The glutathione S-transferase Gstt1 drives survival and dissemination in metastases.

Identifying the adaptive mechanisms of metastatic cancer cells remains an elusive question in the treatment of metastatic disease, particularly in pancreatic cancer (pancreatic adenocarcinoma, PDA). A loss-of-function shRNA targeted screen in metastatic-derived cells identified Gstt1, a member of the glutathione S-transferase superfamily, as uniquely required for dissemination and metastasis, but dispensable for primary tumour growth. Gstt1 is expressed in latent disseminated tumour cells (DTCs), is retained within a subpopulation of slow-cycling cells within existing metastases, and its inhibition leads to complete regression of macrometastatic tumours. This distinct Gstt1high population is highly metastatic and retains slow-cycling phenotypes, epithelial-mesenchymal transition features and DTC characteristics compared to the Gstt1low population. Mechanistic studies indicate that in this subset of cancer cells, Gstt1 maintains metastases by binding and glutathione-modifying intracellular fibronectin, in turn promoting its secretion and deposition into the metastatic microenvironment. We identified Gstt1 as a mediator of metastasis, highlighting the importance of heterogeneity and its influence on the metastatic tumour microenvironment.

Injury Patterns in Highly Specialized Youth Athletes: A Comparison of 2 Pathways to Specialization.

CONTEXT: Sport specialization, commonly defined as intensive year-round training in a single sport to the exclusion of other sports, has been associated with an increased risk for overuse injury. Two pathways to becoming highly specialized are recognized: (1) having only ever played 1 sport (exclusive highly specialized) and (2) quitting other sports to focus on a single sport (evolved highly specialized). Understanding the differences in injury patterns between these groups of highly specialized athletes will inform the development of injury-prevention strategies. OBJECTIVE: To compare the distribution of injury types (acute, overuse, serious overuse) among evolved highly specialized athletes, exclusive highly specialized athletes, and low-moderately specialized athletes. DESIGN: Cross-sectional study. SETTING: Tertiary care pediatric sports medicine clinic between January 2015 and April 2019. PATIENTS OR OTHER PARTICIPANTS: A total of 1171 patients (age = 12.01-17.83 years, 59.8% female) who played ≥1 organized sports, presented with a sport-related injury, and completed a sports participation survey. MAIN OUTCOME MEASURE(S): Distribution of injury types (acute, overuse, serious overuse). RESULTS: The percentage of injuries due to overuse was similar between the exclusive and evolved highly specialized athletes (59.2% versus 53.9%; P = .28). Compared with low-moderately specialized athletes, exclusive and evolved highly specialized athletes had a higher percentage of overuse injuries (45.3% versus 59.2% and 53.9%, respectively; P = .001). Multivariate analysis of the highly specialized groups revealed sport type to be a significant predictor of a higher percentage of injuries due to overuse, with individual-sport athletes having increased odds of sustaining an overuse injury compared with team-sport athletes (odds ratio = 1.95; 95% CI = 1.17, 3.24). CONCLUSIONS: The distribution of injury types was similar between evolved and exclusive highly specialized youth athletes, with both groups having a higher percentage of injuries due to overuse compared with low-moderately specialized athletes. Among highly specialized athletes, playing an individual sport was associated with a higher proportion of overuse injuries compared with playing a team sport.

Immune Responses in Checkpoint Myocarditis Across Heart, Blood, and Tumor.

Immune checkpoint inhibitors (ICIs) are widely used anti-cancer therapies that can cause morbid and potentially fatal immune-related adverse events (irAEs). ICI-related myocarditis (irMyocarditis) is uncommon but has the highest mortality of any irAE. The pathogenesis of irMyocarditis and its relationship to anti-tumor immunity remain poorly understood. We sought to define immune responses in heart, tumor, and blood during irMyocarditis and identify biomarkers of clinical severity by leveraging single-cell (sc)RNA-seq coupled with T cell receptor (TCR) sequencing, microscopy, and proteomics analysis of 28 irMyocarditis patients and 23 controls. Our analysis of 284,360 cells from heart and blood specimens identified cytotoxic T cells, inflammatory macrophages, conventional dendritic cells (cDCs), and fibroblasts enriched in irMyocarditis heart tissue. Additionally, potentially targetable, pro-inflammatory transcriptional programs were upregulated across multiple cell types. TCR clones enriched in heart and paired tumor tissue were largely non-overlapping, suggesting distinct T cell responses within these tissues. We also identify the presence of cardiac-expanded TCRs in a circulating, cycling CD8 T cell population as a novel peripheral biomarker of fatality. Collectively, these findings highlight critical biology driving irMyocarditis and putative biomarkers for therapeutic intervention.

A Rare Presentation of Aggressive Renal Cell Carcinoma and the Utility of Early Molecular Testing in Rapidly Progressing Malignancies: A Case Report.

In rapidly progressing cancers, appropriate selection of first-line therapy is essential in prolonging survival. Alongside immunohistochemistry (IHC), comprehensive genomics, including whole exome and transcriptome sequencing (WES/WTS), can improve diagnostic accuracy and guide therapeutic management. Here, we report a young patient with rapidly progressing malignancy and unexpected post-mortem results, a scenario that may have been altered by early, comprehensive genomic sequencing. A 43-year-old man with no relevant medical history presented to the emergency department with progressive cough and dyspnea despite treatment for pneumonia. Radiology revealed enlarged subcarinal, hilar, retroperitoneal, and mesenteric lymph nodes, suspicious for metastasis, and a right kidney mass. Pathologic analysis of a retroperitoneal lymph node was felt to be most consistent with metastatic epithelioid angiomyolipoma (mEAML). Three weeks later, he was urgently treated with an mTOR inhibitor for presumed mEAML due to rapid clinical decline, and a subsequent 4R lymph node biopsy was performed to confirm the diagnosis and identify genomic targets via IHC and WES/WTS. Unfortunately, he developed hypoxic respiratory failure, and only posthumously did WES/WTS reveal pathogenic variants in BAP1 and VHL, consistent with clear cell renal cell carcinoma (ccRCC). With an earlier ccRCC diagnosis, he would have received combination immunotherapy/tyrosine kinase inhibition, which has significantly greater activity than mTOR inhibition in ccRCC. He could have received systemic treatment earlier, with optimal therapy, while potentially carrying lower tumor burden and greater clinical stability. In cases of rapidly progressing malignancies with complex histopathological presentations, early comprehensive molecular-based testing can aid in diagnosis and critical therapeutic decision-making.

Association of Injury Rates Among Players in the National Football League With Playoff Qualification, Travel Distance, Game Timing, and the Addition of Another Game: Data From the 2017 to 2022 Seasons.

Background: Injury incidence is higher in the National Football League (NFL) than in other collision sports. Although previous research has identified that scheduling variations, including overseas games and bye week timing, does not affect concussion risk, data are currently lacking regarding the effects of scheduling variation on season-long musculoskeletal injury incidence. Purpose: To determine whether higher cumulative travel distance, overseas play, an early season bye week, and an expansion of the regular season is associated with higher injury rates in the NFL. Study Design: Descriptive epidemiology study. Methods: All 1275 injuries across 5 NFL seasons from 2017 to 2018 through 2021 to 2022 were reviewed retrospectively. Injury data and travel distances were extracted from publicly available sources, which were cross-referenced for validation. Injury rates were calculated per 1000 athletic-exposures (AEs). Cumulative team travel distances were compared statistically using a linear regression. Single factor analysis of variance was used to compare categorical variables. Results: Travel distance did not significantly predict injury rates (P = .47), and there was no difference in injury rates between teams that played a game overseas versus teams that did not (19.3 injuries per 1000 AEs for both; P = .96). In addition, no difference was found in injury rates (F[109,2100[ = 0.704; P = .73) or players placed on the injured reserve list (F[99,778] = 1.70; P = .077) between various bye weeks (P = .73). Injury rates did not differ between the new 17-game regular season (18.4 per 1000 AEs) versus the previous four 16-game regular seasons (19.7 per 1000 AEs; P = .12). However, teams that did not qualify for the playoffs had a significantly higher injury rate (19.9 per 1000 AEs) as well as players on injured reserve (8.0 per 1000 AEs) than playoff-qualifying teams (18.4 and 6.8 per 1000 AEs, respectively; P < .05 for both). Conclusion: Over 5 NFL seasons, cumulative travel distance, overseas play, bye week timing, and adding 1 regular season game were not associated with increased injury rates in NFL players. However, a lack of regular season success was associated with higher injury rates and more players on injured reserve.

Decreased Concussion Incidence Following the Implementation of the Targeting Rules: An Updated Epidemiology of National Football League Concussions From 2017 to 2022.

The incidence of concussions in football, and the ensuing media attention, has garnered scientific investigation, prompted technological advances in protective gear, and altered the rules of the game, including the National Football League's (NFL) "Targeting" rule, which began in 2018, but the impact of these changes is unclear. This study aims to describe the epidemiology of concussions that occurred in five NFL seasons from the 2017-2018 season through the 2021-2022 season and characterize positional differences in rate and games missed. There was a significant decrease (p = 0.02) in total concussions between the 2017-2018 season (102 concussions) and the remaining four seasons (average of 73.80 concussions per year), accounting for a 38% decrease. Offensive and defensive units had decreased concussion rates and average games missed per concussion. Defensive backs (10.46 per 1,000 athlete exposures (AEs)) and tight ends (10.69 per 1,000 AEs) had the highest concussion rates, and the defensive line had the highest average games missed per concussion at 3.97. The introduction of the "Targeting" rule and other rule changes in the NFL in 2018 correlated with a decrease in total concussions per year, total games missed due to concussion, and average games missed per concussion. Offense and defense experienced similar reductions in concussion incidence and severity. Overall, the updated epidemiology of NFL concussions suggests that the incidence of concussions has decreased; however, players continue to experience concussions that require them to miss multiple games.

An Initial Evaluation of Human Plasma cMLC-1: A Potential Protein Biomarker for Trastuzumab-Induced Cardiotoxicity, Breast Cancer Screening and Progression.

Background: Trastuzumab is a targeted therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, trastuzumab-induced cardiotoxicity (TIC) has been reported when trastuzumab is administered to patients as a single agent or combined with anthracycline. Currently no means for detecting the early onset of TIC such as a protein biomarker is available. In this regard and based on promising results from a preliminary animal study, the potential of cardiac myosin light chain 1(cMLC-1) as a biomarker to predict TIC, screen patients for breast cancer and monitor tumor progression in breast cancer patients was evaluated. Methods: Archived plasma samples collected before and after trastuzumab treatment at various fixed time points from 15 HER2+ patients with or without cardiotoxicity, recently collected plasma samples from 79 breast cancer patients (40 HER2+, 39 HER2-), and 46 healthy donors were analyzed for cMLC-1 levels using an enzyme-linked immunosorbent assay (ELISA). Results: An elevated plasma cMLC-1 level was found to be associated with TIC in 3 out of 7 (43%) trastuzumab-treated HER2+ breast cancer patients. However, this study provided an opportunity for us to study plasma cMCL-1 levels in breast cancer patients. It was demonstrated that elevated plasma cMCL-1 is associated with breast cancer. The cutoff cMLC-1 concentration is estimated to be 44.99 ng/mL with a sensitivity of 59.49% (95%CI: 48.47%-69.63%) and specificity of 71.74% (95%CI: 57.45% -82.68%). We also found a noticeable but not significantly more elevated plasma cMCL-1 level in HER2- than in HER2+ breast cancer patients with the given sample sizes. As a result, improved sensitivity of 79.49% (95%CI: 64.47%-89.22%) with the specificity of 63.04% (95%CI:48.60%-75.48%) were obtained for cMLC-1 to predict HER2- breast cancer with the cutoff at 37.17 ng/mL. Moreover, this study determined that cMLC-1 level was significantly higher in patients with metastatic breast cancer than in patients with non-metastatic breast cancer. Conclusions: While the analysis of cMLC-1 levels in the plasma of a limited number of trastuzumab-treated HER2+ breast cancer patients failed to fully support its identification as a blood protein biomarker for predicting TIC, additional analyses of plasma cMLC-1 levels did significantly establish its correlations with breast cancer and disease progression. Our findings shed light on and filled, to some extent, the gap of knowledge of the potential of cMLC-1 as a blood protein biomarker for screening breast cancer and monitoring disease progression of breast cancer.

EGFR Inhibition Potentiates FGFR Inhibitor Therapy and Overcomes Resistance in FGFR2 Fusion-Positive Cholangiocarcinoma.

FGFR inhibitors are approved for the treatment of advanced cholangiocarcinoma harboring FGFR2 fusions. However, the response rate is moderate, and resistance emerges rapidly due to acquired secondary FGFR2 mutations or due to other less-defined mechanisms. Here, we conducted high-throughput combination drug screens, biochemical analysis, and therapeutic studies using patient-derived models of FGFR2 fusion-positive cholangiocarcinoma to gain insight into these clinical profiles and uncover improved treatment strategies. We found that feedback activation of EGFR signaling limits FGFR inhibitor efficacy, restricting cell death induction in sensitive models and causing resistance in insensitive models lacking secondary FGFR2 mutations. Inhibition of wild-type EGFR potentiated responses to FGFR inhibitors in both contexts, durably suppressing MEK/ERK and mTOR signaling, increasing apoptosis, and causing marked tumor regressions in vivo. Our findings reveal EGFR-dependent adaptive signaling as an important mechanism limiting FGFR inhibitor efficacy and driving resistance and support clinical testing of FGFR/EGFR inhibitor therapy for FGFR2 fusion-positive cholangiocarcinoma. SIGNIFICANCE: We demonstrate that feedback activation of EGFR signaling limits the effectiveness of FGFR inhibitor therapy and drives adaptive resistance in patient-derived models of FGFR2 fusion-positive cholangiocarcinoma. These studies support the potential of combination treatment with FGFR and EGFR inhibitors as an improved treatment for patients with FGFR2-driven cholangiocarcinoma. This article is highlighted in the In This Issue feature, p. 1171.

Parallel Genomic Alterations of Antigen and Payload Targets Mediate Polyclonal Acquired Clinical Resistance to Sacituzumab Govitecan in Triple-Negative Breast Cancer.

Sacituzumab govitecan (SG), the first antibody-drug conjugate (ADC) approved for triple-negative breast cancer, incorporates the anti-TROP2 antibody hRS7 conjugated to a topoisomerase-1 (TOP1) inhibitor payload. We sought to identify mechanisms of SG resistance through RNA and whole-exome sequencing of pretreatment and postprogression specimens. One patient exhibiting de novo progression lacked TROP2 expression, in contrast to robust TROP2 expression and focal genomic amplification of TACSTD2/TROP2 observed in a patient with a deep, prolonged response to SG. Analysis of acquired genomic resistance in this case revealed one phylogenetic branch harboring a canonical TOP1 E418K resistance mutation and subsequent frameshift TOP1 mutation, whereas a distinct branch exhibited a novel TACSTD2/TROP2 T256R missense mutation. Reconstitution experiments demonstrated that TROP2T256R confers SG resistance via defective plasma membrane localization and reduced cell-surface binding by hRS7. These findings highlight parallel genomic alterations in both antibody and payload targets associated with resistance to SG. SIGNIFICANCE: These findings underscore TROP2 as a response determinant and reveal acquired SG resistance mechanisms involving the direct antibody and drug payload targets in distinct metastatic subclones of an individual patient. This study highlights the specificity of SG and illustrates how such mechanisms will inform therapeutic strategies to overcome ADC resistance.This article is highlighted in the In This Issue feature, p. 2355.