Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer.

BACKGROUND: Among breast cancers without human epidermal growth factor receptor 2 (HER2) amplification, overexpression, or both, a large proportion express low levels of HER2 that may be targetable. Currently available HER2-directed therapies have been ineffective in patients with these "HER2-low" cancers. METHODS: We conducted a phase 3 trial involving patients with HER2-low metastatic breast cancer who had received one or two previous lines of chemotherapy. (Low expression of HER2 was defined as a score of 1+ on immunohistochemical [IHC] analysis or as an IHC score of 2+ and negative results on in situ hybridization.) Patients were randomly assigned in a 2:1 ratio to receive trastuzumab deruxtecan or the physician's choice of chemotherapy. The primary end point was progression-free survival in the hormone receptor-positive cohort. The key secondary end points were progression-free survival among all patients and overall survival in the hormone receptor-positive cohort and among all patients. RESULTS: Of 557 patients who underwent randomization, 494 (88.7%) had hormone receptor-positive disease and 63 (11.3%) had hormone receptor-negative disease. In the hormone receptor-positive cohort, the median progression-free survival was 10.1 months in the trastuzumab deruxtecan group and 5.4 months in the physician's choice group (hazard ratio for disease progression or death, 0.51; P<0.001), and overall survival was 23.9 months and 17.5 months, respectively (hazard ratio for death, 0.64; P = 0.003). Among all patients, the median progression-free survival was 9.9 months in the trastuzumab deruxtecan group and 5.1 months in the physician's choice group (hazard ratio for disease progression or death, 0.50; P<0.001), and overall survival was 23.4 months and 16.8 months, respectively (hazard ratio for death, 0.64; P = 0.001). Adverse events of grade 3 or higher occurred in 52.6% of the patients who received trastuzumab deruxtecan and 67.4% of those who received the physician's choice of chemotherapy. Adjudicated, drug-related interstitial lung disease or pneumonitis occurred in 12.1% of the patients who received trastuzumab deruxtecan; 0.8% had grade 5 events. CONCLUSIONS: In this trial involving patients with HER2-low metastatic breast cancer, trastuzumab deruxtecan resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast04 ClinicalTrials.gov number, NCT03734029.).

Outcomes of older adults with early-stage triple-negative breast cancer (TNBC) receiving chemotherapy: a single-institution experience.

BACKGROUND: Despite lower chemotherapy use in older triple-negative breast cancer (TNBC) patients, their outcomes match younger counterparts. We compared outcomes in early-stage TNBC patients by age receiving chemotherapy at a major cancer center with a national TNBC database. METHODS: Retrospective study using institutional data on stage I-III TNBC (ER/PR < 10%) women with neoadjuvant/adjuvant chemotherapy. Based on their ages at diagnosis, patients were stratified into four categories: ≤40, 41-59, 60-69, and ≥ 70 years. Demographic and clinical characteristics recorded included race, disease stage, ER/PR positivity, treatment regimen, lymphatic or vascular invasion (LVI), histologic grade, Ki-67 level, body mass index (BMI), and pathologic complete response (pCR) following neoadjuvant treatment and are summarized using descriptive statistics. The primary endpoints were overall survival (OS), disease-free survival (DFS), and distant disease-free survival (DDFS); all were estimated using the Kaplan-Meier method. Both univariate and multivariate (MV) Cox regressions were applied to evaluate the impact of important covariates on these time-to-event endpoints. RESULTS: Of the 2336 patients studied, 492 (21.1%) were ≤ 40 years old, 1239 (53.1%) were 41-59, 461 (19.7%) were 60-69, and 144 (6.2%) were ≥ 70. In the univariate regression model of OS/DFS/DDFS, age ≥ 70 was significantly associated with worse OS (p = 0.0217); other factors associated with worse OS were non-anthracycline-based chemotherapy, higher tumor stage, and neoadjuvant chemotherapy. The multivariate Cox regression model, adjusted for race and stage, showed no significant effects of age on OS; however, patients ≥ 70 years old who received non-anthracycline treatment combinations had worse DFS (hazard ratio = 0.349 vs. 1.049, p = 0.0293) and DDFS (hazard ratio = 0.317 vs. 1.016, p = 0.0251) than patients ≤ 40 years old. DFS from MV model after adjusting for age, race, and disease stage, the hazard ratio between anthracycline + taxane treatments and anthracycline + other treatments in patients ≥ 70 years old was statistically significantly lower than in patients ≤ 40 years old (hazard ratios [HRs] = 0.349 vs. 1.049, p = 0.0293). CONCLUSIONS: Our findings indicate that outcomes such as DFS are less favorable in older compared to younger patients with early-stage TNBC, primarily in those who did not receive an anthracycline based chemotherapy regimen.

Clinical outcomes after 1 versus 2-3 lines of neoadjuvant therapy in stage III inflammatory breast cancer.

PURPOSE: Many stage III inflammatory breast cancer (IBC) patients experience a sufficient response to first-line (1L) neoadjuvant chemotherapy (NAC) to allow surgery, while some require additional NAC. We evaluated the pathologic complete response (pCR), breast cancer-free survival (BCFS) and overall survival (OS) among patients requiring 1 vs. 2-3 lines (L) of NAC prior to surgery. METHODS: Stage III IBC patients from 2 institutions who received 1L or 2-3L of NAC prior to surgery were identified. Hormone receptor and HER2 status, grade, and pCR were evaluated. BCFS and OS were evaluated by the Kaplan-Meier method. Multivariable Cox models were utilized to estimate the hazard ratio (HR). RESULTS: 808 eligible patients (1997-2020) were identified (median age 51 years, median follow-up 69 months). 733 (91%) had 1L and 75 (9%) had 2-3L of NAC. Grade III, triple-negative and HER2-positive disease were more prevalent in 2-3L patients. 178 (24%) 1L and 14 (19%) 2-3L patients had pCR. 376 1L patients and 41 2-3L patients had recurrences. The 5-year BCFS was worse for the 2-3L group (33 vs. 46%, HR = 1.37; 95% CI 0.99-1.91). However, in 192 patients with a pCR, BCFS was similar (76 vs. 83% in 1L vs. 2-3L, respectively). There were 308 deaths (276 among 1L and 32 among 2-3L patients). The 5-year OS in 1L vs. 2-3L was 60 vs. 53% (HR = 1.32, 95% CI 0.91-1.93). CONCLUSIONS: Among stage III IBC patients, pCR rates were similar, irrespective of the NAC lines number, and BCFS and OS were comparable with pCR after 1L and 2-3L.

Somatic mutations reveal asymmetric cellular dynamics in the early human embryo.

Somatic cells acquire mutations throughout the course of an individual's life. Mutations occurring early in embryogenesis are often present in a substantial proportion of, but not all, cells in postnatal humans and thus have particular characteristics and effects. Depending on their location in the genome and the proportion of cells they are present in, these mosaic mutations can cause a wide range of genetic disease syndromes and predispose carriers to cancer. They have a high chance of being transmitted to offspring as de novo germline mutations and, in principle, can provide insights into early human embryonic cell lineages and their contributions to adult tissues. Although it is known that gross chromosomal abnormalities are remarkably common in early human embryos, our understanding of early embryonic somatic mutations is very limited. Here we use whole-genome sequences of normal blood from 241 adults to identify 163 early embryonic mutations. We estimate that approximately three base substitution mutations occur per cell per cell-doubling event in early human embryogenesis and these are mainly attributable to two known mutational signatures. We used the mutations to reconstruct developmental lineages of adult cells and demonstrate that the two daughter cells of many early embryonic cell-doubling events contribute asymmetrically to adult blood at an approximately 2:1 ratio. This study therefore provides insights into the mutation rates, mutational processes and developmental outcomes of cell dynamics that operate during early human embryogenesis.

Long-term Oncologic Outcomes in Patients with Inflammatory Breast Cancer with Supraclavicular Nodal Involvement.

BACKGROUND: Inflammatory breast cancer (IBC) is a rare and aggressive subtype of breast cancer characterized by rapid progression and early metastasis, often with advanced nodal locations, including the supraclavicular (SCV) nodal basin. Previously considered M1 disease, ipsilateral clinical supraclavicular node involvement (N3c) disease is now considered locally advanced disease and warrants treatment with intent to cure. The objective of this study was to evaluate the long-term outcomes of patients with IBC and N3c disease. PATIENTS AND METHODS: This study was conducted using a prospectively collected database of all patients with IBC treated at a dedicated cancer center from 2007 to 2019. Surgical patients with SCV nodal involvement and complete follow-up were identified. Our primary outcome was 5-year overall survival (OS). Multivariate Cox proportional hazards models were used to determine predictors for survival. Event-free survival (EFS) and OS were calculated using the Kaplan-Meier method. RESULTS: There were 70 patients who met inclusion criteria. All patients underwent comprehensive trimodality therapy. The majority of patients had complete (66.2%) radiologic response in the SCV nodal basins following neoadjuvant therapy. Six patients (8.6%) had a locoregional recurrence, with two (2.9%) occurring in the supraclavicular fossa. The 5-year OS was 60.2% [95% confidence interval (CI) 47.7-72.7%]. Increasing age (hazard ratio 2.7; p = 0.03) and triple-negative subtype (hazard ratio 4.9; p = 0.03) were associated with poor OS. The 5-year EFS was 56.1% (95% CI 40.9-68.8%). The presence of more than ten positive axillary nodes on final surgical pathology (hazard ratio 5.5; p = 0.01) predicted poor EFS. CONCLUSIONS: With comprehensive trimodality therapy and multidisciplinary team approach, patients with IBC with supraclavicular nodal involvement experience excellent locoregional control and favorable survival.

Lymphedema in Inflammatory Breast Cancer Patients Following Trimodal Treatment.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is a debilitating sequela of breast cancer treatment and is becoming a greater concern in light of improved long-term survival. Inflammatory breast cancer (IBC) is a rare and aggressive malignancy for which systemic therapy, surgery, and radiotherapy remain the standard of care, thereby making IBC patients highly susceptible to developing BCRL. This study evaluated BCRL in IBC following trimodal therapy. METHODS: IBC patients treated from 2016 to 2019 were identified from an institutional database. Patients were excluded if they presented with recurrent disease, underwent bilateral axillary surgery, did not complete trimodal therapy, or were lost to follow-up. Demographic, clinicopathologic factors, oncologic outcomes, and perometer measurements were recorded. BCRL was defined by clinician diagnosis and/or objective perometer measurements when available. Time to development of BCRL and treatment received were captured. RESULTS: Eighty-three patients were included. Median follow-up was 33 months. The incidence of BCRL was 50.6% (n = 42). Mean time to BCRL from surgery was 13 (range 2-24) months. Demographic and clinicopathologic features were similar between patients with and without BCRL with exception of higher proportion receiving delayed reconstruction in the BCRL group (38.1% vs. 14.6%, p = 0.03). Forty patients (95.2%) underwent BCRL treatment, which included physical therapy (n = 39), compression (n = 38), therapeutic lymphovenous bypass (n = 13), and/or vascularized lymph node transfer (n = 12). CONCLUSIONS: IBC patients are at high-risk for BCRL after treatment, impacting 51% of patients in this cohort. Strategies to reduce or prevent BCRL and improve real-time diagnosis should be implemented to better direct early management in this patient population.

Body composition and breast cancer risk and treatment: mechanisms and impact.

PURPOSE: The purpose of this review is to clarify the association of body composition with breast cancer risk and treatment, including physiological mechanisms, and to elucidate strategies for overcoming unfavorable body composition changes that relate to breast cancer progression. METHODS: We have summarized updated knowledge regarding the mechanism of the negative association of altered body composition with breast cancer risk and treatment. We also review strategies for reversing unfavorable body composition based on the latest clinical trial results. RESULTS: Body composition changes in patients with breast cancer typically occur during menopause or as a result of chemotherapy or endocrine therapy. Dysfunction of visceral adipose tissue (VAT) in the setting of obesity underlies insulin resistance and chronic inflammation, which can lead to breast cancer development and progression. Insulin resistance and chronic inflammation are also observed in patients with breast cancer who have sarcopenia or sarcopenic obesity. Nutritional support and a personalized exercise program are the fundamental interventions for reversing unfavorable body composition. Other interventions that have been explored in specific situations include metformin, testosterone, emerging agents that directly target the adipocyte microenvironment, and bariatric surgery. CONCLUSIONS: A better understanding of the biology of body composition phenotypes is key to determining the best intervention program for patients with breast cancer.

A 95-gene signature stratifies recurrence risk of invasive disease in ER-positive, HER2-negative, node-negative breast cancer with intermediate 21-gene signature recurrence scores.

PURPOSE: A subset of patients with intermediate 21-gene signature assay recurrence score may benefit from adjuvant chemoendocrine therapy, but a predictive strategy is needed to identify such patients. The 95-gene signature assay was tested to stratify patients with intermediate RS into high (95GC-H) and low (95GC-L) groups that were associated with invasive recurrence risk. METHODS: Patients with ER-positive, HER2-negative, node-negative breast cancer and RS 11-25 who underwent definitive surgery and adjuvant endocrine therapy without any cytotoxic agents were included. RNA was extracted from archived formalin-fixed, paraffin-embedded samples, and 95-gene signature was calculated. RESULTS: 206 patients had RS of 11-25 (95GC-L, N = 163; 95GC-H, N = 43). In Cox proportional hazards model, 95GC-H was significantly associated with shorter time to recurrence than was 95GC-L (HR 5.94; 95%CI 1.81-19.53; P = 0.005). The correlation between 95-gene signature and 21-gene signature assay scores was not strong (correlation coefficient r = 0.27), which might suggest that 95-gene signature reflects biological characteristics differing from what 21-gene signature shows. CONCLUSIONS: The 95-gene signature stratifies patients with ER-positive, HER2-negative, node-negative invasive breast cancer and intermediate RS of 11-25 into high and low groups that are associated with recurrence risk of invasive disease. Further retrospective analysis in the prospectively accrued TAILORx population is warranted to confirm that 95-gene signature can identify patients who would benefit from adjuvant chemoendocrine therapy.

Nonphosphorylatable PEA15 mutant inhibits epithelial-mesenchymal transition in triple-negative breast cancer partly through the regulation of IL-8 expression.

BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that lacks targeted therapies. Patients with TNBC have a very poor prognosis because the disease often metastasizes. New treatment approaches addressing drivers of metastasis and tumor growth are crucial to improving patient outcomes. Developing targeted gene therapy is thus a high priority for TNBC patients. PEA15 (phosphoprotein enriched in astrocytes, 15 kDa) is known to bind to ERK, preventing ERK from being translocated to the nucleus and hence blocking its activity. The biological function of PEA15 is tightly regulated by its phosphorylation at Ser104 and Ser116. However, the function and impact of phosphorylation status of PEA15 in the regulation of TNBC metastasis and in epithelial-to-mesenchymal transition (EMT) are not well understood. METHODS: We established stable cell lines overexpressing nonphosphorylatable (PEA15-AA) and phospho-mimetic (PEA15-DD) mutants. To dissect specific cellular mechanisms regulated by PEA15 phosphorylation status, we performed RT-PCR immune and metastasis arrays. In vivo mouse models were used to determine the effects of PEA15 phosphorylation on tumor growth and metastasis. RESULTS: We found that the nonphosphorylatable mutant PEA15-AA prevented formation of mammospheres and expression of EMT markers in vitro and decreased tumor growth and lung metastasis in in vivo experiments when compared to control, PEA15-WT and phosphomimetic PEA15-DD. However, phosphomimetic mutant PEA15-DD promoted migration, mesenchymal marker expression, tumorigenesis, and lung metastasis in the mouse model. PEA15-AA-mediated inhibition of breast cancer cell migratory capacity and tumorigenesis was the partial result of decreased expression of interleukin-8 (IL-8). Further, we identified that expression of IL-8 was possibly mediated through one of the ERK downstream molecules, Ets-1. CONCLUSIONS: Our results show that PEA15 phosphorylation status serves as an important regulator for PEA15's dual role as an oncogene or tumor suppressor and support the potential of PEA15-AA as a therapeutic strategy for treatment of TNBC.

The Role of Mastectomy in De Novo Stage IV Inflammatory Breast Cancer.

INTRODUCTION: The role of modified radical mastectomy (MRM) in patients with de novo stage IV inflammatory breast cancer (IBC) remains controversial. We evaluated the impact of MRM on outcomes in this population. METHODS: Ninety-seven women presenting with stage IV IBC were identified in an institutional database (2007-2016) and were stratified by receipt of MRM or no surgery (non-MRM). Demographic, clinicopathologic, and treatment factors were compared. Local-regional recurrence patterns were described and survival analyses were conducted. RESULTS: All patients initially received chemotherapy. Fifty-two patients (53.6%) underwent MRM; 47 received post-mastectomy radiation. Differences between the non-MRM and MRM groups included tumor receptor subtypes (hormone receptor-positive [HR+]/human epidermal growth factor receptor 2-positive [HER2+]: 4.4% vs. 19.2%; HR+/HER2-negative [HER2-]: 31.1% vs. 44.2%; HR-negative [HR-]/HER2+: 24.4% vs. 15.4%; and HR-/HER2-: 40.0% vs. 21.2%; p = 0.03), number of metastatic sites (3 vs. 2; p = 0.01), and clinical partial/complete response to chemotherapy (13.3% vs. 75.0%; p < 0.001). Of the 47 patients who completed trimodality therapy, 6 (12.8%) had a local-regional recurrence. Median overall survival (OS) was 19 months in the non-MRM group and 58 months in the MRM group (p < 0.001). On multivariable analysis, clinical N3 disease (hazard ratio 2.16, 95% confidence interval [CI] 1.07-4.37; p = 0.03) as well as tumor subtypes HR+/HER2- (hazard ratio 4.98, 95% CI 1.15-21.47; p = 0.03) and HR-/HER2- (hazard ratio 7.18, 95% CI 1.66-31.07; p = 0.008) were associated with decreased OS. Partial/complete response of distant disease to chemotherapy (hazard ratio 0.43, 95% CI 0.24-0.77; p = 0.005) and receipt of MRM (hazard ratio 0.52, 95% CI 0.29-0.93; p = 0.03) were independently associated with improved OS. CONCLUSIONS: In our retrospective study, MRM in de novo stage IV IBC patients is an independent factor associated with improved OS. Our findings strongly support the need for prospective randomized trials evaluating possible survival benefits of MRM in de novo stage IV IBC patients.

Inflammatory Breast Cancer at the Extremes of Age.

BACKGROUND: Inflammatory breast cancer (IBC) is a rare breast malignancy with poor outcomes compared with non-IBC. Age-related differences in tumor biology, treatment, and clinical outcomes have been described in non-IBC. This study evaluated age-related differences in IBC. METHODS: From an institutional prospective database, patients with an IBC diagnosed from 2010 to 2019 were identified. Age was categorized as 40 years or younger, 41 to 64 years, and 65 years or older. Demographics, clinicopathologic features, and treatment received were compared. Recurrence and survival outcomes were analyzed using the log-rank test and the Cox proportional hazards model. RESULTS: Of 523 IBC patients, 113 (21.6%) were age 40 years or younger, and 72 (13.8%) were age 65 years or older. The groups did not differ statistically by race/ethnicity, N stage, clinical stage, or tumor subtype. The younger patients included a higher proportion of Hispanic and Asian patients, triple-negative breast cancer (TNBC), and clinical N2/N3. Trimodality therapy was received by 92% of the stage 3 patients, with no difference in pathologic complete response (pCR) by age (23.3% vs 28.6%; p = 0.46). During a median follow-up period of 40 months, 17% of the patients experienced locoregional recurrence and 42.8% had distant metastasis. No difference in 3-year recurrence-free survival (57.9% vs 42.6% vs 54%; p = 0.42, log rank) or overall survival (OS) (75.6% vs 77.1% vs 64.4%; p = 0.31, log rank) by age was observed, and no difference in OS by age in de novo stage 4 disease was observed. In the multivariate analysis, worse OS was associated with TNBC (hazard ratio [HR], 1.99, 95% confidence interval [CI], 1.31-3.05) and no pCR (HR, 4.45; 95% CI, 2.16-9.18). CONCLUSION: No significant differences were observed in demographics, treatment patterns, or clinical outcomes for IBC patients age 40 years or younger compared with those age 65 years or older treated by a specialized multidisciplinary team. These findings do not support age-related treatment de-escalation in IBC.

Contralateral Axillary Metastasis in Patients with Inflammatory Breast Cancer.

BACKGROUND: Nearly one-third of patients with inflammatory breast cancer (IBC) present with de novo stage IV disease. There are limited data on frequency and clinical outcomes of contralateral axillary metastasis (CAM) in IBC with no consensus diagnostic and treatment guidelines. PATIENTS AND METHODS: Frequency of synchronous CAM was calculated in unilateral IBC patients at a single center (10/2004-6/2019). Clinicopathologic variables, diagnostic evaluation, treatment received, and overall survival (OS) were assessed and compared. RESULTS: Of 588 unilateral IBC patients, 49 (8.3%) had synchronous CAM. Of these, 32 (65.3%) also presented with metastatic disease at another distant site. CAM was not associated with age, tumor laterality, breast cancer subtype, grade, or cN stage (p > 0.05). The sensitivity/specificity to detect CAM was as follows: mammography (18.2%/99.2%), ultrasound (92.3%/95.5%), PET (90.1/99.1%), and MRI (76.0%/98.6%). Following systemic therapy, 22 patients had contralateral axillary surgery, and 18 received adjuvant contralateral nodal radiation. On multivariable analysis including tumor receptor subtypes, patients with stage IV-isolated CAM has statistically similar survival to stage III patients (HR 1.37, 95% CI 0.70-2.69, p = 0.36). Patients with Stage IV non-CAM (HR 2.18, 95% CI 1.66-2.85, p < 0.001) and stage IV-CAM plus other distant metastasis (HR 2.57, 95% CI 1.59-4.16, p < 0.001) had higher risk of death (reference: stage III disease). CONCLUSIONS: CAM in IBC was diagnosed in 8.3% of patients at presentation and was best identified by ultrasound and PET. We recommend routine contralateral axillary ultrasound as part of staging for all IBC patients. Diagnosis of CAM is a key first step toward much-needed prospective clinical trials evaluating management and outcomes of CAM in IBC.

The CD151-midkine pathway regulates the immune microenvironment in inflammatory breast cancer.

The immune microenvironment in inflammatory breast cancer (IBC) is poorly characterised, and molecular and cellular pathways that control accumulation of various immune cells in IBC tissues remain largely unknown. Here, we discovered a novel pathway linking the expression of the tetraspanin protein CD151 in tumour cells with increased accumulation of macrophages in cancerous tissues. It is notable that elevated expression of CD151 and a higher number of tumour-infiltrating macrophages correlated with better patient responses to chemotherapy. Accordingly, CD151-expressing IBC xenografts were characterised by the increased infiltration of macrophages. In vitro migration experiments demonstrated that CD151 stimulates the chemoattractive potential of IBC cells for monocytes via mechanisms involving midkine (a heparin-binding growth factor), integrin α6ß1, and production of extracellular vesicles (EVs). Profiling of chemokines secreted by IBC cells demonstrated that CD151 increases production of midkine. Purified midkine specifically stimulated migration of monocytes, but not other immune cells. Further experiments demonstrated that the chemoattractive potential of IBC-derived EVs is blocked by anti-midkine antibodies. These results demonstrate for the first time that changes in the expression of a tetraspanin protein by tumour cells can affect the formation of the immune microenvironment by modulating recruitment of effector cells to cancerous tissues. Therefore, a CD151-midkine pathway can be considered as a novel target for controlled changes of the immune landscape in IBC. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Chemical generation of small molecule-based bispecific antibody-drug conjugates for broadening the target scope.

Antibody-drug conjugates (ADCs) hold great therapeutic promise for cancer indications; however, treating tumors with intratumor heterogeneity remains challenging. We hypothesized that ADCs that can simultaneously target two different cancer antigens could address this issue. Here, we report controlled production and evaluation of bispecific ADCs chemically functionalized with tumor-targeting small molecules. Enzyme-mediated conjugation of bi-functional branched linkers and following sequential orthogonal click reactions with payload and tumor targeting modules (folic acid or RGD peptide) afforded homogeneous bispecific ADCs with defined ligand/drug-to-antibody ratios ranging from 4 + 4 to 16 + 4 (ligand/payload). Most bispecific ADCs were stable under physiological conditions for 14 days. Functionalization with the cancer-specific ligands did not impair cathepsin B-mediated payload release from ADCs. Bispecific ADCs targeting the folate receptor (FR)/human epidermal growth factor receptor 2 (HER2) demonstrated specific binding and high cell killing potency only in cells expressing either antigen (FR or HER2). Integrin/HER2 bispecific ADCs equipped with RGD peptides also showed target-specific binding and cytotoxicity in integrin- or HER2-positive cells. These findings suggest that our small-molecule based bispecific ADCs have the potential to effectively treat tumors with heterogeneous antigen expression.

Prognostic Value of HER2 to CEP17 Ratio on Fluorescence In Situ Hybridization Ratio in Patients with Nonmetastatic HER2-Positive Inflammatory and Noninflammatory Breast Cancer Treated with Neoadjuvant Chemotherapy with or without Trastuzumab.

BACKGROUND: We previously reported that in patients with HER2-positive (HER2+) locally advanced breast cancer treated with neoadjuvant trastuzumab-containing regimens, high HER2 to centromere enumerator probe 17 ratio on fluorescence in situ hybridization (HER2 FISH ratio) was an independent predictor of high pathologic complete response (pCR) rate, which translated into improved recurrence-free survival (RFS). We sought to determine whether high HER2 FISH ratio is a predictor of pCR and prognosis in patients with HER2+ nonmetastatic inflammatory breast cancer (IBC) and non-IBC treated with neoadjuvant chemotherapy with or without trastuzumab. MATERIALS AND METHODS: This study included all patients with histologically proven stage III, HER2+ primary IBC, and non-IBC treated with neoadjuvant chemotherapy with or without trastuzumab and definitive surgery during 1999-2012. Univariate and multivariate logistic regression models were applied to assess the effect of covariates on pCR. Kaplan-Meier estimates with log-rank test were employed for survival analysis. Univariate and multivariate Cox proportional hazards models were used to assess the effect of covariates on RFS and overall survival (OS). RESULTS: The study included 555 patients with stage III, HER+ breast cancer, 181 patients with IBC, and 374 with non-IBC. In the IBC cohort, HER2 FISH ratio was not significantly associated with pCR, RFS, or OS. In the non-IBC cohort, higher HER2 FISH ratio was significantly associated with higher pCR rate and longer OS. CONCLUSION: HER2 FISH ratio showed prognostic value among patients with HER2+ non-IBC but not HER2+ IBC treated with neoadjuvant chemotherapy. This disparity may be due to the underlying aggressive nature of IBC. IMPLICATIONS FOR PRACTICE: The findings of this study indicate that the HER2 to fluorescence in situ hybridization ratio as a continuous variable has promise as a predictor of pathologic complete response to neoadjuvant chemotherapy in patients with HER2-positive (HER2+) noninflammatory breast cancer (non-IBC) regardless of the results on HER2 immunohistochemical testing. In the future, some patients with HER2+ non-IBC and a high HER2 FISH ratio might even be offered personalized treatment options, such as nonsurgical treatment.

The efficacy of first-line chemotherapy in endocrine-resistant hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer.

PURPOSE: Combinations of endocrine therapy (ET) and targeted therapy (CDK4/6 or mTOR inhibitors) are standard of care for HR+/HER2- metastatic breast cancer (MBC). When ET is not effective, chemotherapy is commonly used. However, clinical outcomes of chemotherapy in the endocrine-resistant setting are limited. The purpose of this study was to identify predictive factors and the compare efficacies of chemotherapy agents in endocrine-resistant MBC. METHODS: We conducted a retrospective study of patients with HR+/HER2- MBC who received chemotherapy after progression on ET with or without targeted therapy at MD Anderson Cancer Center from 1999 to 2017. We collected baseline clinicopathological and all treatment data. Primary endpoint was time to treatment failure (TTF) of first-line chemotherapy for MBC. RESULTS: For the 1258 patients analyzed, mean age was 55.3 years (range 21-91). Previous treatment with targeted therapy was recorded for 390 patients (31%): 264 with CDK4/6 inhibitor, 205 with mTOR inhibitor, and 79 treated with both. The most frequent chemotherapy agents were capecitabine (48.9%) and taxanes (28.6%). After adjustment for all factors in a multivariate model, previous treatment with a CDK4/6 inhibitor had the strongest negative effect on TTF regardless of ET duration (hazard ratio [HR] 1.84; 95%CI 1.49-2.27; p < 0.001). Conversely, capecitabine had significantly longer median TTF than taxanes regardless of whether patients had prior exposure to taxanes in primary setting (6.1 vs 4.9 months; HR 0.64; 95%CI 0.55-0.75; p < 0.001). CONCLUSIONS: Previous exposure to CDK4/6 inhibitor had a negative predictive effect for the efficacy of chemotherapy. Capecitabine had the best efficacy against endocrine-resistant breast cancer.

Inflammatory breast cancer cells are characterized by abrogated TGFß1-dependent cell motility and SMAD3 activity.

PURPOSE: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer with elevated metastatic potential, characterized by tumor emboli in dermal and parenchymal lymph vessels. This study has investigated the hypothesis that TGFß signaling is implicated in the molecular biology of IBC. METHODS: TGFß1-induced cell motility and gene expression patterns were investigated in three IBC and three non-IBC (nIBC) cell lines. Tissue samples from IBC and nIBC patients were investigated for the expression of nuclear SMAD2, SMAD3, and SMAD4. SMAD protein levels were related to gene expression data. RESULTS: TGFß1-induced cell motility was strongly abrogated in IBC cells (P = 0.003). Genes differentially expressed between IBC and nIBC cells post TGFß1 exposure revealed attenuated expression of SMAD3 transcriptional regulators, but overexpression of MYC target genes in IBC. IBC patient samples demonstrated a near absence of SMAD3 and -4 expression in the primary tumor compared to nIBC patient samples (P < 0.001) and a further reduction of staining intensity in tumor emboli. Integration of gene and protein expression data revealed that a substantial fraction of the IBC signature genes correlated with SMAD3 and these genes are indicative of attenuated SMAD3 signaling in IBC. CONCLUSION: We demonstrate attenuated SMAD3 transcriptional activity and SMAD protein expression in IBC, together with obliterated TGFß1-induced IBC cell motility. The further reduction of nuclear SMAD expression levels in tumor emboli suggests that the activity of these transcription factors is involved in the metastatic dissemination of IBC cells, possibly by enabling collective invasion after partial EMT.

Factors Associated with Pathological Node Negativity in Inflammatory Breast Cancer: Are There Patients Who May be Candidates for a De-Escalation of Axillary Surgery?

BACKGROUND: Modified radical mastectomy (MRM), which includes axillary dissection, is the standard of care for inflammatory breast cancer (IBC). While more limited axillary staging after neoadjuvant chemotherapy (NAC) in clinically node-positive non-IBC has been increasingly adopted, the impact of these techniques in IBC is not clear. To inform patient selection for further study of limited axillary surgery, we aimed to describe the frequency and factors associated with pathological node-negativity (ypN0) in IBC. METHODS: Patients with IBC who received NAC and MRM were identified from a prospective institutional database (2004-2019). Binary logistic regression analyses were conducted to identify factors associated with ypN0. RESULTS: Of 453 patients, 189 (41.7%) had a post-NAC clinical nodal stage (ycN stage) of N0 (ycN1: 150, 33.1%; ycN2: 4, 0.9%; ycN3: 47, 10.4%; unknown: 63, 13.9%); 156 (34%) were ypN0. On multivariable analysis, higher tumor grade was not associated with ypN0 (odds ratio [OR] 1.59, 95% confidence interval [CI] 0.90-2.81, p =0.11). Compared with hormone receptor (HR)-negative/human epidermal growth factor receptor 2 (HER2)-negative tumors (n =113, 24.9%), HR-positive/HER2-negative tumors (n =169, 37.3%) had a trend toward less ypN0 (OR 0.55, 95% CI 0.29-1.02, p =0.06); HR-positive/HER2-positive tumors (n =79, 17.4%) were similar to HR-negative/HER2-negative tumors (OR 0.72, 95% CI 0.35-1.48, p =0.37); and HR-negative/HER2-positive tumors (n =92, 20.3%) were associated with increased ypN0 (OR 4.82, 95% CI 2.41-9.63, p <0.001). As ycN stage increased, the likelihood of ypN0 decreased compared with ycN0 patients (ycN1/2: OR 0.54, 95% CI 0.32-0.89, p =0.02; ycN3: OR 0.29, 95% CI 0.13-0.67, p =0.004). CONCLUSIONS: One-third of patients with IBC who received NAC and MRM had pathologically negative nodes. Factors associated with ypN0 included ycN0 status and HR-negative/HER2-positive subtype. Large, prospective studies are needed to investigate the feasibility of alternative nodal evaluation strategies in IBC, with consideration to these subgroups.

Quantitative hormone receptor (HR) expression and gene expression analysis in HR+ inflammatory breast cancer (IBC) vs non-IBC.

BACKGROUND: The purpose of this study was to determine the prognostic role of hormone receptor (HR) on inflammatory breast cancer (IBC) to elucidate its aggressive biological behavior. METHODS: We evaluated the expression of estrogen receptor (ER) and progesterone receptor (PR) by immunohistochemical staining and determined the predictive and prognostic role of HR expression on 189 patients with HR+/HER2- IBC and 677 patients with HR+/HER2- stage III non-IBC. Furthermore, we performed gene expression (GE) analyses on 137 patients with HR+/HER2- IBC and 252 patients with HR+/HER2- non-IBC to detect genes that are specifically overexpressed in IBC. RESULTS: The expression of ER% was significantly associated with longer distant disease-free survival and overall survival. However, there was no significant relationship between ER% and neoadjuvant chemotherapy outcome. In the GE study, 84 genes were identified as significantly distinguishing HR+ IBC from non-IBC. Among the top 15 canonical pathways expressed in IBC, the ERK/MAPK, PDGF, insulin receptor, and IL-7 signaling pathways were associated with the ER signaling pathway. Upregulation of the MYC gene was observed in three of these four pathways. Furthermore, HR+/HER2- IBC had significantly higher MYC amplification, and the genetic alteration was associated with poor survival outcome. CONCLUSIONS: Higher ER expression was significantly associated with improved survival in both HR+/HER2- IBC and HR+/HER2- stage III non-IBC patients. HR+/HER2- IBC had several activated pathways with MYC upregulation, and the genetic alteration was associated with poor survival outcome. The results indicate that MYC may be a key gene for understanding the biology of HR+/HER2- IBC.

JNK Signaling in Stem Cell Self-Renewal and Differentiation.

C-JUN N-terminal kinases (JNKs), which belong to the mitogen-activated protein kinase (MAPK) family, are evolutionarily conserved kinases that mediate cell responses to various types of extracellular stress insults. They regulate physiological processes such as embryonic development and tissue regeneration, playing roles in cell proliferation and programmed cell death. JNK signaling is also involved in tumorigenesis and progression of several types of malignancies. Recent studies have shown that JNK signaling has crucial roles in regulating the traits of cancer stem cells (CSCs). Here we describe the functions of the JNK signaling pathway in self-renewal and differentiation, which are essential features of various types of stem cells, such as embryonic, induced pluripotent, and adult tissue-specific stem cells. We also review current knowledge of JNK signaling in CSCs and discuss its role in maintaining the CSC phenotype. A better understanding of JNK signaling as an essential regulator of stemness may provide a basis for the development of regenerative medicine and new therapeutic strategies against malignant tumors.