Understanding the Decomposition of Dimethyl Methyl Phosphonate on Metal-Modified TiO2(110) Surfaces Using Ensembles of Product Configurations

The decomposition of dimethyl methyl phosphonate (DMMP), a simulant for the nerve agent sarin, was investigated on Cu4/TiO2(110) and K/Cu4/TiO2(110) surfaces using a combination of near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory calculations (DFT). Mass-selected Cu4 clusters and potassium (K) atoms were deposited onto TiO2(110) as a metal catalyst and alkali promoter to improve the reactivity and recyclability of the TiO2 surface after exposure to DMMP. Surface reaction products resulting from decomposition of DMMP were probed by NAP-XPS measurements of phosphorus (P) 2p and carbon 1s core-level spectra. The Cu4/TiO2(110) surface is found to be very active for DMMP decomposition with highly reduced P-species observed even at room temperature (RT). The codeposition of K atoms and Cu4 clusters further improves the reactivity with no intact DMMP detectable. Temperature-dependent measurements show that the presence of K atoms promotes the removal of residual P-species at temperatures > 600 K. Detailed DFT calculations were performed to determine the surface structures and energetically accessible pathways for DMMP decomposition on Cu4/TiO2(110) and K/Cu4/TiO2(110) surfaces. The calculations show that DMMP and P-containing reaction products preferentially bind to the TiO2 surface, while the molecular fragments, i.e., methoxy and methyl, bind to both the Cu4 clusters and TiO2. The Cu4 clusters make the P-O, O-C, and P-C bond cleavages of DMMP markedly more exothermic. The Cu4 clusters are highly fluxional with atomic structures that depend on the configuration of fragments bound to them. Finally, the manifold of P 2p chemical shifts calculated for a large number of energetically favorable configurations of decomposition products is in good agreement with the observed XPS spectra and provides an alternative way of interpreting incompletely resolved core-level spectra using an ensemble of observed structures.

The current multidisciplinary management of rectal cancer

Multidisciplinary management of rectal cancer has rapidly evolved over the last several years. This review describes recent data surrounding total neoadjuvant therapy, organ preservation, and management of lateral pelvic lymph nodes. It then presents our treatment algorithm for management of rectal cancer at The University of Texas MD Anderson Cancer Center in the context of this and other existing literature. As part of this discussion, the review describes how we tailor management based upon both patient and tumor-related factors in an effort to optimize patient outcomes.

Metastasis and the Microbiome: The Impact of Bacteria in Disseminated Colorectal Cancer

Metastasis remains a leading cause of mortality for patients with solid tumors. An expanding body of literature suggests interplay between the host, gut, and tumoral microbiomes may play a role in cancer initiation and distant dissemination. These associations have been particularly well-studied in colorectal cancer, where gut dysbiosis and an endotoxin-induced inflammatory milieu foster premalignant polyp formation, setting the stage for carcinogenesis. Subsequent violation of the gut vascular barrier enables dissemination of bacterial agents to sites such as the liver, where they contribute to establishment of pre-metastatic niches, which promote tumor cell extravasation and metastatic outgrowth. Intriguingly, breakdown of this vascular barrier has been shown to be aided by the presence of tumoral bacteria. The presence of similar species, including Fusobacterium nucleatum and Escherichia Coli, in both primary and metastatic colorectal tumors, supports this hypothesis and their presence is associated with chemotherapy resistance and an overall poor prognosis. Specific gut microbial populations are also associated with differential response to immunotherapy, which has a growing role in microsatellite unstable colorectal cancers. Recent work suggests that modulation of gut microbiome using dietary modification, targeted antibiotics, or fecal microbiota transplantation may improve response to immunotherapy and oncologic outcomes. Elucidation of the precise mechanistic links between the microbiome and cancer dissemination will open the doors to additional therapeutic possibilities.

Immuno-Oncology: New Insights into Targets and Therapies

The role of immunotherapy in the care of surgical oncology patients promises to expand as investigators and clinicians evaluate new targets and approaches. Currently active clinical trials evaluate new immune checkpoints, including lymphocyte activation gene 3, T cell immunoreceptor with Ig and ITIM domains, and killer Ig-like receptor 2DL1/2L3. Vaccines delivered through mRNA have demonstrated exciting results in early clinical trials and hold promise for expanded application. Investigational approaches include dendritic cell vaccines, peptide vaccines, cytokines therapies, and cellular therapies. These studies have the potential to revolutionize the management of surgical oncology patients and promote durable cures following surgical resection.

Androgen drives melanoma invasiveness and metastatic spread by inducing tumorigenic fucosylation

Melanoma incidence and mortality rates are historically higher for men than women. Although emerging studies have highlighted tumorigenic roles for the male sex hormone androgen and its receptor (AR) in melanoma, cellular and molecular mechanisms underlying these sex-associated discrepancies are poorly defined. Here, we delineate a previously undisclosed mechanism by which androgen-activated AR transcriptionally upregulates fucosyltransferase 4 (FUT4) expression, which drives melanoma invasiveness by interfering with adherens junctions (AJs). Global phosphoproteomic and fucoproteomic profiling, coupled with in vitro and in vivo functional validation, further reveal that AR-induced FUT4 fucosylates L1 cell adhesion molecule (L1CAM), which is required for FUT4-increased metastatic capacity. Tumor microarray and gene expression analyses demonstrate that AR-FUT4-L1CAM-AJs signaling correlates with pathological staging in melanoma patients. By delineating key androgen-triggered signaling that enhances metastatic aggressiveness, our findings help explain sex-associated clinical outcome disparities and highlight AR/FUT4 and its effectors as potential prognostic biomarkers and therapeutic targets in melanoma.

Serum Tumor Markers and Outcomes in Patients With Appendiceal Adenocarcinoma

Importance

Serum tumor markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) have been useful in the management of gastrointestinal and gynecological cancers; however, there is limited information regarding their utility in patients with appendiceal adenocarcinoma.

Objective

To assess the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes and pathologic and molecular features in patients with appendiceal adenocarcinoma.

Design, Setting, and Participants

This is a retrospective cohort study at a single tertiary care comprehensive cancer center. The median (IQR) follow-up time was 52 (21-101) months. Software was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least 1 tumor marker measured at MD Anderson between March 2016 and May 2023. Data were analyzed from January to December 2023.

Main Outcomes and Measures

Association of serum tumor markers with survival in patients with appendiceal adenocarcinoma. Cox proportional hazards regression analyses were also performed to assess associations between clinical factors (serum tumor marker levels, demographics, and patient and disease characteristics) and patient outcomes (overall survival).

Results

A total of 1338 patients with appendiceal adenocarcinoma were included, with a median (range) age at diagnosis of 56.5 (22.3-89.6) years. The majority of the patients had metastatic disease (1080 patients [80.7%]). CEA was elevated in 742 of the patients tested (56%), while CA19-9 and CA125 were elevated in 381 patients (34%) and 312 patients (27%), respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; elevated vs normal was 81% vs 95% for CEA (hazard ratio [HR], 4.0; 95% CI, 2.9-5.6), 84% vs 92% for CA19-9 (HR, 2.2; 95% CI, 1.4-3.4), and 69% vs 93% for CA125 (HR, 4.6; 95% CI, 2.7-7.8) (P < .001 for all). Quantitative evaluation of tumor markers was associated with outcomes. Patients with highly elevated (top 10th percentile) CEA, CA19-9, or CA125 had markedly worse survival, with 5-year survival rates of 59% for CEA (HR, 9.8; 95% CI, 5.3-18.0), 64% for CA19-9 (HR, 6.0; 95% CI, 3.0-11.7), and 57% for CA125 (HR, 7.6; 95% CI, 3.5-16.5) (P < .001 for all). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease, elevated CEA, CA19-9, or CA125 were all still associated worse survival (HR for CEA, 3.4; 95% CI, 2.5-4.8; P < .001; HR for CA19-9, 1.8; 95% CI, 1.2-2.7; P = .002; and HR for CA125, 3.9; 95% CI, 2.4-6.4; P < .001). Interestingly, tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high-grade tumors relative to low-grade tumors (mean value, 18.3 vs 15.0; difference, 3.3; 95% CI, 0.9-3.7; P < .001). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with an 11-fold increased risk of death in patients with all 3 tumor markers elevated relative to those with none elevated. Somatic mutations in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9.

Conclusions and Relevance

In this retrospective study of serum tumor markers in patients with appendiceal adenocarcinoma, CEA, CA19-9, and CA125 were associated with overall survival in appendiceal adenocarcinoma. Given their value, all 3 biomarkers should be included in the initial workup of patients with a diagnosis of appendiceal adenocarcinoma.

Repeat Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Recurrent Mucinous Appendiceal Adenocarcinoma: A Viable Treatment Strategy with Demonstrable Benefit

INTRODUCTION

Many patients with mucinous appendiceal adenocarcinoma experience peritoneal recurrence despite complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Prior work has demonstrated that repeat CRS/HIPEC can prolong survival in select patients. We sought to validate these findings using outcomes from a high-volume center.

PATIENTS AND METHODS

Patients with mucinous appendiceal adenocarcinoma who underwent CRS/HIPEC at MD Anderson Cancer Center between 2004 and 2021 were stratified by whether they underwent CRS/HIPEC for recurrent disease or as part of initial treatment. Only patients who underwent complete CRS/HIPEC were included. Initial and recurrent groups were compared.

RESULTS

Of 437 CRS/HIPECs performed for mucinous appendiceal adenocarcinoma, 50 (11.4%) were for recurrent disease. Patients who underwent CRS/HIPEC for recurrent disease were more often treated with an oxaliplatin or cisplatin perfusion (35%/44% recurrent vs. 4%/1% initial, p < 0.001), had a longer operative time (median 629 min recurrent vs. 511 min initial, p = 0.002), and had a lower median length of stay (10 days repeat vs. 13 days initial, p < 0.001). Thirty-day complication and 90-day mortality rates did not differ between groups. Both cohorts enjoyed comparable recurrence free survival (p = 0.82). Compared with patients with recurrence treated with systemic chemotherapy alone, this select cohort of patients undergoing repeat CRS/HIPEC enjoyed better overall survival (p < 0.001).

CONCLUSIONS

In appropriately selected patients with recurrent appendiceal mucinous adenocarcinoma, CRS/HIPEC can provide survival benefit equivalent to primary CRS/HIPEC and that may be superior to that conferred by systemic therapy alone in select patients. These patients should receive care at a high-volume center in the context of a multidisciplinary team.

Treatment Variation and Long-Term Outcomes of Low-Grade Appendiceal Neoplasms

BACKGROUND

Heterogenous nomenclature describing appendiceal neoplasms has added to uncertainty around their appropriate treatment. Although a recent consensus has established the term low-grade appendiceal neoplasm (LAMN), we hypothesize that significant variation remains in the treatment of LAMNs.

METHODS

We retrospectively reviewed our prospectively maintained appendiceal registry, identifying patients with LAMNs from 2009 to 2019. We assessed variability in treatment, including whether patients underwent colectomy, spread of disease at presentation, and long-term outcomes.

RESULTS

Of 136 patients with LAMNs, 88 (35%) presented with localized disease and 48 (35%) with disseminated peritoneal disease. Median follow-up was 2.9 years (IQR 1.9-4.4), and 120 (88%) patients underwent pre-referral surgery. Among 26 pre-referral colectomy patients, 23 (88%) were performed for perceived oncologic need/nodal evaluation; no nodal metastases were identified. In patients with resected LAMNs without radiographic evidence of disseminated disease, 41 (47%) underwent second look diagnostic laparoscopy (DL) to evaluate for occult metastases. No peritoneal metastases were identified. Patients with disseminated disease were treated with cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC). For patients undergoing CRS/HIPEC, 5-year recurrence-free survival was 94% (95% CI 81-98%). For patients with localized disease, 5-year RFS was 98% (95% CI 85-99%).

CONCLUSIONS

Significant variation exists in treatment patterns for LAMNs, particularly prior to referral to a high-volume center. Patients frequently underwent colectomy without apparent oncologic benefit. In the current era of high-quality cross sectional imaging, routine use of DL has low yield and is not recommended. Recurrence in this population is rare, and low-intensity surveillance can be offered. Overall prognosis is excellent, even with peritoneal disease.

Communication Frameworks for Palliative Surgical Consultations: A Randomized Study of Advanced Cancer Patients

OBJECTIVE

To evaluate whether patients with advanced cancer prefer surgeons to use the best case/worst case (BC/WC) communication framework over the traditional risk/benefit (R/B) framework in the context of palliative surgical scenarios.

BACKGROUND

Identifying the patient's preferred communication frameworks may improve satisfaction and outcome measures during difficult clinical decision-making.

METHODS

In a video-vignette-based randomized, double-blinded study from November 2020 to May 2021, patients with advanced cancer viewed 2 videos depicting a physician-patient encounter in a palliative surgical scenario, in which the surgeon uses either the BC/WC or the R/B framework to discuss treatment options. The primary outcome was the patients' preferred video surgeon.

RESULTS

One hundred fifty-five patients were approached to participate; 66 were randomized and 58 completed the study (mean age 55.8 ± 13.8 years, 60.3% males). 22 patients (37.9%, 95% CI: 25.4%-50.4%) preferred the surgeon using the BC/WC framework, 21 (36.2%, 95% CI: 23.8%-48.6%) preferred the surgeon using the R/B framework, and 15 (25.9%, 95% CI: 14.6%-37.2%) indicated no preference. High trust in the medical profession was inversely associated with a preference for the surgeon using BC/WC framework (odds ratio: 0.83, 95% CI: 0.70-0.98, P = 0.03). The BC/WC framework rated higher for perceived surgeon's listening (4.6 ± 0.7 vs 4.3±0.9, P = 0.03) and confidence in the surgeon's trustworthiness (4.3 ± 0.8 vs 4.0 ± 0.9, P = 0.04).

CONCLUSIONS

Surgeon use of the BC/WC communication framework was not universally preferred but was as acceptable to patients as the traditional R/B framework and rated higher in certain aspects of communication. A preference for a surgeon using BC/WC was associated with lower trust in the medical profession. Surgeons should consider the BC/WC framework to individualize their approach to challenging clinical discussions.

Intraperitoneal Paclitaxel Is a Safe and Effective Therapeutic Strategy for Treating Mucinous Appendiceal Adenocarcinoma

Appendiceal adenocarcinomas (AA) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, which has partly contributed to AA remaining an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given the localization of AA to the peritoneal space, intraperitoneal delivery of chemotherapy could be an effective treatment strategy. Here, we tested the efficacy of paclitaxel given by intraperitoneal administration using three orthotopic patient-derived xenograft (PDX) models of AA established in immunodeficient NSG mice. Weekly intraperitoneal paclitaxel treatment dramatically reduced AA tumor growth in all three PDX models. Comparing the safety and efficacy of intravenous with intraperitoneal administration, intraperitoneal delivery of paclitaxel was more effective, with reduced systemic side effects in mice. Given the established safety record of intraperitoneal paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of intraperitoneal paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of intraperitoneal paclitaxel in a prospective clinical trial.

SIGNIFICANCE

The activity and safety of intraperitoneal paclitaxel in orthotopic PDX models of mucinous appendiceal adenocarcinoma supports the evaluation of intraperitoneal paclitaxel in a prospective clinical trial of this rare tumor type.

Young-onset Rectal Cancer: Unique Tumoral Microbiome and Correlation With Response to Neoadjuvant Therapy

OBJECTIVE

External exposures, the host, and the microbiome interact in oncology. We aimed to investigate tumoral microbiomes in young-onset rectal cancers (YORCs) for profiles potentially correlative with disease etiology and biology.

BACKGROUND

YORC is rapidly increasing, with 1 in 4 new rectal cancer cases occurring under the age of 50 years. Its etiology is unknown.

METHODS

YORC (<50 y old) or later-onset rectal cancer (LORC, ≥50 y old) patients underwent pretreatment biopsied of tumor and tumor-adjacent normal (TAN) tissue. After whole genome sequencing, metagenomic analysis quantified microbial communities comparing tumors versus TANs and YORCs versus LORCs, controlling for multiple testing. Response to neoadjuvant therapy (NT) was categorized as major pathological response (MPR, ≤10% residual viable tumor) versus non-MPR.

RESULTS

Our 107 tumors, 75 TANs from 37 (35%) YORCs, and 70 (65%) LORCs recapitulated bacterial species were previously associated with colorectal cancers (all P <0.0001). YORC and LORC tumoral microbiome signatures were distinct. After NT, 13 patients (12.4%) achieved complete pathologic response, whereas MPR occurred in 47 patients (44%). Among YORCs, MPR was associated with Fusobacterium nucleaum , Bacteroides dorei, and Ruminococcus bromii (all P <0.001), but MPR in LORC was associated with R. bromii ( P <0.001). Network analysis of non-MPR tumors demonstrated a preponderance of oral bacteria not observed in MPR tumors.

CONCLUSIONS

Microbial signatures were distinct between YORC and LORC. Failure to achieve an MPR was associated with oral bacteria in tumors. These findings urge further studies to decipher correlative versus mechanistic associations but suggest a potential for microbial modulation to augment current treatments.

Aggregation of Size-Selected Oxide Clusters Deposited onto Au(111)

Kinetic Monte Carlo (kMC) simulations along with density functional theory (DFT) calculations were used to investigate the aggregation of size-selected Nb3Oy (y = 5, 6, 7) clusters deposited onto the Au(111) surface. Recent STM experiments showed that the cluster binding sites and sizes of the cluster assemblies on the Nb3Oy/Au(111) surfaces strongly depend on the stoichiometry of the clusters, i.e., the oxygen-to-niobium ratio. To better understand the origins of these differences, kMC simulations of the nucleation and growth of cluster assemblies were performed using energy barriers for diffusion and intercluster interactions estimated from DFT calculations of cluster binding and dimerization energies, respectively. Comparisons of the kMC simulations with STM images of the as-deposited Nb3Oy/Au(111) surfaces at RT and after high temperature annealing were used to further optimize the energetics and gauge the importance of nearest neighbor interactions. The kMC simulations demonstrate that the assembly of Nb3Oy clusters on Au(111) are largely controlled by the magnitude of the barriers for diffusion and interparticle-bond formation, while changes at higher temperatures are sensitive to the binding energies between nearest neighbors. Simulations for the Nb3O5 and Nb3O6 clusters, which exhibit smaller cluster assembly sizes in STM, required larger diffusion barriers as well as different barriers for interparticle binding, which reflected differences in DFT calculated dimerization energies. The results demonstrate the effectiveness of combined DFT and kMC calculations for understanding how the stoichiometry affects the aggregation of small oxide clusters on a metal surface.

The Clinical Significance of CEA, CA19-9, and CA125 in Management of Appendiceal Adenocarcinoma

Importance

Serum tumor markers CEA, CA19-9, & CA125 have been useful in the management of gastrointestinal and gynecological cancers, however there is limited information regarding their utility in patients with appendiceal adenocarcinoma.

Objective

Assessing the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes, pathologic, and molecular features in patients with appendiceal adenocarcinoma.

Design

This is a retrospective study with results reported in 2023. The median follow-up time was 43 months.

Setting

Single tertiary care comprehensive cancer center.

Participants

Under an approved Institutional Review Board protocol, the Palantir Foundry software system was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least one tumor marker measured at MD Anderson between 2016 and 2023.

Results

A total of 1,338 patients with appendiceal adenocarcinoma were included, with a median age of 56.5 years. The majority of the patients had metastatic disease (80.7%). CEA was elevated in more than half of the patients tested (56%), while CA19-9 and CA125 were elevated in 34% and 27%, respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; 82% vs 95%, 84% vs 92%, and 69% vs 93% elevated vs normal for CEA, CA19-9, and CA125 respectively (all p<0.0001). Quantitative evaluation of tumor markers increased prognostic ability. Patients with highly elevated (top 10th percentile) CEA, CA19-9 or CA125 had markedly worse survival with 5-year survival rates of 59%, 64%, and 57%, respectively (HR vs. normal : 9.8, 6.0, 7.6, all p<0.0001). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease elevated CEA, CA19-9 or CA125 were all still associated worse survival (HR vs. normal : 3.4, 1.8, 3.9, p<0.0001 for CEA and CA125, p=0.0019 for CA19-9). Interestingly tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high relative to low-grade tumors (18.3 vs. 15.0, p=0.0009). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with a 11-fold increased risk of death in patients with all three tumor markers elevated relative to those with none elevated. Mutation in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9.

Conclusions

These findings demonstrate the utility of measuring CEA, CA19-9, and CA125 in the management of appendiceal adenocarcinoma. Given their prognostic value, all three biomarkers should be included in the initial workup of patients diagnosed with appendiceal adenocarcinoma.

Stranger Things: New Roles and Opportunities for Androgen Receptor in Oncology Beyond Prostate Cancer

The androgen receptor (AR) is one of the oldest therapeutic targets in oncology and continues to dominate the treatment landscape for advanced prostate cancer, where nearly all treatment regimens include some form of AR modulation. In this regard, AR remains the central driver of prostate cancer cell biology. Emerging preclinical and clinical data implicate key roles for AR in additional cancer types, thereby expanding the importance of this drug target beyond prostate cancer. In this mini-review, new roles for AR in other cancer types are discussed as well as their potential for treatment with AR-targeted agents. Our understanding of these additional functions for AR in oncology expand this receptor's potential as a therapeutic target and will help guide the development of new treatment approaches.

Antitumor activity of intraperitoneal paclitaxel in orthotopic patient-derived xenograft models of mucinous appendiceal adenocarcinoma

Appendiceal adenocarcinomas (AAs) are a rare and heterogeneous mix of tumors for which few preclinical models exist. The rarity of AA has made performing prospective clinical trials difficult, and in part because of this AA remains an orphan disease with no chemotherapeutic agents approved by the FDA for its treatment. AA has a unique biology in which it frequently forms diffuse peritoneal metastases, but almost never spreads via a hematogenous route and rarely spreads to lymphatics. Given its localization to the peritoneal space we hypothesized that intraperitoneal (IP) delivery of chemotherapy could be an effective treatment strategy. Here we tested the efficacy paclitaxel given by IP administration using three orthotopic PDX models of AA established in NSG mice. Weekly treatment of 25.0 mg/kg of IP paclitaxel dramatically reduced AA tumor growth in TM00351 (81.9% reduction vs. control), PMP-2 (98.3% reduction vs. control), and PMCA-3 (71.4% reduction vs. control) PDX models. Comparing the safety and efficacy of intravenous (IV) to IP administration in PMCA-3, neither 6.25 nor 12.5 mg/kg of IV paclitaxel significantly reduced tumor growth. These results suggest that IP administration of paclitaxel is favorable to IV administration. Given the established safety record of IP paclitaxel in gastric and ovarian cancers, and lack of effective chemotherapeutics for AA, these data showing the activity of IP paclitaxel in orthotopic PDX models of mucinous AA support the evaluation of IP paclitaxel in a prospective clinical trial.

The Influence of the Microbiome on Metastatic Colorectal Cancer

The microbiome (bacteria, viruses, and fungi) that exist within a patient's gastrointestinal tract and throughout their body have been increasingly understood to play a critical role in a variety of disease, including a number of cancer histologies. These microbial colonies are reflective of a patient's overall health state, their exposome, and germline genetics. In the case of colorectal adenocarcinoma, significant progress has been made in understanding the mechanism the microbiome plays beyond mere associations in both disease initiation and progression. Importantly, this improved understanding holds the potential to further identify the role these microbes play in colorectal cancer. We hope this improved understanding will be able to be leveraged in the future through either biomarkers or next-generation therapeutics to augment contemporary treatment algorithms through the manipulation of a patient's microbiome-whether through diet, antibiotics, prebiotics, or novel therapeutics. Here we review the role of the microbiome in the setting of patients with stage IV colorectal adenocarcinoma in both the development and progression or disease as well as response to therapeutics.

Fucosylation of HLA-DRB1 regulates CD4+ T cell-mediated anti-melanoma immunity and enhances immunotherapy efficacy

Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs); thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the major histocompatibility complex (MHC)-II protein HLA-DRB1 in melanoma cells, triggering CD4+ T cell-mediated increases in itICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-programmed cell death protein 1 (PD1) responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity and, importantly, suggest that L-fucose is a powerful agent for safely increasing itICs and immunotherapy efficacy in melanoma.

Momentum-Resolved Exciton Coupling and Valley Polarization Dynamics in Monolayer WS_{2}

Using time- and angle-resolved photoemission, we present momentum- and energy-resolved measurements of exciton coupling in monolayer WS_{2}. We observe strong intravalley coupling between the B_{1s} exciton and A_{n>1} states. Our measurements indicate that the dominant valley depolarization mechanism conserves the exciton binding energy and momentum. While this conservation is consistent with Coulomb exchange-driven valley depolarization, we do not observe a momentum or energy dependence to the depolarization rate as would be expected for the exchange-based mechanism.

A role for the claustrum in cognitive control

Early hypotheses of claustrum function were fueled by neuroanatomical data and yielded suggestions that the claustrum is involved in processes ranging from salience detection to multisensory integration for perceptual binding. While these hypotheses spurred useful investigations, incompatibilities inherent in these views must be reconciled to further conceptualize claustrum function amid a wealth of new data. Here, we review the varied models of claustrum function and synthesize them with developments in the field to produce a novel functional model: network instantiation in cognitive control (NICC). This model proposes that frontal cortices direct the claustrum to flexibly instantiate cortical networks to subserve cognitive control. We present literature support for this model and provide testable predictions arising from this conceptual framework.

Abstract B027: Circulating tumor DNA in colorectal carcinomatosis: Detection and prognostic value

Background: Circulating tumor DNA (ctDNA) of patients with colorectal peritoneal metastases (PM) was obtained to identify prognostic factors associated for ctDNA detection and with overall survival (OS). Prior studies have identified a correlation between ctDNA detection and OS in colorectal liver metastases (CRLM) and after resection of primary tumors. However, detection rates for PM may be lower than other metastatic sites. Methods: Peripheral blood was drawn from 152 patients after diagnosis with PM with or without other synchronous sites of disease. Patients who underwent cytoreduction were excluded. Next-generation sequencing of a panel of 70 genes commonly mutated in colorectal cancer was performed on all samples. Mutations were identified and variant allele frequencies (VAFs) calculated. Clinical data including OS from time of CRCC diagnosis, tumor grade, tumor histology, synchronous non-peritoneal metastases and patient demographics were obtained from medical records .Chi-squared tests were performed to compare differences in ctDNA detection based on clinical factors, and Cox regression analyses were performed to identify associations with ctDNA characteristics and OS. Results: The overall detection rate of any mutation in ctDNA was 74.3% (110/145 patients). The most frequently detected mutations were TP53 (55%), APC (47%), KRAS (32%), and PIK3CA (14%). Sensitivity for detecting individual mutations ranged from 50%-63%. Mucinous and signet-ring cell histology were more common in patients with PM alone (Mucinous: 37% vs 24%, p=0.0003, Signet Ring Cell: 10% vs. 2.2%, p=0.0001) and associated with lower sensitivity (mucinous: 59%, signet-ring cell: 57% and adenocarcinoma 85%, p=0.002). Synchronous CRLM were associated with increased detection compared to PM alone (88% vs. 68%, p=0.011). After adjustment for differences in histology, synchronous CRLM (OR 3.32, 95CI: 1.52-8.02, p=0.016) was associated with higher detection rates. Grade was not associated with detection (moderately differentiated: 79%, poorly differentiated: 74%, p=0.81). Detection of any ctDNA was associated with a trend towards worse OS (HR 2.18, 95% CI: 0.98-4.95, p=0.06). KRAS (HR 2.02, 95% CI: 1.14-3.60, p=0.017) and PIK3CA (HR 2.26, 95% CI: 1.07-4.78, p=0.033) ctDNA detection was associated worse OS. Detection of multiple mutations (HR: 0.85, 95% CI 0.50-1.42, p=0.52) and maximum VAF (HR 0.99, 95% CI: 0.97- 1.01, p=0.17) were not associated with OS. Conclusion: ctDNA detection is lower in patients with PM alone compared to those with PM and CRLM. Mucinous tumors had lower rates of ctDNA detection after accounting for extra-PM metastases. Presence of ctDNA is associated with a trend towards worse OS, especially for patients with detectable mutations in KRAS or PIK3CA. Quantification of ctDNA by number of mutations or VAF was not associated with OS. Interpretation of ctDNA results for PM patients should take into consideration the lower sensitivity in the absence of other metastatic sites, but may have prognostic utility.

Citation Format: Abhineet Uppal, Michael G. White, George J. Chang, Scott Kopetz, John Paul Y. C. Shen. Circulating tumor DNA in colorectal carcinomatosis: Detection and prognostic value [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr B027.

The Microbiome in Gastrointestinal Cancers

The human microbiome has been recognized as increasingly important to health and disease. This is especially prescient in the development of various cancers, their progression, and the microbiome's modulation of various anticancer therapeutics. Mechanisms behind these interactions have been increasingly well described through modulation of the host immune system as well as induction of genetic changes and local inactivation of cancer therapeutics. Here, we review these associations for a variety of gastrointestinal malignancies as well as contemporary strategies proposed to leverage these associations to improve cancer treatment outcomes.

Androgen receptor blockade promotes response to BRAF/MEK-targeted therapy

Treatment with therapy targeting BRAF and MEK (BRAF/MEK) has revolutionized care in melanoma and other cancers; however, therapeutic resistance is common and innovative treatment strategies are needed^1,2. Here we studied a group of patients with melanoma who were treated with neoadjuvant BRAF/MEK-targeted therapy ( NCT02231775 , n = 51) and observed significantly higher rates of major pathological response (MPR; ≤10% viable tumour at resection) and improved recurrence-free survival (RFS) in female versus male patients (MPR, 66% versus 14%, P = 0.001; RFS, 64% versus 32% at 2 years, P = 0.021). The findings were validated in several additional cohorts^2-4 of patients with unresectable metastatic melanoma who were treated with BRAF- and/or MEK-targeted therapy (n = 664 patients in total), demonstrating improved progression-free survival and overall survival in female versus male patients in several of these studies. Studies in preclinical models demonstrated significantly impaired anti-tumour activity in male versus female mice after BRAF/MEK-targeted therapy (P = 0.006), with significantly higher expression of the androgen receptor in tumours of male and female BRAF/MEK-treated mice versus the control (P = 0.0006 and P = 0.0025). Pharmacological inhibition of androgen receptor signalling improved responses to BRAF/MEK-targeted therapy in male and female mice (P = 0.018 and P = 0.003), whereas induction of androgen receptor signalling (through testosterone administration) was associated with a significantly impaired response to BRAF/MEK-targeted therapy in male and female patients (P = 0.021 and P < 0.0001). Together, these results have important implications for therapy.

The Microbiome: the Link to Colorectal Cancer and Research Opportunities

OPINION STATEMENT

In recent years, we have seen an increase in the study and interest of the role of the microbiome in the development of malignancies, their progression, and evasion of therapies. This has been particularly fruitful in the case of colorectal cancer; multiple investigators have described correlative observations as well as hypotheses strengthened in preclinical studies that have begun to elucidate the critical role the gut and tumoral microbiome plays in carcinogenesis. Furthermore, these landmark studies lay the groundwork in describing the microbiome's role in carcinogenesis and provide a rich field of future study. Here, we review contemporary understandings of these observations and proposed mechanisms behind them.

Tumor MHC Class I Expression Associates with Intralesional Interleukin-2 Response in Melanoma

Cancer immunotherapy can result in lasting tumor regression, but predictive biomarkers of treatment response remain ill-defined. Here, we performed single-cell proteomics, transcriptomics, and genomics on matched untreated and interleukin-2 (IL-2) injected metastases from patients with melanoma. Lesions that completely regressed following intralesional IL-2 harbored increased fractions and densities of non-proliferating CD8+ T cells lacking expression of PD-1, LAG-3 and TIM-3 (PD-1-LAG-3-TIM-3-). Untreated lesions from patients who subsequently responded with complete eradication of all tumor cells in all injected lesions (individuals referred to herein as "extreme responders") were characterized by proliferating CD8+ T cells with an exhausted phenotype (PD-1+LAG-3+TIM-3+), stromal B-cell aggregates, and expression of IFNgamma and IL-2 response genes. Loss of membranous MHC class I expression in tumor cells of untreated lesions was associated with resistance to IL-2 therapy. We validated this finding in an independent cohort of metastatic melanoma patients treated with intralesional or systemic IL-2. Our study suggests that intact tumor cell antigen presentation is required for melanoma response to IL-2 and describes a multi-dimensional and spatial approach to develop immuno-oncology biomarker hypotheses using routinely collected clinical biospecimens.

Generalized Electrical Substitution Methods and Detectors for Absolute Optical Power Measurements

We have developed generalized methods for electrical substitution optical measurements, as well as cryogenic detectors which can be used to implement them. The new methods detailed here enable measurement of arbitrary periodic waveforms by an electrical substitution radiometer (ESR), which means that spectral and dynamic optical power can be absolutely calibrated directly by a primary standard detector. Cryogenic ESRs are not often used directly by researchers for optical calibrations due to their slow response times and cumbersome operation. We describe two types of ESRs with fast response times, including newly developed cryogenic bolometers with carbon nanotube absorbers, which are manufacturable by standard microfabrication techniques. These detectors have response times near 10 ms, spectral coverage from the ultraviolet to far-infrared, and are ideal for use with generalized electrical substitution. In our first tests of the generalized electrical substitution method with FTS, we have achieved uncertainty in detector response of 0.13 % (k=1) and total measurement uncertainty of 1.1 % (k=1) in the mid-infrared for spectral detector responsivity calibrations. The generalized method and fast detectors greatly expand the range of optical power calibrations which can be made using a wideband primary standard detector, which can shorten calibration chains and improve uncertainties.

Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response

Gut bacteria modulate the response to immune checkpoint blockade (ICB) treatment in cancer, but the effect of diet and supplements on this interaction is not well studied. We assessed fecal microbiota profiles, dietary habits, and commercially available probiotic supplement use in melanoma patients and performed parallel preclinical studies. Higher dietary fiber was associated with significantly improved progression-free survival in 128 patients on ICB, with the most pronounced benefit observed in patients with sufficient dietary fiber intake and no probiotic use. Findings were recapitulated in preclinical models, which demonstrated impaired treatment response to anti–programmed cell death 1 (anti–PD-1)–based therapy in mice receiving a low-fiber diet or probiotics, with a lower frequency of interferon-γ–positive cytotoxic T cells in the tumor microenvironment. Together, these data have clinical implications for patients receiving ICB for cancer.

Gastrointestinal Surgical Emergencies in the Neutropenic Immunocompromised Patient

Surgeons encounter neutropenic patients through elective or emergency consultation with increasing regularity. As medical management continues to extend the lives of patients with benign hematologic diseases, hematologic malignancies, solid malignancies, or iatrogenic neutropenia, more patients are presenting with infectious complications caused and/or complicated by their neutropenia. This leaves surgeons in the difficult position of managing medically fragile patients with unusual presentations of common disease processes. These patients often fall outside of classical guidelines and treatment pathways. Many studies addressing these issues are retrospective and non-randomized. Here, we review common emergency gastrointestinal surgery scenarios and their management in the setting of a neutropenic patient. While biliary disease, appendicitis, anorectal disease, and perforations will be covered in detail, an extensive appreciation of a patient's medical or oncologic disease course and appropriate utilization of consultants such as interventional radiology, gastroenterology, and hematology is often necessary.

Short-term treatment with multi-drug regimens combining BRAF/MEK-targeted therapy and immunotherapy results in durable responses in Braf-mutated melanoma

Targeted and immunotherapy regimens have revolutionized the treatment of advanced melanoma patients. Despite this, only a subset of patients respond durably. Recently, combination strategies of BRAF/MEK inhibitors with immune checkpoint inhibitor monotherapy (α-CTLA-4 or α-PD-1) have increased the rate of durable responses. Based on evidence from our group and others, these therapies appear synergistic, but at the cost of significant toxicity. We know from other treatment paradigms (e.g. hematologic malignancies) that combination strategies with multi-drug regimens (>4 drugs) are associated with more durable disease control. To better understand the mechanism of these improved outcomes, and to identify and prioritize new strategies for testing, we studied several multi-drug regimens combining BRAF/MEK targeted therapy and immunotherapy combinations in a Braf-mutant murine melanoma model (Braf^V600E/Pten^−/−). Short-term treatment with α-PD-1 and α-CTLA-4 monotherapies were relatively ineffective, while treatment with α-OX40 demonstrated some efficacy [17% of mice with no evidence of disease, (NED), at 60-days]. Outcomes were improved in the combined α-OX40/α-PD-1 group (42% NED). Short-term treatment with quadruplet therapy of immunotherapy doublets in combination with targeted therapy [dabrafenib and trametinib (DT)] was associated with excellent tumor control, with 100% of mice having NED after combined DT/α-CTLA-4/α-PD-1 or DT/α-OX40/α-PD-1. Notably, tumors from mice in these groups demonstrated a high proportion of effector memory T cells, and immunologic memory was maintained with tumor re-challenge. Together, these data provide important evidence regarding the potential utility of multi-drug therapy in treating advanced melanoma and suggest these models can be used to guide and prioritize combinatorial treatment strategies.

Identification of MicroRNA-mRNA Networks in Melanoma and Their Association with PD-1 Checkpoint Blockade Outcomes

Metastatic melanoma is a deadly malignancy with poor outcomes historically. Immuno-oncology (IO) agents, targeting immune checkpoint molecules such as cytotoxic T-lymphocyte associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1), have revolutionized melanoma treatment and outcomes, achieving significant response rates and remarkable long-term survival. Despite these vast improvements, roughly half of melanoma patients do not achieve long-term clinical benefit from IO therapies and there is an urgent need to understand and mitigate mechanisms of resistance. MicroRNAs are key post-transcriptional regulators of gene expression that regulate many aspects of cancer biology, including immune evasion. We used network analysis to define two core microRNA-mRNA networks in melanoma tissues and cell lines corresponding to 'MITF-low' and 'Keratin' transcriptomic subsets of melanoma. We then evaluated expression of these core microRNAs in pre-PD-1-inhibitor-treated melanoma patients and observed that higher expression of miR-100-5p and miR-125b-5p were associated with significantly improved overall survival. These findings suggest that miR-100-5p and 125b-5p are potential markers of response to PD-1 inhibitors, and further evaluation of these microRNA-mRNA interactions may yield further insight into melanoma resistance to PD-1 inhibitors.

Surface structure of mass-selected niobium oxide nanoclusters on Au(111)

The structures formed by the deposition of mass-selected niobium oxide clusters, Nb₃O_y(y = 5, 6, 7), onto Au(111) were studied by scanning tunneling microscopy. The as-deposited Nb₃O₇clusters assemble into large dendritic structures that grow on the terraces as well as extend from the top and bottom of step edges. The Nb₃O₆cluster also forms dendritic assemblies but they are generally much smaller in size. The assemblies are composed of smaller discrete structures (<1 nm) which are likely to be single clusters. The dendritic assemblies for both the Nb₃O₇and Nb₃O₆clusters have fractal dimensions of about 1.7 which is very close to that expected for simple diffusion limited aggregation. Annealing the Nb₃O_7,6/Au(111) surfaces up to 550 K results in changes in assembly sizes and increases in heights, while heating to 700 results in the disruption of the assemblies into smaller structures. By contrast, the as-deposited Nb₃O₅/Au(111) surface at RT exhibits compact cluster structures which become 3D nanoparticles when annealed above 550 K. Differences in the observed surface structures and thermal stability are attributed to differences in metal-oxygen stoichiometry which can influence cluster binding energies, mobility and inter-cluster interactions.

Gut microbiota signatures are associated with toxicity to combined CTLA-4 and PD-1 blockade

Treatment with combined immune checkpoint blockade (CICB) targeting CTLA-4 and PD-1 is associated with clinical benefit across tumor types, but also a high rate of immune-related adverse events. Insights into biomarkers and mechanisms of response and toxicity to CICB are needed. To address this, we profiled the blood, tumor and gut microbiome of 77 patients with advanced melanoma treated with CICB, with a high rate of any ≥grade 3 immune-related adverse events (49%) with parallel studies in pre-clinical models. Tumor-associated immune and genomic biomarkers of response to CICB were similar to those identified for ICB monotherapy, and toxicity from CICB was associated with a more diverse peripheral T-cell repertoire. Profiling of gut microbiota demonstrated a significantly higher abundance of Bacteroides intestinalis in patients with toxicity, with upregulation of mucosal IL-1β in patient samples of colitis and in pre-clinical models. Together, these data offer potential new therapeutic angles for targeting toxicity to CICB.

Combined mechanical and oral antibiotic bowel preparation is associated with prolonged recurrence-free survival following surgery for colorectal cancer

BACKGROUND AND OBJECTIVES

Recent studies suggest that bacteria influence the pathogenesis of primary colorectal cancer (CRC), yet their role in recurrence after resection is largely unknown. We have discovered that collagenase-producing bacteria promote cancer recurrence in mice, and that antibiotic bowel decontamination decreases colonization of these same organisms in humans. We hypothesized that preoperative combined mechanical and oral antibiotic bowel preparation would improve disease-free survival (DFS) in patients undergoing surgery for CRC.

METHODS

We reviewed a cancer registry of patients treated for CRC at a tertiary center. Patients who received bowel preparation were compared to those that did not via a 1:1-propensity score matched for follow-up, age, sex, BMI, stage, location, chemoradiation, infection, anastomotic leak, and blood transfusion.

RESULTS

One thousand two hundred and seventy-nine patients met inclusion criteria. Following propensity score matching, 264 patients receiving bowel prep were matched to 264 patients who did not. Kaplan-Meier estimates showed that patients who received bowel prep had a significantly improved 5-year DFS compared to those that did not (76.3% vs. 64.2%; p < .01). Cox regression demonstrated that bowel prep was associated with improved DFS (HR, 0.57; 95% CI, 0.37-0.89; p < .01).

CONCLUSION

Combined mechanical and oral antibiotic bowel preparation is independently associated with improved recurrence-free survival in patients undergoing surgery for CRC.

Abstract 2909: Tumor microbiota profiles are associated with molecular subtype and survival in colorectal cancer patients

Background: The intestinal microbiome is intimately involved in the pathogenesis of colorectal cancer and likely holds further insights to improve the treatment and management of this deadly disease. In a clinical cohort of patients with colon and rectal cancers, we characterized the tumor microbiota of surgical specimens and evaluated associations with prognostic factors, consensus molecular subtypes (CMS), and survival.

Methods: In 167 patients diagnosed with stage II through IV colon and/or rectal cancer who underwent evaluation and surgical resection (no prior systemic therapy) at The University of Texas MD Anderson Cancer, we characterized the tumor microbiome via 16S rRNA gene sequencing. Each patient's tumor was classified via CMS, a gene expression-based colorectal cancer classification system; and all patients were prospectively followed for disease progression, recurrence, or death. Microbiota diversity and composition were assessed with regard to clinicopathologic and tumor features; and associations with survival were further evaluated in multivariable Cox proportional hazards models.

Results: Left- vs. right-sided colon tumors were characterized by higher microbial diversity, distinct community features, and increased abundance of Bacteroides and Fusobacterium. CMS1 (microsatellite instability immune) vs. CMS2 (canonical) tumors were characterized by higher Bacteroides and Fusobacterium and lower Escherichia (all P&lt;0.05). Fusobacterium-positive and Escherichia-positive tumors were associated with improved 5-year overall survival [presence vs. absence, multivariable-adjusted HR and 95% CI: 0.43 (0.20-0.93) and 0.32 (0.19-0.78), respectively]. Bacteroides was enriched among stage II/III patients who progressed within 2-years (log-rank p&lt;0.001).

Conclusions: Our findings are consistent with those of other groups suggesting the landscape of the tumor microbiome differs by sidedness and molecular subtype, holding important clues and exploitable targets to improve outcomes in colorectal cancer patients.

Citation Format: Fangyu Li, Michael G. White, Jennifer Davis, Kristi L. Hoffman, David Menter, Nadim Ajami, Xiaotao Zhang, Jeffrey S. Morris, Robert R. Jenq, Joseph Petrosino, Jennifer A. Wargo, Scott Kopetz, Carrie R. Daniel. Tumor microbiota profiles are associated with molecular subtype and survival in colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2909.

Robotic Completion Radical Cholecystectomy with Fluorescence Guidance

The application of minimally invasive surgery (MIS) techniques in the treatment of hepatobiliary malignancies offers advantages of shorter length of stay, quicker functional recovery, and decreased need for postoperative opioids. However, MIS completion radical cholecystectomy for incidentally diagnosed gallbladder cancer can be challenging due to a reoperative field and lack of tactile feedback. This video demonstrates the utility of the robotic platform and highlights the ways in which it assists surgeons in overcoming these limitations. These include (1) versatile wristed instruments and excellent visualization that facilitate a thorough regional lymphadenectomy; and (2) built-in fluorescence imaging technology that can be used with intravenous indocyanine green (ICG) to confirm porta hepatis anatomy in a reoperative field. ICG pharmacokinetics enable fluorescence angiography 15-20 s after ICG injection and fluorescence cholangiography 15-20 min after ICG injection as the dye accumulates in the biliary system. Systematic and intentional application of these techniques allows for the safe performance of robotic completion radical cholecystectomy following sound oncologic principles, with excellent perioperative outcomes.

Heterogeneity in PD-L1 expression in malignant peritoneal mesothelioma with systemic or intraperitoneal chemotherapy

Programmed death-ligand 1 (PD-L1) expression has been described in patients with malignant peritoneal mesothelioma (MPM), but treatment strategies utilising immune checkpoint inhibition are yet to be defined. Here, we examine levels of PD-L1 expression in MPM patients treated with systemic and/or intraperitoneal chemotherapy using tissue from patient tumour biopsies or resections at multiple time points. We found the mean PD-L1 expression was higher in those with a germline mutation and/or those with a higher somatic mutation burden. Moreover, PD-L1 expression was lower in patients who had received prior chemotherapy as compared to the treatment-naive cohort. Twenty patients who received chemotherapy, either systemic and/or peritoneal, between PD-L1 measurements showed marked heterogeneity. Six (30%) patients demonstrated upregulation of PD-L1, while eight (40%) demonstrated downregulation. Heterogeneity in PD-L1 expression in MPM before and after cytotoxic therapies may present an additional consideration when initiating immune checkpoint inhibition in this rare and challenging disease.

Room temperature laser power standard using a microfabricated, electrical substitution bolometer

The design and performance of a room temperature electrical substitution radiometer for use as an absolute standard for measuring continuous-wave laser power over a wide range of wavelengths, beam diameters, and powers are described. The standard achieves an accuracy of 0.46% (k = 2) for powers from 10 mW to 100 mW and 0.83% (k = 2) for powers from 1 mW to 10 mW and can accommodate laser beam diameters (1/e²) up to 11 mm and wavelengths from 300 nm to 2 μm. At low power levels, the uncertainty is dominated by sensitivity to fluctuations in the thermal environment. The core of the instrument is a planar, silicon microfabricated bolometer with vertically aligned carbon nanotube absorbers, commercial surface mount thermistors, and an integrated heater. Where possible, commercial electronics and components were used. The performance was validated by comparing it to a National Institute of Standards and Technology primary standard through a transfer standard silicon trap detector and by comparing it to the legacy "C-series" standards in operation at the U.S. Air Force Metrology and Calibration Division (AFMETCAL).

Measurement of Portal Vein Blood Circulating Tumor Cells is Safe and May Correlate With Outcomes in Resected Pancreatic Ductal Adenocarcinoma

BACKGROUND

This study investigated the safety and feasibility of intraoperative portal vein blood (PVB) collection at the time of pancreatic ductal adenocarcinoma (PDAC) resection. Relationships of circulating tumor cells (CTCs) in PVB and peripheral blood (PB) with overall survival (OS) and recurrence-free survival were studied.

METHODS

Patients undergoing PDAC resection were offered enrollment in a prospective liquid biopsy protocol. The patients had PB drawn before incision and PVB drawn before tumor mobilization, then again immediately after resection. Using standard CellSearch protocols, CTCs were identified and compared with OS.

RESULTS

Of the 34 patients enrolled in this study, 23 (68%) underwent pancreaticoduodenectomy, 8 (23%) underwent distal pancreatectomy, and 3 (9%) underwent total pancreatectomy. Peripheral blood was available for 22 (65%) and PVB for 31 (91%) of the patients. No bleeding or thrombotic complications occurred with the PVB draws. The CTC counts per 7.5 mL of PVB collected before and after resection were highly correlated (R² = 0.89). The study found CTCs in 11 (50%) of 22 PB samples and 22 (71%) of 31 PVB samples. The OS rate at 18 months was 92% for the patients with < 3 CTCs, 71% for the patients with ≥ 3 CTCs per 7.5 mL of PB (p = 0.30), 100% for the patients without PVB CTCs, and 70% for the patients with PVB CTCs (p < 0.01).

CONCLUSIONS

Collection of PVB during PDAC resection is safe. In this pilot study, PVB CTC counts but not PB CTC counts were significantly correlated with OS. This opens the door for future studies on selective omission of adjuvant chemotherapy for patients treated preoperatively and tailored surveillance intensity for patients without PVB CTCs at PDAC resection.

Comparison of Molecular Methods and BRAF Immunohistochemistry (VE1 Clone) for the Detection of BRAF V600E Mutation in Papillary Thyroid Carcinoma: A Meta-Analysis

The evaluation of surgically resected papillary thyroid carcinomas (PTC) by immunohistochemistry (IHC) for BRAF mutation has diagnostic, prognostic and therapeutic implications. The goal of this meta-analysis was to perform a systematic review of studies using the VE1 clone (specific for detection of the BRAF V600E mutation) on formalin-fixed paraffin embedded (FFPE) thyroid surgical resection specimens for primary papillary thyroid carcinoma. The authors' molecular techniques, immunohistochemistry protocols, and scoring methods for VE1 immunostaining were also evaluated. This study included 4079 PTCs representing data from 23 studies. The results extracted from each study were split into two different groups, direct sequencing group or PCR group, based on the molecular "gold standard" method used to compare VE1 IHC staining. In the direct sequencing group, the IHC sensitivity was 100% (95% CI 0.97-1.00) and specificity 84% (95% 0.72-0.91). In the PCR group the sensitivity was 98% (95% CI 0.96-0.99) and specificity 89% (95% CI 0.82-0.94). Although immunohistochemical procedures varied by author, the overall performance of the VE1 clone shows that it is highly sensitive and relatively specific for detecting the BRAF V600E mutation in surgical resection specimens. However, standardization of immunohistochemical procedural method and scoring/interpretation criteria may improve the reliability and reproducibility for the use of VE1 clone for future practice.

Gut Microbes' Impact on Oncogenic Drivers: Location Matters

Recent work by Kadosh et al. (2020) suggests that mutant p53 activity in gut epithelia is influenced by local production of microbial metabolites. The switch of p53 from tumor suppressor to oncogene is location-dependent and is impacted by microbially derived gallic acid.