Summary Regulatory T cells (Tregs) are a barrier to anti-tumor immunity. Neuropilin-1 (Nrp1) is required to maintain intratumoral Treg stability and function but is dispensable for peripheral immune tolerance. Treg-restricted Nrp1 deletion results in profound tumor resistance due to Treg functional fragility. Thus, identifying the basis for Nrp1 dependency and the key drivers of Treg fragility could help to improve immunotherapy for human cancer. We show that a high percentage of intratumoral NRP1+ Tregs correlates with poor prognosis in melanoma and head and neck squamous cell carcinoma. Using a mouse model of melanoma where Nrp1-deficient (Nrp1−/−) and wild-type (Nrp1+/+) Tregs can be assessed in a competitive environment, we find that a high proportion of intratumoral Nrp1−/− Tregs produce interferon-γ (IFNγ), which drives the fragility of surrounding WT Tregs, boosts anti-tumor immunity, and facilitates tumor clearance. We also show that IFNγ-induced Treg fragility is required for response to anti-PD1, suggesting that cancer therapies promoting Treg fragility may be efficacious.

We evaluated neoadjuvant ipilimumab in patients with surgically operable regionally advanced melanoma in order to define markers of activity in the blood and tumor as assessed at baseline (before ipilimumab) and early on-treatment. Patients were treated with ipilimumab (10 mg/kg intravenously every 3 weeks ×2 doses) bracketing surgery. Tumor and blood biospecimens were obtained at baseline and at surgery. Flow cytometry and immunohistochemistry for select biomarkers were performed. Thirty five patients were enrolled; IIIB (3; N2b), IIIC (32; N2c, N3), IV (2). Worst toxicities included Grade 3 diarrhea/colitis (5; 14%), hepatitis (2; 6%), rash (1; 3%), elevated lipase (3; 9%). Median follow up was 18 months: among 33 evaluable patients, median progression free survival (PFS) was 11 months, 95% CI (6.2–19.2). There was a significant decrease in circulating myeloid derived suppressor cells (MDSC). Greater decrease in circulating monocyte gate MDSC Lin1−/HLA-DR−/CD33+/CD11b+ was associated with improved PFS (p = 0.03). There was a significant increase in circulating regulatory T cells (Treg; CD4+CD25hi+Foxp3+) that, unexpectedly, was associated with improved PFS (HR = 0.57; p = 0.034). Baseline evidence of fully activated type I CD4+ and CD8+ antigen-specific T cell immunity against cancer-testis (NY-ESO-1) and melanocytic lineage (MART-1, gp100) antigens was detected and was significantly potentiated after ipilimumab. In tumor, there was a significant increase in CD8+ T cells after ipilimumab (p = 0.02). Ipilimumab induced increased tumor infiltration by fully activated (CD69+) CD3+/CD4+ and CD3+/CD8+ T cells with evidence of induction/potentiation of memory T cells (CD45RO+). The change in Treg observed within the tumor showed an inverse relationship with clinical benefit and greater decrease in tumor MDSC subset Lin1−/HLA-DR−/CD33+/CD11b+ was associated with improved PFS at one year. Neoadjuvant evaluation revealed a significant immunomodulating role for ipilimumab on Treg, MDSC and effector T cells in the circulation and tumor microenvironment that warrants further pursuit in the quest for optimizing melanoma immunotherapy.

Background Papillary thyroid carcinoma (PTC) has relatively indolent behavior, although some tumors recur and disseminate to distant sites. The aggressive biological behavior of PTC is difficult to predict. MicroRNAs (miRNAs) are dysregulated in various tumors types, and some of them serve as markers of poor prognosis. In this study, we evaluated miRNA expression as a marker of more aggressive behavior in PTC. Methods miRNA array was used to identify a subset of differentially expressed miRNAs between aggressive and non-aggressive PTC. These miRNAs were further validated by real-time RT-PCR in a cohort of 17 PTC with local tumor recurrence or distant metastases and 15 PTC with no extrathyroidal dissimination and correlated with BRAF, RAS, and RET/PTC mutations and MET expression. Results The miRNA array identified miR-146b, -221, -222, -155, -31 upregulation and miR-1, -34b, -130b, -138 downregulation in aggressive compared to non-aggressive PTC. Significant miRNA deregulation was confirmed in the validation cohort, with upregulation of miR-146b and miR-222 and downregulation of miR-34b and miR-130b seen in aggressive PTC. Among BRAF positive tumors, miR-146b showed strong association with aggressive PTC. MET was identified as a potential target gene for two downregulated miRNAs (miR-34b and miR-1), and significantly higher level of MET expression was observed in aggressive PTC. Conclusions We demonstrate that miR-146b, -222, -34b, -130b are differentially expressed in aggressive as compared to non-aggressive PTC. Among BRAF positive tumors, overexpression of miR-146b was associated with aggressive behavior, suggesting that it may further refine the prognostic importance of BRAF.

Oncotype DX is a commercial assay frequently used for making chemotherapy decisions in estrogen receptor (ER)-positive breast cancers. The result is reported as a recurrence score ranging from 0 to 100, divided into low-risk (<18), intermediate-risk (18–30), and high-risk (≥31) categories. Our pilot study showed that recurrence score can be predicted by an equation incorporating standard morphoimmunohistologic variables (referred to as original Magee equation). Using a data set of 817 cases, we formulated three additional equations (referred to as new Magee equations 1, 2, and 3) to predict the recurrence score category for an independent set of 255 cases. The concordance between the risk category of Oncotype DX and our equations was 54.3%, 55.8%, 59.4%, and 54.4% for original Magee equation, new Magee equations 1, 2, and 3, respectively. When the intermediate category was eliminated, the concordance increased to 96.9%, 100%, 98.6%, and 98.7% for original Magee equation, new Magee equations 1, 2, and 3, respectively. Even when the estimated recurrence score fell in the intermediate category with any of the equations, the actual recurrence score was either intermediate or low in more than 80% of the cases. Any of the four equations can be used to estimate the recurrence score depending on available data. If the estimated recurrence score is clearly high or low, the oncologists should not expect a dramatically different result from Oncotype DX, and the Oncotype DX test may not be needed. Conversely, an Oncotype DX result that is dramatically different from what is expected based on standard morphoimmunohistologic variables should be thoroughly investigated.

Screening for EGFR and KRAS mutations in patients with lung adenocarcinomas can be used to predict the patient's response to EGFR tyrosine kinase inhibitors, but there is a lack of guidelines for testing in clinical practice. We analyzed the morphological and clinicopathological characteristics, including tumor stage, size, presence of scar, inflammatory response, angiolymphatic and pleural invasion, of 345 surgically treated primary lung adenocarcinomas with respect to their EGFR and KRAS mutational profile and EGFR FISH. EGFR and KRAS mutations were found in 33 (10%) and 78 (23%) of lung adenocarcinomas, respectively, whereas 226 (67%) cases were negative for both mutations. There was a large overlap in the analyzed clinicopathological characteristics among the three study groups. Statistically significant predictors for the presence of EGFR mutations included history of never smoking (OR 5.939; 95% Wald confidence limit 1.662-21.223, P ¼ 0.0149), mild lymphocytic host response (OR 4.724; 95% Wald confidence limit 1.33-1.776; P ¼ 0.0163), female gender (OR 2.571; 95% Wald confidence limit 1.015-6.511, P ¼ 0.0463) and absence of solid growth pattern. Statistically significant predictors for the presence of KRAS mutations included older age (OR 1.034; 95% Wald confidence limit 1.007-1.062, P ¼ 0.0132), history of smoking (OR 0.617, 95% Wald confidence limit 0.357-1.066, P ¼ 0.0412) and mucinous differentiation. EGFR FISH positivity as defined by the Colorado criteria was a significant predictor of EGFR mutations, with high polysomy as the strongest predictive criteria. Despite statistically significant differences among the study groups and because of the large overlap in the analyzed clinicopathological criteria, none of these could be implemented as the selection criteria for molecular testing in clinical practice. The cost-effectiveness of lung carcinoma mutational testing would be improved by initial determination of KRAS mutational status as negative predictor of the patient's response to EGFR tyrosine kinase inhibitors, followed by EGFR mutational analysis, if necessary.