Characterization of KIF20B as a novel prognostic biomarker and therapeutic target for breast cancer.

Despite advances in treatment and early detection, breast cancer remains one of the most common types of cancer and is the second leading cause of cancer death after lung cancer in women. Therefore, there is an urgent need to develop new biomarkers and therapeutic targets for the treatment of breast cancer. Based on gene expression profiles and subsequent screening performed in a preliminary study, kinesin family member 20B (KIF20B) was selected as a candidate target molecule, because it was highly and frequently expressed in all subtypes of breast cancer and barely detected in normal tissues. Reverse transcription­quantitative PCR and western blotting revealed that KIF20B mRNA and protein expression levels were upregulated in most breast cancer cell lines but were scarcely expressed in normal mammary epithelial cells. Immunohistochemical staining of a tissue microarray showed that KIF20B was detected in 145 out of 251 (57.8%) breast cancer tissues. Strong KIF20B expression was significantly related to advanced pathological N stage. Moreover, patients with breast cancer and strong KIF20B expression exhibited a significantly worse prognosis than those with weak or negative KIF20B expression (P<0.0001, log­rank test). In multivariate analysis, strong expression was an independent prognostic factor for patients with breast cancer. Furthermore, knockdown of KIF20B expression by small interfering RNA inhibited breast cancer cell proliferation and induced apoptosis. In addition, Matrigel cell invasion assays revealed that the invasiveness of breast cancer cells was significantly decreased by KIF20B silencing. Since KIF20B is an oncoprotein that is strongly expressed in highly malignant clinical breast cancer and serves a pivotal role in breast cancer cell proliferation, survival and invasion, KIF20B could be considered a candidate biomarker for prognostic prediction and a potential molecular target for developing new therapeutics, such as small molecule inhibitors, for a wide variety of breast cancers.

FXYD3 functionally demarcates an ancestral breast cancer stem cell subpopulation with features of drug-tolerant persisters.

The heterogeneity of cancer stem cells (CSCs) within tumors presents a challenge in therapeutic targeting. To decipher the cellular plasticity that fuels phenotypic heterogeneity, we undertook single-cell transcriptomics analysis in triple-negative breast cancer (TNBC) to identify subpopulations in CSCs. We found a subpopulation of CSCs with ancestral features that is marked by FXYD domain-containing ion transport regulator 3 (FXYD3), a component of the Na+/K+ pump. Accordingly, FXYD3+ CSCs evolve and proliferate, while displaying traits of alveolar progenitors that are normally induced during pregnancy. Clinically, FXYD3+ CSCs were persistent during neoadjuvant chemotherapy, hence linking them to drug-tolerant persisters (DTPs) and identifying them as crucial therapeutic targets. Importantly, FXYD3+ CSCs were sensitive to senolytic Na+/K+ pump inhibitors, such as cardiac glycosides. Together, our data indicate that FXYD3+ CSCs with ancestral features are drivers of plasticity and chemoresistance in TNBC. Targeting the Na+/K+ pump could be an effective strategy to eliminate CSCs with ancestral and DTP features that could improve TNBC prognosis.

Glutamine deficiency drives transforming growth factor-ß signaling activation that gives rise to myofibroblastic carcinoma-associated fibroblasts.

Tumor-promoting carcinoma-associated fibroblasts (CAFs), abundant in the mammary tumor microenvironment (TME), maintain transforming growth factor-ß (TGF-ß)-Smad2/3 signaling activation and the myofibroblastic state, the hallmark of activated fibroblasts. How myofibroblastic CAFs (myCAFs) arise in the TME and which epigenetic and metabolic alterations underlie activated fibroblastic phenotypes remain, however, poorly understood. We herein show global histone deacetylation in myCAFs present in tumors to be significantly associated with poorer outcomes in breast cancer patients. As the TME is subject to glutamine (Gln) deficiency, human mammary fibroblasts (HMFs) were cultured in Gln-starved medium. Global histone deacetylation and TGF-ß-Smad2/3 signaling activation are induced in these cells, largely mediated by class I histone deacetylase (HDAC) activity. Additionally, mechanistic/mammalian target of rapamycin complex 1 (mTORC1) signaling is attenuated in Gln-starved HMFs, and mTORC1 inhibition in Gln-supplemented HMFs with rapamycin treatment boosts TGF-ß-Smad2/3 signaling activation. These data indicate that mTORC1 suppression mediates TGF-ß-Smad2/3 signaling activation in Gln-starved HMFs. Global histone deacetylation, class I HDAC activation, and mTORC1 suppression are also observed in cultured human breast CAFs. Class I HDAC inhibition or mTORC1 activation by high-dose Gln supplementation significantly attenuates TGF-ß-Smad2/3 signaling and the myofibroblastic state in these cells. These data indicate class I HDAC activation and mTORC1 suppression to be required for maintenance of myCAF traits. Taken together, these findings indicate that Gln starvation triggers TGF-ß signaling activation in HMFs through class I HDAC activity and mTORC1 suppression, presumably inducing myCAF conversion.

Increased RUNX3 expression mediates tumor-promoting ability of human breast cancer-associated fibroblasts.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are a major stromal component of human breast cancers and often promote tumor proliferation, progression and malignancy. We previously established an experimental CAF (exp-CAF) cell line equipped with a potent tumor-promoting ability. It was generated through prolonged incubation of immortalized human mammary fibroblasts with human breast cancer cells in a tumor xenograft mouse model. RESULTS: Herein, we found that the exp-CAFs highly express Runt-related transcription factor 3 (RUNX3), while counterpart fibroblasts do not. In breast cancer patients, the proportion of RUNX3-positive stromal fibroblast-like cells tends to be higher in cancerous regions than in non-cancerous regions. These findings suggest an association of RUNX3 with CAF characteristics in human breast cancers. To investigate the functional role of RUNX3 in CAFs, the exp-CAFs with or without shRNA-directed knockdown of RUNX3 were implanted with breast cancer cells subcutaneously in immunodeficient mice. Comparison of the resulting xenograft tumors revealed that tumor growth was significantly attenuated when RUNX3 expression was suppressed in the fibroblasts. Consistently, Ki-67 and CD31 immunohistochemical staining of the tumor sections indicated reduction of cancer cell proliferation and microvessel formation in the tumors formed with the RUNX3-suppressed exp-CAFs. CONCLUSION: These results suggest that increased RUNX3 expression could contribute to the tumor-promoting ability of CAFs through mediating cancer cell growth and neoangiogenesis in human breast tumors.

Fulvestrant with or without anti-HER2 therapy in patients in a postmenopausal hormonal state and with ER-positive HER2-positive advanced or metastatic breast cancer: A subgroup analysis of data from the Safari study (JBCRG-C06).

BACKGROUND: The role of endocrine therapy in the treatment of patients in a postmenopausal hormonal state and with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer (AMBC) is unclear. METHODS: We analyzed the data from 94 patients with ER-positive HER2-positive AMBC enrolled in the Safari study (UMIN000015168), a retrospective cohort study of 1072 ER-positive AMBC patients in a postmenopausal hormonal state who received fulvestrant 500 mg (F500): (1) to compare time to treatment failure (TTF) and overall survival (OS) by treatment group, and TTF by treatment line; (2) in patients who received endocrine therapy (including F500) or anti-HER2 therapy as initial systemic therapy before chemotherapy, to investigate relations between TTF for the first-line therapy or time to chemotherapy (TTC) and OS; (3) to investigate factors associated with OS. RESULTS: The TTF was longer in the patients treated with F500 as first- or second-line therapy (n = 20) than in those who received later-line F500 therapy (n = 74) (6.6 vs. 3.7 months; HR, 1.98; p = 0.014). In the 59 patients who received endocrine therapy or anti-HER2 therapy as initial systemic therapy before chemotherapy, those with TTC ≥3 years had longer median OS than those with TTC <3 years (10.5 vs. 5.9 years; HR, 0.32; p = 0.001). Longer TTC was associated with prolonged OS. CONCLUSIONS: In patients with ER-positive HER2-positive AMBC enrolled in the Safari study, TTF was longer in patients who received F500 as first- or second-line therapy. In patients who received chemotherapy-free initial systemic therapy, the prolonged OS in those with TTC ≥3 years suggests that this value may be a helpful cut-off for indicating clinical outcomes.

Clinical Significance of Cancer Stem Cell Markers in Primary and Metastatic Tissues in Patients With Breast Cancer.

BACKGROUND/AIM: This study aimed to examine the clinical significance of the protein expression of the cancer stem cell (CSC) markers ALDH1A1, CD133, CD44, and MSI-1 in primary and metastatic tissues of patients with breast cancer (BC). PATIENTS AND METHODS: ALDH1A1, CD133, CD44, and MSI-1 protein expression in pairs of primary and metastatic tissues of 55 patients with BC with metastases treated at Kanagawa Cancer Center between January 1970 and December 2016 were evaluated using immunohistochemical assay and their association with clinicopathological factors and survival was examined. RESULTS: There were no significant differences in CSC marker expression rates between primary and metastatic tissues for any CSC markers. Regarding the relationship between CSC marker expression in primary tissues and survival, patients with high CD133 expression had significantly lower recurrence-free survival (DFS) and overall survival. On multivariate analysis, they were also a poor independent predictor of DFS (hazard ratio=4.993, 95%CI=2.189-11.394, p=0.0001). In contrast, there was no significant association between the expression of any CSC marker in metastatic tissues and survival. CONCLUSION: CD133 expression in the primary BC tissue may be a useful risk factor for recurrence in patients with BC.

Bone marrow adipocytes induce cancer-associated fibroblasts and immune evasion, enhancing invasion and drug resistance.

Bone metastasis occurs frequently in cancer patients. Conventional therapies have limited therapeutic outcomes, and thus, exploring the mechanisms of cancer progression in bone metastasis is important to develop new effective therapies. In the bone microenvironment, adipocytes are the major stromal cells that interact with cancer cells during bone metastasis. However, the comprehensive functions of bone marrow adipocytes in cancer progression are not yet fully understood. To address this, we investigated the role of bone marrow adipocytes on cancer cells, by focusing on an invasive front that reflects the direct effects of stromal cells on cancer. In comprehensive histopathological and genetic analysis using bone metastasis specimens, we examined invasive fronts in bone metastasis and compared invasive fronts with adipocyte-rich bone marrow (adipo-BM) to those with hematopoietic cell-rich bone marrow (hemato-BM) as a normal counterpart of adipocytes. We found morphological complexity of the invasive front with adipo-BM was significantly higher than that with hemato-BM. Based on immunohistochemistry, the invasive front with adipo-BM comparatively had a significantly increased cancer-associated fibroblast (CAF) marker-positive area and lower density of CD8+ lymphocytes compared to that with hemato-BM. RNA sequencing analysis of primary and bone metastasis cancer revealed that bone metastasized cancer cells acquired drug resistance-related gene expression phenotypes. Clearly, these findings indicate that bone marrow adipocytes provide a favorable tumor microenvironment for cancer invasion and therapeutic resistance of bone metastasized cancers through CAF induction and immune evasion, providing a potential target for the treatment of bone metastasis.

Effect of Trastuzumab Deruxtecan on QT/QTc Interval and Pharmacokinetics in HER2-Positive or HER2-Low Metastatic/Unresectable Breast Cancer.

HER2-targeted anticancer therapies may be associated with cardiovascular adverse events. This study evaluated effects of the HER2-targeted antibody-drug conjugate trastuzumab deruxtecan (T-DXd, DS-8201a) on QT/QTc interval and its pharmacokinetics. Patients with heavily pretreated, metastatic HER2-expressing breast cancer were enrolled at seven study sites in Japan. T-DXd was administered intravenously at 6.4 mg/kg on day 1 of each 21-day cycle. Primary end points were baseline-adjusted QTcF interval and pharmacokinetics parameters. Key secondary end points included safety events, serum concentration of T-DXd and DXd at the time of electrocardiographic measurements, and antitumor activity parameters. Among 51 total patients, 47 (92.2%) had HER2-low breast cancer (immunohistochemistry 1+ or 2+ and in situ hybridization-negative/equivocal/missing). Pharmacokinetic parameters after a single dose of T-DXd were consistent with previous studies. After multiple doses, T-DXd showed moderate accumulation (accumulation ratio (cycle 3/cycle 1), 1.35), but DXd showed minimal accumulation (1.09). The upper bound of the 90% confidence interval for mean ΔQTcF interval was < 10 ms at all timepoints, and at mean maximum serum concentration was also < 10 ms. Based on concentration-QT analysis, ΔQTcF increased with increasing concentrations of T-DXd and DXd. No clinically meaningful QTcF prolongation was observed. T-DXd had a manageable safety profile and showed antitumor activity in HER2-low breast cancer. In this study, a T-DXd dose of 6.4 mg/kg, higher than the 5.4-mg/kg dose currently approved for breast cancer, was not associated with clinically relevant QTcF prolongation in heavily pretreated patients with HER2-expressing metastatic breast cancer. This study adds to our understanding of T-DXd for treatment of HER2-low breast cancer.

Efficacy and exploratory biomarker analysis of entinostat plus exemestane in advanced or recurrent breast cancer: phase II randomized controlled trial.

BACKGROUND: We aimed to confirm the efficacy and safety of the oral histone deacetylase inhibitor entinostat in Japanese patients with hormone receptor-positive advanced/recurrent breast cancer and to explore potential biomarkers. METHODS: This phase II, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov; NCT03291886) was conducted at 28 Japanese sites (September 2017-July 2020; interim analysis cutoff: April 2019). Patients with progression/relapse following non-steroidal aromatase inhibitors were randomized 1:1 to entinostat (5 mg/week) or placebo, plus exemestane (25 mg/day). Primary endpoint was progression-free survival; secondary endpoints included overall survival and safety. Exploratory biomarker outcomes included lysine acetylation, immune cell profiles, estrogen receptor 1 mutations and plasma chemokines. RESULTS: Of 133 randomized patients, 131 (65 entinostat, 66 placebo) who received study drug were analyzed. Median (95% confidence interval) progression-free survival was 5.8 (3.2-7.8) months for entinostat and 3.3 (3.1-5.8) months for placebo (hazard ratio [95% confidence interval]: 0.75 [0.50 - 1.14]; P = 0.189). Median overall survival was not reached in either group. Entinostat tended to prolong progression-free survival in patients aged ≥65 years, not endocrine resistant, or with estrogen receptor 1 Y537S mutation. Candidate biomarkers of efficacy (progression-free survival) included lysine acetylation in CD3+ cells, plasma interferon gamma-induced protein 10, dendritic cell CD86 expression, and CD4+ cell expression of human leukocyte antigen-DR and inducible T-cell co-stimulator. Safety was similar to non-Japanese populations; however, seven entinostat-treated patients (10.8%) had reversible lung injury. CONCLUSIONS: In Japanese patients, the safety of entinostat plus exemestane was acceptable and progression-free survival was prolonged, although not significantly. Exploratory analyses identified potential biomarkers, including lysine acetylation, of efficacy.

Retrospective study on the effectiveness of medroxyprogesterone acetate in the treatment of ER-positive/HER2-negative post-menopausal advanced breast cancer: an additional analysis of the JBCRG-C06 Safari study.

BACKGROUND: Only old evidence exists to back up the use of medroxyprogesterone acetate. Therefore, this study aimed to explore the factors that influence the time to treatment failure of medroxyprogesterone acetate in real-world settings as late-line treatment. METHODS: This was a cohort study that used the database of the Safari study on oestrogen receptor-positive post-menopausal advanced breast cancer (UMIN000015168). We created Kaplan-Meier curves for time to treatment failure with medroxyprogesterone acetate. Further, univariate and multivariate analyses were performed using a Cox hazard model of the clinicopathological factors involved in the time to treatment failure of medroxyprogesterone acetate. RESULTS: From the 1031 patients in the Safari study, 279 patients were selected as the population for the analysis of effectiveness of medroxyprogesterone acetate monotherapy. In the analysis of medroxyprogesterone acetate by treatment line, the median time to treatment failure was 3.0 months for third-line treatment and 4.1 months for fourth and subsequent treatment lines. In cases where medroxyprogesterone acetate was used as a third-line or later endocrine treatment, multivariate analysis showed that the length of the disease-free interval was correlated with the length of time to treatment failure of medroxyprogesterone acetate (P = 0.004). With medroxyprogesterone acetate monotherapy as the fourth-line or later treatment, 20% of the patients achieved a time to treatment failure of 12 months or longer. CONCLUSION: In actual clinical practice, patients treated with medroxyprogesterone acetate alone as the fourth or subsequent treatment lines showed a time to treatment failure of 4 months, suggesting that there is merit in using medroxyprogesterone acetate even in late treatment lines, especially in patients with long disease-free interval and those who are difficult to treat using other antineoplastic agents.

Multicenter Randomized Open-Label Phase II Clinical Study Comparing Outcomes of NK105 and Paclitaxel in Advanced or Recurrent Breast Cancer.

Background: NK105 is a paclitaxel (PTX)-incorporating "core-shell-type" polymeric micellar nanoparticle formulation composed of block copolymers (polyethylene glycol and a polyamino acid). The efficacy and safety of NK105 and paclitaxel in advanced or recurrent breast cancer have never been compared at equivalent dose levels. Patients and Methods: Patients were randomly assigned to either NK105 or PTX in a 1:1 ratio. The study drug was administered on Day 1, 8, and 15 of a 28-day cycle with 80 mg/m2. The primary endpoint was overall response rate (ORR), secondary endpoints were progression-free survival (PFS), overall survival (OS), and adverse events. Results: A total of 123 patients (NK105, n=62; PTX, n=61) received one of the two drugs. There was no significant difference in ORR, the median PFS, or OS (NK105 group: 41.9%, 9.1, and 27.5 months, respectively; PTX group: 45.9%, 7.8, and 32.4 months, respectively). Neutropenia occurred more frequently in the NK105 group, but most patients did not require granulocyte-colony stimulating factor or dose-reduction. The median time to onset of peripheral sensory neuropathy (PSN) in the NK105 group was significantly longer than that in the PTX group (p=0.001), and PSN (≥ grade 3) was not observed in the NK105 group. Conclusion: Weekly NK105 administration was well-tolerated. Efficacy was similar in both groups. The PSN profile was better in the NK105 group.

Trastuzumab Deruxtecan in HER2-Positive Metastatic Breast Cancer Patients with Brain Metastases: A DESTINY-Breast01 Subgroup Analysis.

DESTINY-Breast01 (NCT03248492) evaluated trastuzumab deruxtecan (T-DXd; DS-8201) in patients with heavily pretreated HER2-positive metastatic breast cancer (mBC). We present a subgroup of 24 patients with a history of treated brain metastases (BM), a population with limited treatment options. In patients with BMs, the confirmed objective response rate (cORR) was 58.3% [95% confidence interval (CI), 36.6%-77.9%], and the median progression-free survival (mPFS) was 18.1 months (95% CI, 6.7-18.1 months). In patients without BMs (n = 160), cORR was 61.3% and mPFS was 16.4 months. Eight patients (47.1%) experienced a best overall intracranial response of partial response or complete response. Seven patients (41.2%) had a best percentage change in brain lesion diameter from baseline consistent with stable disease. Two patients (8.3%) with BMs and two (1.3%) without BMs experienced progression in the brain. The safety profile of T-DXd was consistent with previous studies. The durable clinical activity of T-DXd in this population warrants further investigation. SIGNIFICANCE: Advances in treating HER2-positive metastatic breast cancer have greatly improved patient outcomes, but intracranial progression remains an important risk for which few therapeutic options are currently available. T-DXd demonstrated durable efficacy in patients with stable, treated BMs. This article is highlighted in the In This Issue feature, p. 2711.

Efficacy and safety of talazoparib in Japanese patients with germline BRCA-mutated locally advanced or metastatic breast cancer: results of the phase 1 dose-expansion study.

BACKGROUND: Talazoparib, a poly(ADP-ribose) polymerase enzyme inhibitor, is approved for the treatment of patients with germline BRCA1/2 (gBRCA1/2)-mutated HER2-negative advanced breast cancer. This two-part study, a recently published dose-escalation part followed by the dose-expansion part reported here, evaluated the efficacy and safety of talazoparib in Japanese patients with gBRCA1/2-mutated advanced breast cancer. METHODS: In this open-label, multicenter phase 1 study (NCT03343054), the primary endpoint of the dose-expansion part was confirmed objective response rate (ORR), determined by investigator assessment (RECIST 1.1). Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety, and pharmacokinetics. Patients received the recommended phase 2 dose (1 mg/day; 0.75 mg/day moderate renal impairment). RESULTS: Nineteen Japanese patients with gBRCA1/2-mutated locally advanced or metastatic breast cancer were enrolled. Confirmed ORR was 57.9% (11/19; 90% confidence interval [CI] 36.8-77.0). Stable disease was observed in 36.8% (7/19) of patients. Per investigator assessment, median PFS was 7.2 months (95% CI 4.1-not estimable) and 12-month OS rate was 84.7% (90% CI 57.5-95.1). Median OS was not reached; 17/19 patients were alive and censored at 12 months. All patients experienced treatment-related adverse events (AEs); the majority were hematologic. The most common treatment-related AE was anemia (68.4%; [13/19]). Grade 3/4 treatment-related AEs were observed in 52.6% (10/19) of patients. During the safety period, there were no grade 5 treatment-emergent AEs, treatment-related serious AEs, or deaths. CONCLUSIONS: In Japanese patients with gBRCA mutations and locally advanced or metastatic breast cancer, talazoparib monotherapy was generally well tolerated and resulted in clinically meaningful ORRs. GOV IDENTIFIER: NCT03343054.

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.).

Subgroup analysis of Japanese patients in a phase III randomized, controlled study of neoadjuvant atezolizumab or placebo, combined with nab-paclitaxel and anthracycline-based chemotherapy in early triple-negative breast cancer (IMpassion031).

BACKGROUND: In the global phase III IMpassion031 study, neoadjuvant atezolizumab plus nab-paclitaxel/anthracycline-based chemotherapy improved pathological complete response in patients with early stage triple-negative breast cancer. Here, we report primary analysis results from a subgroup of Japanese patients. METHODS: Patients with histologically documented, previously untreated, stage cT2-cT4, cN0-cN3, cM0 triple-negative breast cancer were randomized 1:1 to receive intravenous atezolizumab 840 mg or placebo every 2 weeks in combination with chemotherapy consisting of nab-paclitaxel intravenous 125 mg/m2 once a week, followed by doxorubicin intravenous 60 mg/m2 and cyclophosphamide intravenous 600 mg/m2 every 2 weeks. Patients then underwent surgery. Pathological complete response (ypT0/is ypN0) in the intention-to-treat and PD-L1-positive (≥1% PD-L1-expressing tumor-infiltrating immune cells) populations were co-primary endpoints. RESULTS: This subanalysis (data cutoff: 3 April 2020) included 36 patients from Japan (intention-to-treat; atezolizumab arm, n = 17; placebo arm, n = 19). Pathological complete response occurred in 41% (n = 7; 95% confidence interval, 18-67) of patients in the atezolizumab arm and 37% (n = 7; 95% confidence interval, 16-62) in the placebo arm. In the PD-L1-positive population, pathological complete response occurred in 50% (n = 5; 95% confidence interval, 19-81) of patients in the atezolizumab arm and 45% (n = 5; 95% confidence interval, 17-77) in the placebo arm. Treatment-related grade 3-4 adverse events occurred in 71% and 68% of patients in the respective arms. CONCLUSION: Atezolizumab added to neoadjuvant chemotherapy numerically improved pathological complete response versus placebo in this small exploratory analysis of Japanese patients with early stage triple-negative breast cancer, a trend directionally consistent with the global study results. No new safety signals were identified.

Efficacy of Clinical Guidelines in Identifying All Japanese Patients with Hereditary Breast and Ovarian Cancer.

Clinical screening using the National Comprehensive Cancer Network (NCCN) testing criteria may fail to identify all patients with hereditary breast and ovarian cancers. Thus, this study aimed to evaluate the strategy of expanding target patients for genetic testing among Japanese patients. We reviewed the medical records of 91 breast cancer patients who underwent genetic testing. Among 91 patients, eight were diagnosed with pathogenic or likely pathogenic variants: BRCA1 (n = 4) and BRCA2 (n = 4). Among 50 patients meeting the testing criteria of the guidelines, 6 (12%) were diagnosed with pathogenic or likely pathogenic variants. The sensitivity and specificity of screening using the testing criteria were 75% and 47%, respectively. Expanding the NCCN criteria to include all women diagnosed with breast cancer aged ≤65 years achieved 88% sensitivity but 8% specificity. The expansion of the NCCN criteria could benefit Japanese patients; however, larger studies are necessary to change clinical practice.

Development of an intraoperative breast cancer margin assessment method using quantitative fluorescence measurements.

Breast-conserving surgery has become the preferred treatment method for breast cancer. Surgical margin assessment is performed during surgery, as it can reduce local recurrence in the preserved breast. Development of reliable and lower-cost ex vivo cancer detection methods would offer several benefits for patient care. Here, a practical and quantitative evaluation method for the ex vivo fluorescent diagnosis of breast lesions was developed and confirmed through a three-step clinical study. Gamma-glutamyl-hydroxymethyl rhodamine green (gGlu-HMRG) has been reported to generate fluorescence in breast lesions. Using this probe, we constructed a reliable and reproducible procedure for the quantitative evaluation of fluorescence levels. We evaluated the reliability of the method by considering reproducibility, temperature sensitivity, and the effects of other clinicopathological factors. The results suggest that the fluorescence increase of gGlu-HMRG is a good indicator of the malignancy of breast lesions. However, the distributions overlapped. A 5 min reaction with this probe could be used to distinguish at least part of the normal breast tissue. This method did not affect the final pathological examination. In summary, our results indicate that the methods developed in this study may serve as a feasible intraoperative negative-margin assessment tool during breast-conserving surgery.

Factors associated with overall survival after recurrence in patients with ER-positive/HER2-negative postmenopausal breast cancer: an ad hoc analysis of the JBCRG-C06 Safari study.

BACKGROUND: The Safari study (UMIN000015168) was a retrospective, multicenter study in which 1072 consecutive cases of estrogen receptor-positive advanced breast cancer treated using 500 mg fulvestrant were registered. We previously reported the relationship between the patient factors and overall survival after the diagnosis using the same cases and the same factors for the analysis of time to treatment failure in patients with estrogen receptor-positive advanced breast cancer. The current study is an ad hoc analysis that focused on the relationship between the patient factors and overall survival after recurrence by adding factors generally associated with overall survival after recurrence. METHODS: The overall survival after recurrence in patients with estrogen receptor-positive human epidermal growth factor receptor 2 negative recurrent breast cancer was analyzed via univariate and multivariate analyses with a Cox proportional hazards model. RESULTS: A total of 598 cases were used for the analysis of overall survival after recurrence. Multivariate analysis revealed that favorable overall survival (median, 6.4 years) was significantly correlated with long time from recurrence to fulvestrant use (≥3 years), low nuclear or histological grade (G3 vs. G1), long time to treatment failure of initial palliative endocrine therapy (≥12 months) and long time to initial palliative chemotherapy (≥2 years). CONCLUSION: The results of this study indicate that sequential endocrine monotherapy may be a useful treatment option for patients with estrogen receptor-positive/human epidermal growth factor receptor 2 negative recurrent breast cancer who have been successfully treated with initial long-term palliative endocrine therapy.

Evaluation of a novel medical device for pegfilgrastim administration.

Pegfilgrastim, a pegylated form of granulocyte colony-stimulating factor, has reduced the risk of developing febrile neutropenia, which is associated with an increase in severe infection and prolonged hospitalization. However, pegfilgrastim administration requires that patients visit hospital following cancer chemotherapy, thus imposing a burden on patients and those around them. An on-body injector (OBI), which automatically administers pegfilgrastim about 27 hours after chemotherapy, was used in this study. The OBI, which consists of a main pump unit and infusion set, is a drug delivery device designed to be attached to the patient's body, with a timer-controlled dosing function. This study was conducted in breast cancer patients to evaluate the safety of pegfilgrastim administered subcutaneously via the OBI. The study period consisted of screening and treatment observation periods involving four cycles of neoadjuvant or adjuvant chemotherapy with docetaxel plus cyclophosphamide. One 3.6-mg pegfilgrastim dose was administered subcutaneously via OBI during each cycle of chemotherapy. The study enrolled 35 patients, and no serious adverse events or febrile neutropenia occurred. Administration of pegfilgrastim was successfully completed at all times when the OBI was attached to the patient, and no safety concerns associated with OBI function arose. For outpatients requiring pegfilgrastim following cancer chemotherapy, the use of an OBI was considered to be a safe option to reduce the need for outpatient visits that restrict their activities of daily living.

Machine learning-based image analysis for accelerating the diagnosis of complicated preneoplastic and neoplastic ductal lesions in breast biopsy tissues.

PURPOSE: Diagnosis of breast preneoplastic and neoplastic lesions is difficult due to their similar morphology in breast biopsy specimens. To diagnose these lesions, pathologists perform immunohistochemical analysis and consult with expert breast pathologists. These additional examinations are time-consuming and expensive. Artificial intelligence (AI)-based image analysis has recently improved, and may help in ordinal pathological diagnosis. Here, we showed the significance of machine learning-based image analysis of breast preneoplastic and neoplastic lesions for facilitating high-throughput diagnosis. METHODS: Images were obtained from normal mammary glands, hyperplastic lesions, preneoplastic lesions and neoplastic lesions, such as usual ductal hyperplasia (UDH), columnar cell lesion (CCL), ductal carcinoma in situ (DCIS), and DCIS with comedo necrosis (comedo DCIS) in breast biopsy specimens. The original enhanced convoluted neural network (CNN) system was used for analyzing the pathological images. RESULTS: The AI-based image analysis provided the following area under the curve values (AUC): normal lesion versus DCIS, 0.9902; DCIS versus comedo DCIS, 0.9942; normal lesion versus CCL, 0.9786; and UDH versus DCIS, 1.000. Multiple comparison analysis showed precision and recall scores similar to those of single comparison analysis. Based on the gradient-weighted class activation mapping (Grad-CAM) used to visualize the important regions reflecting the result of CNN analysis, the ratio of stromal tissue in the whole weighted area was significantly higher in UDH and CCL than that in DCIS. CONCLUSIONS: These analyses may provide a more accurate and rapid pathological diagnosis of patients. Moreover, Grad-CAM identifies uncharted important histological characteristics for newer pathological findings and targets of research for understanding diseases.