Cancer is a multifactorial pathology and it represents the second leading cause of death worldwide. In the recent years, numerous studies highlighted the dual role of the gut microbiota in preserving host’s health. Gut resident bacteria are able to produce a number of metabolites and bioproducts necessary to protect host’s and gut’s homeostasis. Conversely, several microbiota subpopulations may expand during pathological dysbiosis and therefore produce high levels of toxins capable, in turn, to trigger both inflammation and tumorigenesis. Importantly, gut microbiota can interact with the host either modulating directly the gut epithelium or the immune system. Numerous gut populating bacteria, called probiotics, have been identified as protective against the genesis of tumors. Given their capability of preserving gut homeostasis, probiotics are currently tested to help to fight dysbiosis in cancer patients subjected to chemotherapy and radiotherapy. Most recently, three independent studies show that specific gut resident species may potentiate the positive outcome of anti-cancer immunotherapy. The highly significant studies, uncovering the tight association between gut microbiota and tumorigenesis, as well as gut microbiota and anti-cancer therapy, are here described. The role of the Lactobacillus rhamnosus GG (LGG), as the most studied probiotic model in cancer, is also reported. Overall, according to the findings here summarized, novel strategies integrating probiotics, such as LGG, with conventional anti-cancer therapies are strongly encouraged.

Purpose: Cancer stem cells (CSC) are thought to represent the population of tumorigenic cells responsible for tumor development. The stem cell antigen CD133 identifies such a tumorigenic population in a subset of glioblastoma patients. We conducted a prospective study to explore the prognostic potential of CSC analysis in glioblastoma patients. Experimental Design: We investigated the relationship between the in vitro growth potential of glioblastoma CSCs and patient death or disease progression in tumors of 44 consecutive glioblastoma patients treated with complete or partial tumorectomy followed by radiotherapy combined with temozolomide treatment. Moreover, we evaluated by immunohistochemistry and immunofluorescence the prognostic value of the relative presence of CD133⁺ and CD133⁺/Ki67⁺ cells in patient tumors. Results:In vitro CSC generation and the presence of ≥2% CD133⁺ cells in tumor lesions negatively correlated with overall (P = 0.0001 and 0.02, respectively) and progression-free (P = 0.0002 and 0.01, respectively) survival of patients. A very poor overall (P = 0.007) and progression-free (P = 0.001) survival was observed among patients whose tumors contained CD133⁺ cells expressing Ki67. Taking into account symptom duration, surgery type, age, O⁶-methylguanine-DNA methyltransferase promoter methylation, and p53 status, generation of CSCs and CD133/Ki67 coexpression emerged as highly significant independent prognostic factors, with an adjusted hazard ratio of 2.92 (95% confidence interval, 1.37-6.2; P = 0.005) and 4.48 (95% confidence interval, 1.68-11.9; P = 0.003), respectively. Conclusions: The analysis of CSCs may predict the survival of glioblastoma patients. In vitro CSC generation and presence of CD133⁺/Ki67⁺ cells are two considerable prognostic factors of disease progression and poor clinical outcome.

Importance: Randomized clinical trials (RCTs) with neoadjuvant immune checkpoint inhibitors (ICIs) plus chemotherapy (ICI-chemotherapy) for patients with early-stage non–small cell lung cancer (NSCLC) have reported consistent associations with event-free survival (EFS) and pathologic complete response (pCR) pending longer follow-up for overall survival data.Objective: To assess the pooled benefit of ICI-chemotherapy in 2-year EFS and pCR among patients with NSCLC and examine the impact of clinical, pathologic, and treatment-related factors.Data Sources: Full-text articles and abstracts in English were searched in EMBASE, PubMed, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews through November 1, 2023, and in oncology conference proceedings from January 1, 2008, to November 1, 2023.Study Selection: Phase 2 or 3 RCTs with neoadjuvant ICI-chemotherapy with or without adjuvant ICIs vs neoadjuvant chemotherapy alone with or without placebo or observation in patients with previously untreated NSCLC staged IB to IIIB were included.Data Extraction and Synthesis: Data extraction of prespecified data elements was performed by 2 reviewers using a structured data abstraction electronic form. A random-effects model was used for meta-analysis. The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline.Main Outcomes and Measures: Two-year EFS and pCR were the outcomes of interest in patients who received neoadjuvant ICI-chemotherapy (experimental arm) or neoadjuvant chemotherapy alone (control arm). Aggregated pooled hazard ratios (HRs) for time-to-event outcomes (2-year EFS) and risk ratios (RRs) for dichotomous outcomes (pCR) with their respective 95% CIs were calculated.Results: Eight trials with 3387 patients were included, with some concerns of risk of bias as assessed by the Cochrane Collaboration method, mainly related to outcomes measurements. Neoadjuvant ICI-chemotherapy was associated with improved 2-year EFS (HR, 0.57; 95% CI, 0.50-0.66; P < .001) and increased pCR rate (RR, 5.58; 95% CI, 4.27-7.29; P < .001) in the experimental vs control treatment arms. This association was not significantly modified by the main patient characteristics; tumor- or treatment-related factors, including tumor programmed cell death ligand 1 (PD-L1) status; type of platinum-compound chemotherapy; number of cycles of neoadjuvant ICI-chemotherapy; or addition of adjuvant ICIs. Patients whose tumor cells were negative for PD-L1 were at higher risk of relapse (HR, 0.75; 95% CI, 0.62-0.91) than were those with low (HR, 0.61; 95% CI, 0.37-0.71) or high PD-L1 (HR, 0.40; 95% CI, 0.27-0.58) (P = .005).Conclusions and Relevance: In this systematic review and meta-analysis of neoadjuvant ICI-chemotherapy RCTs in patients with early-stage NSCLC, 3 cycles of neoadjuvant platinum-based ICI-chemotherapy were associated with a meaningful improvement in 2-year EFS and pCR.