Tumor-derived extracellular vesicles as a biomarker for breast cancer diagnosis and metastasis monitoring.

It is imperative to explore biomarkers that are both precise and readily accessible in the comprehensive management of breast cancer. A multicenter cohort, including 512 breast cancer patients and 198 nonneoplastic individuals, was recruited to detect the level of tumor-derived extracellular vesicles using our method based on dual DNA tetrahedral nanostructures. The level of tumor-derived extracellular vesicles was significantly higher in newly diagnosed breast cancer patients than in nonneoplastic individuals at a cutoff value of 3.58 U/µL. For postoperative metastasis monitoring, the level of tumor-derived extracellular vesicles was significantly higher in breast cancer patients with metastasis than in those without metastasis at a cutoff value of 3.91 U/µL. Its efficacy of diagnosis and metastasis monitoring was superior to traditional tumor markers. Elevated level of tumor-derived extracellular vesicles served as a predictive biomarker for diagnosis and metastasis monitoring in breast cancer patients.

Hypoxia stimulates CTC-platelet cluster formation to promote breast cancer metastasis.

Circulating tumor cell clusters/micro-emboli (CTM) possess greater metastatic capacity and survival advantage compared to individual circulating tumor cell (CTC). However, the formation of CTM subtypes and their role in tumor metastasis remain unclear. In this study, we used a microfluidic Cluster-Chip with easy operation and high efficiency to isolate CTM from peripheral blood, which confirmed their correlation with clinicopathological features and identified the critical role of CTC-platelet clusters in breast cancer metastasis. The correlation between platelets and CTM function was further confirmed in a mouse model and RNA sequencing of CTM identified high-expressed genes related to hypoxia stimulation and platelet activation which possibly suggested the correlation of hypoxia and CTC-platelet cluster formation. In conclusion, we successfully developed the Cluster-Chip platform to realize the clinical capture of CTMs and analyze the biological properties of CTC-platelet clusters, which could benefit the design of potential treatment regimens to prevent CTM-mediated metastasis and tumor malignant progression.

Comparative Analysis of Predictive Biomarkers for PD-1/PD-L1 Inhibitors in Cancers: Developments and Challenges.

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) have dramatically changed the landscape of cancer therapy. Both remarkable and durable responses have been observed in patients with melanoma, non-small-cell lung cancer (NSCLC), and other malignancies. However, the PD-1/PD-L1 blockade has demonstrated meaningful clinical responses and benefits in only a subset of patients. In addition, several severe and life-threatening adverse events were observed in these patients. Therefore, the identification of predictive biomarkers is urgently needed to select patients who are more likely to benefit from ICI therapy. PD-L1 expression level is the most commonly used biomarker in clinical practice for PD-1/PD-L1 inhibitors. However, negative PD-L1 expression cannot reliably exclude a response to a PD-1/PD-L1 blockade. Other factors, such as tumor microenvironment and other tumor genomic signatures, appear to impact the response to ICIs. In this review, we examine emerging data for novel biomarkers that may have a predictive value for optimizing the benefit from anti-PD-1/PD-L1 immunotherapy.

Variants with a low allele frequency detected in genomic DNA affect the accuracy of mutation detection in cell-free DNA by next-generation sequencing.

BACKGROUND: Next-generation sequencing of cell-free DNA (cfDNA) has been shown to be a useful noninvasive test for detecting mutations in solid tumors. METHODS: Targeted gene sequencing was performed with a panel of 263 cancer-related genes for cfDNA and genomic DNA of peripheral blood mononuclear cells (PBMCs) obtained from presurgical specimens of 6 lung cancer patients, and mutation calls in these samples were compared with those of primary tumors and corresponding patient-derived xenografts (PDXs). RESULTS: Approximately 67% of the mutations detected in the tumor samples (primary tumors and/or PDXs) were also detected in genomic DNA from PBMCs as background mutations. These background mutations consisted of germline polymorphisms and a group of mutations with low allele frequencies, mostly <10%. These variants with a low allele frequency were repeatedly detected in all types of samples from the same patients and at similarly low allele frequency levels in PBMCs from different patients; this indicated that their detection might be derived from common causes, such as homologous sequences in the human genome. Allele frequencies of mutations detected in both primary tumors and cfDNA showed 2 patterns: 1) low allele frequencies (approximately 1%-10%) in cfDNA but high allele frequencies (usually >10% or >3-fold increase) in primary tumors and further enrichment in PDXs and 2) similar allele frequencies across samples. CONCLUSIONS: Because only a small fraction of total cfDNA might be derived from tumor cells, only mutations with the first allele frequency pattern may be regarded as tumor-specific mutations in cfDNA. Effective filtering of background mutations will be required to improve the accuracy of mutation calls in cfDNA. Cancer 2018;124:1061-9. © 2017 American Cancer Society.

Overcoming resistance to anti-PD immunotherapy in a syngeneic mouse lung cancer model using locoregional virotherapy.

Anti-PD-1 and anti-PD-L1 immunotherapy has provided a new therapeutic opportunity for treatment of advanced-stage non-small cell lung cancer (NSCLC). However, overall objective response rates are approximately 15%-25% in all NSCLC patients who receive anti-PD therapy. Therefore, strategies to overcome primary resistance to anti-PD immunotherapy are urgently needed. We hypothesized that the barrier to the success of anti-PD therapy in most NSCLC patients can be overcome by stimulating the lymphocyte infiltration at cancer sites through locoregional virotherapy. To this end, in this study, we determined combination effects of anti-PD immunotherapy and oncolytic adenoviral vector-mediated tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL) gene therapy (Ad/E1-TRAIL) or adenoviral-mediated TP53 (Ad/CMV-TP53) gene therapy in syngeneic mice bearing subcutaneous tumors derived from M109 lung cancer cells. Both anti-PD-1 and anti-PD-L1 antibodies failed to elicit obvious therapeutic effects in the M109 tumors. Intratumoral administration of Ad/E1-TRAIL or Ad/CMV-TP53 alone suppressed tumor growth in animals preexposed to an adenovector and bearing subcutaneous tumors derived from M109 cells. However, combining either anti-PD-1 or anti-PD-L1 antibody with these two adenoviral vectors elicited the strongest anticancer activity in mice with existing immunity to adenoviral vectors. Dramatically enhanced intratumoral immune response was detected in this group of combination therapy based on infiltrations of CD4+ and CD8+ lymphocytes and macrophages in tumors. Our results demonstrate that resistance to anti-PD-1 immunotherapy in syngeneic mouse lung cancer can be overcome by locoregional virotherapy.