High Expression of Urokinase-Type Plasminogen Activator Is Associated with Lymph Node Metastasis of Invasive Ductal Carcinoma of the Breast

Breast cancer vaccines: New insights into immunomodulatory and nano-therapeutic approaches

Breast cancer (BC) is known to be a highly heterogeneous disease that is clinically subdivided into four primary molecular subtypes, each having distinct morphology and clinical implications. These subtypes are principally defined by hormone receptors and other proteins involved (or not involved) in BC development. BC therapeutic vaccines [including peptide-based vaccines, protein-based vaccines, nucleic acid-based vaccines (DNA/RNA vaccines), bacterial/viral-based vaccines, and different immune cell-based vaccines] have emerged as an appealing class of cancer immunotherapeutics when used alone or combined with other immunotherapies. Employing the immune system to eliminate BC cells is a novel therapeutic modality. The benefit of active immunotherapies is that they develop protection against neoplastic tissue and readjust the immune system to an anti-tumor monitoring state. Such immunovaccines have not yet shown effectiveness for BC treatment in clinical trials. In recent years, nanomedicines have opened new windows to increase the effectiveness of vaccinations to treat BC. In this context, some nanoplatforms have been designed to efficiently deliver molecular, cellular, or subcellular vaccines to BC cells, increasing the efficacy and persistence of anti-tumor immunity while minimizing undesirable side effects. Immunostimulatory nano-adjuvants, liposomal-based vaccines, polymeric vaccines, virus-like particles, lipid/calcium/phosphate nanoparticles, chitosan-derived nanostructures, porous silicon microparticles, and selenium nanoparticles are among the newly designed nanostructures that have been used to facilitate antigen internalization and presentation by antigen-presenting cells, increase antigen stability, enhance vaccine antigenicity and remedial effectivity, promote antigen escape from the endosome, improve cytotoxic T lymphocyte responses, and produce humoral immune responses in BC cells. Here, we summarized the existing subtypes of BC and shed light on immunomodulatory and nano-therapeutic strategies for BC vaccination. Finally, we reviewed ongoing clinical trials on BC vaccination and highlighted near-term opportunities for moving forward.

Current immunoassay methods and their applications to clinically used biomarkers of breast cancer

Breast cancer is the leading cause of cancer-related mortality worldwide, with a higher incidence in developed countries. The biomarkers for breast cancer such as estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, CA (cancer antigen) 15-3, CA 27.29, and carcinoembryonic antigen have been recommended for use in the laboratory based on the guidelines of American and European societies. Immunoassays have been frequently and consistently used to detect these clinically established biomarkers of breast cancer. Despite the higher accessibility of serum biomarkers, including CA 15-3, CA 27.29, and CEA, compared to tissue markers, variations in immunoassays affect their standardization and clinical utility. When reviewing the immunoassays used to detect these serum markers, we found that the most frequently used immunoassay was enzyme-linked immunosorbent assay, followed by electrochemiluminescent immunoassay, and then chemiluminescence immunoassay for CA 15-3 and CEA. Meanwhile, the chemiluminescence immunoassay was the most common technique for CA27.29. The electrochemiluminescent immunoassay and monoclonal fluorometric assay have become the preferred methods in 2010-2019 compared to 2000-2009. Analytical and clinical performance factors such as sensitivity, specificity, detection limit, hazard risk to laboratory personnel, speed, and economic feasibility influenced these changes in user preference. When using the immunoassays, there should be a comprehensive understanding of the principles, advantages, vulnerability, and precautions for interpretation. In the future, a combination of immunological biomarkers and genetic platforms will benefit patients with breast cancer by facilitating prognosis prediction and guiding therapeutic intervention.

The prognostic relevance of urokinase-type plasminogen activator (uPA) in the blood of patients with metastatic breast cancer

In breast cancer (BC), elevated levels of urokinase-type plasminogen activator (uPA) in tumor tissue have been confirmed as a strong prognostic factor in level-of-evidence-1 studies. The aim of the present study was to evaluate the clinical relevance of uPA levels in serum of metastatic BC patients and to compare uPA with other blood-based biomarkers. 252 patients were enrolled in this prospective, multicentre study. Blood samples were collected before begin of first-line or later-line systemic treatment. Serum uPA was quantified by a commercially available ELISA. Circulating tumor cells (CTCs) were detected using CellSearch; other biomarkers (EGFR, VEGF, HER2, RAS p21, TIMP1, CAIX) by ELISA. Using the ROC analysis, the optimal cut-off value (determined by the Youden index) of serum uPA was 2.52 ng/ml. Using this value, 26% of patients had elevated uPA levels. Patients with visceral metastasis and more than one metastatic site were significantly more likely to present with elevated uPA levels. CTC status, serum HER2, RAS p21, CAIX, TIMP1 and VEGF correlated significantly with uPA levels. Elevated uPA levels predicted shorter overall and progression-free survival in univariate analysis (median OS: 7.5 months [95%-CI 4.5–10.5 months] vs. not reached, p < 0.001; PFS: 4.8 [95%-CI: 3.1–6.5] vs. 9.1 [7.4–10.8] months, p < 0.001). In multivariate analysis, elevated uPA, presence of ≥5 CTCs, elevated RAS p21, higher grading and higher line of therapy were independent predictors of shorter OS, while elevated CTC counts, higher line of therapy and negative estrogen receptor status were independent predictors of shorter PFS. In conclusion, elevated uPA levels independently predict reduced overall survival and improved prognostication in patients with known CTC status. Whether high serum uPA might identify patients most likely to benefit from therapies targeting uPA, remains to be evaluated in future trials.

Association of uPA and PAI-1 tumor levels and 4G/5G variants of PAI-1 gene with disease outcome in luminal HER2-negative node-negative breast cancer patients treated with adjuvant endocrine therapy

BACKGROUND

The aim of this study was to evaluate the prognostic potential of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) tumor tissue levels and examine the association between these biomarkers and classical prognostic factors in early node-negative luminal breast cancer patients. The clinical value of 4G/5G variants of PAI-1 gene was evaluated.

PATIENTS AND METHODS

This study involved 81 node-negative, estrogen receptor-positive and/or progesterone receptor-positive and human epidermal growth factor receptor 2-negative operable breast cancer patients who underwent radical surgical resection and received adjuvant endocrine therapy. Determination of uPA and PAI-1 concentrations in the breast cancer tissue extracts was performed using FEMTELLE® uPA/PAI-1 ELISA. An insertion (5G)/deletion (4G) polymorphism at position - 675 of the PAI-1 gene was detected by PCR-RFLP analysis.

RESULTS

Our research showed that patients with uPA tumor tissue levels higher than 3 ng/mg of protein had significantly reduced disease-free survival (DFS) and overall survival (OS) when compared to patients with uPA tumor tissue levels lower or equal to 3 ng/mg of protein. Patients with PAI-1 tumor tissue levels higher than 14 ng/mg of protein had significantly decreased OS in comparison with patients with PAI-1 tumor tissue levels lower or equal to 14 ng/mg of protein. ROC analysis confirmed the uPA and PAI-1 discriminative potential for the presence/absence of relevant events in these patients and resulted in higher cut-off values (5.65 ng/mg of protein for uPA and 27.10 ng/mg of protein for PAI-1) than standard reference cut-off values for both biomarkers. The prognostic importance of uPA and PAI-1 ROC cut-off values was confirmed by the impact of uPA higher than 5.65 ng/mg of protein and PAI-1 higher than 27.10 ng/mg of protein on poorer DFS, OS and event-free survival (EFS). We observed that patients with dominant allele in PAI-1 genotype (heterozygote and dominant homozygote, - 675 4G/5G and - 675 5G/5G) had significantly increased DFS, OS and EFS when compared with patients with recessive homozygote genotype (- 675 4G/4G).

CONCLUSION

Our study indicates that uPA and PAI-1 tumor tissue levels and 4G/5G variants of PAI-1 gene might be of prognostic significance in early node-negative luminal HER2-negative breast cancer patients treated with adjuvant endocrine therapy.