Molecular characterization of squamous cell carcinoma of the anal canal.

BACKGROUND: Squamous cell carcinoma of the anal canal (SCCA) is an uncommon malignancy with limited therapeutic options. Nivolumab and pembrolizumab show promising results in patients with SCCA. Human papillomavirus (HPV)-negative tumors are frequently TP53-mutated (TP53-MT) and often resistant to therapy. METHODS: We present a large molecularly-profiled cohort of SCCA, exploring the underlying biology of SCCA, differences between TP53-wild type (TP53-WT) and TP53-MT tumors, and differences between local and metastatic tumors. SCCA specimens (n=311) underwent multiplatform testing with immunohistochemistry (IHC), in situ hybridization (ISH) and next-generation sequencing (NGS). Tumor mutational burden (TMB) was calculated using only somatic nonsynonymous missense mutations. Chi-square testing was used for comparative analyses. RESULTS: The most frequently mutated genes included PIK3CA (28.1%), KMT2D (19.5%), FBXW7 (12%), TP53 (12%) and PTEN (10.8%). The expression of PD-1 was seen in 68.8% and PD-L1 in 40.5% of tumors. High TMB was present in 6.7% of specimens. HER2 IHC was positive in 0.9%, amplification by chromogenic in situ hybridization (CISH) was seen 1.3%, and mutations in ERBB2 were present in 1.8% of tumors. The latter mutation has not been previously described in SCCA. When compared with TP53-WT tumors, TP53-MT tumors had higher rates of CDKN2A, EWSR1, JAK1, FGFR1 and BRAF mutations. PD-1 and PD-L1 expression were similar, and high TMB did not correlate with PD-1 (P=0.50) or PD-L1 (P=0.52) expression. CONCLUSIONS: Molecular profiling differences between TP53-MT and TP53-WT SCCA indicate different carcinogenic pathways which may influence response to therapy. Low frequency mutations in several druggable genes may provide therapeutic opportunities for patients with SCCA.

Molecular Profiling in Metastatic Colorectal Cancer.

Colorectal cancer (CRC) is a commonly diagnosed malignancy. Although chemotherapy remains the backbone of treatment, the landscape of treating metastatic CRC (mCRC) is changing with the understanding of its heterogeneity and molecular blueprint. Colon cancer sidedness has proven to hold prognostic implications, with right-sided tumors having higher incidence of BRAF and KRAS mutations and being microsatellite instability-high (MSI-H); overall, they have a worse prognosis compared with left sided-tumors. Results of molecular research have demonstrated the need to profile each mCRC patient for RAS and BRAF mutations, MSI-H status, HER2 amplifications, and NTRK fusions. Ongoing clinical trials using targeted agents aim to further improve survival outcomes. We emphasize the epidemiology, knowledge of primary tumor location, and mutational landscape of mCRC, as well as novel treatment options for patients harboring unique subtypes of these characteristics.

Immunotherapy with single agent nivolumab for advanced leiomyosarcoma of the uterus: Results of a phase 2 study.

BACKGROUND: Immunotherapy has changed the therapeutic landscape in oncology. Advanced uterine leiomyosarcoma (ULMS) remains an incurable disease in most cases, and despite new drug approvals, improvements in overall survival have been modest at best. The goal of this study was to evaluate programmed-death 1 (PD-1) inhibition with nivolumab in this patient population. METHODS: This single-center phase 2 trial completed enrollment between May and October 2015. Patients received 3 mg/kg of intravenous nivolumab on day 1 of each 2-week cycle until disease progression or unacceptable toxicity. The primary endpoint was objective response rate. We assessed PD-1, PD-ligand 1 (PD-L1), and PD-L2 expression in archival tumor samples and variations in immune-phenotyping of circulating immune cells during treatment. RESULTS: Twelve patients were enrolled in the first stage of the 2-stage design. A median of 5 (range, 2-6) 2-week cycles of nivolumab were administered. Of the 12 patients, none responded to treatment. The overall median progression-free survival was 1.8 months (95% confidence interval, 0.8-unknown). The study did not open the second stage due to lack of benefit as defined by the statistical plan. Archival samples were available for 83% of patients. PD-1 (>3% of cells), PD-L1, and PD-L2 (>5% and >10% of tumor cells, respectively) expression were observed in 20%, 20%, and 90% of samples, respectively. No significant differences were observed between pre- and posttreatment cell phenotypes. CONCLUSION: Single-agent nivolumab did not demonstrate a benefit in this cohort of previously treated advanced ULMS patients. Further biomarker-driven approaches and studies evaluating combined immune checkpoint-modulators should be considered. Cancer 2017;123:3285-90. © 2017 American Cancer Society.

Effect of DNase I treatment and neutrophil depletion on acute limb ischemia-reperfusion injury in mice.

OBJECTIVE: Extracellular traps (ETs) consisting of DNA-protein complexes formed after tissue injury contribute to the inflammatory and thrombosis cascades, thereby exacerbating injury. Exogenous DNase I has been suggested as a therapeutic strategy to limit injury in the brain and myocardium. These studies were designed to evaluate the effects of exogenous DNase I treatment on skeletal muscle injury after acute hindlimb ischemia-reperfusion (IR) injury in mice and to determine whether neutrophils are a major source of ETs in postischemic muscle tissue. METHODS: C57BL6 mice were subjected to 1.5 hours of tourniquet ischemia and 24 hours of reperfusion with and without human recombinant DNase I treatment. A separate set of mice was subjected to neutrophil depletion (ND), followed by the same intervals of IR. Laser Doppler imaging and tissue harvesting were done at 24 hours for assessment of limb perfusion, muscle fiber injury, adenosine triphosphate (ATP) level, markers of inflammation, thrombosis, and formation of ETs. RESULTS: DNase I treatment significantly reduced detection of ETs in postischemic muscle but did not alter skeletal muscle fiber injury, levels of proinflammatory molecules, or ATP level. DNase I treatment did enhance postischemic hindlimb perfusion, decreased infiltrating inflammatory cells, and reduced the expression of thrombin-antithrombin III. ND resulted in a significant yet small reduction in ETs in the postischemic muscle. ND did not alter skeletal muscle fiber injury, hindlimb perfusion, or ATP levels. CONCLUSIONS: These data suggest that neither DNase I treatment nor ND was protective against IR injury, even though both decreased detection of ETs in skeletal muscle after IR. Neutrophils are not the only source of ETs after IR.