Prediction of the short-term efficacy and recurrence of photodynamic therapy in the treatment of oral leukoplakia based on deep learning.

BACKGROUND: The treatment of oral leukoplakia (OLK) with aminolaevulinic acid photodynamic therapy (ALA-PDT) is widespread. Nonetheless, there is variation in efficacy. Therefore, this study constructed a model for predicting the short-term efficacy and recurrence of OLK after ALA-PDT. METHODS: The short-term efficacy and recurrence of ALA-PDT were calculated by statistical analysis, and the relevant influencing factors were analyzed by Logistic regression and COX regression model. Finally, prediction models for total response (TR) rate, complete response (CR) rate and recurrence in OLK patients after ALA-PDT treatment were established. Features from pathology sections were extracted using deep learning autoencoder and combined with clinical variables to improve prediction performance of the model. RESULTS: The logistic regression analysis showed that the non-homogeneous (OR: 4.911, P: 0.023) OLK and lesions with moderate to severe epithelial dysplasia (OR: 4.288, P: 0.042) had better short-term efficacy. The area under receiver operating characteristic curve (AUC) of CR, TR and recurrence predict models after the ALA-PDT treatment of OLK patients is 0.872, 0.718, and 0.564, respectively. Feature extraction revealed an association between inflammatory cell infiltration in the lamina propria and recurrence after PDT. Combining clinical variables and deep learning improved the performance of recurrence model by more than 30 %. CONCLUSIONS: ALA-PDT has excellent short-term efficacy in the management of OLK but the recurrence rate was high. Prediction model based on clinicopathological characteristics has excellent predictive effect for short-term efficacy but limited effect for recurrence. The use of deep learning and pathology images greatly improves predictive value of the models.

Pemphigus oral lesions area index (POLAI): A new scoring scale for assessing oral pemphigus vulgaris.

OBJECTIVES: Current scales for Pemphigus vulgaris (PV) do not adequately represent the clinical variability of oral lesions. This study aimed to develop an independent scale, the Pemphigus Oral Lesions Area Index (POLAI), for assessment of oral PV exclusively, and compare POLAI, Pemphigus Disease Area Index (PDAI), Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and Oral Disease Severity Score (ODSS) regarding inter- and intra-observer reliability and validity. MATERIALS AND METHODS: Retrospective cohort included 209 sets of digital-photographs. Additional clinical cohort included 32 PV patients. All visits were assessed by four clinicians using the PDAI, ABSIS, ODSS and POLAI, and were rated by three specialists using the Physician's Global Assessment (PGA). RESULTS: The intraclass correlation coefficient showed the inter-observer reliability with 0.89 and 0.86 for PDAI, 0.87 for ABSIS, 0.93 for ODSS, 0.96 for POLAI, and 0.97 and 0.96 for PGA. Intra-observer agreements showed excellent reliability for all 4 scores. Highest correlation was observed between PGA and POLAI (correlation coefficients were 0.96). The mean time taken to complete each scale was within 1.5 min. CONCLUSION: POLAI is valid for the assessment of oral PV with superior inter- and intra-observer reliability to PDAI, ABSIS and ODSS, and is feasible in clinic.

Progress and trends in photodynamic therapy research in oral science: A bibliometric analysis.

BACKGROUND: Photodynamic therapy is garnering increasing attention in oral science. Despite its promising potential, further exploration is warranted to delve into the research paradigms and evolving trends within oral science. Therefore, this study aimed to conduct a comprehensive bibliometric analysis of photodynamic therapy in oral science (PDTOS), investigating research landscapes, identifying key contributors, analyzing collaborative networks, pinpointing emerging research directions, and exploring factors influencing high citations. METHODS: Research and review articles in PDTOS were retrieved from the Web of Science Core Collection database up to December 31, 2023. The R package "bibliometrix" and VOSviewer were utilized for visualizing collaboration networks and keyword co-occurrence, alongside trend analysis. Negative binomial regression was used to model factors affecting citation counts. RESULTS: A total of 2784 articles with significant international collaboration (23.14 %) were analyzed. Brazil, China, the USA, Iran, and Italy led in publications, with predominant USA-European collaborations. The University of Sao Paulo in Brazil was the most published institution in the field. Photodiagnosis and Photodynamic Therapy was the core journal in the field and has the highest number of publications. The main research fields included photodynamic therapy, antibacterial and anticancer treatment, management, and peri­implant periodontitis, with a recent focus on peri­implantitis. Factors such as international cooperation, funding, article age, type, author count, and references significantly influenced citations. CONCLUSIONS: This research provided valuable insights into PDTOS trends and knowledge structures. These findings underscored a significant increase in the number of PDTOS publications, urging strengthened international cooperation. Emerging research has focused on peri­implantitis and nano-photosensitizer materials. Authors should consider various citation-related factors in their research endeavors.

A Simply Synthesized Shaking-induced Small Molecule System with Repeatableand Instantaneous Discoloration Response.

Force-related discoloration materials are highly valuable because of their characteristics of visualization, easy operation, and environment friendliness. Most force-related discoloration materials focus on polymers and depend on bond scission, which leads to insensitivity and unrecoverable. Small-molecule systems based on well-defined molecular structures and simple composition with high sensitivity would exhibit considerable mechanochromic potential. However, to date, researches about force-related discoloration materials based on small molecule solution remain limited and are rarely reported. In this study, we developed a repeatable and instantaneous discoloration small molecule solution system by simple one-pot synthesis method. It exhibited an instantaneous chromic change from yellowish to dark green under shaking and reverting back to yellow within 1 minute after removal of the shaking. Experimental results confirmed that the discoloration mechanism is attributed to the oscillation accelerating the production of unstable ortho-OH phenoxyl radical. The newly developed shaking-induced discoloration small molecule system (SDSMS) promises in field of mechanical force sensing and optical encryption.

Oral epithelial dysplasia detection and grading in oral leukoplakia using deep learning.

BACKGROUND: The grading of oral epithelial dysplasia is often time-consuming for oral pathologists and the results are poorly reproducible between observers. In this study, we aimed to establish an objective, accurate and useful detection and grading system for oral epithelial dysplasia in the whole-slides of oral leukoplakia. METHODS: Four convolutional neural networks were compared using the image patches from 56 whole-slide of oral leukoplakia labeled by pathologists as the gold standard. Sequentially, feature detection models were trained, validated and tested with 1,000 image patches using the optimal network. Lastly, a comprehensive system named E-MOD-plus was established by combining feature detection models and a multiclass logistic model. RESULTS: EfficientNet-B0 was selected as the optimal network to build feature detection models. In the internal dataset of whole-slide images, the prediction accuracy of E-MOD-plus was 81.3% (95% confidence interval: 71.4-90.5%) and the area under the receiver operating characteristic curve was 0.793 (95% confidence interval: 0.650 to 0.925); in the external dataset of 229 tissue microarray images, the prediction accuracy was 86.5% (95% confidence interval: 82.4-90.0%) and the area under the receiver operating characteristic curve was 0.669 (95% confidence interval: 0.496 to 0.843). CONCLUSIONS: E-MOD-plus was objective and accurate in the detection of pathological features as well as the grading of oral epithelial dysplasia, and had potential to assist pathologists in clinical practice.

Photodynamic therapy for refractory erosive oral lichen planus: a case series study.

Oral lichen planus is a chronic inflammatory disease that occurs on the oral mucosa and is an oral potentially malignant disease. Treatment of oral lichen planus aims to promote healing of the erosion, relieve pain, reduce recurrence of the erosion, and prevent canceration. Corticosteroids are the first line of treatment for oral lichen planus. Refractory oral lichen planus is a clinical classification of oral lichen planus that has not responded to corticosteroid treatment for more than 2 months. Topical 5-aminolevulinic acid-mediated photodynamic therapy is an innovative and effective treatment for potentially malignant oral diseases and has been reported as an alternative treatment to conventional therapies for oral lichen planus. On this basis, we report 3 cases of refractory erosive oral lichen planus in which persistent erosive lesions healed after topical application of 5-aminolevulinic acid-mediated photodynamic therapy without any adverse effects or any signs of recurrence. Topical 5-aminolevulinic acid-mediated photodynamic therapy will become an effective clinical treatment for refractory erosive oral lichen planus.

Single-Cell Transcriptomes and Immune Repertoires Reveal the Cell State and Molecular Changes in Pemphigus Vulgaris.

The etiology and pathogenesis of pemphigus vulgaris (PV) entail intricate interactions between immune cells and epithelial cells. However, the specific subtypes of immune cells involved in PV, along with their respective roles, remain elusive. Likewise, the precise functions and mechanisms by which glucocorticoids affect cell types within the disease context require further elucidation. To address these knowledge gaps, we performed 5' single-cell RNA sequencing, combined with V(D)J enrichment on buccal mucosal lesions and peripheral blood samples from treatment-naive patients with PV, in conjunction with post-treatment peripheral blood samples obtained after oral prednisone treatment. Our findings suggest that the IL-1α signaling pathway, myeloid APCs, inflammatory CD8+ resident memory T cells, and dysfunctional CD4+ regulatory T cells are involved in the pathogenesis of PV. Part of these findings were validated by immunohistochemical assays and multiplex immunofluorescence assays. Furthermore, our results highlight the significant impact of prednisone treatment on monocytes and mucosal-associated invariant T cells while revealing a limited effect on CD4+ regulatory T cells. Additionally, we present the CDR3 amino acid sequence of BCR related to PV disease and investigate the characteristics of TCR/BCR clonotypes. In conclusion, our study provides a comprehensive understanding of PV, particularly focusing on the mucosal-dominant type, and sheds light on the effects of glucocorticoids within the PV context. These insights hold promise for the development of new therapeutic strategies in this autoimmune disorder.

Circular RNA from Tyrosylprotein Sulfotransferase 2 Gene Inhibits Cisplatin Sensitivity in Head and Neck Squamous Cell Carcinoma by Sponging miR-770-5p and Interacting with Nucleolin.

Chemoresistance poses a significant challenge in the treatment of advanced head and neck squamous cell cancer (HNSCC). The role and mechanism of circular RNAs (circRNAs) in HNSCC chemoresistance remain understudied. We conducted circRNA microarray analysis to identify differentially expressed circRNAs in HNSCC. The expression of circRNAs from the tyrosylprotein sulfotransferase 2 (TPST2) gene and miRNAs was evaluated through qPCR, while the circular structure of circTPST2 was verified using Sanger sequencing and RNase R. Through Western blotting, biotin-labeled RNA pulldown, RNA immunoprecipitation, mass spectrometry, and rescue experiments, we discovered miR-770-5p and nucleolin as downstream targets of circTPST2. Functional tests, including CCK8 assays and flow cytometry, assessed the chemoresistance ability of circTPST2, miR-770-5p, and Nucleolin. Additionally, FISH assays determined the subcellular localization of circTPST2, miR-770-5p, and Nucleolin. IHC staining was employed to detect circTPST2 and Nucleolin expression in HNSCC patients. circTPST2 expression was inversely correlated with cisplatin sensitivity in HNSCC cell lines. Remarkably, high circTPST2 expression correlated with lower overall survival rates in chemotherapeutic HNSCC patients. Mechanistically, circTPST2 reduced chemosensitivity through sponge-like adsorption of miR-770-5p and upregulation of the downstream protein Nucleolin in HNSCC cells. The TCGA database revealed improved prognosis for patients with low circTPST2 expression after chemotherapy. Moreover, analysis of HNSCC cohorts demonstrated better prognosis for patients with low Nucleolin protein expression after chemotherapy. We unveil circTPST2 as a circRNA associated with chemoresistance in HNSCC, suggesting its potential as a marker for selecting chemotherapy regimens in HNSCC patients. Further exploration of the downstream targets of circTPST2 advanced our understanding and improved treatment strategies for HNSCC.

A multi-center cross-sectional study of 1495 Chinese oral lichen planus patients.

OBJECTIVE: To explore the clinical epidemiological characteristics of oral lichen planus (OLP) and risk factors for erosive/ulcerative OLP. MATERIALS AND METHODS: Patients diagnosed with OLP from 11 different hospitals were included in the study. Descriptive statistical methods were used to explore the clinical epidemiological characteristics and logistic regression, sensitivity analysis, and subgroup analysis were utilized to explore the risk factors for erosive/ulcerative OLP. RESULTS: The average age of patients was 49.2 ± 13.3 years, and 61.4% of the patients were women. The ratios of patients with reticular, hyperemic/erythematous, and erosive/ulcerative lesions were 47.9%, 27.8%, and 24.2%, respectively. Analysis of risk factors for erosive/ulcerative OLP identified the following variables: age, course of disease of 12 months or more, II°-III° dental calculus, hypertension, diabetes, and heart disease, as well as regions of habitation. Subgroup analysis showed significant differences in risk factors for erosive/ulcerative OLP in patients with and without risk behaviors. CONCLUSION: The clinical epidemiological characteristics of patients with OLP in the Chinese population in this study are basically consistent with existing reports in developed countries. And we identified clinical characteristics associated with erosive/ulcerative OLP through clinical epidemiological analysis.

Identification of the causal relationship between sleep quality, insomnia, and oral ulcers.

BACKGROUND: Multiple epidemiological studies have posited a potential association between sleep quality and the risk of oral diseases, yet the resulting conclusions have remained contentious, and the presence of a causal link remains equivocal. In this study, we aimed to investigate the causal relationship between sleep duration, insomnia, and common oral diseases. METHODS: We utilized genetic correlation and two-sample Mendelian randomization analyses based on summary statistics from genome-wide association studies of sleep duration (N = 460,099), insomnia (N = 462,341), mouth ulcer (N = 385,026), oral cavity cancer (N = 4,151), and periodontal disease (N = 527,652). RESULTS: Our results revealed a negative genetic correlation between sleep duration and mouth ulcer (genetic correlation: -0.09, P = 0.007), while a positive genetic correlation between insomnia and mouth ulcer was observed (genetic correlation: 0.18, P = 2.51E-06). Furthermore, we demonstrated that longer sleep duration is significantly associated with a reduced risk of mouth ulcers (OR: 0.67, 95% CI: 0.54-0.83, P = 2.84E-04), whereas insomnia is nominally associated with an increased risk of mouth ulcers (OR: 1.40, 95% CI: 1.01-1.95, P = 0.044). In contrast, no significant association was detected between sleep quality and periodontal disease or oral cavity cancer. CONCLUSIONS: This work provides robust evidence to support the notion that enhanced sleep quality may confer a decreased risk of oral ulcers, thereby bearing considerable clinical relevance.

Amyloidosis initially only manifesting as oral mucosal hemorrhagic lesions: a case series report.

Amyloidosis is a heterogeneous series of diseases associated with extracellular amyloid protein depositions, which can involve multiple organs and tissues, leading to tissue structure alterations and organ dysfunction. The tongue is the most frequently involved site of oral amyloidosis, and one of its characteristic clinical presentations is macroglossia. Here, we report 3 extremely rare cases of amyloidosis exclusively appearing as multiple blood blisters, petechiae, and ecchymoses of the oral mucosa, in the absence of common clinical manifestations of oral and systemic amyloidosis. In a word, we highlight the possibility of oral mucosal hemorrhagic lesions as the initial clinical signs of systemic amyloidosis and the significance of the early and timely diagnosis of amyloidosis.

Photodynamic therapy in focal epithelial hyperplasia.

Focal epithelial hyperplasia (FEH) is an uncommon benign disorder affecting the oral mucosa. It is primarily associated with human papillomavirus (HPV) infection and presents as multiple white or pink soft papules or nodules. Typically, FEH is asymptomatic. Conventional treatment approaches for FEH include topical medication, surgical excision, CO2 laser ablation, cryotherapy, etc., but their efficacy varies. Photodynamic therapy (PDT) is a non-invasive and selective photochemotherapy method widely utilized in clinical practice. By employing specific light wavelengths to activate photosensitizers and induce the generation of reactive oxygen, PDT exerts cytotoxic effects. However, the application of PDT in treating FEH has not been previously documented. In this study, we present a case demonstrating the complete remission of FEH lesions using PDT, with no recurrence observed over a period of 9 months. This compelling outcome suggests that PDT may be a preferred treatment modality for FEH.

Pyostomatitis vegetans characterized by unilateral circumscribed swelling: a case report.

Pyostomatitis vegetans (PSV) is a rare disease characterized by pustules. The typical manifestations are "snail-track" lesions, which widely involve multiple parts of the oral mucosa. It is often associated with inflammatory bowel disease. This paper reports a case of a patients with PSV and unilateral circumscribed swelling. Ulcerative colitis was revealed by oral lesions. The clinical manifestations as well as histopathological and immunopathological features of PSV were analyzed and summarized to provide ideas for clinical diagnosis and treatment.

Oral manifestations serve as potential signs of ulcerative colitis: A review.

As an immune dysregulation-related disease, although ulcerative colitis (UC) primarily affects the intestinal tract, extraintestinal manifestations of the disease are evident, particularly in the oral cavity. Herein, we have reviewed the various oral presentations, potential pathogenesis, and treatment of oral lesions related to UC. The oral manifestations of UC include specific and nonspecific manifestations, with the former including pyostomatitis vegetans and the latter encompassing recurrent aphthous ulcers, atrophic glossitis, burning mouth syndrome, angular cheilitis, dry mouth, taste change, halitosis, and periodontitis. Although the aetiology of UC has not been fully determined, the factors leading to its development include immune system dysregulation, dysbiosis, and malnutrition. The principle of treating oral lesions in UC is to relieve pain, accelerate the healing of lesions, and prevent secondary infection, and the primary procedure is to control intestinal diseases. Systemic corticosteroids are the preferred treatment options, besides, topical and systemic administration combined with dietary guidance can also be applied. Oral manifestations of UC might accompany or precede the diagnosis of UC, albeit with the absence of intestinal symptoms; therefore, oral lesions, especially pyostomatitis vegetans, recurrent aphthous ulcer and periodontitis, could be used as good mucocutaneous signs to judge the occurrence and severity of UC, thus facilitating the early diagnosis and treatment of UC and avoiding severe consequences, such as colon cancer.

Manganese suppresses the development of oral leukoplakia by activating the immune response.

OBJECTIVE: Manganese ion (Mn2+ ) is reported to promote the antitumor immune response by activating the cGAS-STING pathway, but it is unknown whether Mn2+ can prevent the malignant transformation of precancerous lesions. The effects of Mn2+ in treating oral leukoplakia (OLK) were explored in this work. METHODS: Peripheral blood Mn analysis of the patients was performed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). A coculture model of dendritic cells (DCs)/macrophages, CD8+ T cells, and dysplastic oral keratinocytes (DOKs) was employed to analyze the role and mechanism of Mn2+ in a simulated OLK immune microenvironment. Western blot, RT-PCR, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and lactate dehydrogenase (LDH) assays were adopted to detect the mechanism of Mn2+ in this model. 4-nitroquinoline oxide (4NQO)-induced OLK mice were used to assess the role of Mn2+ in suppressing OLK progression, and a novel Mn2+ -loaded guanosine-tannic acid hydrogel (G-TA@Mn2+ hydrogel) was fabricated and evaluated for its advantages in OLK therapy. RESULTS: The content of Mn in patients' peripheral blood was negatively related to the progression of OLK. Mn2+ promoted the maturation and antigen presentation of DCs and macrophages and enhanced the activation of CD8+ T cells in the coculture model, resulting in effective killing of DOKs. Mechanistic analysis found that Mn2+ enhanced the anti-OLK immune response by activating the cGAS-STING pathway. Moreover, Mn2+ suppressed the development of 4NQO-induced carcinogenesis in the mouse model. In addition, the G-TA@Mn2+ hydrogel had better anti-OLK effects. CONCLUSIONS: Mn2+ enhanced the anti-OLK immune response by activating the cGAS-STING pathway, and the G-TA@Mn2+ hydrogel is a potential novel therapeutic approach for OLK treatment.

Laser-assisted photodynamic therapy in proliferative verrucous oral leukoplakia.

Proliferative verrucous leukoplakia (PVL) is a rapidly progressing, easily relapsed, and cancer-prone oral potential malignant disease (OPMD), for which treatment options are currently limited. Non-invasive photodynamic therapy (PDT) uses specific wavelengths of light to excite photosensitizers and generate reactive oxygen species to induce cytotoxic effects, and it is selective for malignant tissues. However, the lesions of PVL often show hyperkeratosis, which limits the penetration of photosensitizers into the tissue and affects the effectiveness of PDT. Laser, a safe and efficient treatment, has shown great advantages in aiding photosensitizer delivery, due to its ability to accelerate the penetration of 5-aminolevulinic acid (5-ALA) and improve the accumulation of protoporphyrin IX (PPIX) in tissues. In the case report, we achieved complete remission and no recurrence at 8 months in a patient with PVL through laser-assisted PDT, which obtained satisfactory clinical effect and well protected the appearance and function of oral cavity.

Loss of KDM4B impairs osteogenic differentiation of OMSCs and promotes oral bone aging.

Aging of craniofacial skeleton significantly impairs the repair and regeneration of trauma-induced bony defects, and complicates dental treatment outcomes. Age-related alveolar bone loss could be attributed to decreased progenitor pool through senescence, imbalance in bone metabolism and bone-fat ratio. Mesenchymal stem cells isolated from oral bones (OMSCs) have distinct lineage propensities and characteristics compared to MSCs from long bones, and are more suited for craniofacial regeneration. However, the effect of epigenetic modifications regulating OMSC differentiation and senescence in aging has not yet been investigated. In this study, we found that the histone demethylase KDM4B plays an essential role in regulating the osteogenesis of OMSCs and oral bone aging. Loss of KDM4B in OMSCs leads to inhibition of osteogenesis. Moreover, KDM4B loss promoted adipogenesis and OMSC senescence which further impairs bone-fat balance in the mandible. Together, our data suggest that KDM4B may underpin the molecular mechanisms of OMSC fate determination and alveolar bone homeostasis in skeletal aging, and present as a promising therapeutic target for addressing craniofacial skeletal defects associated with age-related deteriorations.

Photodynamic therapy combined with laser drilling successfully prevents the recurrence of refractory oral proliferative verrucous leukoplakia.

Oral proliferative verrucous leukoplakia is a potentially malignant disorder with high rates of recurrence and malignant transformation. Proliferative verrucous leukoplakia is often refractory to various treatments, including topical drugs, surgical resection, cryotherapy, and laser therapy. Topical 5-aminolevulinic acid-mediated photodynamic therapy is an innovative and effective treatment for potentially malignant oral disorders and has the potential to control the recurrence of precancerous lesions and cancer. Various pre-treatments or combined therapies have been proposed to increase the efficacy of topical 5-aminolevulinic acid-mediated photodynamic therapy, especially for large, thick, or highly keratinised lesions. We report a case of refractory proliferative verrucous leukoplakia in a 58-year-old female patient who showed rapid recurrence within 1 week of topical 5-aminolevulinic acid-mediated photodynamic therapy despite pre-treatment with microneedle puncture, combined intralesional injection of 5-aminolevulinic acid, and shortened treatment interval. We applied three sessions of topical 5-aminolevulinic acid-mediated photodynamic therapy combined with diode laser drilling pre-treatment at 1-week intervals, which successfully eradicated the lesions without any adverse effects and without any signs of recurrence at the 10-month follow-up. Topical 5-aminolevulinic acid-mediated photodynamic therapy combined with diode laser drilling pre-treatment is safe and well-tolerated and could have synergistic efficacy against refractory oral proliferative verrucous leukoplakia.

Roles of circRNAs in cancer chemoresistance (Review).

Circular RNA (circRNA) is a type of endogenous, high­stability, noncoding RNA. circRNAs exhibit various biological functions, and are involved in physiological and pathological processes occurring in various diseases, including cancers. They can not only act as microRNA and protein sponges, but also interact with proteins, translated peptides, and transcriptional and translational regulators, and compete with pre­mRNA splicing. Chemotherapy is one of the most important types of cancer treatment. However, the resistance of cancer cells to chemotherapy is a leading reason for the failure of chemotherapy. It has been reported that circRNAs play important roles in cancer resistance via a number of mechanisms. The functions of the circRNAs provide insight into their roles in chemoresistance pathways. In addition, some circRNAs may serve as novel biomarkers for the diagnosis and prognosis of cancer resistance. Obtaining improved understanding of the molecular regulatory networks featuring circRNAs in tumors and searching for markers for the diagnosis and treatment of cancer resistance are leading issues in circRNA research. The present review introduced the functions of circRNAs, illustrated the mechanisms underlying drug resistance in cancer, described the contributions of circRNAs to this resistance and discussed the potential application of circRNAs in the treatment of drug­resistant cancer. In particular, the review aimed to reveal the main mechanisms of circRNAs in cancer drug resistance, including mechanisms involving drug transport and metabolism, alterations of drug targets, DNA damage repair, downstream resistance mechanisms, adaptive responses and the tumor microenvironment. The findings may provide novel therapeutic targets for clinical treatment of cancer chemoresistance.