Localizing Positive Axillary Lymph Nodes in Breast Cancer Patients Post Neoadjuvant Therapy.

INTRODUCTION: Multiple trials demonstrated the feasibility of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy. Those trials reported > 10% false-negative rate; however, a subset analysis of the Z1071 trial demonstrated that removing the clipped positive lymph node (LN) during SLNB reduces the false-negative rate to 6.8% post neoadjuvant chemotherapy. This study examines the factors that might contribute to the ability to identify the clipped nodes post neoadjuvant therapy (NAT). MATERIALS AND METHODS: Breast cancer patients with biopsy-proven metastatic axillary LN who underwent NAT, converted to N0, had preoperative localization, and then SLNB between 2018 and 2020 at a single institution were identified. A retrospective chart review was performed. Demographic and preoperative variables were compared between localization and nonlocalization groups. RESULTS: Eighty patients who met inclusion criteria were included. A total of 39 patients were localized after NAT completion (49%). Only half of the patients with ultrasound-detectable marker clips were able to be localized. Minimal LN abnormality was seen in imaging after NAT completion in 39 patients and is significantly associated with localization; 26 (67%) were localized (Odds Ratio 4.31, P = 0.002, 95% Confidence Interval 1.69-10.98). CONCLUSIONS: Our study suggests that radiologically abnormal LNs on preoperative imaging after NAT completion are more likely to be localized. Nodes that ultimately normalize by imaging criteria remain a significant challenge to localize, and thus localization before starting NAT is suggested. A better technology is needed for LN localization after prolonged NAT for best accuracy and avoids repeated procedures.

HiChIRP reveals RNA-associated chromosome conformation.

Modular domains of long non-coding RNAs can serve as scaffolds to bring distant regions of the linear genome into spatial proximity. Here, we present HiChIRP, a method leveraging bio-orthogonal chemistry and optimized chromosome conformation capture conditions, which enables interrogation of chromatin architecture focused around a specific RNA of interest down to approximately ten copies per cell. HiChIRP of three nuclear RNAs reveals insights into promoter interactions (7SK), telomere biology (telomerase RNA component) and inflammatory gene regulation (lincRNA-EPS).

Molecular Tumor Board for Unicorns: Outcomes for rare and ultra-rare cancers using an N-of-One personalized treatment strategy.

Treatment of rare/ultra-rare tumors is an unmet need due to a lack of standardized therapies and clinical trials. We developed the Molecular Tumor Board (MTB), a multidisciplinary team that integrates molecular profiling to generate personalized, N-of-One treatments for advanced cancers. This study evaluates 112 patients with rare/ultra-rare tumors who presented to the MTB and were evaluable for clinical therapeutic outcome. Overall, 46/112 patients (41%) received a treatment regimen with a high degree of matching between tumor molecular alterations and drugs given (reflected by a high Matching Score (≥50%)). Patients with a high versus low Matching Score experienced significantly longer progression-free survival (p = 0.005) and overall survival (p = 0.047), and higher rates of clinical benefit (stable disease ≥6 months, partial response, or complete response) (54% vs. 32% p = 0.027). The MTB facilitated personalized N-of-One matching of drugs to tumor molecular alterations, which was associated with improved clinical outcomes in patients with rare/ultra-rare cancers.

Single-cell chromatin accessibility reveals malignant regulatory programs in primary human cancers.

To identify cancer-associated gene regulatory changes, we generated single-cell chromatin accessibility landscapes across eight tumor types as part of The Cancer Genome Atlas. Tumor chromatin accessibility is strongly influenced by copy number alterations that can be used to identify subclones, yet underlying cis-regulatory landscapes retain cancer type-specific features. Using organ-matched healthy tissues, we identified the "nearest healthy" cell types in diverse cancers, demonstrating that the chromatin signature of basal-like-subtype breast cancer is most similar to secretory-type luminal epithelial cells. Neural network models trained to learn regulatory programs in cancer revealed enrichment of model-prioritized somatic noncoding mutations near cancer-associated genes, suggesting that dispersed, nonrecurrent, noncoding mutations in cancer are functional. Overall, these data and interpretable gene regulatory models for cancer and healthy tissue provide a framework for understanding cancer-specific gene regulation.

Necrotizing Tracheitis Complicated by Tracheal Wall Perforation.

Necrotizing tracheitis is a rare condition, mainly seen in immunocompromised patients, that may lead to pseudomembrane formation, airway obstruction and in severe cases, tracheal perforation. We present a case of a 32-year-old male with poorly controlled diabetes who presented with productive cough, dysphagia, and respiratory distress. Bronchoscopy revealed extensive tracheal necrosis along a 4-5 cm segment of cartilaginous trachea and was complicated by tracheal perforation with false passage into the anterior mediastinum. Once the airway was re-established, a multidisciplinary team discussed options for definitive airway management, including tracheal reconstruction, pulmonary stent, or tracheostomy. Ultimately, a distal XLT tracheostomy was placed. Microbiology specimens of the tracheal tissue were positive for Actinomyces. The patient was started on long-term antibiotics and diabetes management. At three-month follow-up, the trachea was patent with near complete mucosalization of the previously necrotic segment. An area of proximal tracheal stenosis was successfully managed with a customized tracheal T-tube. In conclusion, this is a case of necrotizing tracheitis complicated by tracheal perforation. Successful treatment required a multidisciplinary team for airway management as well as medical treatment of immunocompromising risk factors and antimicrobial therapy. This enabled timely healing of the trachea and a durable airway.

Precision medicine-based therapies in advanced colorectal cancer: The University of California San Diego Molecular Tumor Board experience.

Treatment for advanced colorectal cancer is often limited by complex molecular profiles, which promote resistance to systemic agents and targeted monotherapies. Recent studies suggest that a personalized, combinatorial approach of matching drugs to tumor alterations may be more effective. We implemented a precision medicine strategy by forming a Molecular Tumor Board (MTB), a multidisciplinary team of clinicians, scientists, bioinformaticians and geneticists. The MTB integrated molecular profiling information and patient characteristics to develop N-of-One treatments for 51 patients with advanced colorectal cancer. All patients had metastatic disease and 63% had received ≥ 3 prior therapy lines. Overall, 34/51 patients (67%) were matched to ≥ 1 drug recommended by the MTB based on individual tumor characteristics, whereas 17/51 (33%) patients received unmatched therapies. Patients who received matched therapy demonstrated significantly longer progression-free survival (hazard ratio [HR], 0.41; 95% confidence interval [CI], 0.21-0.81; P = 0.01) and a trend towards higher clinical benefit rates (41% vs. 18%, P = 0.058) (all multivariate) compared to patients receiving unmatched therapy. The MTB facilitated personalized matching of drugs to tumor characteristics, which was associated with improved progression-free survival in patients with advanced colorectal cancer.

Pan-cancer molecular tumor board experience with biomarker-driven precision immunotherapy.

Despite remarkable responses to immune checkpoint blockade (ICB) in some advanced cancers, most patients do not benefit, perhaps due to the complexity of tumor/immune/genome interactions. We implemented a multidisciplinary Molecular Tumor Board (MTB) that reviewed multi-omic cancer characteristics to develop N-of-One therapies for patients in the pan-cancer, advanced, refractory setting. This study evaluates the experience of 80 patients who were presented to the MTB and received a treatment regimen that included ICB. Overall, 60/80 patients (75%) who received ICB following MTB discussion had a high degree of matching between tumor molecular characteristics, including ICB biomarkers (reflected by a high Matching Score (≥50%)) and therapy administered. Patients with high versus low Matching Score experienced significantly longer median progression-free survival (6.4 vs. 3.0 months; p = 0.011) and median overall survival (15.3 vs. 4.7 months; p = 0.014) and higher clinical benefit rates (stable disease ≥6 months/partial response/complete response) (53% vs. 21%, p = 0.019). Although most patients (52/80 (65%)) received a personalized combination therapy (e.g., targeted, hormonal, chemotherapy, or a second immunotherapy agent), administering >1 drug was not associated with outcome. Only degree of matching and age, but no other variables, including individual biomarkers (e.g., microsatellite status, tumor mutational burden, or PD-L1 status), were independently correlated with outcome. In the pan-cancer setting, the MTB facilitated a precision medicine strategy to match therapeutic regimens that included ICB alone or combined with matched targeted drugs to patients with advanced malignancy, which was associated with improved clinical outcomes.

BAP1: Not just a BRCA1-associated protein.

BRCA1-Associated Protein 1 (BAP1) is a ubiquitin carboxy-terminal hydrolase that has been established as a tumor suppressor, utilizing its deubiquitinating activity to regulate a number of processes including DNA damage repair, cell cycle control, chromatin modification, programmed cell death, and the immune response. Mutations in the BAP1 gene commonly result in a number of aggressive cancers; predominantly uveal melanoma, malignant mesothelioma, renal cell carcinoma, and cutaneous melanoma. Importantly, germline mutations in the BAP1 gene have been established as a novel tumor predisposition syndrome, conferring an increased risk of hereditary, early-onset cancers. Current treatment options for cancers with BAP1 alterations are limited to standard therapies. However, several therapeutic avenues have been proposed to specifically target BAP1 alterations in cancer. Molecularly targeted approaches include histone deacetylase inhibitors and EZH2 inhibitors to target the role of BAP1 in chromatin modification and transcriptional regulation, respectively. PARP inhibitors and platinum chemotherapy agents have the potential to target BAP1-altered tumors, due to the role of BAP1 in DNA damage repair. Lastly, emerging reports suggest that BAP1 alterations in cancer confer distinct immunogenic phenotypes that may be particularly susceptible to novel cancer immunotherapies. This review aims to present a concise and up to date report on the BAP1 gene in cancer, surveying its functional roles, characteristics and clinical manifestations. Furthermore, we highlight the established and emerging therapeutic options for BAP1-mutated cancers.

Single-cell epigenomic analyses implicate candidate causal variants at inherited risk loci for Alzheimer's and Parkinson's diseases.

Genome-wide association studies of neurological diseases have identified thousands of variants associated with disease phenotypes. However, most of these variants do not alter coding sequences, making it difficult to assign their function. Here, we present a multi-omic epigenetic atlas of the adult human brain through profiling of single-cell chromatin accessibility landscapes and three-dimensional chromatin interactions of diverse adult brain regions across a cohort of cognitively healthy individuals. We developed a machine-learning classifier to integrate this multi-omic framework and predict dozens of functional SNPs for Alzheimer's and Parkinson's diseases, nominating target genes and cell types for previously orphaned loci from genome-wide association studies. Moreover, we dissected the complex inverted haplotype of the MAPT (encoding tau) Parkinson's disease risk locus, identifying putative ectopic regulatory interactions in neurons that may mediate this disease association. This work expands understanding of inherited variation and provides a roadmap for the epigenomic dissection of causal regulatory variation in disease.

The chromatin accessibility landscape of primary human cancers.

We present the genome-wide chromatin accessibility profiles of 410 tumor samples spanning 23 cancer types from The Cancer Genome Atlas (TCGA). We identify 562,709 transposase-accessible DNA elements that substantially extend the compendium of known cis-regulatory elements. Integration of ATAC-seq (the assay for transposase-accessible chromatin using sequencing) with TCGA multi-omic data identifies a large number of putative distal enhancers that distinguish molecular subtypes of cancers, uncovers specific driving transcription factors via protein-DNA footprints, and nominates long-range gene-regulatory interactions in cancer. These data reveal genetic risk loci of cancer predisposition as active DNA regulatory elements in cancer, identify gene-regulatory interactions underlying cancer immune evasion, and pinpoint noncoding mutations that drive enhancer activation and may affect patient survival. These results suggest a systematic approach to understanding the noncoding genome in cancer to advance diagnosis and therapy.