Immunotherapy has become an established pillar of cancer treatment improving the prognosis of many patients with a broad variety of hematological and solid malignancies. The two main drivers behind this success are checkpoint inhibitors (CPIs) and chimeric antigen receptor (CAR) T cells. This review summarizes seminal findings from clinical and translational studies recently presented or published at important meetings or in top-tier journals, respectively. For checkpoint blockade, current studies focus on combinational approaches, perioperative use, new tumor entities, response prediction, toxicity management and use in special patient populations. Regarding cellular immunotherapy, recent studies confirmed safety and efficacy of CAR T cells in larger cohorts of patients with acute lymphoblastic leukemia or diffuse large B cell lymphoma. Different strategies to translate the striking success of CAR T cells in B cell malignancies to other hematological and solid cancer types are currently under clinical investigation. Regarding the regional distribution of registered clinical immunotherapy trials a shift from PD-1 / PD-L1 trials (mainly performed in the US and Europe) to CAR T cell trials (majority of trials performed in the US and China) can be noted.

In patients with pancreatic ductal adenocarcinoma (PDAC), the tumor microenvironment consists of cellular and stromal components that influence prognosis. Hence, tumor-infiltrating lymphocytes (TILs) may predict prognosis more precisely than conventional staging systems. Studies on the impact of TILs are heterogeneous and further research is needed. Therefore, this study aims to point out the importance of peritumoral TILs, tumor-infiltrating neutrophils (TINs), and immune subtype classification in PDAC. Material from 57 patients was analyzed with immunohistochemistry performed for CD3, CD8, CD20, CD66b, α-sma, and collagen. Hot spots with peritumoral TILs and TINs were quantified according to the QTiS algorithm and the distance of TILs hot spots to the tumor front was measured. Results were correlated with overall (OS) and progression-free survival (PFS). High densities of peritumoral hot spots with CD3⁺, CD8⁺, and CD20⁺ TILs correlated significantly with improved OS and PFS. Combined immune cell subtypes predicted improved OS and PFS. High infiltration of CD3⁺ TILs predicted progression after 12 months. The location of TILs’ hot spots and their distance to the tumor front did not correlate with patient survival. Peritumoral TILs and the composition of the stroma predict OS and PFS in PDAC.

Myeloid-derived suppressor cells (MDSCs) are one of the main suppressive cell population of the immune system. They play a pivotal role in the establishment of the tumor microenvironment (TME). In the context of cancers or other pathological conditions, MDSCs can differentiate, expand, and migrate in large quantities during circulation, inhibiting the cytotoxic functions of T cells and NK cells. This process is regulated by ROS, iNOS/NO, arginase-1, and multiple soluble cytokines. The definition of MDSCs and their phenotypes in humans are not as well represented as in other organisms such as mice, owing to the absence of the cognate molecule. However, a comprehensive understanding of the differences between different species and subsets will be beneficial for clarifying the immunosuppressive properties and potential clinical values of these cells during tumor progression. Recently, experimental evidence and clinical investigations have demonstrated that MDSCs have a close relationship with poor prognosis and drug resistance, which is considered to be a leading marker for practical applications and therapeutic methods. In this review, we summarize the remarkable position of MDSCs in solid tumors, explain their classifications in different models, and introduce new treatment approaches to target MDSCs to better understand the advancement of new approaches to cancer treatment.

Unlike traditional cancer therapies, cancer vaccines (CVs) harness a high specificity of the host’s immunity to kill tumor cells. CVs can train and bolster the patient’s immune system to recognize and eliminate malignant cells by enhancing immune cells’ identification of antigens expressed on cancer cells. Various features of antigens like immunogenicity and avidity influence the efficacy of CVs. Therefore, the choice and application of antigens play a critical role in establishing and developing CVs. Tumor-associated antigens (TAAs), a group of proteins expressed at elevated levels in tumor cells but lower levels in healthy normal cells, have been well-studied and developed in CVs. However, immunological tolerance, HLA restriction, and adverse events are major obstacles that threaten TAA-based CVs’ efficacy due to the “self-protein” characteristic of TAAs. As “abnormal proteins” that are completely absent from normal cells, tumor-specific antigens (TSAs) can trigger a robust immune response against tumor cells with high specificity and without going through central tolerance, contributing to cancer vaccine development feasibility. In this review, we focus on the unique features of TAAs and TSAs and their application in vaccines, summarizing their performance in preclinical and clinical trials.

Protective antibody levels persist long-term in a majority of healthcare workers after initial immunization. Those without protective levels have a rapid and robust response to a booster vaccine, suggesting that immunologic memory is long-lasting and booster vaccination is probably unnecessary. Background. Follow-up studies of recipients of hepatitis B vaccine from endemic areas have reported loss of antibody to hepatitis B surface antigen (anti-HBs) in a high proportion of persons vaccinated at birth. In contrast, the long-term durability of antibody in persons vaccinated as adults in nonendemic areas is not well defined. We aimed to assess the durability of anti-HBs among healthcare workers (HCWs) vaccinated as adults and response to a booster among those without protective levels of antibody. Methods. Adult HCWs aged 18–60 at the time of initial vaccination were recruited. All were tested for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HBs level. HCWs with anti-HBs <12 mIU/mL were offered a booster and levels were measured 1, 7, and 21 days afterward. Results. Anti-HBs levels were 20 years postvaccination, respectively, (P = ns). Four HCWs were anti-HBc positive; none had HBsAg. By logistic regression, older age at vaccination was the only predictor of inadequate anti-HBs level (P = .0005). Thirty-four of 36 subjects with inadequate anti-HBs levels received a booster and 32 (94%) developed levels >12 mIU/mL within 3 weeks. Conclusions. Anti-HBs levels decrease after 10–31 years and fall below a level considered protective in approximately 25% of cases. The rapid and robust response to a booster vaccine suggests a long-lasting amnestic response. Hepatitis B vaccination provides long-term protection against hepatitis B and booster vaccination does not appear to be necessary in HCWs. Clinical Trials Registration. NCT01182311.