Single-cell protein activity analysis identifies recurrence-associated renal tumor macrophages.

Clear cell renal carcinoma (ccRCC) is a heterogeneous disease with a variable post-surgical course. To assemble a comprehensive ccRCC tumor microenvironment (TME) atlas, we performed single-cell RNA sequencing (scRNA-seq) of hematopoietic and non-hematopoietic subpopulations from tumor and tumor-adjacent tissue of treatment-naive ccRCC resections. We leveraged the VIPER algorithm to quantitate single-cell protein activity and validated this approach by comparison to flow cytometry. The analysis identified key TME subpopulations, as well as their master regulators and candidate cell-cell interactions, revealing clinically relevant populations, undetectable by gene-expression analysis. Specifically, we uncovered a tumor-specific macrophage subpopulation characterized by upregulation of TREM2/APOE/C1Q, validated by spatially resolved, quantitative multispectral immunofluorescence. In a large clinical validation cohort, these markers were significantly enriched in tumors from patients who recurred following surgery. The study thus identifies TREM2/APOE/C1Q-positive macrophage infiltration as a potential prognostic biomarker for ccRCC recurrence, as well as a candidate therapeutic target.

Sequencing Systemic Therapy in Hepatocellular Carcinoma.

OPINION STATEMENT: Multiple treatment options are now approved for unresectable hepatocellular carcinoma (HCC). An immune checkpoint inhibitor (ICI)-containing regimen should be highly considered as the first-line treatment when there is no contraindication, especially in those with hepatitis virus-related HCC, due to proven superior overall survival (OS) compared to sorafenib. Atezolizumab plus bevacizumab and durvalumab plus tremelimumab remain the treatment of choice among all ICI-containing regimens, unless contraindications to either of the medications exist. Although sorafenib is still the only medication currently approved for select patients with Child-Pugh B (CP) HCC in the first-line setting, atezolizumab plus bevacizumab is being studied in this patient population. Moreover, patients with post-liver transplantation recurrence may benefit from tyrosine kinase inhibitors (TKIs), while more studies are still needed to determine the safety of ICIs in this setting. Interestingly, multiple potential biomarkers, including tumor mutational burden (TMB), microsatellite instability (MSI) status, and PD-L1 expression level, have inconsistently predicted response to ICIs in patients with HCC. Limited evidence is available to guide treatment choice in later-line settings after progressing on ICIs, and decisions should be based on the safety profile of the treatment regimen and patient preference. Multiple trials are ongoing to elucidate the optimal treatment sequence. Of note, we believe that TKIs (e.g., cabozantinib, regorafenib, lenvatinib, and sorafenib) could be more beneficial in later-line settings to broaden inhibition of other pathways apart from vascular endothelial growth factor (VEGF). When conventional treatment options are exhausted, tissue biopsy may be helpful to reveal rare targetable mutations, such as RET gene fusions.

A Phase II, Single-Arm, Open-Label, Bayesian Adaptive Efficacy and Safety Study of PBI-05204 in Patients with Stage IV Metastatic Pancreatic Adenocarcinoma.

LESSONS LEARNED: This trial evaluating a novel plant extract, PBI-05204, did not meet its primary endpoint of overall survival but did show signals of efficacy in heavily pretreated mPDA. PBI-05204 was generally well tolerated, with the most common side effects related to treatment being vomiting (23.7%), nausea (18.4%), decreased appetite (18.4%), and diarrhea (15.8%). Additional trials are needed to explore the role of PBI-05204 in cancer treatment. BACKGROUND: Survival for metastatic pancreatic ductal adenocarcinoma (mPDA) is dismal, and novel agents are needed. PBI-05204 is a modified supercritical carbon dioxide extract of Nerium oleander leaves. Oleandrin, the extract's major cytotoxic component, is a cardiac glycoside that has demonstrated antitumor activity in various tumor cell lines with a mechanism involving inhibition of Akt phosphorylation and through downregulation of mTOR. METHODS: A phase II, single-arm, open-label study to determine the efficacy of PBI-05204 in patients with refractory mPDA therapy was conducted. The primary endpoint was overall survival (OS), with the hypothesis that 50% of patients would be alive at 4.5 months. Secondary objectives included safety, progression-free survival (PFS), and overall response rate. Patients received oral PBI-05204 daily until progressive disease (PD), unacceptable toxicity, or patient withdrawal. Radiographic response was assessed every two cycles. RESULTS: Forty-two patients were enrolled, and 38 were analyzed. Ten patients were alive at 4.5 months (26.3%) with a median PFS of 56 days. One objective response (2.6%) was observed for 162 days. Grade ≥ 3 treatment-emergent adverse events occurred in 63.2% of patients with the most common being fatigue, vomiting, nausea, decreased appetite, and diarrhea. CONCLUSION: PBI-05204 did not meet its primary endpoint for OS in this study. Recent preclinical data indicate a role for PBI-05204 against glioblastoma multiforme when combined with chemotherapy and radiotherapy. A randomized phase II trial is currently being designed.

Current Concepts in the Treatment of Resectable Pancreatic Cancer.

PURPOSE OF REVIEW: The diagnosis of pancreatic cancer carries with it a high mortality rate. Despite advances in the field, this has remained relatively unchanged over the last few decades. Current options for the treatment of resectable pancreatic ductal adenocarcinoma will be reviewed here in conjunction with the historical data that support them. We will focus on updates in treatment guidelines and ongoing clinical trials of interest. RECENT FINDINGS: For localized disease, standard of care includes resection followed by adjuvant chemotherapy ± chemoradiation. Recently, a report was published supporting the use of doublet therapy with gemcitabine and capecitabine (as opposed to gemcitabine monotherapy), which prompted a practice-changing update to major treatment guidelines. Multiple trials using neoadjuvant treatment, novel therapies, and different forms of radiation are ongoing. Although pancreatic cancer is an active area of research, outcomes remain dismal. Clinical trials will need to be more robust and innovative to drastically improve survival statistics.

Utility of RNA Expression to Determine the Tissue of Origin of Malignancies with an Inconclusive Histopathology.

We present 2 cases of cancer of unknown origin in which RNA-based cancer classification testing provided vital insight and directed treatment management. The tissue of origin could not be determined in both of these patients utilizing morphology and immunohistochemical analysis of the tissue samples. Next-generation sequencing and tumor-of-origin testing using an RNA-based molecular cancer classifier were performed to elucidate the possible tissue of origin. A 61-year-old male with a history of localized basal cell carcinoma presented with a 4.4-cm axillary lymph node in addition to upper extremity edema and supraclavicular lymphadenopathy. RNA-based tumor origin testing revealed skin basal or squamous cell carcinoma as the likely tissue of origin, with a probability of 97%. He received vismodegib, a hedgehog inhibitor, after progression on cemiplimab and experienced a partial response by RECIST criteria, which is currently ongoing for over a year. A 74-year-old female patient with a remote history of ovarian cancer for which she underwent resection and adjuvant chemotherapy presented 15 years later with abdominal pain. The diagnostic workup revealed a 2-cm pancreatic mass and enlarged peritoneal lymph nodes. RNA sequencing revealed a 99% likelihood of the tissue of origin being serous ovarian carcinoma. Subsequently, she underwent surgery and adjuvant chemotherapy and is currently in remission with letrozole maintenance. Genomic data already plays a crucial role in therapeutic decision-making for individuals with cancer. These cases highlight the complementary role of genomic data in the diagnostic workup of cancer, leading to favorable patient outcomes.

Response to osimertinib in a colorectal cancer patient with an EGFR T790M mutation: A case report.

BACKGROUND: Although common in lung cancer, somatic epidermal growth factor receptor (EGFR) mutations are rarely found in colorectal cancer, occurring in approximately 3% of cases. Treatment with anti-EGFR antibodies is commonplace, but EGFR tyrosine kinase inhibitors are not standard treatments in colorectal cancer. Here we report a case of sustained response to osimertinib in a colorectal cancer patient with an EGFR T790M mutation on cell-free DNA analysis. CASE SUMMARY: A 72-year old woman with a past medical history of post-polio syndrome confined to a wheelchair, scoliosis and hypothyroidism presented with metastatic sigmoid colon adenocarcinoma with hepatic metastases. Next generation sequencing revealed a RAS/RAF wild-type, microsatellite stable, PD-L1 negative malignancy. Mutations in TP3 and APC were also identified, as well as EGFR amplification. Cell-free DNA analysis revealed an EGFR T790M mutation. She was unable to tolerate first-line treatment with panitumumab, 5-fluorouracil and leucovorin, progressed on second-line treatment with trifluridine/tipiracil plus bevacizumab, and was unable to tolerate third-line treatment with regorafenib. She was started on fourth-line treatment with off-label osimertinib, with clinical response - decrease in size of hepatic metastases and a pericardial effusion. She remained on treatment with osimertinib for seven months. CONCLUSION: This case shows the benefit of multi-gene sequencing assays to identify potential therapeutic options in patients with refractory disease.

Molecular profiling and treatment pattern differences between intrahepatic and extrahepatic cholangiocarcinoma.

BACKGROUND: Treatment patterns for intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC) differ, but limited studies exist comparing them. This study examines differences in molecular profiling rates and treatment patterns in these populations, focusing on use of adjuvant, liver-directed, targeted, and investigational therapies. METHODS: This multicenter collaboration included patients with ICC or ECC treated at 1 of 8 participating institutions. Retrospective data were collected on risk factors, pathology, treatments, and survival. Comparative statistical tests were 2-sided. RESULTS: Among 1039 patients screened, 847 patients met eligibility (ICC = 611, ECC = 236). Patients with ECC were more likely than those with ICC to present with early stage disease (53.8% vs 28.0%), undergo surgical resection (55.1% vs 29.8%), and receive adjuvant chemoradiation (36.5% vs 4.2%) (all P < .00001). However, they were less likely to undergo molecular profiling (50.3% vs 64.3%) or receive liver-directed therapy (17.9% vs 35.7%), targeted therapy (4.7% vs 18.9%), and clinical trial therapy (10.6% vs 24.8%) (all P < .001). In patients with recurrent ECC after surgery, the molecular profiling rate was 64.5%. Patients with advanced ECC had a shorter median overall survival than those with advanced ICC (11.8 vs 15.1 months; P < .001). CONCLUSIONS: Patients with advanced ECC have low rates of molecular profiling, possibly in part because of insufficient tissue. They also have low rates of targeted therapy use and clinical trial enrollment. While these rates are higher in advanced ICC, the prognosis for both subtypes of cholangiocarcinoma remains poor, and a pressing need exists for new effective targeted therapies and broader access to clinical trials.

The Cholangiocarcinoma in the Young (CITY) Study: Tumor Biology, Treatment Patterns, and Survival Outcomes in Adolescent Young Adults With Cholangiocarcinoma.

PURPOSE: Increased awareness of the distinct tumor biology for adolescents and young adults (AYAs) with cancer has led to improvement in outcomes for this population. However, in cholangiocarcinoma (CCA), a paucity of data exist on the AYA population. To our knowledge, we present the largest study to date on AYA disease biology, treatment patterns, and survival outcomes in CCA. METHODS: A multi-institutional cohort of patients with CCA diagnosed with intrahepatic cholangiocarcinoma (ICC) or extrahepatic cholangiocarcinoma (ECC) was used for analysis. Retrospective chart review was conducted on patients who were 50 years old and younger (young; n = 124) and older than 50 years (older; n = 723). RESULTS: Among 1,039 patients screened, 847 patients met eligibility (72% ICC, 28% ECC). Young patients had a larger median tumor size at resection compared with older patients (4.2 v 3.6 cm; P = .048), more commonly had N1 disease (65% v 43%; P = .040), and were more likely to receive adjuvant therapy (odds ratio, 4.0; 95% CI, 1.64 to 9.74). Tumors of young patients were more likely to harbor an FGFR2 fusion, BRAF mutation, or ATM mutation (P < .05 for each). Young patients were more likely to receive palliative systemic therapy (96% v 69%; P < .001), targeted therapy (23% v 8%; P < .001), and treatment on a clinical trial (31% v 19%; P = .004). Among patients who presented with advanced disease, young patients had a higher median overall survival compared with their older counterparts (17.7 v 13.5 months; 95% CI, 12.6 to 22.6 v 11.4 to 14.8; P = .049). CONCLUSION: Young patients with CCA had more advanced disease at resection, more commonly received both adjuvant and palliative therapies, and demonstrated improved survival compared with older patients. Given the low clinical trial enrollment and poor outcomes among some AYA cancer populations, data to the contrary in CCA are highly encouraging.

Pembrolizumab in unresectable or metastatic MSI-high colorectal cancer: safety and efficacy.

INTRODUCTION: Microsatellite instability-high (MSI-H) colorectal cancer (CRC) represents a unique subset of CRC characterized by elevated neoantigen expression and a high degree of intraepithelial T-cell infiltrate. These characteristics make MSI-H tumors particularly susceptible to immune checkpoint inhibitors (ICIs) such as pembrolizumab which inhibit the negative regulation of cytotoxic T-cells and promote T-cell mediated anti-tumor activity. AREAS COVERED: We discuss the drug development of pembrolizumab including the seminal studies which enabled the drug to garner FDA approvals in the refractory and first-line settings for patients with MSI-H CRC, the pharmacokinetic & pharmacodynamic profile of the agent, and the adverse event profile of the ICI. We also discuss unmet needs in the arena of ICIs including strategies to overcome tumor resistance and to increase the applicability of the agents to a broader population of CRC patients. EXPERT OPINION: Despite the anti-tumor activity of pembrolizumab in patients with MSI-H CRC, 30-35% of patients fail to derive any benefit. Ongoing research efforts are seeking to identify ICI combinations, which can overcome CRC resistance to pembrolizumab, move ICIs into the treatment paradigm for patients with localized MSI-H CRC and enable ICIs to become meaningful treatment options for patients with microsatellite stable CRC.

Spatially resolved qualified sewage spot sampling to track SARS-CoV-2 dynamics in Munich - One year of experience.

Wastewater-based epidemiology (WBE) is a tool now increasingly proposed to monitor the SARS-CoV-2 burden in populations without the need for individual mass testing. It is especially interesting in metropolitan areas where spread can be very fast, and proper sewage systems are available for sampling with short flow times and thus little decay of the virus. We started in March 2020 to set up a once-a-week qualified spot sampling protocol in six different locations in Munich carefully chosen to contain primarily wastewater of permanent residential areas, rather than industry or hospitals. We used RT-PCR and sequencing to track the spread of SARS-CoV-2 in the Munich population with temporo-spatial resolution. The study became fully operational in mid-April 2020 and has been tracking SARS-CoV-2 RNA load weekly for one year. Sequencing of the isolated viral RNA was performed to obtain information about the presence and abundance of variants of concern in the Munich area over time. We demonstrate that the evolution of SARS-CoV-2 RNA loads (between <7.5 and 3874/ml) in these different areas within Munich correlates well with official seven day incidence notification data (between 0.0 and 327 per 100,000) obtained from the authorities within the respective region. Wastewater viral loads predicted the dynamic of SARS-CoV-2 local incidence about 3 weeks in advance of data based on respiratory swab analyses. Aligning with multiple different point-mutations characteristic for certain variants of concern, we could demonstrate the gradual increase of variant of concern B.1.1.7 in the Munich population beginning in January 2021, weeks before it became apparent in sequencing results of swabs samples taken from patients living in Munich. Overall, the study highlights the potential of WBE to monitor the SARS-CoV-2 pandemic, including the introduction of variants of concern in a local population.

Surgical resection and survival outcomes in metastatic young adult colorectal cancer patients.

BACKGROUND: The incidence of colorectal cancer in adults younger than age 50 has increased with rates expected to continue to increase over the next decade. The objective of this study is to examine the survival benefit of surgical resection (primary and/or metastatic) versus palliative therapy in this patient population. METHODS: We identified 6708 young adults aged 18-45 years diagnosed with metastatic colorectal cancer (mCRC) from 2004 to 2015 from the SEER database. Overall survival (OS) was analyzed using Kaplan-Meier estimation, log rank test, and multivariate Cox proportional hazards model. RESULTS: Sixty-three percent of patients in our study underwent primary tumor resection (PTR), with 40% undergoing PTR alone and 23% undergoing both resection of primary disease and metastasectomy. The median OS for patients who underwent both PTR and metastasectomy was 36 months, compared to 13 months for those who did not receive any surgical intervention. The multivariate analysis showed significant OS benefit of receiving both PTR and metastasectomy (HR 0.34, 95% CI: 0.31-0.37, p < 0.001) compared to palliative therapy. Undergoing PTR only and metastasectomy only were also associated with improved OS (HR 0.46, 95% CI: 0.43-0.49, p < 0.001 and HR 0.64, 95% CI: 0.55-0.76, p < 0.001, respectively). CONCLUSION: This is the largest observational study to evaluate survival outcomes in young-onset mCRC patients and the role of surgical intervention of the primary and/or metastatic site. Our study provides evidence of statistically significant increase in OS for young mCRC patients who undergo surgical intervention of the primary and/or metastatic site.

Counting Induced Subgraphs: A Topological Approach to #W[1]-hardness.

We investigate the problem # IndSub ( Φ ) of counting all induced subgraphs of size k in a graph G that satisfy a given property Φ . This continues the work of Jerrum and Meeks who proved the problem to be # W [ 1 ] -hard for some families of properties which include (dis)connectedness [JCSS 15] and even- or oddness of the number of edges [Combinatorica 17]. Using the recent framework of graph motif parameters due to Curticapean, Dell and Marx [STOC 17], we discover that for monotone properties  Φ , the problem # IndSub ( Φ ) is hard for # W [ 1 ] if the reduced Euler characteristic of the associated simplicial (graph) complex of Φ is non-zero. This observation links # IndSub ( Φ ) to Karp's famous Evasiveness Conjecture, as every graph complex with non-vanishing reduced Euler characteristic is known to be evasive. Applying tools from the "topological approach to evasiveness" which was introduced in the seminal paper of Khan, Saks and Sturtevant [FOCS 83], we prove that # IndSub ( Φ ) is  # W [ 1 ] -hard for every monotone property Φ that does not hold on the Hamilton cycle as well as for some monotone properties that hold on the Hamilton cycle such as being triangle-free or not k-edge-connected for k > 2 . Moreover, we show that for those properties # IndSub ( Φ ) can not be solved in time f ( k ) · n o ( k ) for any computable function f unless the Exponential Time Hypothesis (ETH) fails. In the final part of the paper, we investigate non-monotone properties and prove that # IndSub ( Φ ) is # W [ 1 ] -hard if Φ is any non-trivial modularity constraint on the number of edges with respect to some prime q or if Φ enforces the presence of a fixed isolated subgraph.

Neoadjuvant Chemotherapy for Colon Cancer

Simple Summary Neoadjuvant chemotherapy is commonly used in several solid tumor malignancies, but remains understudied in the setting of locally advanced colon cancer. Advantages of this strategy extrapolated from other disease sites include early treatment of micro-metastatic disease, the ability to decrease local disease burden potentially leading to more effective resections and improved treatment tolerability. Approaches for accurate staging and safe administration of systemic treatment are being investigated in large, randomized clinical trials, but available data are either not mature enough or have not demonstrated a convincing argument for adoption into standard practice warranting further investigation. Abstract Early stage colon cancer is typically managed with surgical resection, although not all patients experience a durable remission. Adjuvant chemotherapy with a fluoropyrimidine, with or without oxaliplatin, is commonly utilized to increase the chance of cure, but its efficacy in the neoadjuvant setting is not well established. Preoperative chemotherapy has demonstrated safety and efficacy in other gastrointestinal malignancies, but there is a paucity of data from large, prospective randomized trials, although multiple are ongoing. In this review, we will discuss the theoretical risks and benefits, logistical difficulties, and available safety and efficacy data pertaining to the use of chemotherapy in locally advanced colon cancer.

Recent advances in the treatment of pancreatic cancer.

Pancreatic ductal adenocarcinoma is one of the deadliest solid tumor malignancies and is projected to become a leading cause of cancer-related death in coming years. Improving quality of life and survival amongst these patients will require new ideas and novel therapies in a multidisciplinary approach. This review will cover the most recent advances in the comprehensive treatment of pancreatic cancer and place them within a historical context when necessary. Treatment of all disease stages will be discussed, but the focus is on systemic therapy as novel drugs and new treatment combinations enter the clinic. This will include more aggressive chemotherapy in earlier disease stages, approved uses for immunotherapy, and targetable mutations. In addition, negative trials of importance and controversial topics will be noted.

Improved Prognosis and Increased Tumor-Infiltrating Lymphocytes in Patients Who Have SCLC With Neurologic Paraneoplastic Syndromes.

BACKGROUND: Approximately 10% of patients with SCLC develop a paraneoplastic syndrome (PNS). Neurologic PNS are thought to improve prognosis, which we hypothesized is related to increased tumor-infiltrating lymphocytes and immune recognition. METHODS: We queried 2,512,042 medical records from a single institution to identify patients who have SCLC with and without PNS and performed manual, retrospective chart review. We then performed multiplexed fluorescence immunohistochemistry and automated quantitative analysis (AQUA Technology) on tumors to assess CD3, CD4, and CD8 T cell infiltrates and programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) interactions. T cell infiltrates and PD-1/PD-L1 interaction scores were compared among patients with neurologic PNS, endocrinologic PNS, and a control group without PNS. Clinical outcomes were analyzed using the Kaplan-Meier method and Cox proportional hazards models. RESULTS: We evaluated 145 SCLC patients: 55 with PNS (25 neurologic and 30 endocrinologic) and 90 controls. Patients with neurologic PNS experienced improved overall survival compared to patients with endocrinologic PNS and controls (median overall survival of 24 months versus 12 months versus 13 months, respectively). Of the 145 patients, we identified tumor tissue from 34 patients that was adequate for AQUA analysis. Among 37 specimens from these 34 patients, patients with neurologic PNS had increased T cell infiltrates (p = 0.033) and PD-1/PD-L1 interaction (p = 0.014) compared to tumors from patients with endocrinologic PNS or controls. CONCLUSIONS: Tumor tissue from patients with SCLC with neurologic PNS showed increased tumor-infiltrating lymphocytes and PD-1/PD-L1 interaction consistent with an inflamed tumor microenvironment.

Search for new urinary biochemical markers of collagen degradation in man.

BACKGROUND: In the human body, collagen degradation produces various fragments released from the extracellular matrix, which end up in the urine as pyridinium cross-links, either free or bound to peptides or sugars. METHODS: We developed a high-performance liquid chromatography (HPLC) technique, which measures not only free pyridinoline (Pyr) and deoxypyridinoline (Dpyr), but also glucosyl-galactosyl-pyridinoline (glc-gal-pyr) and four still unidentified bound pyridinolines. Assuming that in Paget's disease of bone and in growing children the cross-links (CL) mainly originate from bone tissue, whereas after spinal cord injury their high excretion rather reflects the degradation of non-osseous collagen, we compared the urinary output of seven different cross-links, among which four had not been described before. RESULTS: Our results show that one of those, which we called CL1, is essentially originating from bone and is more specific in this respect than Dpyr, whereas glc-gal-pyr also reflects the degradation of non-osseous collagen. The best indicator of non-bone collagen degradation was CL3, one of the newly discovered cross-links. CONCLUSIONS: In conclusion, we demonstrate that new sensitive pyridinoline cross-links can be identified and assayed in human urine and that their specificity helps to distinguish diseases related to bone collagen from those in which other forms of collagen are involved.

Integrated immunoisolation and protein analysis of circulating exosomes using microfluidic technology.

Developing blood-based tests is appealing for non-invasive disease diagnosis, especially when biopsy is difficult, costly, and sometimes not even an option. Tumor-derived exosomes have attracted increasing interest in non-invasive cancer diagnosis and monitoring of treatment response. However, the biology and clinical value of exosomes remains largely unknown due in part to current technical challenges in rapid isolation, molecular classification and comprehensive analysis of exosomes. Here we developed a new microfluidic approach to streamline and expedite the exosome analysis pipeline by integrating specific immunoisolation and targeted protein analysis of circulating exosomes. Compared to the conventional methods, our approach enables selective subpopulation isolation and quantitative detection of surface and intravesicular biomarkers directly from a minimally invasive amount of plasma samples (30 µL) within ~100 min with markedly improved detection sensitivity. Using this device, we demonstrated phenotyping of exosome subpopulations by targeting a panel of common exosomal and tumor-specific markers and multiparameter analyses of intravesicular biomarkers in the selected subpopulation. We were able to assess the total expression and phosphorylation levels of IGF-1R in non-small-cell lung cancer patients by probing plasma exosomes as a non-invasive alternative to conventional tissue biopsy. We foresee that the microfluidic exosome analysis platform will form the basis for critically needed infrastructures for advancing the biology and clinical utilization of exosomes.

Dietary tyramine restriction for hospitalized patients on linezolid: an update.

Linezolid is a weak, reversible monoamine oxidase inhibitor. The current practice at most hospitals is to place patients receiving linezolid on a tyramine-restricted diet. This process typically involves both the hospital's pharmacy department and the food and nutrition department. A literature search assessing the interaction between linezolid and tyramine was conducted, and the amount of tyramine in a typical unrestricted diet for a hospitalized patient was reviewed. Although patients receiving linezolid should avoid consuming large amounts of foods containing high concentrations of tyramine, such foods in large amounts are not components of meals for inpatients. Therefore, dietary tyramine restriction in hospitalized patients is not generally required.