Immunization against Cancer Advancements in Vaccine Strategies

Virlliano Thomas^*
*Correspondence: Virlliano Thomas, Department of Biology, University of Porto, Porto, Portugal, Email:

Introduction

Cancer remains one of the most challenging diseases to combat, claiming millions of lives worldwide every year. Despite significant progress in understanding its mechanisms and developing various treatment modalities, including surgery, chemotherapy, and radiation therapy, the quest for effective cancer prevention methods continues. Immunization against cancer has emerged as a promising strategy, leveraging the body's immune system to recognize and destroy cancer cells. In recent years, significant advancements have been made in vaccine strategies, offering hope for better cancer control and prevention. The immune system plays a crucial role in identifying and eliminating abnormal cells, including cancerous ones [1]. However, cancer cells often evade immune surveillance by adopting various mechanisms to escape detection or suppress immune responses. Cancer immunology aims to understand these mechanisms and develop strategies to harness the power of the immune system against cancer. One of the key concepts in cancer immunology is immune tolerance, where the immune system fails to recognize cancer cells as foreign or harmful. Tumor cells can express molecules that inhibit immune responses, such as Programmed Death-Ligand 1 (PD-L1), which interacts with the programmed cell death protein 1 (PD-1) receptor on immune cells, leading to immune suppression. Additionally, cancer cells can down regulate major histocompatibility complex (MHC) molecules, making them less visible to immune cells [2].

Literature Review

Traditional vaccines work by stimulating the immune system to recognize and remember specific pathogens, such as viruses or bacteria, and mount a rapid response upon subsequent exposure. Cancer vaccines aim to achieve a similar goal by training the immune system to target tumor-specific antigens while avoiding healthy tissues. Peptide vaccines contain specific protein fragments, or peptides, derived from cancer cells' surface proteins. These peptides are presented to immune cells, such as T cells, to induce an immune response against cancer. Peptide vaccines offer several advantages, including precise targeting of tumor antigens and minimal side effects. However, they may be limited by the diversity of tumor antigens and the need for multiple peptides to cover heterogeneous tumors. Dendritic cells are specialized immune cells responsible for initiating and regulating immune responses. Dendritic cell vaccines involve isolating a patient's dendritic cells, loading them with tumor antigens, and then reintroducing them into the patient's body. This approach aims to enhance the immune system's ability to recognize and attack cancer cells. Dendritic cell vaccines have shown promise in stimulating both innate and adaptive immune responses against cancer [3].

Viral vector vaccines use modified viruses, such as adenoviruses or lentiviruses, to deliver tumor antigens into the body. These viruses are engineered to be non-replicating or replication-deficient, ensuring safety while effectively delivering antigenic payloads. Viral vector vaccines can induce robust immune responses against cancer antigens, potentially leading to tumor regression. Moreover, they can be designed to express additional immune-stimulatory molecules, further enhancing their therapeutic efficacy. RNA and DNA vaccines represent another innovative approach to cancer immunization. These vaccines deliver genetic material encoding tumor antigens directly into cells, where they are translated into protein antigens. This process mimics natural infection, triggering immune responses against cancer cells. RNA and DNA vaccines offer advantages such as ease of production, stability, and the ability to induce both humoral and cellular immune responses. Several RNA and DNA vaccine candidates are currently under investigation in preclinical and clinical studies [4].

Discussion

Neoantigens are unique antigens derived from mutations present in cancer cells but not in normal cells. Neoantigen vaccines are designed to target these specific mutations, enabling personalized immunotherapy approaches. By identifying neoantigens through genomic sequencing of individual tumors, researchers can develop customized vaccines tailored to each patient's unique cancer profile. Neoantigen vaccines hold great promise for precision cancer immunotherapy, potentially achieving high response rates with minimal off-target effects. Despite the significant progress in vaccine strategies for cancer immunization, several challenges remain to be addressed. One of the key challenges is tumor heterogeneity, where cancer cells within the same tumor or among different tumors may exhibit diverse antigenic profiles. Developing vaccines that can effectively target this heterogeneity remains a major research priority. Another challenge is immune evasion mechanisms employed by cancer cells, such as the expression of immune checkpoint molecules like PD-L1. Combining cancer vaccines with immune checkpoint inhibitors or other immunomodulatory agents represents a promising approach to overcome immune suppression and enhance antitumor immune responses. Furthermore, the development of robust biomarkers to predict vaccine efficacy and monitor immune responses is essential for optimizing cancer immunization strategies. Biomarkers could help identify patients most likely to benefit from vaccination and guide treatment decisions in clinical settings [5].

Moving from preclinical studies to clinical trials and eventual regulatory approval poses significant challenges for cancer vaccine development. Clinical translation requires rigorous testing of vaccine safety, efficacy, and immunogenicity in human subjects through well-designed clinical trials. These trials often involve multiple phases, starting with small-scale Phase I trials to assess safety and dosing, followed by Phase II trials to evaluate efficacy and immune responses, and culminating in large-scale Phase III trials to confirm therapeutic benefits. Regulatory agencies, such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), play a crucial role in evaluating vaccine candidates for approval. They require comprehensive data on vaccine manufacturing, characterization, stability, and clinical performance to ensure safety and efficacy standards are met. Moreover, regulatory pathways for cancer vaccines may differ from those for traditional drugs, requiring specialized expertise and consideration of unique challenges, such as patient selection criteria and endpoints for clinical trials.

Conclusion

Immunization against cancer holds immense potential as a complementary approach to traditional cancer therapies, offering the prospect of durable responses and long-term protection. Recent advancements in vaccine strategies, including peptide vaccines, dendritic cell vaccines, viral vector vaccines, RNA and DNA vaccines, and neoantigen vaccines, have expanded the therapeutic arsenal against cancer. By leveraging the body's immune system to recognize and eliminate cancer cells, these innovative approaches bring hope for improved outcomes and better quality of life for cancer patients. However, addressing remaining challenges and translating these advancements into clinical practice will require collaborative efforts across disciplines, paving the way for the next era of cancer immunotherapy.

Acknowledgement

None.

Conflict of Interest

None.

References

1. Mahal, Brandon A., Paul J. Catalano, Robert I. Haddad and Glenn J. Hanna, et al. "Incidence and demographic burden of HPV-associated oropharyngeal head and neck cancers in the United States." Cancer Epidemiol Biomark Prev 28 (2019): 1660-1667.

Google Scholar, Crossref, Indexed at

2. Gockley, Allison A., Nancy Pena, Allison Vitonis and Kelly Welch, et al. "Tablet-based patient education regarding human papillomavirus vaccination in colposcopy clinic." J Low Genital Tract Dis 23 (2019): 188-192.

Google Scholar, Crossref, Indexed at

3. Ruiz-López, Tomás, Sagar Sen, Elisabeth Jakobsen and Ameli Tropé, et al. "FightHPV: design and evaluation of a mobile game to raise awareness about human papillomavirus and nudge people to take action against cervical cancer." JMIR Ser Games 7 (2019): e8540.

Google Scholar, Crossref, Indexed at

4. Fiks, Alexander G., Robert W. Grundmeier, Stephanie Mayne and Lihai Song, et al. "Effectiveness of decision support for families, clinicians, or both on HPV vaccine receipt." Pediatrics 131 (2013): 1114-1124.

Google Scholar, Crossref, Indexed at

5. Smulian, Elizabeth A., Krista R. Mitchell and Shannon Stokley. "Interventions to increase HPV vaccination coverage: A systematic review." Hum Vaccin Immunother 12 (2016): 1566-1588.

Google Scholar, Crossref, Indexed at