The potential use of plasma-derived small extracellular vesicles (sEV) as predictors of response to therapy and clinical outcome in chemotherapy-naïve patients with non-small-cell lung cancer (NSCLC) was explored. sEV were isolated by size-exclusion chromatography from the plasma of 79 chemotherapy-naïve NSCLC patients and 12 healthy donors (HD). sEV were characterized with regard to protein content, particle size, counts by qNano, morphology by transmission electron microscopy, and molecular profiles by Western blots. PD-1 and PD-L1 expression on circulating immune cells was analysed by flow cytometry. Pre-treatment levels of total sEV protein (TEP) were correlated with overall (OS) and progression-free survival (PFS). The sEV numbers and protein levels were significantly elevated in the plasma of NSCLC patients compared to HD (p = 0.009 and 0.0001, respectively). Baseline TEP levels were higher in patients who developed progressive disease compared to patients with stable disease (p = 0.007 and 0.001, stage III and IV, respectively). Patient-derived sEV were enriched in immunosuppressive proteins as compared to proteins carried by sEV from HD. TEP levels were positively correlated with CD8⁺PD-1⁺ and CD8⁺PD-L1⁺ circulating T cell percentages and were independently associated with poorer PFS (p < 0.00001) and OS (p < 0.00001). Pre-therapy sEV could be useful as non-invasive biomarkers of response to therapy and clinical outcome in NSCLC.

SCLC is an aggressive cancer type with high metastatic potential and bad prognosis. CTCs are a valuable source of tumor cells in blood circulation and are among the major contributors to metastasis. In this study we evaluated the number of CTCs that express PD-L1 in treatment-naïve ES-SCLC patients receiving ICI in a front-line setting. Moreover, we explored the percentages of different immune T-cell subsets in circulation to assess their potential role in predicting responses. A total of 43 patients were enrolled—6 of them with LS-SCLC, and 37 with ES-SCLC disease. In addition, PBMCs from 10 healthy donors were used as a control group. Different T-cell subtypes were examined through multicolor FACS analysis and patients’ CTCs were detected using immunofluorescence staining. SCLC patients had higher percentages of PD-1-expressing CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cells, as well as elevated PD-1 protein expression compared to healthy individuals. Additionally, in ES-SCLC patients, a positive correlation between CD3⁺CD8⁺PD-1⁺ T-cells and PD-L1⁺ CTCs was detected. Importantly, patients harboring higher numbers of CD3⁺CD8⁺PD-1⁺ T-cells together with PD-L1⁺CTCs had a survival advantage when receiving front-line immunotherapy. Thus, this study proposes, for first time possible, immune cell–CTCs interaction, as well as a potential novel clinical biomarker for ICI responses in ES-SCLC patients.

T-cell-mediated anti-tumoral responses may have significant clinical relevance as a biomarker for response to immunotherapy. The value of peripheral blood pre-existing tumor antigen-specific T cells (PreI⁺) as a predictive immunotherapy biomarker in NSCLC patients was investigated, along with the frequency of various circulating immune cells. Fifty-two treatment-naïve, stage III/IV NSCLC patients, treated with front-line immune checkpoint inhibitors (ICI)-containing regimens were enrolled. PreI was calculated as the percentages of CD3⁺IFNγ⁺ cells after in vitro co-cultures of PBMCs with peptides against four different Tumor-Associated Antigens (TAA). Immunophenotyping of peripheral blood immune cells was performed using multicolor flow cytometry. PreI⁺ T cells were detected in 44% of patients. Median overall survival (OS) was significantly higher in PreI⁺ patients compared to PreI^– patients (not reached vs. 321 days, respectively; p = 0.014). PreI⁺ patients had significantly higher numbers of possible exhausted CD3⁺CD8⁺PD-1⁺ cells and lower percentages of immunosuppressive Tregs compared to PreI⁻ patients. Additionally, patients with PreI⁺ and low numbers of peripheral blood M-MDSCs had a significant survival advantage compared to the rest of the patients. Thus, combining pre-existing tumor antigen-specific immunity before initiation of ICI in NSCLC patients with selected immune-suppressive cells could identify patients who have a favorable clinical outcome when treated with ICI-containing regimens.

Background: Bones, lungs and liver are the most common sites of primary breast tumors. Metastases to the pituitary gland are rare and usually indicate widespread malignant disease. The more frequent manifestations of pituitary gland involvement are diabetes insipidus and visual disturbances. Case Report: This is a 45-year-old woman who was presented with headache, visual disorders, polyuria, polydipsia, significant hypernatremia and dyspnea. The clinical examination revealed a palpable mass in the right breast, while the imaging evaluation showed extensive lung, liver, brain and bone metastases and a metastatic lesion in the pituitary gland, which was compatible with the symptoms of the patient. She received desmopressin for diabetes insipidus control, and underwent whole brain-orbital irradiation and chemotherapy, with resolution of her symptoms and partial remission of the disease. This case shows that diabetes insipidus may be the first manifestation of metastatic breast cancer and early detection and treatment, can improve the associated symptoms.

Background: Small-cell lung cancer (SCLC) is an aggressive type of lung cancer, and several factors are currently used to predict poor outcomes, including performance status (PS), extensive-stage disease, male sex, advanced age, and elevated lactate dehydrogenase (LDH) levels. In this study, we aimed to explore the role of Tegs and inflammatory indices, such as CRP and NLR, in predicting response to immunotherapy. Methods: Fifty-one therapy-naïve ES-SCLC patients and ten healthy donors were enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated and stained with fluorochrome-conjugated monoclonal antibodies. Multicolor flow cytometry was performed to determine the levels of CD8⁺ T cells and CD4⁺ Tregs, as well as their correlation with inflammatory indices and clinical outcomes. Results: ES-SCLC patients harbored higher percentages of CD8⁺ Teffs (p = 0.005) and FOXP3⁺ Tregs (p < 0.0001) in circulation before therapy compared with healthy donors. In addition, high levels of CD3⁺CD8⁺ T effectors were associated with longer PFS (p = 0.018) and longer OS (p = 0.012) compared with patients bearing low levels, while Tregs were not found to be predictive. More importantly, a survival benefit was observed in ES-SCLC patients with a low Treg/Teff ratio, as longer OS was observed in those with high percentages of CD8⁺ Teffs and low FOXP3⁺CTLA-4⁺ Tregs (p = 0.014) compared with those bearing low CD8⁺ Teffs and high FOXP3⁺CTLA-4⁺ Tregs. A low Treg/Teff ratio was further associated with low eosinophil levels and a low NLR before treatment initiation. Conclusions: These findings suggest a novel, easily obtainable blood-based signature that may help predict response to ICIs in ES-SCLC patients.

Immunotherapy has revolutionized the management of patients with cancer. Immune checkpoint inhibition (ICI) is a promising treatment option that targets the molecular mechanisms that cancer cells exploit to prevent immune-mediated elimination. ICI therapy can cause exceptional long-term tumor remissions, in some cases, even after treatment discontinuation. Despite its success, many patients acquire resistance or fail to respond due to immune escape mechanisms mediated by the tumor and its microenvironment. Pre-existing immunity status of individuals seems to play a fundamental role in immunotherapy response and eventually tumor progression, as it orchestrates tumor-immune interactions. Different immune cell subsets, both in the tumor microenvironment and the peripheral blood, are established mediators that contribute to immune escape in various tumor types. Based on these findings, the elucidation of the mechanisms implicated in the regulation of these immune cells has become a priority for investigators focused on improving the efficacy of ICI. This will be essential for identifying responders as well as for developing novel therapeutic modalities to improve clinical outcomes. Herein, we summarize preclinical and clinical evidence proposing a predictive role of pre-existing immunity for clinical responses to immunotherapies.