Dr Craig Gedye

© 2017 The Author(s) Immune cells in the tumor microenvironment modulate cancer progression and are attractive therapeutic targets. Macrophages and T¿cells are key components of the microenvironment, yet their phenotypes and relationships in this ecosystem and to clinical outcomes are ill defined. We used mass cytometry with extensive antibody panels to perform in-depth immune profiling of samples from 73 clear cell renal cell carcinoma (ccRCC) patients and five healthy controls. In 3.5 million measured cells, we identified 17 tumor-associated macrophage phenotypes, 22 T¿cell phenotypes, and a distinct immune composition correlated with progression-free survival, thereby presenting an in-depth human atlas of the immune tumor microenvironment in this disease. This study revealed potential biomarkers and targets for immunotherapy development and validated tools that can be used for immune profiling of other tumor types.

© 2016, Spandidos Publications. All rights reserved. Approved by the Food and Drug Administration in 2011, the anti-cytotoxic T-lymphocyte-associated protein 4 checkpoint inhibitor ipilimumab has delivered a survival benefit of =3 years in a subset of metastatic melanoma patients. After participating in the registration trial, patients were treated with this agent in routine practice. Toxicity and efficacy of agents in ¿real world¿ settings may differ from trials. The present study aimed to evaluate, with respect to toxicity and outcome, all patients treated with ipilimumab to date at the Princess Margaret Hospital (Toronto, Canada). Patients treated with ipilimumab between 2008 and 2013 were identified, and patient characteristics (age, gender, tumour burden, oncogenic mutation status, number of treatments received and toxicities from treatment) were collected. Progression-free survival (PFS) and overall survival (OS) were calculated from the commencement of ipilimumab treatment. Associations between clinical characteristics and outcome or toxicity were assessed. Between 2008 and 2013, 129 patients with metastatic cutaneous melanoma were treated. Since, during this period, ipilimumab was approved in the second line setting, ipilimumab was delivered in the second or subsequent line in all patients, and 70% did not receive any further anticancer therapy. Immune-related toxicities were observed, the onset of which varied from 1 to 162 days. The majority resolved within 6 weeks of the final treatment, with the exception of endocrinopathies and bowel related toxicity. The median PFS and OS were 2.83 and 8.44 months, respectively. No pre-treatment factor independently predicted toxicity. The number of infusions (4 vs. =3) and presence of toxicity were significantly associated with superior survival. The onset of toxicity secondary to ipilimumab could occur later than previously reported. Toxicities were manageable, but required long-term vigilance.

Rare cancer stem cells (CSC) are proposed to be responsible for tumour propagation and re-initiation and are functionally defined by identifying tumour-initiating cells (TICs) using the xenotransplantation limiting dilution assay (LDA). While TICs in clear cell renal cell carcinoma (ccRCC) appeared rare in NOD/SCID/IL2R¿ 3 -/- (NSG) mice, xenografts formed more efficiently from small tumour fragments, indicating the LDA underestimated ccRCC TIC frequency. Mechanistic interrogation of the LDA identified multiple steps that influence ccRCC TIC quantitation. For example, tissue disaggregation destroys most ccRCC cells, common assays significantly overestimate tumour cell viability, and microenvironmental supplementation with human extracellular factors or pharmacological inhibition of anoikis increase clonogenicity and tumourigenicity of ccRCC cell lines and primary tumour cells. Identification of these previously uncharacterized concerns that cumulatively lead to substantial underestimation of TICs in ccRCC provides a framework for development of more accurate TIC assays in the future, both for this disease and for other cancers.

© 2015, Springer Science+Business Media New York. Cancer cell lines can be useful to model cancer stem cells. Infection with Mycoplasma species is an insidious problem in mammalian cell culture. While investigating stem-like properties in early passage melanoma cell lines, we noted poorly reproducible results from an aliquot of a cell line that was later found to be infected with Mycoplasma hyorhinis. Deliberate infection of other early passage melanoma cell lines aliquots induced variable and unpredictable effects on expression of putative cancer stem cell markers, clonogenicity, proliferation and global gene expression. Cell lines established in stem cell media (SCM) were equally susceptible. Mycoplasma status is rarely reported in publications using cultured cells to study the cancer stem cell hypothesis. Our work highlights the importance of surveillance for Mycoplasma infection while using any cultured cells to interrogate tumor heterogeneity.

© 2016 Cancer Research UK. Background:Radiological assessment of response to checkpoint inhibitors remains imperfect. We evaluated individual lesion and inter-patient response by response evaluation (RECIST) 1.1, immune-related response criteria (irRC), CHOI and modified CHOI (mCHOI) and correlated response with overall survival (OS).Methods:Thirty-seven patients with 567 measurable lesions treated with pembrolizumab in the Keynote 001 trial were studied. Association of response with OS was determined.Results:Response varied according to site; lung lesions had the highest rate of complete response (69 out of 163 (42%) vs other sites 71 out of 404 (18%), P < 0.0001). Delayed response post first scan was seen in 2 out of 37 (5%) deemed progressive (PD) by RECIST and 2 out of 14 (14%) deemed PD by irRC. Modified CHOI criteria showed response of 38% (14 out of 37). Change in tumour size and density on first follow-up assessment was associated with OS with each 1000 mm 2 increase in tumour size from baseline increasing the hazard of dying by 25.9% (HR=1.259, (95% CI=1.116-1.420), P=0.0002). Similarly, each 20HU increase in density increased the HR by 15% (HR=1.15, (95% CI 1.045-1.260), P=0.004). Response defined by any criteria had superior OS (CHOI P=0.0084; mCHOI P=0.0183; irRC P < 0.0001 and RECIST P=0.0003).Conclusions:Response by any criterion was prognostic. Novel patterns of response and changes on treatment in tumour density suggest complex anti-tumour responses to immunotherapy.

Malignant melanoma is the most aggressive of all cutaneous tumours, with over 76, 000 new cases and 9700 deaths estimated for 2014 in the United States.1 In Canada, both the incidence and mortality of melanoma are increasing, with a risk of developing melanoma being 1 in 59 for men and 1 in 73 for women.2 The incidence of melanoma is higher in Australia, with a risk of 1 in 14 for males and 1 in 23 for females to age 85 reported for 2009.3 Although early melanoma can be managed surgically, until recently there have been few advances in the treatment of advanced melanoma. However, with the introduction of molecular targeted therapies, the landscape of melanoma treatment has changed dramatically in the past five years, resulting in improved survival rates for patients with metastatic disease. In this review, we will discuss the molecular basis and implementation for some of these novel treatments with particular emphasis on BRAF and BRAF inhibitors.