Cry1Ac Protoxin Confers Antitumor Adjuvant Effect in a Triple-Negative Breast Cancer Mouse Model by Improving Tumor Immunity

The Cry1Ac protoxin from Bacillus thuringiensis is a systemic and mucosal adjuvant, able to confer protective immunity in different infection murine models and induce both Th1 and TCD8+ cytotoxic lymphocyte responses, which are required to induce antitumor immunity. The Cry1Ac toxin, despite having not being characterized as an adjuvant, has also proved to be immunogenic and able to activate macrophages. Here, we investigated the potential antitumor adjuvant effect conferred by the Cry1Ac protoxin and Cry1Ac toxin in a triple negative breast cancer (TNBC) murine model. First, we evaluated the ability of Cry1Ac proteins to improve dendritic cell (DC) activation and cellular response through intraperitoneal (i.p.) coadministration with the 4T1 cellular lysate. Mice coadministered with the Cry1Ac protoxin showed an increase in the number and activation of CD11c+MHCII- and CD11c+MHCII+low in the peritoneal cavity and an increase in DC activation (CD11c+MHCII+) in the spleen. Cry1Ac protoxin increased the proliferation of TCD4+ and TCD8+ lymphocytes in the spleen and mesenteric lymph nodes (MLN), while the Cry1Ac toxin only increased the proliferation of TCD4+ and TCD8+ in the MLN. Remarkably, when tested in the in vivo TNBC mouse model, prophylactic immunizations with 4T1 lysates plus the Cry1Ac protoxin protected mice from developing tumors. The antitumor effect conferred by the Cry1Ac protoxin also increased specific cytotoxic T cell responses, and prevented the typical tumor-related decrease of T cells (TCD3+ and TCD4+) as well the increase of myeloid-derived suppressor cells (MDSC) in spleen. Also in the tumor microenvironment of mice coadministered twice with Cry1Ac protoxin immunological improvements were found such as reductions in immunosupressive populations (T regulatory lymphocytes and MDSC) along with increases in macrophages upregulating CD86. These results show a differential antitumor adjuvant capability of Cry1Ac proteins, highlighting the ability of Cry1Ac protoxin to enhance local and systemic tumor immunity in TNBC. Finally, using a therapeutic approach, we evaluated the coadministration of Cry1Ac protoxin with doxorubicin. A significant reduction in tumor volume and lung metastasis was found, with increased intratumoral levels of tumor necrosis factor-α and IL-6 with respect to the vehicle group, further supporting its antitumor applicability.

Clinicopathological Features Related to the Efficacy of CDK4/6 Inhibitor-Based Treatments in Metastatic Breast Cancer

Background: Resistance to endocrine therapy has been a major obstacle in the management of hormone receptor (HR)-positive metastatic breast cancer (MBC). Meanwhile, a number of treatments are available to such patients, and physicians often encounter difficulties in choosing the most appropriate treatments for individual patients. The combination of CDK 4/6 inhibitors (CDKi) and endocrine therapy has now become a standard treatment for HR-positive and human epidermal growth factor receptor 2 (HER2)-negative MBC. However, no predictive markers for CDKi-based treatments have been established. Considering their side effects and the financial burden on patients, identifying such markers is crucial. Methods: Clinicopathological features of 107 patients with HR-positive HER2-negative MBC, who received CDKi-based treatments at our institution were retrospectively investigated. HR status in distant metastatic lesions and immunocompetent cells in peripheral blood were also studied. Results: Progression-free survival (PFS) was significantly shorter in patients whose primary tumour was high grade ( P = 0.016) or high neutrophil-to-lymphocyte ratio (NLR) at baseline ( P = 0.017). Meanwhile, there were no differences in other factors, such as expression levels of hormone receptors. Patients whose metastatic lesions were of low tumour grade or high Ki67 labelling index had longer PFS, and such trends were more obvious than primary lesions. Conclusion: Our data indicate that tumour grade in primary lesion and NLR are potential predictive factors for CDKi-based treatments. Moreover, pathological assessment of metastatic lesions might also be useful.

An Extract of Taro (Colocasia esculenta) Mediates Potent Inhibitory Actions on Metastatic and Cancer Stem Cells by Tumor Cell-Autonomous and Immune-Dependent Mechanisms

The taro plant, Colocasia esculenta, contains bioactive proteins with potential as cancer therapeutics. Several groups have reported anti-cancer activity in vitro and in vivo of taro-derived extracts (TEs). We reported that TE inhibits metastasis in a syngeneic murine model of Triple-Negative Breast Cancer (TNBC). Purpose: We sought to confirm our earlier studies in additional models and to identify novel mechanisms by which efficacy is achieved. Methods: We employed a panel of murine and human breast and ovarian cancer cell lines to determine the effect of TE on tumor cell viability, migration, and the ability to support cancer stem cells. Two syngeneic models of TNBC were employed to confirm our earlier report that TE potently inhibits metastasis. Cancer stem cell assays were employed to determine the ability of TE to inhibit tumorsphere-forming ability and to inhibit aldehyde dehydrogenase activity. To determine if host immunity contributes to the mechanism of metastasis inhibition, efficacy was assessed in immune-compromised mice. Results: We demonstrate that viability of some, but not all cell lines is inhibited by TE. Likewise, tumor cell migration is inhibited by TE. Using 2 immune competent, syngeneic models of TNBC, we confirm our earlier findings that tumor metastasis is potently inhibited by TE. We also demonstrate, for the first time, that TE directly inhibits breast cancer stem cells. Administration of TE to mice elicits expansion of several spleen cell populations but it was not known if host immune cells contribute to the mechanism by which TE inhibits tumor cell dissemination. In novel findings, we now show that the ability of TE to inhibit metastasis relies on immune T-cell-dependent, but not B cell or Natural Killer (NK)-cell-dependent mechanisms. Thus, both tumor cell-autonomous and host immune factors contribute to the mechanisms underlying TE efficacy. Our long-term goal is to evaluate TE efficacy in clinical trials. Most of our past studies as well as many of the results reported in this report were carried out using an isolation protocol described earlier (TE). In preparation for a near future clinical trial, we have now developed a strategy to isolate an enriched taro fraction, TE-method 2, (TE-M2) as well as a more purified subfraction (TE-M2F1) which can be scaled up under Good Manufacturing Practice (GMP) conditions for evaluation in human subjects. We demonstrate that TE-M2 and TE-M2F1 retain the anti-metastatic properties of TE. Conclusions: These studies provide further support for the continued examination of biologically active components of Colocasia esculenta as potential new therapeutic entities and identify a method to isolate sufficient quantities under GMP conditions to conduct early phase clinical studies.

Male Breast Cancer—Immunohistochemical Patterns and Clinical Relevance of FASN, ATF3, and Collagen IV

Background: Male breast carcinoma (male BC) is an uncommon neoplasia without individualized strategies for diagnosis and therapeutics. Low overall survival (OS) rates have been reported, mostly associated with patients’ advanced stage and older age. Intratumoral heterogeneity versus homogeneity of malignant epithelial cells seems to be an important factor to consider for the development of combination therapies with curative intention. Objective: In this preliminary study, we aim to provide valuable insight into the distinct clinicopathologic features of male BC. Material and methods: In a series of 40 male BC patients, we evaluated by immunohistochemistry androgen receptor; activating transcription factor 3 (ATF3); p16; cyclin D1; fatty acid synthase (FASN); fatty acid transport protein 1 (FATP1); β1, β3, β4, and β6 integrins; collagen I and collagen IV; and their interactions. Kaplan-Meier survival curves and log-rank tests were assessed for statistical analysis. Results: Homogeneous epithelial staining of p16, ATF3, β6 integrin, FASN, and FATP1 was found to be significantly intercorrelated, and associated with high Ki67. These markers also stained tumor stromal fibroblasts. The prognostic analysis showed statistically significant associations of FASN with disease-free survival (DFS) and OS, as well as of ATF3 with OS and collagen IV with DFS. Conclusions: This study highlights, as a novel finding, the relevance of FASN, ATF3, and collagen IV immunophenotypes, which may have innovative application in the clinical management of male BC.

Intravascular Large B Cell Lymphoma of the Breast: A Rare Entity

Intravascular large B-cell lymphoma (IVLBCL) is a rare and high-grade disease of neoplastic lymphoid cells within the vascular lumina of small- to medium-sized vessels. The disease carries a grim prognosis despite robust treatment protocols. We discuss the case of a 58-year-old female who presented with mammographic screening abnormality which led to more investigations and ultimately to this diagnosis. The patient had no prior history of a lymphoma or in situ and invasive carcinoma of the breast. To our knowledge, IVLBCL of the breast is a very rare and an unusual location for this type of a lymphoma and so far, only five reported cases. Through our case report, we not only discuss the case but also review literature on this rare entity.

Association of Sociodemographic Factors, Breast Cancer Fear, and Perceived Self-Efficacy With Breast Cancer Screening Behaviors Among Middle-Aged Nigerian Women

Introduction: Breast cancer (BC) is a major public health problem among women. However, BC screening uptake is abysmally low among Nigerian women. This study evaluated the association of BC fear and perceived self-efficacy with BC screening (clinical breast exam [CBE] and mammography) among middle-aged Nigerian women. Methods: A community-based cross-sectional study was conducted among middle-aged women in Enugu State, southeast Nigeria. The data were collected between September 2019 and February 2020. The BC screening uptake, fear, and self-efficacy were assessed using the validated Breast Cancer Screening Questionnaire (BCSQ), Champion Breast Cancer Fear Scale (CBCFS), and Champion’s Mammography Self-Efficacy Scale (CMSES). Data were analyzed using frequencies and percentages, chi-square test, and univariate analysis of variance. Bivariate and multivariable logistic regression models were used to examine independent associations between selected sociodemographic factors, cancer fear, perceived self-efficacy, and BC screening. Results: The mean age of the participants was 55.3 years (SD: 5.75). More than half of the women (51%) reported having a BC screening in the past 12 months. However, only 12.5% and 16.9% reported having a CBE or mammogram in the past 12 months. The prevalence of a high, moderate, and low level of fear was 68%, 22.3%, and 9.8%, respectively. The prevalence of a high, moderate, and low self-efficacy level was 50.6%, 37.5%, and 12.0%, respectively. The multivariable logistics regression analysis showed that women aged 50-59 years and 60-64 years were 3.5 times (adjusted odds ratio [AOR] = 3.50, 95% confidence interval [CI]: 2.07-5.89, P < .0001), and 5.92 times (AOR = 5.92 95% CI: 2.63-13.35, P < .0001), respectively, more likely to perform mammogram than those aged 40-49 years. Women with a high level of self-efficacy were 2.68 times (AOR = 2.68, 95% CI: 1.15-6.26, P < .0001) more likely to use mammographic screening than those with low self-efficacy. Although not statistically significant, women with a moderate level of BC fear were 0.56 times less likely to use mammogram than women with a low level of BC fear. Conclusion: A low proportion of women underwent CBE or mammography. Women had a high level of BC fear and a moderate level of self-efficacy for BC screening. The findings emphasize the need for health educational and psychosocial interventions that improve self-efficacy and promote regular BC screening among middle-aged women.

Clinicopathological Examination of Metaplastic Spindle Cell Carcinoma of the Breast: Case Series

Background: Spindle cell carcinoma (SpCC) of the breast is a rare histological type, a subtype of metaplastic carcinoma characterized by atypical spindle cell and epithelial carcinoma. The proportions of the spindle cell and epithelial components vary among tumours. Due to its rarity, biological characteristics of this disease have been poorly studied. Methods: In total, 10 patients with SpCC were surgically treated at our institution from January 2007 to December 2018. We retrospectively investigated these SpCC cases, focusing on the differences between spindle cell and epithelial components. Microsatellite status was also examined. Results: Nine cases were triple-negative breast cancer (TNBC). The rates of high tumour grade were 70% in spindle cell components and 56% in epithelial components ( P = .65), while the mean Ki67 labelling index were 63% and 58%, respectively ( P = .71). Mean programmed death ligand 1 (PD-L1) expression in these components was 11% and 1%, respectively ( P = .20). All 10 tumours were microsatellite stable. Patient outcomes of triple-negative SpCC did not differ from those of propensity-matched patients with conventional TNBC. Conclusions: Spindle cell components showed higher values in factors examined, although there was no statistically significant difference. Our data reveal that these 2 components of SpCC may be of different biological nature.

Breast Cancer in Togolese Women: Imaging and Clinicopathological Findings

Background: Breast cancer is the most common cancer in women, and its incidence and mortality rates are expected to increase significantly over the next few years, particularly in developing countries. The aim of this study was to describe the epidemiological, clinical, radiological, histopathological, and prognostic aspects of breast cancer in Togo. Materials and methods: We retrospectively analyzed at our Department of Pathology of Lomé all cases of breast cancer in women confirmed by histology over a period of 20 years (2000-2019). Results: We collected 804 cases of breast cancer in women. The median age was 46.7 years (range, 12-86 years). Patients aged <40 years represented 48.38% of cases, and the left breast was more affected (51.24%). Most women were sexually active (71.52%) and resided in urban areas (66.29%). Carcinomas represented the predominant histological group (796 cases, 99.00%) with a predominance of invasive nonspecific type carcinoma (92.34%). These cancers were diagnosed at late stage III using Nottingham grading (55.10%). The TNM classification showed a predominance of grades T2NxMx (72.45%) and T4N1Mx (17.76%). The luminal B profile (40.85%) was found mostly, and the mutation of BRCA2 and BRCA1 genes was found in 2.61% of cases. Mastectomy was performed in 7.59%, radiotherapy in 3.61%, and chemotherapy in 18.66%. Conclusion: Breast cancer is a frequent pathology in Togolese women, predominant in young adults, often diagnosed at a late stage with limited possibilities of treatment. The establishment of early care programs is essential.

The Prognostic Value of Estrogen Receptor β Isoform With Correlation of Estrogen Receptor α Among Sudanese Breast Cancer Patients

Two estrogen receptor isoforms (ERα and ERβ) have been characterized with variable and sometimes contrasting responses to estrogens, partially explained by different receptor signaling pathways in estrogen-sensitive tissues. This is a retrospective, descriptive, cross-sectional study, aiming to evaluate the expression pattern of ERβ, employing immunohistochemical techniques using specific monoclonal antibody for ERβ, to correlate its expression with that of ERα in a Sudanese population. Two-hundred and fifty formalin-fixed paraffin-wax-embedded breast tissue blocks were used in this study. Of these, 200 were taken from breast cancer patients ascertained as study cases, and the remaining 50 were noninvolved surgical margin considered as normal breast tissue. Receptor expression was demonstrated using immunohistochemical techniques. The immune expression of ERβ was detected in 57.5% of breast cancers. It was differentially expressed in breast tissues encompassing normal, noninvasive, as well as invasive carcinoma ( P = .02). There was no evidence of a significant relationship between ERβ and ERα expression. Among the ERα-negative tumor, 60.4% expressed ERβ. The expression of ERβ among this subgroup was significantly associated with good clinicopathological parameters such as negative Her2/neu, lower grade, and negative lymph node metastasis ( P = .002). This study concludes that ERβ was commonly expressed among Sudanese patients with breast cancer, either co-expressed with ERα or expressed alone. In the ERα-negative subgroup, it was associated with better tumor outcomes suggesting ERβ should be included in the diagnostic protocol as an independent marker for favorable prognosis.

Emerging Therapeutic Drugs in Metastatic Triple-Negative Breast Cancer

Metastatic triple-negative breast cancer (TNBC) is a heterogeneous disease with a poor prognosis and currently with few treatment options. Treatment of these patients is highly based on systemic chemotherapy. Some targeted drugs were recently approved for these patients: two poly(ADP-ribose) polymerase inhibitors in patients with germline BRCA1/2 mutations (olaparib and talazoparib), immune checkpoint inhibitors in association with chemotherapy if programmed death-ligand 1 positive (atezolizumab plus nabpaclitaxel and pembrolizumab plus chemotherapy [nabpaclitaxel, paclitaxel, and carboplatin plus gemcitabine]), and an antibody-drug conjugate sacituzumab-govitecan in heavily pretreated patients (at least 2 previous lines for the metastatic setting). Combinations using these and other targeted treatment options are under investigation in early and late clinical trials, and we will probably have some practice-changing results in the new future. Other targeted drugs explored in phase II and phase III clinical trials are PI3K/AKT pathway inhibitors and androgen receptor antagonists in patients with alterations in these signaling pathways. The definition of molecular subtypes has been essential for the development of these treatment strategies. Soon, the treatment of metastatic TNBC could be based on personalized medicine using molecular testing for targeted drugs instead of only systemic chemotherapy. The authors present a review of emerging treatment options in metastatic TNBC, focusing on targeted drugs, including the recent data published in 2020.