Cervical cancer remains a major malignancy in women worldwide despite advances in human papillomavirus (HPV) vaccination, screening, and multimodal treatment. Persistent high-risk HPV infection is the principal driver of cervical carcinogenesis, yet viral oncogenesis alone cannot fully explain tumor progression, immune escape, and therapeutic failure. Increasing evidence suggests that mitochondrial reprogramming is a critical adaptive process that links HPV-driven transformation to metabolic plasticity, tumor immunity, and resistance to therapy. Beyond their canonical role in ATP production, mitochondria regulate redox homeostasis, mitochondrial dynamics, mitophagy, apoptotic priming, and mitochondria-derived danger signaling, thereby shaping both tumor-cell fitness and the surrounding immune microenvironment. In cervical cancer, HPV-associated oncogenic signaling promotes metabolic and mitochondrial remodeling, while downstream mitochondrial processes help sustain malignant growth, buffer oxidative and therapeutic stress, and influence immune responsiveness. Emerging studies further indicate that mitochondrial stress signals, particularly mitochondrial DNA-mediated innate immune activation, may connect tumor metabolism with anti-tumor immunity and immunotherapeutic sensitivity. At the same time, mitochondrial respiration, redox adaptation, and quality-control mechanisms contribute to chemoresistance and broader treatment tolerance. In this review, we summarize current evidence on how HPV oncogenic signaling reshapes mitochondrial biology in cervical cancer and discuss how mitochondrial reprogramming influences tumor immunity, immune evasion, and therapeutic resistance. We also highlight emerging mitochondria-targeted strategies and propose future directions for mechanistic and translational research. Together, these insights position mitochondrial reprogramming as both a conceptual framework and a potential therapeutic vulnerability in cervical cancer.

Enzalutamide is a potent androgen receptor (AR) inhibitor widely used for the treatment of castration-resistant prostate cancer (CRPC). However, the development of drug resistance severely limits its therapeutic efficacy, and the underlying mechanisms remain poorly understood. We have demonstrated that decorin (DCN), a suppressor of prostate cancer (PCa) progression, is significantly down-regulated in enzalutamide-resistant PCa cells. Therefore, we hypothesized that diminished expression of DCN contributes to enzalutamide resistance in PCa. In this study, we found that DCN was decreased in enzalutamide-resistant LNCaP cells (LNCaP-ER), which exhibited resistance to ferroptosis. Consistently, DCN was significantly reduced in high-grade PCa and CRPC tissues, as well as in those with poor clinical survival outcomes through integrative analysis. Moreover, DCN overexpression re-sensitized LNCaP-ER cells to enzalutamide by activating ferroptosis. What's more, DCN overexpression significantly inhibited tumor growth and metastasis of LNCaP-ER cells in vivo under enzalutamide-treated conditions, in a ferroptosis-dependent manner. Mechanistically, DCN activated calcium-dependent Protein Kinase C Beta II (PKCβII), thereby enhancing phosphorylation of long-chain acyl-CoA synthetase 4 (ACSL4) to regulate lipid remodeling and promote ferroptosis. In addition, enzalutamide-mediated AR nuclear translocation negatively regulates DCN transcription. In conclusion, promoting DCN-mediated ferroptosis might be a potential strategy for enhancing the sensitivity of enzalutamide in PCa cells. This study delineates a novel mechanism by which DCN downregulation suppresses ferroptosis and drives enzalutamide resistance in CRPC.

Taxane-based chemotherapy is a main treatment modality for ovarian cancer and other solid tumors, but chemoresistance limits the clinical efficacy. Studies have shown tumor interaction with macrophages in the tumor microenvironment (TME) plays a significant role in taxane resistance, yet the underlying molecular mechanisms are poorly understood. In this study, we employed translatome profiling of paclitaxel-treated cancer cells, live-cell imaging analysis, gene knockdown/knockout, and in vitro cancer-macrophage coculture assays to unravel a novel chemoresistance mechanism mediated by tumor-macrophage interaction via the NOTCH2-JAG1 axis. The in vitro data were further validated by multiple xenograft, syngeneic and patient-derived xenograft mouse tumor models of ovarian cancer as well as ovarian cancer patient samples. We found paclitaxel selectively induced translational upregulation of NOTCH2 via cytoplasmic polyadenylation, and this NOTCH2 upregulation persisted after mitotic exit. Subsequent NOTCH2 activation by JAG1 expressed mainly on the neighboring macrophages promoted tumor cell survival and simulated cytokine release, such as CSF1 and IL-1β, that recruited JAG1-expressing macrophages, thus forming a positive feedback loop that further enhanced the pro-tumor NOTCH2 activity. Genetic depletion or pharmacological inhibition of NOTCH2 with the γ-secretase inhibitor attenuated macrophage infiltration and sensitized tumor response to paclitaxel in multiple preclinical models of ovarian cancer. Moreover, single-cell RNA sequencing analysis identified a JAG1-high macrophage subset that was enriched by paclitaxel treatment and attenuated by NOTCH inhibition. Clinically, high NOTCH2 expression in ovarian tumors was associated with recurrence and shorter progression-free survival of ovarian cancer patients. Paclitaxel-induced translational upregulation of NOTCH2 enables immediate juxtacrine activation by JAG1-positive macrophages, coupling tumor cell survival with immune remodeling in the tumor microenvironment to drive chemoresistance. Our results suggest NOTCH2 is a viable biomarker for paclitaxel resistance and that combining NOTCH2 inhibitor with taxane is an effective therapeutic strategy to selectively disrupt tumor-macrophage interaction and overcome macrophage-mediated taxane resistance in NOTCH2-positive tumors.

To develop and validate a prognostic model incorporating microRNA-1246 (miR-1246), high-mobility group box 1 (HMGB-1), α1-antitrypsin (A1AT), and inflammatory markers for predicting outcomes in early gastric cardia cancer after endoscopic submucosal dissection (ESD). We retrospectively enrolled 280 patients with early gastric cardia cancer who underwent ESD between January 2021 and December 2023. Patients were divided into a training set (n = 196) and a validation set (n = 84) at a ratio of 7:3. Influencing factors were screened using univariate, Least Absolute Shrinkage and Selection Operator (LASSO), and multivariate logistic regression analyses in the training set. A nomogram was constructed, and the predictive performance was assessed using receiver operating characteristic (ROC) curves and calibration curves. Decision curve analysis (DCA) was used to evaluate the clinical value. The incidence of poor prognosis was comparable between training (43.88

Protein S-palmitoylation, a dynamic and reversible post-translational modification involving the attachment of palmitate to cysteine residues, is a key regulator of protein functionality and cellular signalling. Dysregulation of this modification has emerged as a critical driver of cancer progression. Among the 23 DHHC palmitoyl transferases responsible for catalysing S-palmitoylation, aberrant expression of specific members is linked to tumorigenesis and development, underscoring their potential as promising therapeutic targets. However, the cancer-specific roles and substrates of individual DHHC enzymes remain poorly characterised. In this study, we identified DHHC9 as a crucial regulator of adenocarcinoma progression, including colorectal and lung cancers. Functional studies demonstrated that DHHC9 knockdown profoundly inhibited cell migration in vitro and tumour metastasis in vivo. Proteomic and functional analyses revealed that STRN4, a core component of the STRIPAK complex, was palmitoylated by DHHC9 at cysteine 701. The STRN4 palmitoylation reduced YAP phosphorylation, promoted nuclear translocation of YAP and activated downstream Hippo pathway transcriptional targets—including CCN1, CCN2 and ANKRD1—thereby driving cancer cell migration. Notably, we discovered two small molecules, Treprostinil and 10-HCPT, as potent DHHC9 inhibitors that effectively suppressed adenocarcinoma cell migration. Our findings define the DHHC9-STRN4-YAP axis as a novel mechanism linking palmitoylation to phosphatase regulation and Hippo pathway dysregulation, unveiling DHHC9 as a highly promising therapeutic target in cancer treatment.

ABSTRACT Background Lung cancer, representing a predominant form of pulmonary malignancy, demonstrates significant disease burden and poor clinical outcomes. Circular RNAs (circRNAs) have emerged as critical regulators in various cancers, including lung cancer. However, the specific roles and mechanisms of circRNAs in lung cancer remain largely unexplored. Methods Differential circRNA expression was analyzed using GEO datasets GSE101586 and GSE112214. CircFUT8 was prioritized for its upregulation in lung cancer tissues. In vitro and in vivo functional experiments evaluated its effects on cell proliferation, apoptosis, migration, and invasion. RNA pull‐down, immunofluorescence, and western blotting assessed interactions with ENO1. Macrophage polarization was examined via cocultures and flow cytometry. Results CircFUT8 (hsa_circ_0003028) was significantly upregulated in lung cancer tissues, correlating with advanced stages and poor prognosis. It enhanced lung cancer cell proliferation, migration, and invasion while inhibiting apoptosis in cellular and animal models. Mechanistically, circFUT8 directly binds ENO1 to form an RNA‐protein complex, promoting M2 macrophage polarization. Silencing circFUT8 reversed these effects by suppressing ENO1 and M2 polarization, inhibiting tumor progression. Moreover, ENO1 promotes TNF signaling through glycolytic metabolites. Conclusions Our findings highlight the critical role of circFUT8 in lung cancer progression through its regulation of M2 macrophage polarization via interaction with ENO1. The findings suggest that circFUT8 may serve as both a diagnostic marker and a promising therapeutic target in lung cancer management. This study first identified the regulating oncogenic role of circFUT8 in lung cancer progression and the microenvironment.

BACKGROUND:Prostate cancer (PCa) patients with low prostate-specific antigen (PSA) levels can occasionally present high-grade disease. These patients often exhibit resistance to androgen deprivation therapy and have poor outcomes. The mechanisms underlying these observations remain poorly understood. This study aimed to investigate the clinical characteristics and potential gene expression mechanisms in this subgroup. PATIENTS AND METHODS:Clinical data from 365,558 PCa patients were categorized into four groups based on PSA levels and Gleason score (GS): Group 1 (PSA ≤ 2.5 ng/mL, GS < 8), Group 2 (PSA ≤ 2.5 ng/mL, GS ≥ 8), Group 3 (PSA > 2.5 ng/mL, GS < 8), and Group 4 (PSA > 2.5 ng/mL, GS ≥ 8). Clinical characteristics were compared using Kruskal-Wallis H and Pearson's chi-squared tests. Competing-risks regression assessed prostate cancer-specific mortality (PCSM). Gene set enrichment analysis (GSEA) was performed on 219 PCa patients to compare Group A (PSA ≤ 2.5 ng/mL, GS ≥ 8) with Group B (PSA > 2.5 ng/mL, GS ≥ 8). RESULTS:Group 2 had a significantly higher tumor stage (p < 0.001) and increased hazard ratio for PCSM (p < 0.001). GSEA in Group A identified 156 upregulated gene sets and highlighted several enriched pathways, including the polycomb repressive complex 2, the epidermal growth factor receptor family, retrograde axonal transport, the tumor necrosis factor/nuclear factor-κB pathway, the Rho guanine nucleotide exchange factor/RhoA pathway, and the phosphoinositide 3-kinase signaling pathways (p < 0.05, false discovery rate-adjusted p < 0.25). CONCLUSION:PCa patients with low PSA levels and high GS demonstrated an increased risk of PCSM. They were characterized by the aberrant activation of multiple signaling pathways. Targeted therapeutic strategies aimed at these pathways warrant further investigation for their potential to improve outcomes in this aggressive PCa subtype.

Lactylation, a newly identified post-translational modification, plays a multifaceted role in cancer biology by integrating epigenetic and non-epigenetic mechanisms. This review summarizes the latest research progress on lactylation, including its functions in epigenetic regulation and its broader impact on cellular processes. Lactate, as a metabolic byproduct, not only serves as an energy source for tumor cells but also acts as a signaling molecule driving various oncogenic processes. Lactylation facilitates cancer metabolic reprogramming, enabling tumor cells to adapt to hypoxic and nutrient-deprived microenvironments. Moreover, lactylation mediates immune suppression in the tumor microenvironment, promoting immune evasion and therapy resistance. This review further explores the clinical potential of targeting lactylation, offering new avenues for innovation in cancer research and treatment. These findings highlight the pivotal role of lactylation in cancer progression and its significant value as a potential therapeutic target.

Gastric cancer is one of the major health threats to human beings and has a low response rate to emerging immunotherapy. We herein reported a novel indole-based LSD1-targeted antigastric agent 7ae, which was able to enhance the sensitivity of gastric cancer cells to a T-cell-mediated immune response. It exhibited potent LSD1 inhibitory activity (IC50 = 0.080 ± 0.002 μM) and reduced the expression of PD-L1, which in turn promoted the T-cell killing response in gastric cancer cells. As a result, 7ae acted as an active LSD1 inhibitor, exerting excellent anti-invasion and anti-migration effects in gastric cancer cells and leading to significant suppression of the growth of xenograft gastric tumors without obvious toxicity in vivo. Collectively, 7ae has been demonstrated to be a novel, potent LSD1 inhibitor with the potential to be used as an antigastric agent, as well as a useful tool compound for exploratory studies of T-cell-mediated immunity and/or immunotherapy in gastric cancer.

Endoplasmic reticulum stress (ERS) plays crucial roles in maintaining Treg stability and function, yet the underlying mechanism remains largely unexplored. Here, we demonstrate that ( Tmed4 Delta Treg ) mice with Treg-specific KO of ERS-related protein transmembrane p24 trafficking protein 4 (TMED4) had more Tregs with impaired Foxp3 stability, Treg signatures, and suppressive activity, which led to T cell hyperactivation and an exacerbated inflammatory phenotype and boosted antitumor immunity in mice. Mechanistically, loss of Tmed4 caused defects in ERS and a nuclear factor erythroid 2-related factor 2-related (NRF2-related) antioxidant response, which resulted in excessive ROS that reduced the Foxp3 stability and suppressive function of Tregs in an IRE1 alpha/XBP1 axis-dependent manner. The abnormalities could be effectively rescued by the ROS scavenger, NRF2 inducer, or by forcible expression of IRE1 alpha. Moreover, TMED4 suppressed IRE1 alpha proteosome degradation via the ER-associated degradation (ERAD) system including the ER chaperone binding immunoglobulin protein (BIP). Our study reveals that TMED4 maintained the stability of Tregs and their suppressive function through IRE1 alpha dependent ROS and the NRF2-related antioxidant response.

BACKGROUND:While the currently recommended minimum number of examined lymph nodes (ELNs) for colorectal cancer is 12, the applicability of this standard to colorectal mucinous adenocarcinoma (MAC), a distinct tumor entity with high metastatic potential, remains controversial. This study aimed to establish and validate the optimal ELN threshold during surgery to achieve superior survival outcomes of MAC patients. METHODS:Data from 21 Chinese medical institutions and the Surveillance, Epidemiology, and End Results (SEER) database were analyzed using Cox proportional hazards models to identify prognostic factors affecting MAC patient outcomes. Restricted cubic spline (RCS) analysis was subsequently applied to determine the optimal ELN threshold. RESULTS:The ELN distribution pattern demonstrated significant concordance between the Chinese cohort ( n = 1086) and the SEER cohort ( n = 12 343), with identical median values (17) and overlapping interquartile ranges (SEER: 12-23 vs. China: 13-22). Multivariate analyses adjusted for potential confounders established ELN quantity as an independent prognostic factor (SEER cohort: hazard ratio [HR] = 0.987, 95% confidence interval [CI]: 0.985-0.990, P < 0.001; Chinese cohort: HR = 0.975, 95% CI: 0.957-0.994, P = 0.011). The RCS models in both databases revealed a nonlinear L-shaped association between the ELN count and all-cause mortality risk, with 17 ELNs identified as the optimal threshold. Notably, patients with ≥17 ELNs exhibited significantly reduced mortality risks in both the SEER cohort ( P < 0.001) and the Chinese cohort ( P = 0.045), particularly in node-negative patients and those without adjuvant chemotherapy. CONCLUSION:Elevated ELN counts are correlated with improved survival. Our findings strongly suggest that 17 ELNs is the optimal cutoff for evaluating surgical quality and prognostic stratification in MAC patients, challenging the conventional 12-ELN standard.

Cardamomin has been widely studied in cancer, but its role in cancer bladder cancer has not been mentioned. In this study, we validated the anti-cancer effect of cardamom and whether its potential mechanism is related to the PI3K/AKT pathway. After treating with different doses of cardamomin, the cytotoxicity was studied by CCK8. Secondly, we analyzed the effect of cardamomin on the proliferation, apoptosis and cell movement. Next, we analyzed the regulation of ESR1 by western blot and its impact on the PI3K/AKT pathway. We also transfected ESR1 overexpression and silencing vectors, and verified the transfection efficiency through RT-qPCR. Further, the specific mechanism of the drug's inhibitory effect on bladder cancer was also determined. We constructed the subcutaneous tumor model in vivo. After cardamomin administration, we mainly analyzed the positive expression of KI67 in tumor tissues by immunohistochemistry, and the apoptotic cells in tumor tissues by TUNEL, and related proteins in PI3K/AKT pathway by western blot. In this paper, cardamomin inhibited cell proliferation and invasion ability, blocked the transition of G0/G1 phase to S phase, and increased apoptotic rate of 5637 and HT1376 cells, as well as raised ESR1 expression. Cardamomin exerted anti-tumor effect through PI3K/AKT pathway. In vivo animal experiments indicated the inhibitory effect of cardamomin on subcutaneous implanted tumor. Cardamomin inhibited the positive expression of KI67 and promoted the TUNEL-positive cells in tumor tissues. Consistent with in vitro assay, cardamomin increased the expression of ESR1 and downregulated the PI3K/AKT pathway. Cardamomin has a significant inhibitory effect on bladder cancer, and upregulate the expression of ESR1 in bladder cancer through PI3K/AKT.

Abstract Background The study focuses on PD‐L1 expression as an essential biomarker for gauging the response of EGFR/ALK wild‐type NSCLC patients to FDA‐approved immune checkpoint inhibitors (ICIs). It aims to explore clinical, molecular, and immune microenvironment characteristics associated with PD‐L1 expression in EGFR/ALK wild‐type lung adenocarcinoma patients eligible for ICI therapy. Methods In this retrospective study, tumor samples from 359 Chinese EGFR/ALK wild‐type lung adenocarcinoma patients underwent comprehensive evaluations for PD‐L1 expression and NGS‐targeted sequencing. The investigation encompassed the analysis and comparison of clinical traits, gene mutations, pathways, and immune signatures between two groups categorized by PD‐L1 status: negative (TPS < 1%) and positive (TPS ≥ 1%). Additionally, the study explored the link between genomic changes and outcomes following immunotherapy. Results High tumor mutational burden correlated significantly with PD‐L1 positivity in patients with EGFR/ALK wild‐type lung adenocarcinoma. Gene alterations, including TP53, KRAS, and others, were more pronounced in the PD‐L1 positive group. Pathway analysis highlighted higher frequencies of alterations in pathways like RTK/RAS, p53, and Hippo in PD‐L1‐positive patients. The Hippo pathway's relevance was confirmed in separate immunotherapy cohorts, associated with better outcomes. In terms of immune cell infiltration, Hippo mutants exhibited higher levels of CD68+PD‐L1+ macrophages, CD8+ T cells, and CD8+PD‐1− T cells. Conclusions This study offers insights into genomic features of Chinese EGFR/ALK wild‐type lung adenocarcinoma patients based on PD‐L1 expression. Notably, Hippo pathway alterations were linked to improved immunotherapy outcomes. These findings suggest connections between the Hippo pathway and PD‐L1 expression, warranting further clinical and functional investigations. The research advances our understanding of PD‐L1 expression's genomic context and immunotherapy response in EGFR/ALK wild‐type lung adenocarcinoma.

Background Aberrant activation of mesenchymal epithelial transition (MET) has been considered to mediate primary and acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC). However, mechanisms underlying this process are not wholly clear and the effective therapeutic strategy remains to be determined. Methods The gefitinib-resistant NSCLC cell lines were induced by concentration increase method in vitro. Western blot and qPCR were used to investigate the relationship between MET and vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) signaling pathway. Double luciferase reporter gene and co-immunoprecipitation were used to further reveal the regulation mechanism between MET and VEGF/VEGFR2. The effect of combined inhibition of MET and VEGF/VEGFR2 signaling pathway on the therapeutic sensitivity of EGFR-TKI in gefitinib resistant cell lines with MET aberration was verified ex vivo and in vivo. Results We successfully obtained two gefitinib-resistant NSCLC cell lines with EGFR mutation and abnormal activation of MET. We observed that MET formed a positive feedback loop with the VEGF/VEGFR2 signaling, leading to persistent downstream signaling activation. Specifically, MET up-regulated VEGFR2 expression in a MAPK/ERK/ETS1-dependent manner, while VEGF promoted physical interaction between VEGFR2 and MET, thereby facilitating MET phosphorylation. A MET inhibitor, crizotinib, combined with an anti-VEGF antibody, bevacizumab, enhanced the sensitivity of NSCLC cells to gefitinib and synergistically inhibited the activation of downstream signaling in vitro. Dual inhibition of MET and VEGF combined with EGFR TKIs markedly restrained tumor growth in both human NSCLC xenograft models and in an EGFR/MET co-altered case. Conclusions Our work reveals a positive feedback loop between MET and VEGF/VEGFR2, resulting in continuous downstream signal activation. Combined inhibition of MET and VEGF/VEGFR2 signaling pathway may be beneficial for reversing EGFR TKIs resistance.

ObjectivesEndoscopic full‐thickness resection (EFTR) for submucosal tumors (SMTs) has been technically challenging. This retrospective study aimed to evaluate the feasibility, safety, and efficacy of EFTR for upper gastrointestinal (GI) SMTs, including extraluminal lesions.MethodsWe retrospectively investigated 232 patients with SMTs who underwent EFTR from January 2014 to August 2023. Clinicopathologic characteristics, procedure‐related parameters, adverse events (AEs), and follow‐up outcomes were assessed in all patients.ResultsThe en‐bloc resection and en‐bloc with R0 resection rates were 98.7% and 96.1%, respectively. The average endoscopic tumor size measured 17.2 ± 8.7 mm, ranging from 6 to 50 mm. The resection time and suture time were 49.0 ± 19.4 min and 22.5 ± 11.6 min, respectively. In all, 39 lesions (16.8%) exhibited predominantly extraluminal growth. Gastrointestinal stromal tumors (GISTs) were the predominant pathology, accounting for 78.4% of the cases. Twenty‐one patients (9.1%) encountered complications, including pneumothorax (1/232, 0.43%), hydrothorax (1/232, 0.43%), localized peritonitis (3/232, 1.29%), and fever (16/232, 6.9%). Although the incidence of postoperative fever was notably higher in the predominantly extraluminal group (7/39, 17.9%) compared to the predominantly intraluminal group (9/193, 4.7%, P = 0.008), there were no significant differences in outcomes of the EFTR procedure. No instances of recurrence were observed during the mean follow‐up period of 3.7 ± 2.3 years.ConclusionEFTR was found to be feasible, safe, and effective for resecting upper GI SMTs, including lesions with predominantly extraluminal growth. Further validation in a prospective study is warranted.

Taxanes are widely used in chemotherapy, but primary and acquired resistance limit the clinical efficacy. Studies have shown tumor interaction with macrophages in the tumor microenvironment (TME) plays a significant role in taxane resistance, yet therapeutic strategies that directly deplete or repolarize macrophages are challenging and with considerable risk of side effects. Here we uncovered that tumor-macrophage interaction can be selectively targeted by inhibiting post-mitotic NOTCH2-JAG1 juxtacrine signaling in the TME, which strongly sensitizes paclitaxel response. Using translatome profiling, we found significant NOTCH2 upregulation during paclitaxel-induced prolonged mitosis. NOTCH2 was subsequently activated in the post-mitotic G1 phase by JAG1 expressed on the neighboring macrophages and tumor cells, which promoted tumor cell survival and upregulated cytokines that recruited JAG1-expressing macrophages, thus generating a positive feedback loop that further enhanced the pro-tumor NOTCH2 activity. By targeting this NOTCH2-JAG1 axis using NOTCH2 shRNA or a pan-NOTCH inhibitor, macrophage recruitment and paclitaxel resistance were significantly attenuated in multiple mouse tumor models of ovarian cancer. Clinical samples from paired primary and recurrent ovarian cancer patients also showed significant correlation of higher NOTCH2 expression with worse prognosis. Our results thus point to combining NOTCH2 inhibitor with taxane as an effective therapeutic strategy to selectively disrupt tumor-macrophage interaction in the TME and overcome macrophage-mediated taxane resistance in NOTCH2-positive tumors. ### Competing Interest Statement The authors have declared no competing interest.