Microglia, the principal resident immune cell of the CNS, exert significant influence on neurons during development and in pathological situations. However, if and how microglia contribute to normal neuronal function in the mature uninjured CNS is not well understood. We used the model of the adult mouse retina, a part of the CNS amenable to structural and functional analysis, to investigate the constitutive role of microglia by depleting microglia from the retina in a sustained manner using genetic methods. We discovered that microglia are not acutely required for the maintenance of adult retinal architecture, the survival of retinal neurons, or the laminar organization of their dendritic and axonal compartments. However, sustained microglial depletion results in the degeneration of photoreceptor synapses in the outer plexiform layer, leading to a progressive functional deterioration in retinal light responses. Our results demonstrate that microglia are constitutively required for the maintenance of synaptic structure in the adult retina and for synaptic transmission underlying normal visual function. Our findings on constitutive microglial function are relevant in understanding microglial contributions to pathology and in the consideration of therapeutic interventions that reduce or perturb constitutive microglial function. SIGNIFICANCE STATEMENT Microglia, the principal resident immune cell population in the CNS, has been implicated in diseases in the brain and retina. However, how they contribute to the everyday function of the CNS is unclear. Using the model of the adult mouse retina, we examined the constitutive role of microglia by depleting microglia from the retina. We found that in the absence of microglia, retinal neurons did not undergo overt cell death or become structurally disorganized in their processes. However, connections between neurons called synapses begin to break down, leading to a decreased ability of the retina to transmit light responses. Our results indicate that retinal microglia contribute constitutively to the maintenance of synapses underlying healthy vision.

Background For many years the standard approach to staging of the mediastinum in non-small cell lung cancer (NSCLC) has been surgical using cervical mediastinoscopy, left anterior mediastinotomy or video assisted thoracoscopic surgery (VATS). More recently endobronchial ultrasound (EBUS) and endoscopic ultrasound (EUS) have been reported. We conducted a randomised phase III trial to compare surgical staging versus endoscopic staging. The primary endpoint was detection of mediastinal nodal metastasis (N2/3); secondary endpoints were complication and futile thoracotomy rates. Methods Consecutive patients with potentially resectable (suspected) NSCLC in whom invasive mediastinal staging was indicated based on CT or PET-CT findings were randomly assigned to either Arm A, surgical staging or Arm B, combined EBUS/EUS (followed by surgical staging if endoscopic findings were negative for malignancy). Surgical staging involved mediastinoscopy and/or mediastinotomy and/or VATS. Subsequently, in the absence of mediastinal disease, thoracotomy with systematic lymph node sampling was performed. 240 pts were required to show a 20% increase in sensitivity (power 80% and α=0.05) to detect mediastinal nodal disease with a prevalence of 50%. Results 118 patients were randomised to Arm A and 123 to Arm B. The sensitivity for detection of mediastinal metastases by surgical staging in Arm A was 80% (95% CI, 68 to 89) vs 94% (95% CI, 85 to 98) for endoscopic (± surgical) staging in Arm B (p=0.04). Nodal metastases were found in 41 (35%) of surgically staged patients in Arm A and 62 patients (50%) (56 by EBUS/EUS + 6 by subsequent surgical staging) in Arm B (p=0.019). Overall, the prevalence of mediastinal disease in each arm was similar (p=0.24). Thoracotomy was considered futile in 21 (18%) in those staged in Arm A vs 8 patients (7%) in Arm B (p=0.009). Complication rate was similar in both arms (6 vs 7 patients, p=0.8); however, 12 of 13 complications were due to surgical staging procedures. Conclusions Mediastinal staging for NSCLC should commence with combined EBUS/EUS (followed by surgical staging if endoscopic findings are negative for malignancy) as this improves the detection of nodal metastases and reduces futile thoracotomies compared to surgical staging alone.

Innate and adaptive immune system cells play a major role in regulating the growth of cancer. Although it is commonly thought that an immune response localized to the tumor will inhibit cancer growth, it is clear that some types of inflammation induced in a tumor may also lead to cancer proliferation, invasion, and dissemination. Recent evidence suggests, however, that some patients with cancer can mount an antitumor immune response that has the potential to control or eliminate cancer. Indeed, a so-called “immune response” signature has been described in malignancy that is associated with improved outcomes in several tumor types. Moreover, the presence of specific subsets of T cells, which have the capability to penetrate tumor stroma and infiltrate deep into the parenchyma, identifies patients with an improved prognosis. Immune-based therapies have the potential to modulate the tumor microenvironment by eliciting immune system cells that will initiate acute inflammation that leads to tissue destruction.

Ovarian cancer is the most common cause of death among gynecologic malignant neoplasms in the United States and is responsible for 5% of cancer-related deaths in women.¹ Approximately 239 000 new cases are diagnosed worldwide annually² and more than 70% of US patients are diagnosed with late-stage disease, largely owing to the absence of effective screening.³ Ovarian cancer is a heterogeneous disease with various subtypes that have varying histologic characteristics, molecular characteristics, and prognosis.⁴ Platinum-based chemotherapy, with or without bevacizumab, is the standard-of-care first-line treatment,⁵ although rates of relapse are high (approximately 70% within 3 years).⁶ Clear cell carcinoma, in particular, responds poorly to chemotherapy and has a poorer prognosis than cancers with more common histologic types.^7,8 Standard therapies for platinum-resistant or refractory ovarian cancer, including pegylated liposomal doxorubicin, weekly paclitaxel, and topotecan, provide limited benefits,^3,5,6 and overall survival (OS) in patients with relapsed disease who have received multiple lines of prior treatment is particularly short (eg, median, 10.6 months with fourth-line chemotherapy vs 3.3 months without treatment).⁹ Standard chemotherapy regimens are also associated with a high level of toxic effects. Poly-(ADP [adenosine diphosphate]-ribose) polymerase (PARP) inhibitors have efficacy in patients with BRCA-mutated (BRCA1: OMIM, 113705; and BRCA2: OMIM, 600185) recurrent ovarian cancer^10,11 or with high-grade serous and endometrioid tumors, irrespective of BRCA status, when used as switch-maintenance treatment after platinum-sensitive recurrence.^12-14 Additional treatment options are needed to prolong OS and improve quality of life in patients with advanced ovarian cancer regardless of their treatment history.

PURPOSE: The HER-2/neu protein is a nonmutated tumor antigen that is overexpressed in a variety of human malignancies, including breast and ovarian cancer. Many tumor antigens, such as MAGE and gp100, are self-proteins; therefore, effective vaccine strategies must circumvent tolerance. We hypothesized that immunizing patients with subdominant peptide epitopes derived from HER-2/neu, using an adjuvant known to recruit professional antigen-presenting cells, granulocyte-macrophage colony-stimulating factor, would result in the generation of T-cell immunity specific for the HER-2/neu protein.PATIENTS AND METHODS: Sixty-four patients with HER-2/neu–overexpressing breast, ovarian, or non–small-cell lung cancers were enrolled. Vaccines were composed of peptides derived from potential T-helper epitopes of the HER-2/neu protein admixed with granulocyte-macrophage colony-stimulating factor and administered intradermally. Peripheral-blood mononuclear cells were evaluated at baseline, before vaccination, and after vaccination for antigen-specific T-cell immunity. Immunologic response data are presented on the 38 subjects who completed six vaccinations. Toxicity data are presented on all 64 patients enrolled.RESULTS: Ninety-two percent of patients developed T-cell immunity to HER-2/neu peptides (stimulation index, 2.1 to 59) and 68% to a HER-2/neu protein domain (stimulation index range, 2 to 31). Epitope spreading was observed in 84% of patients and significantly correlated with the generation of a HER-2/neu protein–specific T-cell immunity (P = .03). At 1-year follow-up, immunity to the HER-2/neu protein persisted in 38% of patients.CONCLUSION: The majority of patients with HER-2/neu–overexpressing cancers can develop immunity to both HER-2/neu peptides and protein. In addition, the generation of protein-specific immunity, after peptide immunization, was associated with epitope spreading, reflecting the initiation of an endogenous immune response. Finally, immunity can persist after active immunizations have ended.

Purpose: The primary objectives of this phase I/II study were to evaluate the safety and immunogenicity of combination therapy consisting of concurrent trastuzumab and human epidermal growth factor receptor 2 (HER2)/neu-specific vaccination in patients with HER2/neu-overexpressing metastatic breast cancer. Patients and Methods: Twenty-two patients with stage IV HER2/neu-positive breast cancer receiving trastuzumab therapy were vaccinated with an HER2/neu T-helper peptide-based vaccine. Toxicity was graded according to National Cancer Institute criteria, and antigen specific T-cell immunity was assessed by interferon gamma enzyme-linked immunosorbent spot assay. Data on progression-free and overall survival were collected. Results: Concurrent trastuzumab and HER2/neu vaccinations were well tolerated, with 15% of patients experiencing an asymptomatic decline in left ventricular ejection fraction below the normal range during combination therapy. Although many patients had pre-existing immunity specific for HER2/neu and other breast cancer antigens while treated with trastuzumab alone, that immunity could be significantly boosted and maintained with vaccination. Epitope spreading within HER2/neu and to additional tumor-related proteins was stimulated by immunization, and the magnitude of the T-cell response generated was significantly inversely correlated with serum transforming growth factor beta levels. At a median follow-up of 36 months from the first vaccine, the median overall survival in the study population has not been reached. Conclusion: Combination therapy with trastuzumab and a HER2/neu vaccine is associated with minimal toxicity and results in prolonged, robust, antigen-specific immune responses in treated patients.