Background Clinical responses to ipilimumab are variable in terms of onset, magnitude and duration. Upfront identification of patients who are more likely or unlikely to benefit from treatment is a major need. Patients and methods Prospectively collected data from 720 advanced melanoma patients treated with ipilimumab 3 mg/kg within the Italian expanded access programme were analyzed. The derived neutrophil-to-lymphocyte ratio (dNLR) was calculated from baseline peripheral blood cell counts, and receiver operating characteristic curve was used to evaluate the best cut-off for this marker. Patients were stratified according to dichotomized baseline absolute neutrophil counts (ANC), dNLR, and their combination. The prognostic values of ANC and dNLR for survival were assessed using multivariate Cox proportional hazard models. A subgroup analysis including LDH in the models was also performed. Results The median follow-up was 16.5 months. The optimal cut-off for dNLR was 3. Baseline ANC and dNLR were significantly associated with outcome of ipilimumab-treated melanoma patients, in terms of disease progression and death (P<0.0001 for all). Further, for each elevated variable, prognosis worsened. Patients with both ANC≥7500 and dNLR≥3 had a significantly and independently increased risk of death (HR=5.76; 95%CI: 4.29-7.75) and of progression (HR=4.10; 95%CI: 3.08-5.46) compared to patients with both lower ANC and dNLR. Patients with one of the two factors elevated displayed an intermediate risk of progression and death. The 1-year and 2-years survival rates were 2% and 0%, respectively, for patients with ANC≥7500 and dNLR≥3, and 43% and 24%, respectively, for patients with both lower ANC and dNLR. Conclusions Although these findings need to be confirmed and validated, we suggest that a neutrophil-based index may help risk-group stratification and assist disease management strategies. Further, the potential predictive value of this index for response to ipilimumab should be investigated in randomized clinical trials.

Ipilimumab improves the survival of metastatic melanoma patients. Despite documented, durable objective responses, a significant number of patients fails to benefit from treatment. The aim of this study was to identify an upfront marker for treatment benefit. A total of 187 metastatic melanoma patients treated in three Italian Institutions with 3 mg kg⁻¹ ipilimumab, and 27 patients treated with 10 mg kg⁻¹ ipilimumab, were evaluated. Neutrophil-to-lymphocyte ratio (NLR) was calculated from pre-therapy full blood counts. Progression-free survival (PFS) and overall survival (OS) were assessed using the Kaplan–Meier method, and multivariate Cox models were applied, adjusting for confounders and other prognostic factors. In the training cohort of 69 patients treated at European Institute of Oncology, pre-therapy NLR was identified as the strongest and independent marker for treatment benefit in multivariate analyses. Patients with baseline NLR<5 had a significantly improved PFS (HR=0.38; 95% CI: 0.22–0.66; P=0.0006) and OS (HR=0.24; 95% CI: 0.13–0.46; P<0.0001) compared with those with a NLR5. Associations of low NLR with improved survival were confirmed in three validation cohorts of patients. Our findings show that baseline NLR is strongly and independently associated with outcome of patients treated with ipilimumab, and may serve to identify patients most likely to benefit from this therapy.

A major obstacle for the development of effective immunotherapy is the ability of tumors to escape the immune system. The possibility to kill tumor cells because they are recognized as infected rather than as malignant could help overcome immune escape mechanisms. Here we report a conceptually new approach of cancer immunotherapy based on in vivo infection of tumors and killing of infected tumor cells. Attenuated but still invasive, Salmonella typhimurium can be successfully exploited to invade melanoma cells that can present antigenic determinants of bacterial origin and become targets for anti-Salmonella–specific T cells. However, to fully appreciate the anticancer therapeutic properties of S. typhimurium, tumor-bearing mice need to be vaccinated against S. typhimurium before intratumoral Salmonella injection. Tumor infection when coupled to anti-Salmonella vaccination leads to 50% to 100% tumor-free mice with a better outcome on larger tumors. Invasive Salmonella also exert an indirect toxic effect on tumor cells through the recruitment of inflammatory cells and the cross-presentation of tumor antigens, which allow induction of tumor-specific immune response. This is effective in retarding the growth of untreated established distant tumors and in protecting the mice from subsequent tumor challenges.

Electroporation uses pulsed, high-intensity electric fields to temporarily increase cell membrane permeability by creation of pores, through which small molecules, such as chemotherapeutic agents, can diffuse inside cells before they reseal. The combination of electroporation with the administration of otherwise low-permeant cytotoxic drugs is known as electrochemotherapy (ECT). The two most commonly used drugs are bleomycin and cisplatin. ECT has already been proven to be effective in diverse tumor histotypes, including melanoma and basal and squamous cell carcinoma, Kaposi sarcoma, and breast cancer, also in those cases nonresponding to classical chemotherapies or other loco-regional treatment modalities, with a good safety profile. ECT can be proposed as loco-regional therapy for disseminated cutaneous and subcutaneous tumor lesions as alternative treatment modality to conventional therapies or as palliative care, in order to improve patients' quality of life.

The adhesion molecule L1, which is extensively characterized in the nervous system, is also expressed in dendritic cells (DCs), but its function there has remained elusive. To address this issue, we ablated L1 expression in DCs of conditional knockout mice. L1-deficient DCs were impaired in adhesion to and transmigration through monolayers of either lymphatic or blood vessel endothelial cells, implicating L1 in transendothelial migration of DCs. In agreement with these findings, L1 was expressed in cutaneous DCs that migrated to draining lymph nodes, and its ablation reduced DC trafficking in vivo. Within the skin, L1 was found in Langerhans cells but not in dermal DCs, and L1 deficiency impaired Langerhans cell migration. Under inflammatory conditions, L1 also became expressed in vascular endothelium and enhanced transmigration of DCs, likely through L1 homophilic interactions. Our results implicate L1 in the regulation of DC trafficking and shed light on novel mechanisms underlying transendothelial migration of DCs. These observations might offer novel therapeutic perspectives for the treatment of certain immunological disorders.