Cholesterol metabolism in tumor microenvironment: cancer hallmarks and therapeutic opportunities.

Cholesterol is crucial for cell survival and growth, and dysregulation of cholesterol homeostasis has been linked to the development of cancer. The tumor microenvironment (TME) facilitates tumor cell survival and growth, and crosstalk between cholesterol metabolism and the TME contributes to tumorigenesis and tumor progression. Targeting cholesterol metabolism has demonstrated significant antitumor effects in preclinical and clinical studies. In this review, we discuss the regulatory mechanisms of cholesterol homeostasis and the impact of its dysregulation on the hallmarks of cancer. We also describe how cholesterol metabolism reprograms the TME across seven specialized microenvironments. Furthermore, we discuss the potential of targeting cholesterol metabolism as a therapeutic strategy for tumors. This approach not only exerts antitumor effects in monotherapy and combination therapy but also mitigates the adverse effects associated with conventional tumor therapy. Finally, we outline the unresolved questions and suggest potential avenues for future investigations on cholesterol metabolism in relation to cancer.

Treatment patterns and survival outcomes in patients with non-metastatic early-onset pancreatic cancer.

BACKGROUND: The incidence of patients with early-onset pancreatic cancer (EOPC; age ≤ 50 years at diagnosis) is on the rise, placing a heavy burden on individuals, families, and society. The role of combination therapy including surgery, radiotherapy, and chemotherapy in non-metastatic EOPC is not well-defined. AIM: To investigate the treatment patterns and survival outcomes in patients with non-metastatic EOPC. METHODS: A total of 277 patients with non-metastatic EOPC who were treated at our institution between 2017 and 2021 were investigated retrospectively. Overall survival (OS), disease-free survival, and progression-free survival were estimated using the Kaplan-Meier method. Univariate and multivariate analyses with the Cox proportional hazards model were used to identify prognostic factors. RESULTS: With a median follow-up time of 34.6 months, the 1-year, 2-year, and 3-year OS rates for the entire cohort were 84.3%, 51.5%, and 27.6%, respectively. The median OS of patients with localized disease who received surgery alone and adjuvant therapy (AT) were 21.2 months and 28.8 months, respectively (P = 0.007). The median OS of patients with locally advanced disease who received radiotherapy-based combination therapy (RCT), surgery after neoadjuvant therapy (NAT), and chemotherapy were 28.5 months, 25.6 months, and 14.0 months, respectively (P = 0.002). The median OS after regional recurrence were 16.0 months, 13.4 months, and 8.9 months in the RCT, chemotherapy, and supportive therapy groups, respectively (P = 0.035). Multivariate analysis demonstrated that carbohydrate antigen 19-9 level, pathological grade, T-stage, N-stage, and resection were independent prognostic factors for non-metastatic EOPC. CONCLUSION: AT improves postoperative survival in localized patients. Surgery after NAT and RCT are the preferred therapeutic options for patients with locally advanced EOPC.

TLR5 agonist in combination with anti-PD-1 treatment enhances anti-tumor effect through M1/M2 macrophage polarization shift and CD8+ T cell priming.

Immune checkpoint inhibitors have revolutionized anti-tumor therapy, notably improving treatment responses in various tumors. However, many patients remain non-responsive and do not experience benefits. Given that Toll-like receptors (TLRs) can counteract tumor immune tolerance by stimulating both innate and adaptive immune responses, TLR agonists are being explored as potential immune adjuvants for cancer treatment. In this study, we assessed the potential of enhancing the efficacy of immune checkpoint inhibitors by activating innate immunity with a TLR5 agonist. In a mouse tumor model, combination therapy with TLR5 agonist and anti-PD-1 significantly inhibited tumor growth. The TLR5 agonist shifted the balance from M2-like to M1-like macrophages and upregulated the expression of co-stimulatory molecules in macrophages. Furthermore, TLR5 agonist promoted the activation and tumor infiltration of CD8+ T cells. As a result, the TLR5 agonist augmented the anti-tumor efficacy of anti-PD-1, suggesting its potential in modulating the tumor microenvironment to enhance the anti-tumor response. Our findings point toward the possibility of optimizing immune checkpoint inhibitor therapy using TLR5 agonists.

Birinapant Reshapes the Tumor Immunopeptidome and Enhances Antigen Presentation.

Birinapant, an antagonist of the inhibitor of apoptosis proteins, upregulates MHCs in tumor cells and displays a better tumoricidal effect when used in combination with immune checkpoint inhibitors, indicating that Birinapant may affect the antigen presentation pathway; however, the mechanism remains elusive. Based on high-resolution mass spectrometry and in vitro and in vivo models, we adopted integrated genomics, proteomics, and immunopeptidomics strategies to study the mechanism underlying the regulation of tumor immunity by Birinapant from the perspective of antigen presentation. Firstly, in HT29 and MCF7 cells, Birinapant increased the number and abundance of immunopeptides and source proteins. Secondly, a greater number of cancer/testis antigen peptides with increased abundance and more neoantigens were identified following Birinapant treatment. Moreover, we demonstrate the existence and immunogenicity of a neoantigen derived from insertion/deletion mutation. Thirdly, in HT29 cell-derived xenograft models, Birinapant administration also reshaped the immunopeptidome, and the tumor exhibited better immunogenicity. These data suggest that Birinapant can reshape the tumor immunopeptidome with respect to quality and quantity, which improves the presentation of CTA peptides and neoantigens, thus enhancing the immunogenicity of tumor cells. Such changes may be vital to the effectiveness of combination therapy, which can be further transferred to the clinic or aid in the development of new immunotherapeutic strategies to improve the anti-tumor immune response.

DKK3 Expression in Glioblastoma: Correlations with Biomolecular Markers.

Glioblastoma is the most common malignant primary tumor of the CNS. The prognosis is dismal, with a median survival of 15 months. Surgical treatment followed by adjuvant therapies such as radiotherapy and chemotherapy characterize the classical strategy. The WNT pathway plays a key role in cellular proliferation, differentiation, and invasion. The DKK3 protein, capable of acting as a tumor suppressor, also appears to be able to modulate the WNT pathway. We performed, in a series of 40 patients, immunohistochemical and Western blot evaluations of DKK3 to better understand how the expression of this protein can influence clinical behavior. We used a statistical analysis, with correlations between the expression of DKK3 and overall survival, age, sex, Ki-67, p53, and MGMT and IDH status. We also correlated our data with information included in the cBioPortal database. In our analyses, DKK3 expression, in both immunohistochemistry and Western blot analyses, was reduced or absent in many cases, showing downregulation. To date, no clinical study exists in the literature that reports a potential correlation between IDH and MGMT status and the WNT pathway through the expression of DKK3. Modulation of this pathway through the expression of DKK3 could represent a new tailored therapeutic strategy in the treatment of glioblastoma.

Herbal Medicines for the Treatment of Active Ulcerative Colitis: A Systematic Review and Meta-Analysis.

Herbal medicines are used by patients with IBD despite limited evidence. We present a systematic review and meta-analysis of randomized controlled trials (RCTs) investigating treatment with herbal medicines in active ulcerative colitis (UC). A search query designed by a library informationist was used to identify potential articles for inclusion. Articles were screened and data were extracted by at least two investigators. Outcomes of interest included clinical response, clinical remission, endoscopic response, endoscopic remission, and safety. We identified 28 RCTs for 18 herbs. In pooled analyses, when compared with placebo, clinical response rates were significantly higher for Indigo naturalis (IN) (RR 3.70, 95% CI 1.97-6.95), but not for Curcuma longa (CL) (RR 1.60, 95% CI 0.99-2.58) or Andrographis paniculata (AP) (RR 0.95, 95% CI 0.71-1.26). There was a significantly higher rate of clinical remission for CL (RR 2.58, 95% CI 1.18-5.63), but not for AP (RR 1.31, 95% CI 0.86-2.01). Higher rates of endoscopic response (RR 1.56, 95% CI 1.08-2.26) and remission (RR 19.37, 95% CI 2.71-138.42) were significant for CL. CL has evidence supporting its use as an adjuvant therapy in active UC. Research with larger scale and well-designed RCTs, manufacturing regulations, and education are needed.

Thermo-immune synergy: Camrelizumab plus microwave ablation in preoperative early-stage breast cancer.

Immunotherapy has enhanced breast cancer outcomes, but optimizing combination therapies is crucial. Integrating additional treatment modalities, like physical therapies, holds promise for optimizing efficacy. Pan et al. recently reported that combining preoperative immunotherapy with microwave ablation is safe and feasible in early-stage breast cancer, effectively sensitizing peripheral CD8+ T cells.1.

Assessment of disease control rate and safety of sorafenib in targeted therapy for advanced liver cancer.

OBJECTIVE: The clinical efficacy and safety of sorafenib in patients with advanced liver cancer (ALC) were evaluated based on transarterial chemoembolization (TACE). METHODS: 92 patients with ALC admitted to our hospital from May 2020 to August 2022 were randomly rolled into a control (Ctrl) group and an observation (Obs) group, with 46 patients in each. Patients in the Ctrl group received TACE treatment, while those in the Obs group received sorafenib molecular targeted therapy (SMTT) on the basis of the treatment strategy in the Ctrl group (400 mg/dose, twice daily, followed by a 4-week follow-up observation). Clinical efficacy, disease control rate (DCR), survival time (ST), immune indicators (CD3+, CD4+, CD4+/CD8+), and adverse reactions (ARs) (including mild fatigue, liver pain, hand-foot syndrome (HFS), diarrhea, and fever) were compared for patients in different groups after different treatments. RESULTS: the DCR in the Obs group (90%) was greatly higher to that in the Ctrl group (78%), showing an obvious difference (P < 0.05). The median ST in the Obs group was obviously longer and the median disease progression time (DPT) was shorter, exhibiting great differences with those in the Ctrl group (P < 0.05). Moreover, no great difference was observed in laboratory indicators between patients in various groups (P > 0.05). After treatment, the Obs group exhibited better levels in all indicators. Furthermore, the incidence of ARs in the Obs group was lower and exhibited a sharp difference with that in the Ctrl group (P < 0.05). CONCLUSION: SMTT had demonstrated good efficacy in patients with ALC, improving the DCR, enhancing the immune response of the body, and reducing the incidence of ARs, thereby promoting the disease outcome. Therefore, it was a treatment method worthy of promotion and application.

Immunotherapy in the treatment of advanced or recurrent endometrial cancer.

The standard treatment of patients with advanced or recurrent endometrial cancer has not significantly changed over the past few decades, reflecting a major unmet clinical need. Fortunately, the arrival of immune checkpoint inhibition is rapidly changing this dismal scenario. This review discusses the most recent results from clinical trials evaluating the use of immune checkpoint inhibitors, either as monotherapy or in combination therapy, in both the post-platinum and frontline settings. Additionally, a section is devoted to the future clinical development of immune checkpoint inhibitors in advanced or recurrent endometrial cancer.

The role of cytoreductive surgery and HIPEC for the treatment of primary and secondary peritoneal malignancies-experience from a tertiary care center in Germany.

PURPOSE: Peritoneal surface malignancies (PSM) are commonly known to have a dismal prognosis. Over the past decades, novel techniques such as cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC) have been introduced for the treatment of PSM which could improve the overall survival and quality of life of patients with PSM. The decision to proceed with CRS and HIPEC is often challenging due the complexity of the disease, the extent of the procedure, associated side effects, and potential risks. Here, we present our experience with CRS and HIPEC to add to the ongoing discussion about eligibility criteria, technical approach, and expected outcomes and contribute to the evolution of this powerful and promising tool in the multidisciplinary treatment of patients with primary and secondary PSM. METHODS: A single-center retrospective chart review was conducted and included a total of 40 patients treated with CRS and HIPEC from April 2020 to September 2022 at the University Hospital Münster Department of Surgery. All patients had histologically confirmed primary or secondary peritoneal malignancies of various primary origins. RESULTS: Our study included 22 patients with peritoneal metastases from gastric cancer (55%), 8 with pseudomyxoma peritonei (20%), 4 with mesothelioma of the peritoneum (10%), and 6 patients with PSM originating from other primary tumor locations. Median PCI at time of cytoreduction was 4 (0-25). Completeness of cytoreduction score was 0 in 37 patients (92.5%), 1 in two patients (5%), and 2 in one patient (2.5%). Median overall survival across all patients was 3.69 years. CONCLUSION: Complete cytoreduction during CRS and HIPEC can be achieved for patients with low PCI, for patients with high PCI in low-grade malignancies, and even for patients with initially high PCI in high-grade malignancies following a significant reduction of cancer burden due to extensive preoperative treatment with PIPAC and systemic chemotherapy.

Ependymoma from Benign to Highly Aggressive Diseases: A Review.

Ependymomas comprise biologically distinct tumor types with respect to age distribution, (epi)genetics, localization, and prognosis. Multimodal risk-stratification, including histopathological and molecular features, is essential in these biologically defined tumor types. Gross total resection (GTR), achieved with intraoperative monitoring and neuronavigation, and if necessary, second-look surgery, is the most effective treatment. Adjuvant radiation therapy is mandatory in high-risk tumors and in case of residual tumor. There is yet growing evidence that some ependymal tumors may be cured by surgery alone. To date, the role of chemotherapy is unclear and subject of current studies.Even though standard therapy can achieve reasonable survival rates for the majority of ependymoma patients, long-term follow-up still reveals a high probability of relapse in certain biological entities.With increasing knowledge of biologically distinct tumor types, risk-adapted adjuvant therapy gains importance. Beyond initial tumor control, and avoidance of therapy-induced morbidity for low-risk patients, intensified treatment for high-risk patients comprises another challenge. With identification of specific risk features regarding molecular alterations, targeted therapy may represent an option for individualized treatment modalities in the future.

Multimodal Approach for the Treatment of Complex Hypothalamic Hamartomas.

Hypothalamic hamartomas (HHs) are rare congenital lesions formed by heterotopic neuronal and glial cells attached to the mammillary bodies, tuber cinereum, and hypothalamus.They often present with an intractable epilepsy typically characterized by gelastic seizures but commonly associated with other types of refractory seizures. The clinical course is progressive in most of the cases, starting with gelastic seizures in infancy and deteriorating into complex seizure disorders that result in catastrophic epilepsy associated with cognitive decline and behavioral disturbances.Hamartomas are known to be intrinsically epileptogenic and the site of origin for the gelastic seizures. As antiepileptic drugs are typically ineffective in controlling HH-related epilepsy, different surgical options have been proposed as a treatment to achieve seizure control. Resection or complete disconnection of the hamartoma from the mammillothalamic tract has proved to achieve a long-lasting control of the epileptic syndrome.Usually, symptoms and their severity are typically related to the size, localization, and type of attachment. Precocious puberty appears mostly in the pedunculated type, while epileptic syndrome and behavioral decline are frequently related to the sessile type. For this reason, different classifications of HHs have been developed based on their size, extension, and type of attachment to the hypothalamus.The bigger and more complex hypothalamic hamartomas typically present with severe refractory epilepsy, behavioral disturbances, and progressive cognitive decline posing a formidable challenge for the control of these symptoms.We present here our experience with the multimodal treatment for complex hypothalamic hamartomas. After an in-depth review of the literature, we systematize our approach for the different types of hypothalamic hamartomas.

Update on FDG-PET in pediatric lymphoma.

Lymphoma represent the third most common malignant disease in childhood and adolescence. They are divided into pediatric Hodgkin lymphoma (P-HL) and pediatric non-Hodgkin lymphoma (P-NHL). In P-HL, excellent cure rates are achieved through combined modality treatment using chemotherapy and radiotherapy. For more than 20 years, FDG-PET has been an integral part of the treatment and guides its intensity through improved staging and precise assessment of chemotherapy response. In P-NHL, good cure rates are achieved with chemotherapy alone. At present FDG-PET plays only a subordinate role in the treatment setting. Its potential to contribute to treatment management is far from being fully utilised. In this article, the current status of FDG-PET in pediatric lymphoma is presented in detail. The core elements are the sections on staging and response assessment. In addition, challenges and pitfalls are discussed and future developments are outlined.

An AI-based approach for modeling the synergy between radiotherapy and immunotherapy.

Personalized, ultra-fractionated stereotactic adaptive radiotherapy (PULSAR) is designed to administer tumoricidal doses in a pulsed mode with extended intervals, spanning weeks or months. This approach leverages longer intervals to adapt the treatment plan based on tumor changes and enhance immune-modulated effects. In this investigation, we seek to elucidate the potential synergy between combined PULSAR and PD-L1 blockade immunotherapy using experimental data from a Lewis Lung Carcinoma (LLC) syngeneic murine cancer model. Employing a long short-term memory (LSTM) recurrent neural network (RNN) model, we simulated the treatment response by treating irradiation and anti-PD-L1 as external stimuli occurring in a temporal sequence. Our findings demonstrate that: (1) The model can simulate tumor growth by integrating various parameters such as timing and dose, and (2) The model provides mechanistic interpretations of a "causal relationship" in combined treatment, offering a completely novel perspective. The model can be utilized for in-silico modeling, facilitating exploration of innovative treatment combinations to optimize therapeutic outcomes. Advanced modeling techniques, coupled with additional efforts in biomarker identification, may deepen our understanding of the biological mechanisms underlying the combined treatment.

Single-cell profiling of response to neoadjuvant chemo-immunotherapy in surgically resectable esophageal squamous cell carcinoma.

BACKGROUND: The efficacy of neoadjuvant chemo-immunotherapy (NAT) in esophageal squamous cell carcinoma (ESCC) is challenged by the intricate interplay within the tumor microenvironment (TME). Unveiling the immune landscape of ESCC in the context of NAT could shed light on heterogeneity and optimize therapeutic strategies for patients. METHODS: We analyzed single cells from 22 baseline and 24 post-NAT treatment samples of stage II/III ESCC patients to explore the association between the immune landscape and pathological response to neoadjuvant anti-PD-1 combination therapy, including pathological complete response (pCR), major pathological response (MPR), and incomplete pathological response (IPR). RESULTS: Single-cell profiling identified 14 major cell subsets of cancer, immune, and stromal cells. Trajectory analysis unveiled an interesting link between cancer cell differentiation and pathological response to NAT. ESCC tumors enriched with less differentiated cancer cells exhibited a potentially favorable pathological response to NAT, while tumors enriched with clusters of more differentiated cancer cells may resist treatment. Deconvolution of transcriptomes in pre-treatment tumors identified gene signatures in response to NAT contributed by specific immune cell populations. Upregulated genes associated with better pathological responses in CD8 + effector T cells primarily involved interferon-gamma (IFNγ) signaling, neutrophil degranulation, and negative regulation of the T cell apoptotic process, whereas downregulated genes were dominated by those in the immune response-activating cell surface receptor signaling pathway. Natural killer cells in pre-treatment tumors from pCR patients showed a similar upregulation of gene expression in response to IFNγ but a downregulation of genes in the neutrophil-mediated immunity pathways. A decreased cellular contexture of regulatory T cells in ESCC TME indicated a potentially favorable pathological response to NAT. Cell-cell communication analysis revealed extensive interactions between CCL5 and its receptor CCR5 in various immune cells of baseline pCR tumors. Immune checkpoint interaction pairs, including CTLA4-CD86, TIGIT-PVR, LGALS9-HAVCR2, and TNFSF4-TNFRSF4, might serve as additional therapeutic targets for ICI therapy in ESCC. CONCLUSIONS: This pioneering study unveiled an intriguing association between cancer cell differentiation and pathological response in esophageal cancer patients, revealing distinct subgroups of tumors for which neoadjuvant chemo-immunotherapy might be effective. We also delineated the immune landscape of ESCC tumors in the context of clinical response to NAT, which provides clinical insights for better understanding how patients respond to the treatment and further identifying novel therapeutic targets for ESCC patients in the future.

Efficiency of Protective Interventions on Irinotecan-Induced Diarrhea: A Systematic Review and Meta-Analysis.

BACKGROUND: Irinotecan is widely used in the treatment of various solid tumors, but the adverse effects from it, especially diarrhea, limit its use. Several clinical trials of prophylactic treatment of irinotecan-induced diarrhea (IID) have been ongoing, and some of the data are controversial. This encouraged us to conduct a meta-analysis of the effects of interventions on preventing IID. METHOD: This systematic review was conducted based on the PRISMA statement. We performed literature searches from PubMed, Web of Science, Embase, and Cochrane Library. The number registered in PROSPERO is CRD42022368633. After searching 1034 articles in the database and references, 8 studies were included in this meta-analysis. RESULT: The RR of high-grade diarrhea and all-grade diarrhea were 0.31 (I2 = 51%, 95% CI: 0.14-0.69; P = .004) and .76 (I2 = 65%, 95% CI: 0.62-0.93; P < .008) respectively, thus the use of intervention measures for preventing IID is effective, and the risk reduction of high-grade diarrhea was more significant. Subgroup analysis revealed that the monotherapy group (RR: 0.48, 95% CI: 0.21-1.13, I2 = 0%) and combination therapy group (RR: 0.14, 95% CI: 0.06-0.32, I2 = 0%) in the risk of high-grade diarrhea had no significant heterogeneity within the groups, and traditional herbal medicines (Kampo medicine Hangeshashin-to, PHY906 and hot ironing with Moxa Salt Packet on Tianshu and Shangjuxu) were effective preventive measures (RR:0.20, 95% CI: 0.07-0.60, I2 = 0%). The Jadad scores for traditional herbal medicines studies were 3, and the follow-up duration was only 2 to 6 weeks. CONCLUSION: This systematic review and meta-analysis suggest that preventive treatments significantly reduced the risk of high-grade and all-grade diarrhea, confirming the efficacy in the incidence and severity of IID, among which traditional herbal medicines (baicalin-containing) provided a protective effect in reducing the severity of IID. However, the traditional herbal medicines studies were of low quality. Combined irinotecan therapy can obtain better preventive effects than monotherapy of IID. These would be helpful for the prevention of IID in clinical practice.

Overall Survival with Adjuvant Pembrolizumab in Renal-Cell Carcinoma.

BACKGROUND: Adjuvant pembrolizumab therapy after surgery for renal-cell carcinoma was approved on the basis of a significant improvement in disease-free survival in the KEYNOTE-564 trial. Whether the results regarding overall survival from the third prespecified interim analysis of the trial would also favor pembrolizumab was uncertain. METHODS: In this phase 3, double-blind, placebo-controlled trial, we randomly assigned (in a 1:1 ratio) participants with clear-cell renal-cell carcinoma who had an increased risk of recurrence after surgery to receive pembrolizumab (at a dose of 200 mg) or placebo every 3 weeks for up to 17 cycles (approximately 1 year) or until recurrence, the occurrence of unacceptable toxic effects, or withdrawal of consent. A significant improvement in disease-free survival according to investigator assessment (the primary end point) was shown previously. Overall survival was the key secondary end point. Safety was a secondary end point. RESULTS: A total of 496 participants were assigned to receive pembrolizumab and 498 to receive placebo. As of September 15, 2023, the median follow-up was 57.2 months. The disease-free survival benefit was consistent with that in previous analyses (hazard ratio for recurrence or death, 0.72; 95% confidence interval [CI], 0.59 to 0.87). A significant improvement in overall survival was observed with pembrolizumab as compared with placebo (hazard ratio for death, 0.62; 95% CI, 0.44 to 0.87; P = 0.005). The estimated overall survival at 48 months was 91.2% in the pembrolizumab group, as compared with 86.0% in the placebo group; the benefit was consistent across key subgroups. Pembrolizumab was associated with a higher incidence of serious adverse events of any cause (20.7%, vs. 11.5% with placebo) and of grade 3 or 4 adverse events related to pembrolizumab or placebo (18.6% vs. 1.2%). No deaths were attributed to pembrolizumab therapy. CONCLUSIONS: Adjuvant pembrolizumab was associated with a significant and clinically meaningful improvement in overall survival, as compared with placebo, among participants with clear-cell renal-cell carcinoma at increased risk for recurrence after surgery. (Funded by Merck Sharp and Dohme, a subsidiary of Merck; KEYNOTE-564 ClinicalTrials.gov number, NCT03142334.).

Drug repurposing for cancer therapy.

Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.