Breast Cancer: Current Research
Open Access

Breast cancer; Immunotherapy; Breast cancer stem cells (BCSCs); Antigens; CD44; ALDH1; EpCAM; Tumor heterogeneity

Introduction

Breast cancer continues to be a formidable global health challenge, affecting millions of individuals and their families worldwide. Despite significant progress in understanding the disease’s molecular underpinnings and advances in treatment modalities, breast cancer remains a leading cause of cancer-related morbidity and mortality among women. Its heterogeneous nature, coupled with the persistence of treatment-resistant cells within tumors, poses a particularly daunting challenge for clinicians and researchers alike. Over the past few decades, the field of cancer immunotherapy has garnered increasing attention and enthusiasm. Immunotherapies harness the innate power of the immune system to recognize and eliminate cancer cells, offering a promising alternative or complement to conventional treatments such as surgery, chemotherapy, and radiation therapy. Within this overarching approach, one emerging and compelling strategy focuses on the immunotherapeutic targeting of breast cancer stem cell (BCSC) antigens. Breast cancer stem cells represent a small yet critical subpopulation of cells within breast tumors that are believed to be responsible for tumor initiation, progression, and recurrence. These cells exhibit unique characteristics, including self-renewal capacity and the ability to differentiate into diverse cell types within the tumor. BCSCs are notorious for their resistance to traditional treatments, making them a primary driver of treatment failure and disease relapse. The central premise of this thesis is to explore the concept of immunotherapeutic targeting of BCSC antigens as a novel and promising strategy to address the complexities of breast cancer. Through a comprehensive review of the current state of knowledge, recent developments, challenges, and future directions in this dynamic field, we aim to shed light on the potential of BCSC-specific immunotherapies to transform the landscape of breast cancer treatment. In the following chapters, we will delve into specific BCSC-specific antigens, such as CD44, ALDH1, and EpCAM,evaluating their roles in BCSC biology and their potential as targets for immunotherapy. We will also examine the challenges inherent in BCSC-specific immunotherapy, including tumor heterogeneity, resistance mechanisms, and the intricacies of clinical translation. Strategies for overcoming these challenges, such as personalized medicine approaches and combination therapies, will be discussed. As we progress through this thesis, it is our hope that readers will gain a deeper understanding of the promise and limitations of BCSC-specific immunotherapies and recognize the significant implications of this research for the broader field of cancer immunotherapy. Ultimately, our collective efforts in advancing BCSC-specific immunotherapies may bring us closer to a future where breast cancer is not only effectively managed but also, potentially, cured [1-4].

Discussion

Breast cancer remains a significant global health challenge, affecting millions of individuals every year. While advances in early detection and treatment have improved survival rates, there is still a pressing need for more effective therapies, especially for aggressive forms of the disease. One promising avenue of research involves targeting breast cancer stem cell antigens as immunotherapeutic targets. Breast cancer stem cells (BCSCs) are a small subpopulation of cells within tumors believed to play a pivotal role in tumor initiation, progression, and recurrence. By understanding and targeting BCSC-specific antigens, researchers hope to develop novel immunotherapies that can effectively eradicate these elusive cancer cells.

Breast cancer stem cells: the key to tumor persistence

Breast cancer is a heterogeneous disease, consisting of various cell types with distinct characteristics. BCSCs are a subpopulation of cells within breast tumors that possess unique properties, making them resistant to traditional therapies and capable of initiating tumor growth. These properties include self-renewal, differentiation potential, and high tumorigenicity. BCSCs are believed to be responsible for tumor recurrence and metastasis, posing a significant challenge in breast cancer treatment [5].

Immunotherapy: a revolutionary approach

Immunotherapy has emerged as a groundbreaking approach in the fight against cancer. Instead of directly targeting cancer cells, immunotherapies harness the body’s immune system to recognize and attack cancer. Immune checkpoint inhibitors, adoptive cell therapies, and cancer vaccines are some of the techniques used to boost the immune response against cancer cells.

Targeting BCSC-specific antigens

One promising avenue of immunotherapy research focuses on BCSC-specific antigens. These antigens are proteins or molecules present on the surface of BCSCs but absent or minimally expressed on normal cells. By developing therapies that target these antigens, researchers aim to selectively eliminate BCSCs while sparing healthy tissue [6 ].

CD44

CD44 is one of the most widely studied BCSC-specific antigens. It is a cell surface glycoprotein involved in cell adhesion and migration. CD44 is often overexpressed on BCSCs and has been identified as a potential target for immunotherapy. Preclinical studies have shown promising results in targeting CD44-positive BCSCs with monoclonal antibodies and chimeric antigen receptor (CAR) T-cell therapies.

ALDH1

Aldehyde dehydrogenase 1 (ALDH1) is another BCSC-specific antigen that has gained attention. ALDH1 is involved in detoxifying aldehydes and is thought to play a role in BCSC self-renewal. Researchers are exploring the use of ALDH1-targeted vaccines and CAR-T cell therapies to eliminate ALDH1-positive BCSCs.

EpCAM

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein found on BCSCs and is associated with tumor initiation and metastasis. Immunotherapies targeting EpCAM, such as monoclonal antibodies and bispecific T-cell engagers (BiTEs), are being investigated in clinical trials for breast cancer [7,8].

Challenges

Tumor heterogeneity

Challenge: Breast cancer is known for its high degree of heterogeneity, both within and between tumors. BCSCs may express different antigens in different patients, complicating the development of universal immunotherapies.

Solution: Personalized medicine approaches that tailor immunotherapies to the specific antigen profile of an individual’s tumor may help address this challenge.

Resistance mechanisms

Challenge: BCSCs are adept at developing resistance to therapies, including immunotherapies. Understanding and overcoming these resistance mechanisms is crucial for long-term treatment success.

Solution: Combining BCSC-targeted immunotherapies with other treatment modalities, such as chemotherapy or radiation therapy, may be necessary to combat resistance effectively.

Clinical translation

Challenge: Transitioning BCSC-specific immunotherapies from promising preclinical results to successful clinical outcomes is a complex and resource-intensive process.

Solution: Rigorous clinical trials are essential for validating the safety and efficacy of BCSC-specific immunotherapies in diverse patient populations. Continued investment in clinical research is crucial.

Off-target effects

Challenge: Immunotherapies can sometimes lead to off-target effects or unintended immune responses, potentially causing harm to healthy tissues.

Solution: Precision in targeting BCSC-specific antigens and minimizing collateral damage to healthy cells is vital. Advances in immunotherapy design and delivery may help reduce off-target effects.

Immunosuppressive tumor microenvironment

BCSCs can create an immunosuppressive microenvironment within tumors, inhibiting the effectiveness of immunotherapies.

Strategies to modulate the tumor microenvironment, such as checkpoint inhibitors or immune-stimulating agents, may enhance the immune response against BCSCs [9-11 ].

Future Directions

Combination therapies

Investigate and optimize combination therapies that integrate BCSC-specific immunotherapies with other treatment modalities. Combinations could enhance the overall anti-cancer response and minimize resistance.

Personalized medicine

Develop personalized BCSC-specific immunotherapies tailored to an individual’s tumor antigen profile. Advances in genomics and proteomics will facilitate the identification of unique antigens for each patient.

Improved biomarkers

Identify and validate robust biomarkers that can predict BCSC presence, behavior, and response to immunotherapies. These biomarkers will aid in patient selection and treatment monitoring.

Advanced delivery systems

Explore innovative delivery systems, such as nanoparticles or viral vectors, to enhance the precision and efficiency of BCSC-specific immunotherapies while minimizing side effects.

Immunotherapy combinations

Investigate the synergy of BCSC-specific immunotherapies with other immunomodulatory approaches, including checkpoint inhibitors, adoptive cell therapies, and cancer vaccines.

Clinical trials and data sharing

Continue conducting well-designed clinical trials to validate the safety and efficacy of BCSC-specific immunotherapies. Encourage data sharing and collaboration among researchers and institutions to accelerate progress.

Patient-centered care

Focus on patient-centered care by considering the individual needs and preferences of breast cancer patients in the development and administration of BCSC-specific immunotherapies [12,13].

Conclusion

Immunotherapeutic targeting of breast cancer stem cell (BCSC) antigens represents a promising strategy in the ongoing battle against breast cancer. Through a comprehensive exploration of this dynamic field, including its challenges and future directions, it becomes evident that the potential benefits of BCSC-specific immunotherapies are substantial. Breast cancer, with its heterogeneity and resistance mechanisms, continues to challenge conventional treatment modalities. However, BCSC-specific immunotherapies offer new avenues for intervention. These therapies aim to selectively target BCSCs, the elusive culprits behind tumor initiation, progression, and recurrence, while sparing healthy tissue. Challenges, such as tumor heterogeneity and resistance, are substantial but not insurmountable. Personalized medicine approaches, advanced delivery systems, and combination therapies provide hope for overcoming these hurdles. Moreover, the identification and validation of robust biomarkers will be pivotal in patient selection and treatment monitoring, ensuring more precise and effective therapies. Looking ahead, the future of BCSC-specific immunotherapy is bright. Combination therapies, personalized medicine, and innovative delivery systems hold the promise of enhanced treatment efficacy. Clinical trials will continue to play a vital role in validating these therapies, and data sharing and collaboration will expedite progress. In this patient-centered era of healthcare, the development of BCSC-specific immunotherapies not only offers hope for improved outcomes but also underscores the importance of tailoring treatments to individual patients’ needs and preferences. By addressing the challenges and pursuing future directions, we move closer to a future where breast cancer is not just managed but, potentially, cured. As we conclude this exploration of BCSC-specific immunotherapy, it is clear that ongoing research and collaboration within the scientific and medical communities hold the key to transforming the landscape of breast cancer treatment.

Conflict of Interest

None

Acknowledgment

None

1. Cynae AJ, Deepthi J, Amelita M, Mona Armaos (2019) Cervical Cancer: An Overview of Pathophysiology and Management. Semin Oncol Nurs 35: 166-174.

Indexed at, Google Scholar, Crossref

2. Sharmila AP, Gauravi AM (2019) Global strategies for cervical cancer prevention and screening. Minerva Ginecol 71: 313-320.

Indexed at, Google Scholar, Crossref

3. Aamod DS, Dinesh N, Peter V, Kallestrup P (2018) Cervical Cancer Prevalence, Incidence and Mortality in Low and Middle Income Countries: A Systematic Review. Asian Pac J Cancer Prev 19: 319-324.

Indexed at, Google Scholar, Crossref

4. Marzieh SGN, Nourossadat K, Abbas E, Ozgoli G, Vida G, et al. (2018) Educational Interventions for Cervical Cancer Screening Behavior of Women: A Systematic Review. Asian Pac J Cancer Prev 19: 875-884.

Indexed at, Google Scholar, Crossref

5. Mohammed S, Mayur V, Sanaz J, Sherif BE, Priya B, et al. (2020) Cervical Cancer: 2018 Revised International Federation of Gynecology and Obstetrics Staging System and the Role of Imaging. AJR Am J Roentgenol 214: 1182-1195.

Indexed at, Google Scholar, Crossref

6. Melissa SL, Ellen SB, Mauricio M, Georgia FC, Aldo L, et al.(2017) Cervical cancer prevention and treatment in Latin America. J Surg Oncol 115: 615-618.

Indexed at, Google Scholar, Crossref

7. Mark S, Nicolas W, Sholom W, Walter K, Julia CG, et al. (2011) Human papillomavirus testing in the prevention of cervical cancer. J Natl Cancer Inst 103: 368-383.

Indexed at, Google Scholar, Crossref

8. Rana S, Russel JR, Hamed M, Somayyeh NT, Zatollah A (2019) Melatonin: A new inhibitor agent for cervical cancer treatment. J Cell Physiol 234: 21670-21682.

Indexed at,, Google Scholar, Crossref

9. Tilmann B, Harald L, Alwin K (2018) Diagnosis and management of metastatic neoplasms with unknown primary. Semin Diagn Pathol 35: 199-206.

Indexed at, Google Scholar, Crossref

10. Philip EC, Walter KK, Cheung LC, Julia CG, Barbara F, Nancy EP, et al. (2017) Why does cervical cancer occur in a state-of-the-art screening program?. Gynecol Oncol 146: 546-553.

Indexed at, Google Scholar,, Crossref

11. Bertha EF, Gayle JA (2013) Older Hispanic women, health literacy, and cervical cancer screening. Clin Nurs Res 22: 402-415.

Indexed at, Google Scholar, Crossref

12. Malitha P, Rajitha DW, Wijesuriya MWAB, Chinthana H (2021) Surgical management of cervical cancer in a resource-limited setting: One year of data from the National Cancer Institute, Sri Lanka. Int J Gynaecol Obstet 152: 78-81.

Indexed at,, Google Scholar, Crossref

13. Lee H, Kim SW, Kwon DY, Kang HW, Jung MJ, et al. (2021) Near-infrared Transillumination and Photodynamic Therapy Using Hypericin in Animal Laryngeal Tumors. Tissue Eng Regen Med 18: 941-951.

Indexed at, Google Scholar, Crossref