior 3-year EFS among RCB-II patients (65% vs. 87%, P = 0.044) and shows a trend for inferior EFS among RCB-III patients (13% vs. 40%, P = 0.081). On multivariate analysis accounting for T stage and nodal status, RCB class and ctDNA status independently predict EFS (HR = 5.16, P = 0.016 for RCB class; HR = 3.71, P = 0.020 for ctDNA status). End-of-treatment ctDNA is detectable in one-third of TNBC patients with residual disease after NAST. ctDNA status and RCB are independently prognostic in this setting.

EGFR as a potent CAR T target in triple negative breast cancer brain metastases.

PURPOSE: There is currently no curative treatment for patients diagnosed with triple-negative breast cancer brain metastases (TNBC-BM). CAR T cells hold potential for curative treatment given they retain the cytolytic activity of a T cell combined with the specificity of an antibody. In this proposal we evaluated the potential of EGFR re-directed CAR T cells as a therapeutic treatment against TNBC cells in vitro and in vivo. METHODS: We leveraged a TNBC-BM tissue microarray and a large panel of TNBC cell lines and identified elevated epidermal growth factor receptor (EGFR) expression. Next, we designed a second-generation anti-EGFR CAR T construct incorporating a clinically relevant mAb806 tumor specific single-chain variable fragment (scFv) and intracellular 4-1BB costimulatory domain and CD3ζ using a lentivirus system and evaluated in vitro and in vivo anti-tumor activity. RESULTS: We demonstrate EGFR is enriched in TNBC-BM patient tissue after neurosurgical resection, with six of 13 brain metastases demonstrating both membranous and cytoplasmic EGFR. Eleven of 13 TNBC cell lines have EGFR surface expression ≥ 85% by flow cytometry. EGFR806 CAR T treated mice effectively eradicated TNBC-BM and enhanced mouse survival (log rank p < 0.004). CONCLUSION: Our results demonstrates anti-tumor activity of EGFR806 CAR T cells against TNBC cells in vitro and in vivo. Given EGFR806 CAR T cells are currently undergoing clinical trials in primary brain tumor patients without obvious toxicity, our results are immediately actionable against the TNBC-BM patient population.

LGR5+ Intestinal Stem Cells Display Sex-Dependent Radiosensitivity.

Tissue radiosensitivity plays a critical role in the overall outcome of radiation therapy. Identifying characteristics that predict how a patient may respond to radiotherapy enables clinicians to maximize the therapeutic window. Limited clinical data have suggested a difference in male and female radiotherapy outcomes. Radiotherapy for gastrointestinal malignancy is still a challenge due to intestinal sensitivity to radiation toxicity. In this manuscript, we demonstrated sex-specific differences in intestinal epithelial radiosensitivity. In a mouse model of abdominal irradiation, we observed a significant increase in oxidative stress and injury in males compared to females. Lgr5+ve intestinal stem cells from male mice showed higher sensitivity to radiation-induced toxicity. However, sex-specific differences in intestinal radiosensitivity were not dependent on sex hormones, as we demonstrated similar sex-specific radiosensitivity differences in pre-pubescent mice. In an ex vivo study, we found that patient-derived intestinal organoid (PID) from males showed higher sensitivity to radiation compared to females as evident from loss of budding crypts, organoid size, and membrane integrity. Transcriptomic analysis of human Lgr5+ intestinal stem cells suggested radiation-induced upregulation of mitochondrial oxidative metabolism in males compared to females, a possible mechanism for radiosensitivity differences.

A novel Bayesian adaptive design incorporating both primary and secondary endpoints for randomized IIB chemoprevention study of women at increased risk for breast cancer.

BACKGROUND: Our randomized controlled clinical trial will explore the potential of bazedoxifene plus conjugated estrogen to modulate breast tissue-based risk biomarkers as a surrogate for breast cancer risk reduction. This paper investigates the statistical design features of the trial and the rationale for the final choice of its design. Group sequential designs are a popular design approach to allow a trial to stop early for success or futility, potentially saving time and money over a fixed trial design. While Bayesian adaptive designs enjoy the same properties as group sequential designs, they have the added benefit of using prior information as well as inferential interpretation conditional on the data. Whether a frequentist or Bayesian trial, most adaptive designs have interim analyses that allow for early stopping, typically utilizing only the primary endpoint. A drawback to this approach is that the study may not have enough data for adequate comparisons of a single, key secondary endpoint. This can happen, for example, if the secondary endpoint has a smaller effect than the primary endpoint. METHODS: In this paper, we investigate a trial design called two-endpoint adaptive, which stops early only if a criterion is met for primary and secondary endpoints. The approach focuses the final analysis on the primary endpoint but ensures adequate data for the secondary analysis. Our study has two arms with a primary (change in mammographic fibroglandular volume) and secondary endpoint (change in mammary tissue Ki-67). RESULTS: We present operating characteristics including power, trial duration, and type I error rate and discuss the value and risks of modeling Bayesian group sequential designs with primary and secondary endpoints, comparing against alternative designs. The results indicate that the two-endpoint adaptive design has better operating characteristics than competing designs if one is concerned about having adequate information for a key secondary endpoint. DISCUSSION: Our approach balances trial speed and the need for information on the single, key secondary endpoint.

Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2-negative breast cancer.

Triple-negative breast cancer (TNBC) is classically defined by estrogen receptor (ER) and progesterone receptor (PR) immunohistochemistry expression <1% and absence of HER2 amplification/overexpression. HER2-negative breast cancer with low ER/PR expression (1-10%) has a gene expression profile similar to TNBC; however, real-world treatment patterns, chemotherapy response, endocrine therapy benefit, and survival outcomes for the Low-ER group are not well known. 516 patients with stage I-III HER2-negative breast cancer and ER/PR expression ≤10% who were enrolled in a multisite prospective registry between 2011 and 2019 were categorized on the basis of ER/PR expression. TNBC (ER and PR < 1%) and Low-ER (ER and/or PR 1-10%) groups comprised 87.4% (n = 451) and 12.6% (n = 65) of patients, respectively. Demographic, clinical, and treatment characteristics, including prevalence of germline BRCA1/2 mutation, racial and ethnic distribution, and chemotherapy use were not different between TNBC and Low-ER groups. No difference was observed in recurrence-free survival (RFS) and overall survival (OS) between TNBC and Low-ER groups (3-year RFS 82.5% versus 82.4%, respectively, p = 0.728; 3-year OS 88.0% versus 83.4%, respectively, p = 0.632). Among 358 patients receiving neoadjuvant chemotherapy, rates of pathologic complete response were similar for TNBC and Low-ER groups (49.2% vs 51.3%, respectively, p = 0.808). The HER2-negative Low-ER group is often excluded from TNBC clinical trials assessing novel treatments (immunotherapy and antibody-drug conjugates), thus limiting efficacy data for newer effective therapies in this group. Given that HER2-negative Low-ER disease displays clinical characteristics and outcomes similar to TNBC, inclusion of this group in TNBC clinical trials is encouraged.

Human Peripheral Blood Mononucleocyte Derived Myeloid Committed Progenitor Cells Mitigate H-ARS by Exosomal Paracrine Signal.

Radiation-induced loss of the hematopoietic stem cell progenitor population compromises bone marrow regeneration and development of mature blood cells. Failure to rescue bone marrow functions results in fatal consequences from hematopoietic injury, systemic infections, and sepsis. So far, bone marrow transplant is the only effective option, which partially minimizes radiation-induced hematopoietic toxicities. However, a bone marrow transplant will require HLA matching, which will not be feasible in large casualty settings such as a nuclear accident or an act of terrorism. In this study we demonstrated that human peripheral blood mononuclear cell-derived myeloid committed progenitor cells can mitigate radiation-induced bone marrow toxicity and improve survival in mice. These cells can rescue the recipient's hematopoietic stem cells from radiation toxicity even when administered up to 24 h after radiation exposure and can be subjected to allogenic transplant without GVHD development. Transplanted cells deliver sEVs enriched with regenerative and immune-modulatory paracrine signals to mitigate radiation-induced hematopoietic toxicity. This provides a natural polypharmacy solution against a complex injury process. In summary, myeloid committed progenitor cells can be prepared from blood cells as an off-the-shelf alternative to invasive bone marrow harvesting and can be administered in an allogenic setting to mitigate hematopoietic acute radiation syndrome.

Lessons Learned from the Impact of COVID-19 on NCI-sponsored Cancer Prevention Clinical Trials: Moving Toward Participant-centric Study Designs.

The COVID-19 pandemic overloaded health care systems around the globe and brought travel restrictions and other mandates. These effects critically impacted cancer care and conduct of clinical trials, and required medical and research communities to incorporate changes and novel flexible workflows within clinical trials and regulations to improve efficiency. We report the impact of the pandemic on cancer prevention clinical trials managed by the Division of Cancer Prevention within the NCI, focusing on participant-centric, study staff-centric and regulatory elements. Learning lessons from this challenging period, the cancer prevention community has the opportunity to incorporate many of these necessitated novel approaches to future design of clinical trials, to streamline and improve clinical trial efficiency and impact.

Rapid Escalation of High-Volume Exercise during Caloric Restriction; Change in Visceral Adipose Tissue and Adipocytokines in Obese Sedentary Breast Cancer Survivors.

Aerobic exercise reduces risk for breast cancer and recurrence and promotes visceral adipose tissue (VAT) loss in obesity. However, few breast cancer survivors achieve recommended levels of moderate to vigorous physical activity (MVPA) without supervision. In a two-cohort study, feasibility of 12 weeks of partially supervised exercise was started concomitantly with caloric restriction and effects on body composition and systemic risk biomarkers were explored. In total, 22 obese postmenopausal sedentary women (including 18 breast cancer survivors) with median age of 60 and BMI of 37 kg/m2 were enrolled. Using personal trainers twice weekly at area YMCAs, MVPA was escalated to ≥200 min/week over 9 weeks. For cohort 2, maintenance of effect was assessed when study provided trainer services were stopped but monitoring, group counseling sessions, and access to the exercise facility were continued. Median post-escalation MVPA was 219 min/week with median 12-week mass and VAT loss of 8 and 19%. MVPA was associated with VAT loss which was associated with improved adiponectin:leptin ratio. In total, 9/11 of cohort-2 women continued the behavioral intervention for another 12 weeks without trainers. High MVPA continued with median 24-week mass and VAT loss of 12 and 29%. This intervention should be further studied in obese sedentary women.

Change in Blood and Benign Breast Biomarkers in Women Undergoing a Weight-Loss Intervention Randomized to High-Dose ω-3 Fatty Acids versus Placebo.

The inflammation-resolving and insulin-sensitizing properties of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids have potential to augment effects of weight loss on breast cancer risk. In a feasibility study, 46 peri/postmenopausal women at increased risk for breast cancer with a body mass index (BMI) of 28 kg/m2 or greater were randomized to 3.25 g/day combined EPA and DHA (ω-3-FA) or placebo concomitantly with initiation of a weight-loss intervention. Forty-five women started the intervention. Study discontinuation for women randomized to ω-3-FA and initiating the weight-loss intervention was 9% at 6 months and thus satisfied our main endpoint, which was feasibility. Between baseline and 6 months significant change (P < 0.05) was observed in 12 of 25 serum metabolic markers associated with breast cancer risk for women randomized to ω-3-FA, but only four for those randomized to placebo. Weight loss (median of 10% for trial initiators and 12% for the 42 completing 6 months) had a significant impact on biomarker modulation. Median loss was similar for placebo (-11%) and ω-3-FA (-13%). No significant change between ω-3-FA and placebo was observed for individual biomarkers, likely due to sample size and effect of weight loss. Women randomized to ω-3-FA exhibiting more than 10% weight loss at 6 months showed greatest biomarker improvement including 6- and 12-month serum adiponectin, insulin, omentin, and C-reactive protein (CRP), and 12-month tissue adiponectin. Given the importance of a favorable adipokine profile in countering the prooncogenic effects of obesity, further evaluation of high-dose ω-3-FA during a weight-loss intervention in obese high-risk women should be considered. PREVENTION RELEVANCE: This study examines biomarkers of response that may be modulated by omega-3 fatty acids when combined with a weight-loss intervention. While focused on obese, postmenopausal women at high risk for development of breast cancer, the findings are applicable to other cancers studied in clinical prevention trials.

Clinical and Biomarker Results from Phase I/II Study of PI3K Inhibitor Alpelisib plus Nab-paclitaxel in HER2-Negative Metastatic Breast Cancer.

PURPOSE: PIK3CA mutations are common in breast cancer and promote tumor progression and treatment resistance. We conducted a phase I/II trial of alpelisib (α-specific PI3K inhibitor) plus nab-paclitaxel in patients with HER2-negative metastatic breast cancer (MBC). PATIENTS AND METHODS: Eligible patients had HER2-negative MBC with any number of prior chemotherapies. Phase I was 3+3 dose-escalation design with three dose levels of alpelisib (250, 300, and 350 mg) daily plus nab-paclitaxel 100 mg/m2 administered on days 1, 8, and 15 every 28 days. Phase II was according to Simon's two-stage design. PIK3CA mutations in tumor/circulating tumor DNA (ctDNA) were assessed. Primary endpoints were recommended phase II dose (RP2D) and objective response rate (ORR). Additional endpoints included safety, pharmacokinetics, progression-free survival (PFS), and association of PIK3CA mutation with outcomes. RESULTS: A total of 43 patients were enrolled (phase I, n = 13 and phase II, n = 30). A total of 84% had visceral disease and 84% had prior taxane. No dose-limiting toxicities occurred in phase I. RP2D was alpelisib 350 mg daily plus nab-paclitaxel 100 mg/m2 on days 1, 8, and 15. Hyperglycemia (grade 3, 26% and grade 4, 0%), neutropenia (grade 3, 23% and grade 4, 7%), diarrhea (grade 3, 5% and grade 4, 0%), and rash (grade 3, 7% and grade 4, 0%) were the most common adverse events. Among 42 evaluable patients, ORR was 59% (complete response, 7% and partial response, 52%), 21% of whom had response lasting >12 months; median PFS was 8.7 months. A total of 40% of patients demonstrated tumor and/or ctDNA PIK3CA mutation; patients with tumor/ctDNA mutation demonstrated better PFS compared with those without mutation (11.9 vs. 7.5 months; HR, 0.44; P = 0.027). Patients with normal metabolic status had longer PFS compared with prediabetic/diabetic patients (12 vs. 7.5 months; P = 0.014). No pharmacokinetics interactions were detected. CONCLUSIONS: The alpelisib plus nab-paclitaxel combination was well tolerated and shows encouraging efficacy, especially in patients with PIK3CA-mutated tumor/ctDNA. The impact of metabolic status on response to this combination merits further investigation.

Randomized Phase II Trial of Anthracycline-free and Anthracycline-containing Neoadjuvant Carboplatin Chemotherapy Regimens in Stage I-III Triple-negative Breast Cancer (NeoSTOP).

PURPOSE: Addition of carboplatin (Cb) to anthracycline chemotherapy improves pathologic complete response (pCR), and carboplatin plus taxane regimens also yield encouraging pCR rates in triple-negative breast cancer (TNBC). Aim of the NeoSTOP multisite randomized phase II trial was to assess efficacy of anthracycline-free and anthracycline-containing neoadjuvant carboplatin regimens. PATIENTS AND METHODS: Patients aged ≥18 years with stage I-III TNBC were randomized (1:1) to receive either paclitaxel (P) weekly × 12 plus carboplatin AUC6 every 21 days × 4 followed by doxorubicin/cyclophosphamide (AC) every 14 days × 4 (CbP → AC, arm A), or carboplatin AUC6 + docetaxel (D) every 21 days × 6 (CbD, arm B). Stromal tumor-infiltrating lymphocytes (sTIL) were assessed. Primary endpoint was pCR in breast and axilla. Other endpoints included residual cancer burden (RCB), toxicity, cost, and event-free (EFS) and overall survival (OS). RESULTS: One hundred patients were randomized; arm A (n = 48) or arm B (n = 52). pCR was 54% [95% confidence interval (CI), 40%-69%] in arm A and 54% (95% CI, 40%-68%) in arm B. RCB 0+I rate was 67% in both arms. Median sTIL density was numerically higher in those with pCR compared with those with residual disease (20% vs. 5%; P = 0.25). At median follow-up of 38 months, EFS and OS were similar in the two arms. Grade 3/4 adverse events were more common in arm A compared with arm B, with the most notable differences in neutropenia (60% vs. 8%; P < 0.001) and febrile neutropenia (19% vs. 0%; P < 0.001). There was one treatment-related death (arm A) due to acute leukemia. Mean treatment cost was lower for arm B compared with arm A (P = 0.02). CONCLUSIONS: The two-drug CbD regimen yielded pCR, RCB 0+I, and survival rates similar to the four-drug regimen of CbP → AC, but with a more favorable toxicity profile and lower treatment-associated cost.

Randomized Phase IIB Trial of the Lignan Secoisolariciresinol Diglucoside in Premenopausal Women at Increased Risk for Development of Breast Cancer.

We conducted a multiinstitutional, placebo-controlled phase IIB trial of the lignan secoisolariciresinol diglucoside (SDG) found in flaxseed. Benign breast tissue was acquired by random periareolar fine needle aspiration (RPFNA) from premenopausal women at increased risk for breast cancer. Those with hyperplasia and ≥2% Ki-67 positive cells were eligible for randomization 2:1 to 50 mg SDG/day (Brevail) versus placebo for 12 months with repeat bio-specimen acquisition. The primary endpoint was difference in change in Ki-67 between randomization groups. A total of 180 women were randomized, with 152 ultimately evaluable for the primary endpoint. Median baseline Ki-67 was 4.1% with no difference between arms. Median Ki-67 change was -1.8% in the SDG arm (P = 0.001) and -1.2% for placebo (P = 0.034); with no significant difference between arms. As menstrual cycle phase affects proliferation, secondary analysis was performed for 117 women who by progesterone levels were in the same phase of the menstrual cycle at baseline and off-study tissue sampling. The significant Ki-67 decrease persisted for SDG (median = -2.2%; P = 0.002) but not placebo (median = -1.0%). qRT-PCR was performed on 77 pairs of tissue specimens. Twenty-two had significant ERα gene expression changes (<0.5 or >2.0) with 7 of 10 increases in placebo and 10 of 12 decreases for SDG (P = 0.028), and a difference between arms (P = 0.017). Adverse event incidence was similar in both groups, with no evidence that 50 mg/day SDG is harmful. Although the proliferation biomarker analysis showed no difference between the treatment group and the placebo, the trial demonstrated use of SDG is tolerable and safe.

Effects of Weight Loss and Weight Regain on Circulating Biomarkers in Overweight/Obese Breast Cancer Survivors Enrolled in a Weight Loss Trial in the Rural Midwest.

BACKGROUND: Obesity is associated with worse breast cancer prognosis, however little is known about the level of weight loss required to improve pathway biomarkers. The effects of weight regain on biomarkers are also largely unknown. METHODS: Overweight/obese breast cancer survivors enrolled in an 18-month behavioral weight loss trial provided weight and serum biomarkers [leptin, adiponectin, insulin, plasminogen activator inhibitor-1 (PAI-1), IL-6, TNFα, and hepatocyte growth factor HGF] at baseline, 6, and 18 months (n = 138). Change in biomarkers over time and by weight loss thresholds were examined. RESULTS: Mean weight loss at 6 months was 13.3 ± 5.0 kg; from 6 to 18 months, mean regain was 4.0 ± 5.2 kg. Favorable biomarker modulations were observed at 6 months for leptin, adiponectin, insulin, PAI-1, IL-6, and HGF (P < 0.006 to P < 0.0001). These changes remained significant overall at 18 months despite attenuation in some. Women who lost <10% of baseline weight showed significantly smaller modulation effects for leptin (P < 0.0001), adiponectin:leptin (A/L) ratio (P < 0.0001), PAI-1 (P < 0.001), and insulin (P = 0.003) compared with women who lost >10%. Women who lost >10% observed a significant increase in adiponectin (P < 0.0001), and these women continued to show improved adiponectin from 6 to 18 months despite weight regain. Physical activity contributed additional effects on biomarker change for leptin, A/L ratio, and PAI-1. CONCLUSIONS: These findings are consistent with a clinical target of 10% weight. IMPACT: Sustained increases in adiponectin likely confer benefits for breast cancer prognosis even with weight regain.

Differential sensitivity of inbred mouse strains to ovarian damage in response to low-dose total body irradiation†.

Radiation induces ovarian damage and accelerates reproductive aging. Inbred mouse strains exhibit differential sensitivity to lethality induced by total body irradiation (TBI), with the BALB/cAnNCrl (BALB/c) strain being more sensitive than the 129S2/SvPasCrl (129) strain. However, whether TBI-induced ovarian damage follows a similar pattern of strain sensitivity is unknown. To examine this possibility, female BALB/c and 129 mice were exposed to a single dose of 1 Gy (cesium-137 γ) TBI at 5 weeks of age, and ovarian tissue was harvested for histological and gene expression analyses 2 weeks post exposure. Sham-treated mice served as controls. 1 Gy radiation nearly eradicated the primordial follicles and dramatically decreased the primary follicles in both strains. In contrast, larger growing follicles were less affected in the 129 relative to BALB/c strain. Although this TBI paradigm did not induce detectable ovarian fibrosis in either of the strains, we did observe strain-dependent changes in osteopontin (Spp1) expression, a gene involved in wound healing, inflammation, and fibrosis. Ovaries from BALB/c mice exhibited higher baseline Spp1 expression that underwent a significant decrease in response to radiation relative to ovaries from the 129 strain. A correspondingly greater change in the ovarian matrix, as evidenced by reduced ovarian hyaluronan content, was also observed following TBI in BALB/c mice relative to 129 mice. These early changes in the ovary may predispose BALB/c mice to more pronounced late effects of TBI. Taken together, our results demonstrate that aspects of ovarian damage mirror other organ systems with respect to overall strain-dependent radiation sensitivity.

Effect of Bazedoxifene and Conjugated Estrogen (Duavee) on Breast Cancer Risk Biomarkers in High-Risk Women: A Pilot Study.

Interventions that relieve vasomotor symptoms while reducing risk for breast cancer would likely improve uptake of chemoprevention for perimenopausal and postmenopausal women. We conducted a pilot study with 6 months of the tissue selective estrogen complex bazedoxifene (20 mg) and conjugated estrogen (0.45 mg; Duavee) to assess feasibility and effects on risk biomarkers for postmenopausal breast cancer. Risk biomarkers included fully automated mammographic volumetric density (Volpara), benign breast tissue Ki-67 (MIB-1 immunochemistry), and serum levels of progesterone, IGF-1, and IGFBP3, bioavailable estradiol and testosterone. Twenty-eight perimenopausal and postmenopausal women at increased risk for breast cancer were enrolled: 13 in cohort A with baseline Ki-67 < 1% and 15 in cohort B with baseline Ki-67 of 1% to 4%. All completed the study with > 85% drug adherence. Significant changes in biomarkers, uncorrected for multiple comparisons, were a decrease in mammographic fibroglandular volume (P = 0.043); decreases in serum progesterone, bioavailable testosterone, and IGF-1 (P < 0.01), an increase in serum bioavailable estradiol (P < 0.001), and for women from cohort B a reduction in Ki-67 (P = 0.017). An improvement in median hot flash score from 15 at baseline to 0 at 6 months, and menopause-specific quality-of-life total, vasomotor, and sexual domain scores were also observed (P < 0.001). Given the favorable effects on risk biomarkers and patient reported outcomes, a placebo-controlled phase IIB trial is warranted.

Circulating adipose stromal cells as a response biomarker in phase II energy balance trials of obese breast cancer survivors and high-risk women.

PURPOSE: Circulating adipose stromal cells (CASC) are thought to be increased in obesity and facilitate angiogenesis, and tumor metastases. METHODS: CASC were identified from buffy coat peripheral blood mononuclear cells (PBMCs) by flow cytometry as CD34brightCD31- CD45- and CASC frequency was compared to adiposity measures in 33 women at increased risk for breast cancer. Feasibility of CASC as a response biomarker for a diet and exercise intervention in ten breast cancer survivors was then explored. RESULTS: For 33 high-risk women, median CASC frequency was 9.7 per million PBMCs and trended positively with body mass index, fat mass index (FMI), and percent android fat. Correlation was significant when BMI was dichotomized at > versus < 35 kg/m2 (p = 0.02). For ten breast cancer survivors with a median BMI of 37 kg/m2, median CASC frequency was 16.4 per million PBMCs. In univariate analyses, change in BMI, total fat and visceral fat were significantly correlated with change in CASC frequency. On multivariate analysis, change in visceral adipose had the strongest association with change in CASC frequency (p < 0.00078). CONCLUSIONS: The association between the reduction in visceral adipose tissue and the decrease in frequency of circulating adipose stromal cells suggests that the latter might be a useful biomarker in clinical trials of obese breast cancer survivors undergoing a weight loss intervention.

Auranofin Protects Intestine against Radiation Injury by Modulating p53/p21 Pathway and Radiosensitizes Human Colon Tumor.

PURPOSE: The radiosensitivity of the normal intestinal epithelium is the major limiting factor for definitive radiotherapy against abdominal malignancies. Radiosensitizers, which can be used without augmenting radiation toxicity to normal tissue, are still an unmet need. Inhibition of proteosomal degradation is being developed as a major therapeutic strategy for anticancer therapy as cancer cells are more susceptible to proteasomal inhibition-induced cytotoxicity compared with normal cells. Auranofin, a gold-containing antirheumatoid drug, blocks proteosomal degradation by inhibiting deubiquitinase inhibitors. In this study, we have examined whether auranofin selectively radiosensitizes colon tumors without promoting radiation toxicity in normal intestine. EXPERIMENTAL DESIGN: The effect of auranofin (10 mg/kg i.p.) on the radiation response of subcutaneous CT26 colon tumors and the normal gastrointestinal epithelium was determined using a mouse model of abdominal radiation. The effect of auranofin was also examined in a paired human colonic organoid system using malignant and nonmalignant tissues from the same patient. RESULTS: Both in the mouse model of intestinal injury and in the human nonmalignant colon organoid culture, auranofin pretreatment prevented radiation toxicity and improved survival with the activation of p53/p21-mediated reversible cell-cycle arrest. However, in a mouse model of abdominal tumor and in human malignant colonic organoids, auranofin inhibited malignant tissue growth with inhibition of proteosomal degradation, induction of endoplasmic reticulum stress/unfolded protein response, and apoptosis. CONCLUSIONS: Our data suggest that auranofin is a potential candidate to be considered as a combination therapy with radiation to improve therapeutic efficacy against abdominal malignancies.

Use of a Small Animal Radiation Research Platform (SARRP) facilitates analysis of systemic versus targeted radiation effects in the mouse ovary.

BACKGROUND: Radiation exposure is known to cause accelerated aging and damage to the ovary, but the contribution of indirect versus direct effects is not well understood. We used the Small Animal Radiation Research Platform (SARRP) (Xstrahl) to deliver radiation to precise fields equivalent to clinical practice, allowing us to investigate systemic versus targeted damage in a structure as small as the mouse ovary. The X-ray dose was kept constant at 1 Gy, but the field varied. Mice either received total body irradiation (TBI), radiation targeted to both ovaries (T2), or radiation targeted to one ovary (left) while the contralateral ovary (right) was spared (T1). Sham mice, handled similarly to the other cohorts but not exposed to radiation, served as controls. Two weeks post-exposure, ovaries were harvested and analyzed histologically to identify and count follicles within each ovary. RESULTS: Radiation significantly reduced primordial follicles in the TBI and T2 cohorts compared to the Sham cohort. There were no significant differences between these two irradiated groups. These findings suggest that at 1 Gy, the extent of damage to the ovary caused by radiation is similar despite the different delivery methods. When investigating the T1 cohort, targeted ovaries showed a significant decrease in primordial and growing follicles compared to non-targeted contralateral ovaries. CONCLUSIONS: These findings demonstrate that the SARRP is an effective strategy for delivering precise ionizing radiation to small organs such as mouse ovaries. Such tools will facilitate identifying the relative risks to ovarian function associated with different radiation fields as well as screening the efficacy of emerging fertoprotective agents.

Pathological Response and Survival in Triple-Negative Breast Cancer Following Neoadjuvant Carboplatin plus Docetaxel.

PURPOSE: Prognostic value of pathologic complete response (pCR) and extent of pathologic response attained with anthracycline-free platinum plus taxane neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) is unknown. We report recurrence-free survival (RFS) and overall survival (OS) according to degree of pathologic response in patients treated with carboplatin plus docetaxel NAC. PATIENTS AND METHODS: One-hundred and ninety patients with stage I-III TNBC were treated with neoadjuvant carboplatin (AUC6) plus docetaxel (75 mg/m2) every 21 days × 6 cycles. pCR (no evidence of invasive tumor in breast and axilla) and Residual cancer burden (RCB) were evaluated. Patients were followed for recurrence and survival. Extent of pathologic response was associated with RFS and OS using the Kaplan-Meier method. RESULTS: Median age was 51 years, and 52% were node-positive. pCR and RCB I rates were 55% and 13%, respectively. Five percent of pCR patients, 0% of RCB I patients, and 58% of RCB II/III patients received adjuvant anthracyclines. Three-year RFS and OS were 79% and 87%, respectively. Three-year RFS was 90% in patients with pCR and 66% in those without pCR [HR = 0.30; 95% confidence interval (CI), 0.14-0.62; P = 0.0001]. Three-year OS was 94% in patients with pCR and 79% in those without pCR (HR = 0.25; 95% CI, 0.10-0.63; P = 0.001). Patients with RCB I demonstrated 3-year RFS (93%) and OS (100%) similar to those with pCR. On multivariable analysis, higher tumor stage, node positivity, and RCB II/III were associated with worse RFS. CONCLUSIONS: Neoadjuvant carboplatin plus docetaxel yields encouraging efficacy in TNBC. Patients achieving pCR or RCB I with this regimen demonstrate excellent 3-year RFS and OS without adjuvant anthracycline.

Clinicopathological correlation of PD-L1 expression in primary and metastatic breast cancer and infiltrating immune cells.

Few studies have evaluated the expression of the programmed cell death-1 and its ligand-1 (PD-L1) in breast cancer. In this study, we correlated differential expression of PD-L1 in breast cancer (BC) and its microenvironment from a cohort of patients with BC, paired locally metastatic disease to regional lymph nodes (LNs) and nonpaired distantly metastatic disease (mets). PD-L1 expression was correlated with several pathologic and clinical parameters in tumor and tumor immune cells (ICs; CD3, CD4, CD8, CD20, and CD68) using the Ventana antibody (SP263) in 41 BCs, 46 paired mets in LNs, and 46 distant mets. There was 100% agreement for PD-L1 expression on tumor and ICs between BC and matched LN. PD-L1 is differentially expressed in primary BC and regional nodal disease. Expression correlated with higher grade, hormone receptor negativity, and highly proliferative tumors (P < .001). In LNs, the high positivity rate was driven by triple-negative status (70% versus 5%; P < .0001). In contrast, there was significantly near-total absence of PD-L1 expression in distant mets compared with BC and LNs (2%-4% in mets versus 17%-20% in BC and LN, P = .009). IC density varied in BC and metastatic tumors with predominance of CD3 and CD68 and near total absence of CD20 cells. PD-L1 expression was mainly associated with CD68 cells. There were consistent higher numbers of CD3 (CD8 > CD4) than CD20 cells in primary and metastatic tumors. Correlation of PD-L1 expression in BC and its microenvironment may be useful for the development of new treatment strategies.