Biomarkers for predicting and monitoring the efficacy of cancer vaccines

Cancer vaccines are a modern approach to personalized anti-tumor therapy for malignant neoplasms based on stimulating the patient's immune system to target tumor cells. Many studies have demonstrated the impressive efficacy of anti-tumor vaccines in treating patients with different localization, type and stage of neoplasm. One of the major obstacles to the widespread implementation of cancer vaccines into clinical practice is the lack of reproducible biomarkers to evaluate and predict the efficacy of tumor vaccine therapy. The most commonly used methods for assessing a patient's immune status are ELISA and flow cytometry, which make it possible to assess the activation of the patient's immune system. However, multiple clinical trials have not yet demonstrated the reproducibility of these study results. This review includes description of efficacy biomarkers and methods for their evaluation used in a number of tumor vaccines' clinical and preclinical trials, and discuss the challenges of applying the biomarkers in real-world clinical practice.