https://orcid.org/0009-0009-6041-7880
Abstract
Radiation esophagitis (RE) and Radiation-induced lung injury (RILI) are the main side effects of radiotherapy for esophageal squamous cell cancer (ESCC), which seriously affect the quality of life and therapeutic effect of patients. Then, how to reduce the incidence of RE and RILI is an important topic. We try to establish RE and RILI’s prediction scheme based on the gene expression patterns in tumor tissues from patients with ESCC. A total of 37 patients who pathological preliminary diagnosed as ESCC and received radical radiotherapy from 2016 January 1 to 2019 December 31 were enrolled in this study. Use 3-plex qPCR to detect gene expression in ESCC. Our results showed that gene expressions in the Mitogen-activated protein (MAP) kinase signaling (HRAS, MAP2K1, MAPK1, CRAF and KRAS) were positively related to Severe RE (SRE), while Fibroblast growth factor (FGF) signaling showed a negative correlation. We established a c-Index calculation model to predict SRE. Receiver operating characteristic curve were applied to determine the prognostic value of the risk model. Besides, patients with SRE seem to be more easily to develop higher-level of RILI. Taken together, we constructed a novel radiotherapy response–related gene signature, which may be developed into a powerful tool for forecasting the risk of SRE in ESCC radiotherapy patients.
Introduction
Esophageal cancer remains one of the most common causes of cancer-related deaths in China, with high incidence and mortality rates.1 In China, ESCC predominates sub-type of esophageal cancer.2 While radiotherapy is an integral part of the treatment for ESCC, it can lead to radiation-induced toxicities, which is a major concern.3
One of the common toxicities associated with radiotherapy for ESCC is radiation esophagitis (RE),4 which is characterized by hyperemia, edema, and erosion of the irradiated esophageal mucosa. These inflammatory reactions can result in dysphagia, pain, esophageal stricture, and even tracheoesophageal fistula in advanced stages.5 These untoward reactions are limiting factors in the effectiveness of the treatment and can reduce the quality of life for patients. Various clinical scoring systems are used to assess the severity of RE, including the Radiation Therapy Oncology Group (RTOG) scoring system and Common Terminology Criteria for Adverse Events.6 RE toxicity of grade 2 or higher is considered clinically significant and may require medical intervention, as it affects the daily life of patients.7 Radiation therapy also carries the risk of radiation-induced lung injury (RILI), which can lead to radiation pneumonia (RP) and radiation lung fibrosis (RLF).8 While the development of intensity modulation, motion management, and image guidance technology has reduced the toxicity of radiotherapy and improved survival rate to some extent,9 RILI remains a significant challenge in the management of cancer patients.10 Moreover, radiation-induced lung injury is usually irreversible.11 RLF can even lead to respiratory failure and death. Thus, clinicians must establish early RILI predictors to ensure safety and individualized radiotherapy.
Several dosimetric factors, including V60 (the esophageal volume receiving ≥60 Gray)12 of the esophagus for RE and mean lung dose (MLD), lung V5 (Volume percentage of lungs exposed to radiation dose of 5 Gray or more), and lung V20 (Volume percentage of lungs exposed to radiation dose of 20 Gray or more) for RILI, have been studied as predictors.13,14 Plasma concentrations of cytokines such as TGF-β1,15 IL-6 and IL-1016 during radiotherapy have also been suggested as possible risk markers. However, individual factors17 and genetics also play a significant role in determining the risk of RE and RILI.18,19 Research indicates that the severity of radiation-induced esophagitis and lung injury experienced during esophageal squamous cell cancer treatment is correlated with the specific gene expression profile of the tumor, meaning that the genetic makeup of the cancer can influence how much damage radiation therapy causes to surrounding tissues like the esophagus and lungs.20 This is because different tumor phenotypes may have varying levels of sensitivity to radiation and different mechanisms of DNA repair, leading to varying degrees of tissue damage in response to treatment. Certain genes involved in DNA repair mechanisms, like ERCC1 and XRCC1, can play a significant role in determining a tumor’s radiosensitivity.21,22 Tumors with high expression of these genes may be more resistant to radiation, potentially leading to less damage to healthy tissues like the esophagus. Genes that control the cell cycle can also influence radiation response.23,24 Alterations in these genes could lead to increased cell death in the tumor, but also potentially in surrounding normal tissues, contributing to radiation-induced damage. In addition, Tumor gene expression can influence the inflammatory response within the tumor microenvironment, which can further impact the extent of radiation-induced tissue damage.25,26 By analyzing the gene expression profile of a patient’s esophageal squamous cell carcinoma, clinicians may be able to better predict the likelihood of developing severe radiation-induced esophagitis or lung injury, allowing for more personalized treatment planning. Moreover, understanding the specific genetic alterations in a tumor could lead to the development of targeted therapies that can enhance the radiosensitivity of the cancer while minimizing damage to normal tissues. Therefore, we aim to investigate the relationship between gene expression and RE and RILI by analyzing the gene expression levels of endoscopic specimens from patients with ESCC. This approach may provide a prediction scheme to optimize the treatment benefits and minimize the risks of radiotoxicity.
Materials and methods
Clinical data-study population
This study enrolled a total of 37 patients who were pathologically diagnosed with ESCC and received radical radiotherapy between 2016 January 1, and 2019 December 31. The inclusion criteria were patients aged 18 yr or older, confirmed ESCC diagnosis based on histopathological results, and no active autoimmune diseases or infections such as acute gastroenteritis, appendicitis, or cholecystitis. Patients were grouped into RE 1–4 and RILI 1–5 categories based on Radiation Therapy Oncology Group (RTOG) grade and Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, respectively.27 In this study, we defined SRE and NSRE as Grade 3–4 and Grade 1–2 RE, respectively, according to RTOG criteria. Supplementary materials Table S1 contains patients’ information.
ESCC gene phenotypes were obtained from NCBI using the following keywords: ESCC, radiotherapy, inflammation, efficacy, prognosis, and side effect. The supplementary materials Table S2 contains the list of gene phenotypes.
Total RNA extraction
FFPE tissue samples obtained from tumor biopsies before radiotherapy were sliced into pieces with a thickness of 5 μM using a microtome, and total RNA was extracted using a kit from Thermofisher Co. (the RecoverAll™ Total Nucleic Acid Isolation Kit, AM1975). Briefly, 8–15 microtome slides were added with 1 mL of 2-methylbenzene and incubated at 50 °C for 3 min to dissolve paraffin wax, then digested with protease following the instructions provided with the kit. Nucleotides were then absorbed to the column, washed, and digested with DNA for 30 min with DNase at room temperature. The total RNA was eluted from the column with 60 μL water, and the concentration and quality were determined by measuring the absorbance at A260/280.
Gene expression qPCR
Gene expression levels were determined using Taqman one-step multi-plex qPCR methods with total RNA as templates. A total of 36 genes for each sample’s total RNA were detected in a triple reaction and normalized with β-actin as the reference gene, expressed as ∆Ct (∆Ct of samples’ target gene = Ct of target gene minus Ct of β-actin). PCR primers and probe designs for gene expression assays followed the principles of Taqman PCR gene expression assays for trans exon detection, and their sequences and assay information can be found in supplementary materials Table S2. During assays, 384-well PCR plates were used, and PCR reactions were performed on the QuantStudio™5 Real-Time PCR Systems, running in triplicate under the conditions and protocols described in supplementary materials Table S3 and Table S4. In this experiment, the amount of target (and endogenous control) in a sample was characterized by the Ct range, with no template control Ct > 40 and rare template Ct > 37 to offset PCR data output. Gene assays with no template Control Ct < 40 or template Ct > 37 were cutoff in the result analysis. The multi-plex qPCR were designed in a triple format with three different gene assays in one reaction well. Probes were labeled with FAM, VIC, NED dye separately and ROX used as a passive reference.
Statistical analysis
Chi-square tests and Mann–Whitney U Tests were performed to explore clinical and pathological data, respectively for enumeration data and ranked data. Results of miRNAs were expressed as the mean ± SD. D’Agostino & Pearson tests were adopted for normality test. Student’s t-tests were used for comparisons. The c-Index was calculated from correlated variables previously using binary logistic regression analysis. For colonies developed with different grades of RILI, one-way ANOVA and multifactor regression analysis were used to explore the differences of radiation parameters and grades of RE. SPSS version 25.0 and Graphpad 10.0 were used for statistical analyses. A p-value of < 0.05 was considered significant.
Results
Evaluation of 3-plex qPCR
To acquire as much as more gene expression information from the limited RNA samples, we developed a set of 3-plex qPCR reactions, which made the gene expression quantization from one gene to three genes in the same amount of RNA input. The sufficiency and reliability of the 3-plex qPCR were well characterized and evaluated, showing that the 3-plex qPCRs applied in this study were comparable to their corresponding single-plex qPCRs with a coefficient of correlation R2 equal to 0.99 and reliable amplification curves. Representative results are shown in supplementary materials Fig. S1.
After evaluation and successful running of 3-plex real-time qPCRs for all sample RNAs, a qPCR Ct raw data set was output for 37 individual RNA samples, each with 36 genes detected. Data sheet is available in the supplementary materials Table S5.
Ct values that pass the critics for gene assays described in material and methods were normalized with reference gene and gave a true gene mRNA level as defined as 2-∆Ct.
Relevance of factors to SRE
To screen factors that influence patients with SRE, we first performed a comparison including patients’ age, gender, staging, karnofsky performance score (KPS), etc. Table 1 shows the details of this study and patients’ basal characteristics.
The details of this study and patients’ basal characteristics.
| Patient Characteristics | NSRE | SRE | statistic | P value | |
|---|---|---|---|---|---|
| Age | |||||
| <60 | 8 | 1 | x2 = 1.349 | 0.245 | |
| ≥60 | 17 | 11 | |||
| Gender | |||||
| Male | 21 | 12 | / | 0.282 | |
| female | 4 | 0 | |||
| Staging | |||||
| II | 3 | 1 | U = 111.5 | 0.212 | |
| III | 14 | 4 | |||
| IVA | 8 | 7 | |||
| KPS | |||||
| <80 | 5 | 3 | x2 = 0.000 | 1.000 | |
| ≥80 | 20 | 9 | |||
| Radiotherapy dose | 50.4(50.2, 55.0) | 50.4(50.0, 54.0) | U = 131 | 0.5382 | |
| Concurrent chemotherapy | |||||
| Yes | 12 | 3 | x2 = 0.953 | 0.329 | |
| No | 13 | 9 | |||
| Patient Characteristics | NSRE | SRE | statistic | P value | |
|---|---|---|---|---|---|
| Age | |||||
| <60 | 8 | 1 | x2 = 1.349 | 0.245 | |
| ≥60 | 17 | 11 | |||
| Gender | |||||
| Male | 21 | 12 | / | 0.282 | |
| female | 4 | 0 | |||
| Staging | |||||
| II | 3 | 1 | U = 111.5 | 0.212 | |
| III | 14 | 4 | |||
| IVA | 8 | 7 | |||
| KPS | |||||
| <80 | 5 | 3 | x2 = 0.000 | 1.000 | |
| ≥80 | 20 | 9 | |||
| Radiotherapy dose | 50.4(50.2, 55.0) | 50.4(50.0, 54.0) | U = 131 | 0.5382 | |
| Concurrent chemotherapy | |||||
| Yes | 12 | 3 | x2 = 0.953 | 0.329 | |
| No | 13 | 9 | |||
Abbreviations: NSRE Non-severe radiation-induced esophagitis, SRE Severe radiation-induced esophagitis, KPS karnofsky performance score
The details of this study and patients’ basal characteristics.
| Patient Characteristics | NSRE | SRE | statistic | P value | |
|---|---|---|---|---|---|
| Age | |||||
| <60 | 8 | 1 | x2 = 1.349 | 0.245 | |
| ≥60 | 17 | 11 | |||
| Gender | |||||
| Male | 21 | 12 | / | 0.282 | |
| female | 4 | 0 | |||
| Staging | |||||
| II | 3 | 1 | U = 111.5 | 0.212 | |
| III | 14 | 4 | |||
| IVA | 8 | 7 | |||
| KPS | |||||
| <80 | 5 | 3 | x2 = 0.000 | 1.000 | |
| ≥80 | 20 | 9 | |||
| Radiotherapy dose | 50.4(50.2, 55.0) | 50.4(50.0, 54.0) | U = 131 | 0.5382 | |
| Concurrent chemotherapy | |||||
| Yes | 12 | 3 | x2 = 0.953 | 0.329 | |
| No | 13 | 9 | |||
| Patient Characteristics | NSRE | SRE | statistic | P value | |
|---|---|---|---|---|---|
| Age | |||||
| <60 | 8 | 1 | x2 = 1.349 | 0.245 | |
| ≥60 | 17 | 11 | |||
| Gender | |||||
| Male | 21 | 12 | / | 0.282 | |
| female | 4 | 0 | |||
| Staging | |||||
| II | 3 | 1 | U = 111.5 | 0.212 | |
| III | 14 | 4 | |||
| IVA | 8 | 7 | |||
| KPS | |||||
| <80 | 5 | 3 | x2 = 0.000 | 1.000 | |
| ≥80 | 20 | 9 | |||
| Radiotherapy dose | 50.4(50.2, 55.0) | 50.4(50.0, 54.0) | U = 131 | 0.5382 | |
| Concurrent chemotherapy | |||||
| Yes | 12 | 3 | x2 = 0.953 | 0.329 | |
| No | 13 | 9 | |||
Abbreviations: NSRE Non-severe radiation-induced esophagitis, SRE Severe radiation-induced esophagitis, KPS karnofsky performance score
Age: There was a tendency of elder ones (over or equal to 60 yr old) to develop SRE, but statistically not significant. This result may be a consequence of small number of the study population.
Gender: No correlation of gender with SRE was found in this study.
Staging: Patients developed SRE seems to be distributed in advanced stages, while no statistical significance.
Karnofsky performance score (KPS): The majority of patients had good basic health condition no matter whether developed SRE.
Radiotherapy dose: The radiation strength applied to subjects for esophagus cancer therapy in this study was standard uniform dose, and therefore, was not considered as a SRE influence factor in the analysis.
Concurrent chemotherapy: No correlation was found.
Gene expression: When scanning the gene expression data of SRE development, a series of genes displayed a tendency of increased or decreased expression related to SRE. Among them, HRAS, MAP2K1, MAPK1, CRAF, KRAS and FGF1 showed a correlation and statistically significant (P < 0.05), suggesting their roles in the SRE need further study. All of those miRNAs except FGF1 fostered the occurrence of SRE, however, FGF1 suppressed it. Relevant results are as shown in Fig. 1 and supplementary materials Fig. S2.
Tumor MAP kinase and FGF signaling correlated with RE grades. Analysis results of gene expression levels and RE grades correlation are shown graphically. X axis numbers represent RE grades. Relative gene expression mRNA level are plotted in Y axis as 2-ΔCt normalized by β-actin. Results showed that HRAS, MAP2K1, MAPK1, CRAF and KRAS are positively correlated with the occurrence and development of RE; however, FGF1 is negatively correlated.
Tumor MAP kinase and FGF signaling related to SRE
Gene expressions were compared in two major groups, group1 that included RE grade 1–2 subjects and group2 that included RE grade 3–4 patient. One of the most phenomenal observations from miRNAs comparison was that five genes involved in the MAP kinase signaling, HRAS, MAP2K1, MAPK1, CRAF, KRAS and one gene in the FGF signaling, FGF1, displayed strong correlation when we grouped patients into NSRE and SRE, suggesting their significant roles in RE progresses. Interestingly, gene expressions in the MAP kinase signaling (HRAS, MAP2K1, MAPK1, CRAF and KRAS) were positively related to SRE, while FGF signaling showed a negative correlation (Fig. 2).
Heatmap showing the expression level of 36 genes in different groups (NSRE: n = 25, SRE: n = 12). It can be seen that MAP kinase associated genes (HRAS, MAP2K1, MAPK1, CRAF, KRAS) are upregulated and FGF associated genes (FGF1) are down-regulated.
Tumor MAP kinase and FGF signaling to predict SRE development
We combined multiple miRNAs that correlated with SRE to predict SRE development, which was validated by receiver operating characteristic (ROC) curves. All miRNAs previously proved to be related with SRE seems to be able to predict it (P < 0.05). The result of ROC curves illustrated better prediction efficiency of combine index (c-Index) with AUC of 0.98 (P < 0.001) (Fig. 3). We used SPSS to construct c-Index based on six related mRNA, and took whether SRE occurs as a grouping variable. Then we carried out binary logistic regression analysis on six independent variables: FGF1, HRAS, KRAS, CRAF, MAP2K1 and MAPK1, and obtained the following c-Index equation. c-Index = − 72.626–35.092*FGF1 + 12.130*HRAS + 12.571*KRAS + 43.167*CRAF + 29.273*MAP2K1 + 1.703*MAPK1.
Receiver operating characteristic (ROC) curves illustrating the relative predict power of these factors. And c-index seems to be a better predictor for SRE with areas under the curve (AUC) values of 0.98, P < 0.001. Besides that, FGF1, AUC = 0.847; CRAF: AUC = 0.823.
Increased RE level may exaggerate RILI
We further explored the repercussion of SRE in RILI using one-way ANOVA. Results showed the higher-level of RILI in patients with SRE. Especially, two cases dead of RILI were both developed grade 4 of RE (Fig. 4). One-way ANOVA also described that MLD-R, MLD-L, V5-R, V5-L, V20-R, V20-L were not concerned with RILI (Fig. 5). Then we took more factors including radiotherapy dose of total (DT), mean lung dose (MLD), V5 and V20 into considerations in multi-factor regression analysis, and found that RE Grade was the only RILI correlative factor (Table 2).
They were grouped according to the RE grade. It can be seen that when the RE grade is greater than or equal to 3, the difference of RILI grade between the two groups is statistically significant. In other words, RILI is more severe in patients with SRE. The other two cases of fatal RILI occurred in patients with RE grade4.
The patients were divided into 4 groups according to the severity of RILI. Results showed that there was no statistical difference between the radiotherapy parameters of different groups.
RE grade, radiotherapy dose and lung related radiotherapy parameters were included in multivariate regression analysis.
| Variables | Unstandardized Coefficients | Standardized Coefficients | t | Sig. | |
|---|---|---|---|---|---|
| β | Std. Error | Beta | |||
| (Constant) | 0.824 | 1.801 | 0.457 | 0.651 | |
| RE Grade | 0.918 | 0.207 | 0.683 | 4.439 | 0.000 |
| DT(Gy) | −0.039 | 0.033 | −0.209 | −1.158 | 0.257 |
| MLD-R(Gy) | 0.077 | 0.140 | 0.125 | 0.552 | 0.585 |
| MLD-L(Gy) | 0.060 | 0.128 | 0.145 | 0.471 | 0.642 |
| V5-R(%) | 0.000 | 0.030 | 0.003 | 0.013 | 0.990 |
| V5-L(%) | 0.012 | 0.025 | 0.141 | 0.497 | 0.623 |
| V20-R(%) | −0.035 | 0.055 | −0.161 | −0.634 | 0.531 |
| V20-L(%) | −0.039 | 0.062 | −0.162 | −0.628 | 0.535 |
| Variables | Unstandardized Coefficients | Standardized Coefficients | t | Sig. | |
|---|---|---|---|---|---|
| β | Std. Error | Beta | |||
| (Constant) | 0.824 | 1.801 | 0.457 | 0.651 | |
| RE Grade | 0.918 | 0.207 | 0.683 | 4.439 | 0.000 |
| DT(Gy) | −0.039 | 0.033 | −0.209 | −1.158 | 0.257 |
| MLD-R(Gy) | 0.077 | 0.140 | 0.125 | 0.552 | 0.585 |
| MLD-L(Gy) | 0.060 | 0.128 | 0.145 | 0.471 | 0.642 |
| V5-R(%) | 0.000 | 0.030 | 0.003 | 0.013 | 0.990 |
| V5-L(%) | 0.012 | 0.025 | 0.141 | 0.497 | 0.623 |
| V20-R(%) | −0.035 | 0.055 | −0.161 | −0.634 | 0.531 |
| V20-L(%) | −0.039 | 0.062 | −0.162 | −0.628 | 0.535 |
Dependent Variable: RILI grade
RE grade, radiotherapy dose and lung related radiotherapy parameters were included in multivariate regression analysis.
| Variables | Unstandardized Coefficients | Standardized Coefficients | t | Sig. | |
|---|---|---|---|---|---|
| β | Std. Error | Beta | |||
| (Constant) | 0.824 | 1.801 | 0.457 | 0.651 | |
| RE Grade | 0.918 | 0.207 | 0.683 | 4.439 | 0.000 |
| DT(Gy) | −0.039 | 0.033 | −0.209 | −1.158 | 0.257 |
| MLD-R(Gy) | 0.077 | 0.140 | 0.125 | 0.552 | 0.585 |
| MLD-L(Gy) | 0.060 | 0.128 | 0.145 | 0.471 | 0.642 |
| V5-R(%) | 0.000 | 0.030 | 0.003 | 0.013 | 0.990 |
| V5-L(%) | 0.012 | 0.025 | 0.141 | 0.497 | 0.623 |
| V20-R(%) | −0.035 | 0.055 | −0.161 | −0.634 | 0.531 |
| V20-L(%) | −0.039 | 0.062 | −0.162 | −0.628 | 0.535 |
| Variables | Unstandardized Coefficients | Standardized Coefficients | t | Sig. | |
|---|---|---|---|---|---|
| β | Std. Error | Beta | |||
| (Constant) | 0.824 | 1.801 | 0.457 | 0.651 | |
| RE Grade | 0.918 | 0.207 | 0.683 | 4.439 | 0.000 |
| DT(Gy) | −0.039 | 0.033 | −0.209 | −1.158 | 0.257 |
| MLD-R(Gy) | 0.077 | 0.140 | 0.125 | 0.552 | 0.585 |
| MLD-L(Gy) | 0.060 | 0.128 | 0.145 | 0.471 | 0.642 |
| V5-R(%) | 0.000 | 0.030 | 0.003 | 0.013 | 0.990 |
| V5-L(%) | 0.012 | 0.025 | 0.141 | 0.497 | 0.623 |
| V20-R(%) | −0.035 | 0.055 | −0.161 | −0.634 | 0.531 |
| V20-L(%) | −0.039 | 0.062 | −0.162 | −0.628 | 0.535 |
Dependent Variable: RILI grade
Discussion
In this study, we examined the expression level of 36 mRNAs in tumor tissue from 37 ESCC patients. The result demonstrated that SRE in ESCC patients receiving radiotherapy was related to alterations in specific genes, which were HRAS, MAP2K1, MAPK1, CRAF, KRAS and FGF1.
Regardless of whether radiation esophagitis (RE) or radiation-induced lung injury (RILI) occurs, the underlying pathophysiology of radiotoxicity involves inflammatory responses. Radiation-induced damage to the esophageal mucosa and lung tissue can activate the inflammatory signal pathway and lead to the secretion of numerous inflammatory mediators.
Our study showed that the decreased FGF1 gene expression corelated with worse RE. FGF1 is one of the four ligands of FGFRs in the human FGF superfamily.28 FGF signaling has been implicated in many chronic inflammatory processes, such as increased FGF1-FGFR signaling in idiopathic pulmonary fibrosis,29 diabetic nephropathy30 and chronic liver disease.31 However, in acute pancreatitis-induced damage,32 FGF signaling appears to be a protective factor. The mechanisms of the radioprotective effects of FGF signaling remain unclear, but may be related to its ability to promote cell proliferation and differentiation by inhibiting endothelial apoptosis.33
In the alternate pathway, MAP kinase signaling had the opposite outcome, stimulating inflammatory responses,34 including those induced by radiation.35,36 The MAP kinase p38 is a central transducer of cellular stress-signaling pathways.37 The p38/MK2 pathway is activated when the cell is exposed to stressors, such as radiation, and promotes tumor inflammation in a variety of cancers,38 such as head and neck tumors. MAP kinase signaling could be a mediator of radiation-induced inflammation by upregulating the production of inflammatory cytokines.39
Before undergoing radiotherapy, it may be effective to detect the expression level of specific genes mentioned above in order to predict and prevent SRE. These gene expression level prior to radiation may reflect an individual’s properties and therefore have predictive value in SRE. Based on the expression level of these mRNAs, we established a c-Index calculation model to predict the development of SRE. This relatively simple prediction method takes into account individualized factors, which greatly improves patient compliance. Additionally, it helps clinicians predict the risk of SRE and guide individualized radiotherapy dosage, allowing radiologists to formulate a reasonable treatment plan for ESCC and achieve the best therapeutic effect.
SRE and RILI are both important adverse reactions in radiotherapy for ESCC. While we believe that dosimetric parameters have been fully considered and strictly controlled in clinical practice, our study found that dosimetric parameters of the lung, such as MLD, V5, and V20, which are commonly used to predict and control RILI clinically, showed no significant correlation with RILI. So far clinicians have not considered the occurrence of SRE as a risk factor for RILI. Our research suggests that SRE can indeed affect the occurrence and development of RILI, and a new study has found a possible correlation between SRE and RILI. The study’s results showed that acute radiation esophagitis (SARE, grade ≥ 2) was a significant predictor of symptomatic radiation pneumonitis (SRP) (P < 0.001), with a sensitivity of 91.9% and a negative predictive value of 93.5%. The incidence of SRP in different grades of ARE were as follows: Grade 0–1: 6.5%; Grade 2: 36.9%; Grade 3: 80.0%; Grade 4: 100%.
The current treatment of RILI is still symptomatic, including supportive treatment and the application of glucocorticoid. However, controlling its progression to the stage of irreversible RLF is the main problem in clinical practice. Our findings suggesting that if clinical radiation oncologists can be more guarded when SRE occurs, the occurrence of RILI may be reduced.
In summary, our research highlights the importance of considering SRE as a significant risk factor for RILI during radiotherapy for ESCC. By exercising greater caution when SREs occur, clinical radiation oncologists may be able to reduce the incidence of RILI. Furthermore, detecting the expression level of specific genes before radiotherapy may be an effective method for predicting and preventing RE, guiding individualized radiotherapy dosage, and improving patient compliance. The mechanisms of the radioprotective effects of FGF signaling and the role of MAP kinase signaling in radiation-induced inflammation require further investigation.
Conclusion
This retrospective study aimed to investigate the expression level of mRNAs in biopsied tumor samples and identify a set of genes that are crucial for the occurrence of SRE. The study found that different expression levels of these genes in tumor tissues may be relevant to the occurrence of SRE after exposure to esophageal radiation cancer therapy.
Furthermore, the study found that by using gene expression levels, a prediction model may be developed to help clinicians predict the risk of SRE and guide individualized radiotherapy dosage. This information can be vital for clinicians to optimize the radiation therapy plan and minimize the risk of SRE.
Additionally, the study found that RILI may also be predicted when SRE occurs. This is significant because RILI can have serious consequences for patients who undergo radiation therapy. By identifying RILI early, clinicians can implement appropriate interventions to prevent the progression of the condition.
However, there is still much to learn about how tumor gene expressions impact esophageal inflammatory reactions and the interaction between SRE and RILI. Future investigations are necessary to understand these complex mechanisms better.
In summary, this study highlights the importance of identifying the expression level of mRNAs in biopsied tumor samples to predict the risk of SRE and RILI in patients who undergo radiation therapy for ESCC. The findings have significant implications for optimizing radiation therapy plans, minimizing the risk of SRE and RILI, and improving the overall quality of care for patients with ESCC.
Acknowledgments
The authors would like to acknowledge the contribution of staff in Anhui Medical University Third Affiliated Hospital, China.
Author contributions
Hongxia Li conceived of the study. Wenwen Xu performed data collection, data analysis, and produced the figured and scripts, with overall guidance from Yi Wang. All authors wrote the manuscript. Congshu Zhang and Yunhong Xia deposited the data.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: 1.) Anhui Provincial Key Research and Development Plan (project ID 2022e07020060); and 2.) Scientific Research Foundation of Education Department of Anhui Province of China (project ID 2022AH050777).
Conflict of interest statement
The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data availability statement
The authors confirm that the data supporting the findings of this study are available within the article [and/or its supplementary materials].
Ethics statement
This study was approved by the Ethics Committee of The Third Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, China, in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki), and human materials were used with permission.
References
Nesheiwat Z, Akbar H, Kahloon A, Mahajan K.
