S100A12 is a promising biomarker in papillary thyroid cancer

Exosome-Mediated Communication in Thyroid Cancer: Implications for Prognosis and Therapeutic Targets

Thyroid cancer (THCA) is one of the most common malignancies of the endocrine system. Exosomes have significant value in performing molecular treatments, evaluating the diagnosis and determining tumor prognosis. Thus, the identification of exosome-related genes could be valuable for the diagnosis and potential treatment of THCA. In this study, we examined a set of exosome-related differentially expressed genes (DEGs) (BIRC5, POSTN, TGFBR1, DUSP1, BID, and FGFR2) by taking the intersection between the DEGs of the TCGA-THCA and GeneCards datasets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of the exosome-related DEGs indicated that these genes were involved in certain biological functions and pathways. Protein‒protein interaction (PPI), mRNA‒miRNA, and mRNA-TF interaction networks were constructed using the 6 exosome-related DEGs as hub genes. Furthermore, we analyzed the correlation between the 6 exosome-related DEGs and immune infiltration. The Genomics of Drug Sensitivity in Cancer (GDSC), the Cancer Cell Line Encyclopedia (CCLE), and the CellMiner database were used to elucidate the relationship between the exosome-related DEGs and drug sensitivity. In addition, we verified that both POSTN and BID were upregulated in papillary thyroid cancer (PTC) patients and that their expression was correlated with cancer progression. The POSTN and BID protein expression levels were further examined in THCA cell lines. These findings provide insights into exosome-related clinical trials and drug development.

Neutrophil diversity is associated with T-cell immunity and clinical relevance in patients with thyroid cancer

Neutrophil heterogeneity is involved in autoimmune diseases, sepsis, and several cancers. However, the link between neutrophil heterogeneity and T-cell immunity in thyroid cancer is incompletely understood. We investigated the circulating neutrophil heterogeneity in 3 undifferentiated thyroid cancer (UTC), 14 differentiated thyroid cancer (DTC) (4 Stage IV, 10 Stage I-II), and healthy controls (n = 10) by transcriptomic data and cytometry. Participants with UTC had a significantly higher proportion of immature high-density neutrophils (HDN) and lower proportion of mature HDN in peripheral blood compared to DTC. The proportion of circulating PD-L1+ immature neutrophils were significantly increased in advanced cancer patients. Unsupervised analysis of transcriptomics data from circulating HDN revealed downregulation of innate immune response and T-cell receptor signaling pathway in cancer patients. Moreover, UTC patients revealed the upregulation of glycolytic process and glutamate receptor signaling pathway. Comparative analysis across tumor types and stages revealed the downregulation of various T-cell-related pathways, such as T-cell receptor signaling pathway and T-cell proliferation in advanced cancer patients. Moreover, the proportions of CD8+ and CD4+ T effector memory CD45RA+ (TEMRA) cells from peripheral blood were significantly decreased in UTC patients compared to DTC patients. Finally, we demonstrated that proportions of tumor-infiltrated neutrophils were increased and related with poor prognosis in advanced thyroid cancer using data from our RNA-seq and TCGA (The Cancer Genome Atlas) data. In conclusion, observed prevalence of circulating immature high-density neutrophils and their immunosuppressive features in undifferentiated thyroid cancers underscore the importance of understanding neutrophil dynamics in the context of tumor progression in thyroid cancer.

The role of surgical tissue injury and intraoperative sympathetic activation in postoperative immunosuppression after breast-conserving surgery versus mastectomy: a prospective observational study

BACKGROUND

Breast cancer is the second most common cause of death from cancer in women worldwide. Counterintuitively, large population-based retrospective trials report better survival after breast-conserving surgery (BCS) compared to mastectomy, corrected for tumour- and patient variables. More extensive surgical tissue injury and activation of the sympathetic nervous system by nociceptive stimuli are associated with immune suppression. We hypothesized that mastectomy causes a higher expression of plasma damage associated molecular patterns (DAMPs) and more intraoperative sympathetic activation which induce postoperative immune dysregulation. Immune suppression can lead to postoperative complications and affect tumour-free survival.

METHODS

In this prospective observational study, plasma DAMPs (HMGB1, HSP70, S100A8/A9 and S100A12), intraoperative sympathetic activation (Nociception Level (NOL) index from 0 to 100), and postoperative immune function (plasma cytokine concentrations and ex vivo cytokine production capacity) were compared in patients undergoing elective BCS (n = 20) versus mastectomy (n = 20).

RESULTS

Ex vivo cytokine production capacity of TNF, IL-6 and IL-1β was nearly absent in both groups one hour after surgery. Levels appeared recovered on postoperative day 3 (POD3), with significantly higher ex vivo production capacity of IL-1β after BCS (p = .041) compared to mastectomy. Plasma concentration of IL-6 was higher one hour after mastectomy (p = .045). Concentrations of plasma alarmins S100A8/A9 and S100A12 were significantly higher on POD3 after mastectomy (p = .003 and p = .041, respectively). Regression analysis showed a significantly lower percentage of NOL measurements ≤ 8 (absence of nociception) during mastectomy when corrected for norepinephrine equivalents (36% versus 45% respectively, p = .038). Percentage of NOL measurements ≤ 8 of all patients correlated with ex vivo cytokine production capacity of IL-1β and TNF on POD3 (r = .408; p = .011 and r = .500; p = .001, respectively).

CONCLUSIONS

This pilot study revealed substantial early postoperative immune suppression after BCS and mastectomy that appears to recover in the following days. Differences between BCS and mastectomy in release of DAMPs and intraoperative sympathetic activation could affect postoperative immune homeostasis and thereby contribute to the better survival reported after BCS in previous large population-based retrospective trials. These results endorse further exploration of (1) S100 alarmins as potential therapeutic targets in breast cancer surgery and (2) suppression of intraoperative sympathetic activation to substantiate the observed association with postoperative immune dysregulation.

Circulating tumor cells reveal early predictors of disease progression in patients with stage III NSCLC undergoing chemoradiation and immunotherapy

Circulating tumor cells (CTCs) are early signs of metastasis and can be used to monitor disease progression well before radiological detection by imaging. Using an ultrasensitive graphene oxide microfluidic chip nanotechnology built with graphene oxide sheets, we were able to demonstrate that CTCs can be specifically isolated and molecularly characterized to predict future progression in patients with stage III non-small cell lung cancer (NSCLC). We analyzed CTCs from 26 patients at six time points throughout the treatment course of chemoradiation followed by immune checkpoint inhibitor immunotherapy. We observed that CTCs decreased significantly during treatment, where a larger decrease in CTCs predicted a significantly longer progression-free survival time. Durvalumab-treated patients who have future progression were observed to have sustained higher programmed death ligand 1+ CTCs compared to stable patients. Gene expression profiling revealed phenotypically aggressive CTCs during chemoradiation. By using emerging innovative bioengineering approaches, we successfully show that CTCs are potential biomarkers to monitor and predict patient outcomes in patients with stage III NSCLC.

Extracellular vesicle-carried GTF2I from mesenchymal stem cells promotes the expression of tumor-suppressive FAT1 and inhibits stemness maintenance in thyroid carcinoma

Through bioinformatics predictions, we identified that GTF2I and FAT1 were downregulated in thyroid carcinoma (TC). Further, Pearson's correlation coefficient revealed a positive correlation between GTF2I expression and FAT1 expression. Therefore, we selected them for this present study, where the effects of bone marrow mesenchymal stem cell-derived EVs (BMSDs-EVs) enriched with GTF2I were evaluated on the epithelial-to-mesenchymal transition (EMT) and stemness maintenance in TC. The under-expression of GTF2I and FAT1 was validated in TC cell lines. Ectopically expressed GTF2I and FAT1 were found to augment malignant phenotypes of TC cells, EMT, and stemness maintenance. Mechanistic studies revealed that GTF2I bound to the promoter region of FAT1 and consequently upregulated its expression. MSC-EVs could shuttle GTF2I into TPC-1 cells, where GTF2I inhibited TC malignant phenotypes, EMT, and stemness maintenance by increasing the expression of FAT1 and facilitating the FAT1-mediated CDK4/FOXM1 downregulation. In vivo experiments confirmed that silencing of GTF2I accelerated tumor growth in nude mice. Taken together, our work suggests that GTF2I transferred by MSC-EVs confer antioncogenic effects through the FAT1/CDK4/FOXM1 axis and may be used as a promising biomarker for TC treatment.

S100 proteins in head and neck squamous cell carcinoma (Review)

The most common tumor affecting the head and neck is head and neck squamous cell carcinoma (HNSCC). The characteristics of HNSCC include a rapid onset, a lack of early diagnosis, drug resistance, relapse and systemic adverse effects, leading to inadequate prevention, diagnosis and treatment. Notably, previous research suggests that there is an association between S100 proteins and HNSCC. S100A8, S100A9 and S100A14 interfere with tumor cell proliferation by blocking the cell cycle. The present review discusses this association. S100A4 enhances cancer stem cell properties, and interacts with actin and tropomyosin to promote tumor cell migration. S100A1, S100A8, S100A9, S100A10, S100A14 and S100P are involved in the initiation and progression of HNSCC via Hippo, nuclear factor κB, phosphatidylinositol kinase/protein kinase B/mammalian target of rapamycin and other signaling pathways. In addition, certain long non-coding RNAs and microRNAs are involved in regulating the expression of S100 proteins in HNSCC. Reducing the expression of certain members of the S100 protein family may enhance the chemosensitivity of HNSCC. Collectively, it is suggested that S100 proteins may function as markers and targets for the prevention, diagnosis and treatment of HNSCC.

Induction of Antimicrobial Protein S100A15 Expression by Oral Microbial Pathogens Is Toll-like Receptors-Dependent Activation of c-Jun-N-Terminal Kinase (JNK), p38, and NF-κB Pathways

The antimicrobial protein S100A15 belongs to the S100 family, which is differentially expressed in a variety of normal and pathological tissues. Although the function of S100A15 protein has been discussed in several studies, its induction and regulation in oral mucosa, so far, are largely unknown. In this study, we demonstrate that S100A15 is induced by the stimulation of oral mucosa with gram− or gram+ bacterial pathogens, as well as with the purified membrane components, namely lipopolysaccharides (LPS) and lipoteichoic acid (LTA). The stimulation of the human gingival fibroblast (GF) and the human mouth epidermal carcinoma (KB) cell lines with either gram− or gram+ bacterial pathogens or their purified membrane components (LPS and LTA) results in the activation of NF-κB, apoptosis-regulating kinase1 (ASK1), and MAP kinase signaling pathways including, c-Jun N-terminal kinase (JNK) and p38 together with their physiological substrates AP-1 and ATF-2, respectively. Inhibition of S100A15 by antibodies-mediated Toll-like receptor 4 (TLR4) or Toll-like receptor 2 (TLR2) neutralization reveals the induction of S100A15 protein by LPS/gram− bacterial pathogens to be TLR4- dependent mechanism, whereas induction by LTA/gram+ bacterial pathogens to be TLR2- dependent mechanism. Pre-treatment of GF and KB cells with JNK (SP600125), p38 (SB-203580), or NF-κB (Bay11-7082) specific inhibitors further demonstrates the importance of JNK, p38 and NF-κB pathways in the regulation of gram−/gram+ bacterial pathogen-induced S100A15 expression. Our data provide evidence that S100A15 is induced in cancer and non-cancer oral mucosa-derived cell lines by gram−/gram+ bacterial pathogens and provide insight into the molecular mechanisms by which gram− and gram+ bacterial pathogens induce S100A15 expression in the oral mucosa.

Deciphering the Function of New Therapeutic Targets and Prospective Biomarkers in the Management of Psoriasis

Psoriasis is an immune-mediated skin condition affecting people worldwide, presenting at any age, and leading to a substantial burden physically and mentally. The innate and adaptive immune systems interact intricately with the pathomechanisms that underlie disease. T cells can interact with keratinocytes, macrophages, and dendritic cells through the cytokines they secrete. According to recent research, psoriasis flare-ups can cause systemic inflammation and various other co-morbidities, including depression, psoriatic arthritis, and cardio-metabolic syndrome. Additionally, several auto-inflammatory and auto-immune illnesses may be linked to psoriasis. Although psoriasis has no proven treatment, care must strive by treating patients as soon as the disease surfaces, finding and preventing concurrent multimorbidity, recognising and reducing bodily and psychological distress, requiring behavioural modifications, and treating each patient individually. Biomarkers are traits that are assessed at any time along the clinical continuum, from the early stages of a disease through the beginning of treatment (the foundation of precision medicine) to the late stages of treatment (outcomes and endpoints). Systemic therapies that are frequently used to treat psoriasis provide a variety of outcomes. Targeted therapy selection, better patient outcomes, and more cost-effective healthcare would be made possible by biomarkers that reliably predict effectiveness and safety. This review is an attempt to understand the role of Antimicrobial peptides (AMP), Interleukin-38 (IL-38), autophagy 5 (ATG5) protein and squamous cell carcinoma antigen (SCCA) as biomarkers of psoriasis.

Identification of immune-related and autophagy-related genes for the prediction of survival in bladder cancer

Background

Bladder cancer has the characteristics of high morbidity and mortality, and the prevalence of bladder cancer has been increasing in recent years. Immune and autophagy related genes play important roles in cancer, but there are few studies on their effects on the prognosis of bladder cancer patients.

Methods

Using gene expression data from the TCGA-BLCA database, we clustered bladder cancer samples into 6 immune-related and autophagy-related molecular subtypes with different prognostic outcomes based on 2208 immune-related and autophagy-related genes. Six subtypes were divided into two groups which had significantly different prognosis. Differential expression analysis was used to explore genes closely related to the progression of bladder cancer. Then we used Cox stepwise regression to define a combination of gene expression levels and immune infiltration indexes to construct the risk model. Finally, we built a Nomogram which consist of risk score and several other prognosis-related clinical indicators.

Results

The risk model suggested that high expression of C5AR2, CSF3R, FBXW10, FCAR, GHR, OLR1, PGLYRP3, RASGRP4, S100A12 was associated with poor prognosis, while high expression level of CD96, IL10, MEFV pointed to a better prognosis. Validation by internal and external dataset suggested that our risk model had a high ability to discriminate between the outcomes of patients with bladder cancer. The immunohistochemical results basically confirmed our results. The C-Index value and Calibration curves verified the robustness of Nomogram.

Conclusions

Our study constructed a model that included a risk score for patients with bladder cancer, which provided a lot of helps to predict the prognosis of patients with bladder cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01073-7.

Therapeutic potential of targeting the receptor for advanced glycation end products (RAGE) by small molecule inhibitors

Receptor for advanced glycation end products (RAGE) is a 45 kDa transmembrane receptor of immunoglobulin family that can bind to various endogenous and exogenous ligands and initiate the inflammatory downstream signaling pathways. RAGE is involved in various disorders including cardiovascular and neurodegenerative diseases, cancer, and diabetes. This review summarizes the structural features of RAGE and its various isoforms along with their pathological effects. Mainly, the article emphasized on the translational significance of antagonizing the interactions of RAGE with its ligands using small molecules reported in the last 5 years and discusses future approaches that could be employed to block the interactions in the treatment of chronic inflammatory ailments. The RAGE inhibitors described in this article could prove as a powerful approach in the management of immune‐inflammatory diseases. A critical review of the literature suggests that there is a dire need to dive deeper into the molecular mechanism of action to resolve critical issues that must be addressed to understand RAGE‐targeting therapy and long‐term blockade of RAGE in human diseases.

S100A1 is a Potential Biomarker for Papillary Thyroid Carcinoma Diagnosis and Prognosis

S100 calcium binding protein A1 (S100A1) is an important member of the S100 family and known to express in a variety of cancers. However, the biological functions of S100A1 in thyroid carcinoma have not been thoroughly studied. In this report, bioinformatics analyses and immunohistochemistry assays were applied to assess the expression profile of S100A1 as well as its relationship with the pathological features and prognosis of papillary thyroid carcinoma (PTC). Meanwhile, functions of S100A1 in PTC cells were analyzed with either in vitro or in vivo experiments. S100A1 was significantly up-regulated in PTC tissues compared with adjacent non-cancerous tissues. S100A1 protein expression was significantly associated with tumor size (p=0.0032) or lymph node metastasis (p=0.0331). More importantly, an elevated S100A1 expression was significantly correlated with a worse recurrence-free survival (RFS) (HR=2.26, p=0.042). Further, knockdown of S100A1 dramatically inhibited cell proliferation and migration as well as increased apoptosis of PTC cells. S100A1 knockdown inhibited tumor progression as seen in in vivo experiments. In terms of mechanism, down-regulation of S100A1 induced yes associated protein (YAP) phosphorylation in the cytoplasm and diminished Hippo/YAP pathway activation. Therefore, S100A1 may serve as a novel oncogene and a promising biomarker for PTC diagnosis and prognosis.

Evaluation of S100A12 protein levels in children with familial Mediterranean fever

Background/aim

Familial Mediterranean fever (FMF), the most common autoinflammatory disease in children, is characterized by recurrent febrile episodes. FMF is known to progress with chronic inflammation, particularly during attack periods. This study aimed to investigate the relationship of S100A12, an inflammatory marker, with attacks and inflammatory events in FMF patients.

Materials and methods

The study included 57 patients diagnosed with FMF, 43 in an attack-free period and 14 in an attack period, and 31 healthy children as the control group. Only white blood cell (WBC) count, C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), and S100A12 level were analyzed in the control group. In addition, serum amyloid A (SAA), and fibrinogen levels were measured, and a mutation analysis was performed in the patient group. The results were compared among the attack-free period, acute attack FMF and control groups.

Results

The mean age of patients and control group was 10 (2.5–18) and 9.5 (2.5–16) years, respectively. The CRP (p = 0.001), S100A12 (p = 0.003) and ESR (p= 0.001) values differed significantly between the FMF and control groups. S100A12 level (p = 0.027), WBC count (p = 0.003), CRP level (p = 0.0001), ESR (p = 0.004), and fibrinogen level (p = 0.001) differed significantly between the acute attack and attack-free period groups. SAA level (p = 0.05), ESR (p = 0.001), fibrinogen level (p = 0.001), WBC count (p = 0.001), and S100A12 level (p = 0.027) were higher in M694V homozygous FMF patients than in other FMF patients.

Conclusion

Patients with FMF had higher S100A12 levels than the control group, while the mean S100A12 concentration was higher in acute attack period patients than in attack-free period patients. S100A12 level might be an important indicator in the monitoring of chronic inflammation in patients with FMF.

Comprehensive Profiling Reveals Distinct Microenvironment and Metabolism Characterization of Lung Adenocarcinoma

Lung adenocarcinoma has entered into an era of immunotherapy with the development of immune checkpoint inhibitors (ICIs). The identification of immune subtype is crucial to prolonging survival in patients. The tumor microenvironment (TME) and metabolism have a profound impact on prognosis and therapy. The majority of previous studies focused on only one aspect, while both of them are essential to the understanding of tumorigenesis and development. We hypothesized that lung adenocarcinoma can be stratified into immune subgroups with alterations in the TME infiltration. We aimed to explore the "TME-Metabolism-Risk" patterns in each subtypes and the mechanism behind. Glycolysis and cholesterol were selected for the analysis of metabolic states based on the first half of the study. Bioinformatic analysis was performed to investigate the transcriptomic and clinical data integrated by three lung adenocarcinoma cohorts (GSE30219, GSE31210, GSE37745, N = 415). The results were validated in an independent cohort (GSE50081, N = 127). In total, 415 lung adenocarcinoma samples were integrated and analyzed. Four major immune subtypes were indentified using bioinformatic analysis. Subtype NC1, characterized by a high level of glycolysis, with extremely low microenvironment cell infiltration. Subtype NC2, characterized by the "Silence" and "Cholesterol biosynthesis Predominant" metabolic states, with a middle degree infiltration of microenvironment cell. Subtype NC3, characterized by the lack of "Cholesterol biosynthesis Predominant" metabolic state, with abundant microenvironment cell infiltration. Subtype NC4, characterized by "Mixed" metabolic state, with a relatively low microenvironment cell infiltration. Least absolute shrinkage and selection operator (LASSO) regression and multivariate analyses were performed to calculate the risk of each sample, and we attempted to find out the potential immune escape mechanism in different subtypes. The result revealed that the lack of immune cells infiltration might contribute to the immune escape in subtypes NC1 and NC4. NC3 was characterized by the high expression of immune checkpoint molecules and fibroblasts. NC2 had defects in activation of innate immune cells. There existed an obviously survival advantage in subtype NC2. Gene set enrichment analysis (GSEA) and Gene Ontology analysis indicated that the PI3K-AKT-mTOR, TGF-β, MYC-related pathways might be correlated with this phenomenon. In addition, some differentially expressed genes (DEGs) were indentified in subtype NC3, which might be potential targets for survival phenotype transformation.

Comprehensive Analysis of the Prognosis and Correlations With Immune Infiltration of S100 Protein Family Members in Hepatocellular Carcinoma

S100 protein family members (S100s) are commonly dysregulated in various tumors including hepatocellular carcinoma (HCC). However, the diverse expression, mutation, prognosis and associations with immune infiltration of S100s in HCC have yet to be analyzed. Herein we investigated the roles of S100s in HCC from the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Human Protein Atlas, Kaplan-Meier Plotter, cBioPortal and TIMER databases. Compared with para-cancer tissues, the expression levels of S100A4/S100A6/S100A10/S100A11/S100A13/S100A14/S100P were higher in HCC tissues, while the expression levels of S100A8/S100A9/S100A12 were decreased in tumor tissues. The mRNA levels of S100A2/S100A7/S100A7A/S100A8/S100A9/S100A11 were correlated with advanced tumor stage. Besides, higher mRNA expressions of S100A6/S100A10/S100A11/S100A13/S100A14/S100P were shown to have shorter overall survival (OS), while higher expression of S100A12 was associated with favorable OS. Further, the mutation rate of S100s was investigated, and the high mutation rate (53%) was associated with shorter OS. Additionally, the expressions of S100s were found to be significantly associated with various immune infiltrating cells. Hence, our results showed that S100A6/S100A10/S100A11/S10012/S100A13/S100A14/S100P may be regarded as new prognostic or therapeutic markers and S100s inhibitors may be helpful in the combination of immunotherapies.

Identification of the prognostic value of immune gene signature and infiltrating immune cells for esophageal cancer patients

BACKGROUND

Esophageal cancer (ESCA) is one of the deadliest solid malignancies with worse survival rate worldwide. Here, we aimed to establish an immune-gene prognostic signature for predicting patients' survival and providing accurate targets for personalized therapy or immunotherapy.

METHODS

Gene expression profile of patients with ESCA were download from The Cancer Genome Atlas (TCGA) database (dataset 1: n = 159) and immune-related genes from the ImmPORT database. Dataset 1 was subdivided into two groups (dataset 2: n = 80; dataset 3: n = 79). Kaplan-Meier and receiver operating characteristic (ROC) curves were plotted to validate the predictive effect of the prognostic signature on the three datasets. TIMER and CIBERSORT analysis were used to evaluate the correlation between the prognostic signature and infiltrating immune cells.

RESULTS

We constructed a prognostic signature composed of six immune genes (HSPA6, S100A12, FABP3, DKK1, OSM and NR2F2). Kaplan-Meier curves validated the good predictive ability of the prognostic signature in datasets 1, 2 and 3 (P = 0.0034, P = 0.0081, and P = 0.0363, respectively). The area under the curve (AUC) of the ROC curves validated the predictive accuracy of the immune signature (AUCs = 0.757, 0.800, and 0.701, respectively). We also revealed the good prognostic value of the immune cells, including activated memory CD4 T cells, T follicular helper cells and monocytes. Potential target drugs, including Olopatadine and Amlexanox, were identified for clinical therapies to improve patients' survival outcomes.

CONCLUSION

Our study indicated that the immune-related prognostic signature could serve as a novel biomarker for predicting patients' prognosis and providing new immunotherapy targets in ESCA.

Roles of S100 family members in drug resistance in tumors: Status and prospects

Chemotherapy and targeted therapy can significantly improve survival rates in cancer, but multiple drug resistance (MDR) limits the efficacy of these approaches. Understanding the molecular mechanisms underlying MDR is crucial for improving drug efficacy and clinical outcomes of patients with cancer. S100 proteins belong to a family of calcium-binding proteins and have various functions in tumor development. Increasing evidence demonstrates that the dysregulation of various S100 proteins contributes to the development of drug resistance in tumors, providing a basis for the development of predictive and prognostic biomarkers in cancer. Therefore, a combination of biological inhibitors or sensitizers of dysregulated S100 proteins could enhance therapeutic responses. In this review, we provide a detailed overview of the mechanisms by which S100 family members influence resistance of tumors to cancer treatment, with a focus on the development of effective strategies for overcoming MDR.