Impact of plasma Epstein-Barr virus DNA in posttreatment nasopharyngeal carcinoma patients after SARS-CoV-2 infection.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is prevalent in southern China. EBV DNA is the most useful biomarker in NPC. However, the value of EBV DNA in posttreatment NPC patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear. METHODS: Sixty-four eligible NPC patients were enrolled between December 2022 and February 2023. Patients who met the following criteria were included: had non-metastatic NPC, completed radical treatment, were first firstly infected with SARS-CoV-2 and their EBV DNA changed from undetectable to detectable. RESULTS: At the end of follow-up, 81.25% (52/64) of patients were confirmed not to relapse with undetectable EBV DNA (no-relapse). In addition, 18.75% (12/64) of patients experienced relapse with consistent detection of EBV DNA (yes-relapse). For all 64 patients, the average time from diagnosis of coronavirus disease 2019 (COVID-19) to detection of detectable EBV DNA was 35.41 days (2 to 139 days). For 52 no-relapse patients, the average time from EBV DNA changing from detectable to undetectable was 63.12 days (6 to 147 days). The levels of EBV DNA were greater in yes-relapse patients than that in no-relapse patients, and the average of EBV DNA levels were 1216 copies/ml and 53.18 copies/ml, respectively. Using 62.3 copies/mL as the threshold, the area under the curve for EBV DNA was 0.88 for distinguishing yes-relapse patients from no-relapse patients. The sensitivity and specificity were 81.97% (95% CI 0.71-0.95) and 86.67% (95% CI 0.70-0.95), respectively. CONCLUSION: For NPC patients infected with SARS-CoV-2, EBV DNA alone is insufficient for monitoring relapse after radical therapy. Long-term follow-up and underlying mechanistic investigations of EBV DNA changes are urgently needed.

Selectively sparing of the supraclavicular area during intensity-modulated radiotherapy in nasopharyngeal carcinoma: A double-center observation study.

BACKGROUND AND PURPOSE: This study was aimed at evaluating the feasibility of sparing the supraclavicular area, namely levels IVb and Vc, during intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC) patients with N1-2 disease[except N1 disease with purely restropharyngeal lymph nodes(RPN) involvement], and providing a basis for the revision of International Guideline for the delineation of the clinical target volume (CTV). PATIENTS AND MATERIALS: Patients with NPC (stage TanyN1-2M0) diagnosed pathologically in Fujian Cancer Hospital (Center 1, Only Lin SJ's attending group) from January 2014 to March 2018 and Jiangxi Cancer Hospital(Center 2) from January 2014 to December 2015 were included. According to our principle, the supraclavicular area (levels IVb and Vc) were excluded from the CTVnd. Survival outcomes focused on regional recurrence-free survival (RRFS) and recurrence rates of levels IVb and Vc were analysed. RESULTS: A total of 672 eligible patients were recruited (Center 1, n = 362; Center 2, n = 310). There was no significant difference in 5-year RRFS (97.33 % vs. 97.24 %, p = 0.980), overall survival (OS) (89.14 % vs. 88.56 %, p = 0.327), local recurrence-free survival (LRFS) (94.90 % vs. 95.30 %, p = 0.593) and distant metastasis-free survival (DMFS) (89.38 % vs. 86.60 %, p = 0.130) between Center 1 and Center 2. Twenty patients developed regional failure (median: 36 months), among them, only one case (0.15 %) was recorded as levels IVb and Vc recurrence. CONCLUSION: Omitting the supraclavicular area (levels IVb and Vc) during IMRT should be safe and feasible for N1-2 disease (except N1 disease with purely RPN involvement). Well-designed multicenter prospective trials should be conducted to confirm our findings.

Comparison the acute toxicity of two different induction chemotherapy schedules with cisplatin and fluorouracil in nasopharyngeal carcinoma patients.

PURPOSE: To compare the acute toxicity of two different induction chemotherapy (IndCT) regimen followed by the same IMRT in patients with advanced nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: From July 2015 to December 2016, 110 NPC patients with stage III-IV diseases were prospectively randomized to receive either a conventional triweekly cisplatin + 5-fluorouracil (PF) for 3 cycles or weekly P-F for 10 doses, followed by the same IMRT to both arms. The primary endpoints of this study were grade 3/4 and any grade acute toxicities during IndCT period. The secondary endpoints included tumor response and various survivals. RESULTS: Baseline patient characteristics were comparable in both groups. Patients who received weekly P-F experienced significant reduction of grade 3/4 acute toxicities, including neutropenia (12.7% vs. 40.0%, P = 0.0012), anorexia (0% vs. 14.6%, P = 0.0059), mucositis (0% vs. 14.6%, P = 0.0059), and hyponatremia (0% vs. 16.4%, P = 0.0027), compared with the triweekly PF group, resulting in fewer IndCT interruptions (1.8% vs. 16.4%, P = 0.0203), emergency room visits (0% vs. 12.7%, P = 0.0128), and additional hospitalizations (0% vs. 9.1%, P = 0.0568). The acute toxicities during IMRT period were similar. Weekly P-F arm had higher complete response rates (83.6% vs. 61.8%, P = 0.0152) and lower relapse rates (16.4% vs. 33.3%, P = 0.0402) after a median follow-up of 67 months. Kaplan-Meier survival analyses revealed a better trend of locoregional failure-free (P = 0.0892), distant metastasis failure-free (P = 0.0775), and progression-free (P = 0.0709) survivals, favoring the weekly P-F arm. CONCLUSION: IndCT of weekly schedule does reduce acute toxicities without compromised tumor response and survivals.

Constructing an individualized surveillance framework for nasopharyngeal carcinoma based on a dynamic risk-adapted approach.

BACKGROUND AND PURPOSE: This study aims to evaluate the dynamic survival and recurrence hazard of nasopharyngeal carcinoma(NPC) patients after definitive chemoradiotherapy utilizing conditional survival(CS) analysis, and to propose a personalized surveillance strategy at different clinical stages. MATERIALS AND METHODS: Non-metastatic NPC patients who received curative chemotherapy between June 2005 and December 2011 were included. The Kaplan-Meier method was used to calculate the CS rate. RESULTS: A total of 1616 patients were analyzed. With the prolongation of survival time, both conditional locoregional recurrence free survival and distant metastatic free survival increased gradually. Changing pattern of annual recurrence risk over time varied among different clinical stages. The annual locoregional recurrence(LRR) risk in stage I-II was always less than 2%, while in stage III-IVa, it was greater than 2% for the first three years and decreased to below 2% only after the third year. The annual distant metastases (DM) risk was always less than 2% in stage I, but higher than 2% in stage II for the first 3 years (2.5-3.8%). For those with stage III-IVa, the annual DM risk retained at a high level(>5%), and only decreased to < 5% after the third year. Based on the dynamic changes in survival probability over time, we established a surveillance plan with different follow-up intensities and frequencies for different clinical stages. CONCLUSION: The annual risk of LRR and DM decrease over time. Our individual surveillance model will provide critical prognostic information to optimize clinical decision-making, and promote to formulate surveillance counseling and help with resources allocation.

Identification of immune-related genes contributing to head and neck squamous cell carcinoma development using weighted gene co-expression network analysis.

BACKGROUND: This study aimed to identify genes related to the degree of immune cell infiltration in head and neck squamous cell carcinoma (HNSCC), explore their new biological functions, and evaluate their diagnostic and prognostic value in HNSCC. METHODS: Transcriptomic data from The Cancer Genome Atlas (TCGA) HNSCC dataset was used to screen differentially expressed genes between tumors and normal tissues, followed by weighted correlation network analysis (WGCNA) to identify immune-related modules. Differential gene expression, immune cell infiltration, and survival analyses were performed to screen key genes. The expression of these key genes was validated in Oncomine and gene expression omnibus (GEO) datasets and by immunohistochemistry (IHC). RESULTS: 1869 and 1578 genes were significantly upregulated and downregulated in HNSCC. WGCNA showed that the brown module was associated with the most significant number of immune-related genes. PPI network analysis demonstrated that PPL, SCEL, KRT4, KRT24, KRT78, KRT13, SPRR3, TGM3, CRCT1, and CRNN were key components in the brown module. Furthermore, the expression levels of KRT4, KRT78, KRT13, and SPRR3 in HNSCC correlated with infiltration levels of CD8+ T cells and macrophages. Survival analyses revealed that the expression of KRT78, KRT13, and SPRR3 in HNSCC correlated with overall survival (OS). The IHC assay indicated that KRT13 (p = .042), KRT78 (p < .001), and SPRR3 (p = .022) protein expression levels in HNSCC were significantly lower than in normal tissues. Analysis of GSE65858 and GSE41613 datasets showed that a worse OS was associated with low expression of KRT78 (p = .0086, and p = .005) and SPRR3 (p = .017, and p = .02). CONCLUSIONS: Our findings suggest that KRT4, KRT78, KRT13, and SPRR3 are related to the occurrence and development of HNSCC. Importantly, KRT78 and SPRR3 might serve as diagnostic and prognostic biomarkers of HNSCC.

Level Ib sparing intensity-modulated radiation therapy in selected nasopharyngeal carcinoma patients based on the International Guideline.

BACKGROUND AND PURPOSE: To investigate the feasibility of level Ib sparing in selected nasopharyngeal carcinoma (NPC) patients during intensity-modulated radiation therapy (IMRT) based on the International Guideline. PATIENTS AND MATERIALS: Patients with histologically-proven NPC who received definitive IMRT at our group were candidates for this analysis. Other eligibility criteria for analysis were designed according to the recommendation of International Guideline for selective coverage of level Ib. Survival outcomes focused on regional recurrence-free survival (RRFS) and level Ib recurrence rate were analyzed. RESULTS: A total of 450 patients were included, 60 of them received level Ib-covering IMRT due to the first three principles of the International Guideline according to our protocol. Of note, patients with level Ib involvement would receive ultrasound guided puncture, only those with positive pathological results would undergo level Ib-covering IMRT. For the remaining 390 patients who only fulfilled the last two criteria and/or level Ib involvement with negative pathological results, level Ib-sparing IMRT was delivered, with a median follow-up time of 112 months (range 6 to 194 months), reported 5- and 10-year RRFS were 95.4% and 92.9%, respectively. Twenty-two patients occurred regional recurrence at censorship (median 44.5 months), only 4(4/390, 1.03%) were recorded as level Ib recurrence. CONCLUSION: Level Ib-sparing IMRT should be safe and feasible for patients who only had level II involvement with ECE, and/or had a MAD of greater than 2 cm in level II, and/or level Ib involvement with negative pathological results. Further well-designed multi-center prospective trials should be conducted.

Re-evaluation of the prognostic significance of retropharyngeal node metastasis in nasopharyngeal carcinoma patients treated with intensity-modulated radiotherapy.

BACKGROUND AND PURPOSE: To investigate the prognostic value of retropharyngeal lymphadenopathy in nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy. MATERIALS AND METHODS: Retrospective studies were performed in a total of 1197 patients. We evaluated the incidence of the retropharyngeal node (RPN) metastasis and the characteristics of the metastatic RPN including laterality, size, necrosis, and extranodal neoplastic spread. RESULTS: RPN metastasis occured in 86.3% of patients. The RPN and level II metastasis shared similar survival outcomes. RPN metastasis was an independent prognostic factor for distant failure (hazard ratio = 1.615; 95% confidence interval, 1.063-2.452; P = 0.025), in which the laterality of RPN metastasis significantly influences both the distant failure (P = 0.006) and disease progression (P = 0.001). In N1 disease, the occurrence of unilateral and bilateral RPN metastasis resulted in significantly different outcomes of the disease-specific survival (P = 0.045) and progression-free survival (P = 0.049). The co-occurrence of bilateral RPN and cervical lymph nodes (CLN) metastasis was an independent adverse prognostic factor (P < 0.01) for distant failure and disease progression but not for locoregional recurrence. CONCLUSION: Both the RPN and level II are the first stations of NPC lymph node metastasis. For N1-stage NPC patients, RPN metastasis, especially co-occurrence of bilateral RPN and CLN metastasis, have an adverse influence on survival outcomes.

Comparison of radiotherapy combined with nimotuzumab vs. chemoradiotherapy for locally recurrent nasopharyngeal carcinoma.

BACKGROUND: The present study compared the effectiveness and toxicity of two treatment modalities, namely radiotherapy combined with nimotuzumab (N) and chemoradiotherapy (CRT) in patients with locally recurrent nasopharyngeal carcinoma (LR-NPC). METHODS: Patients with LR-NPC who were treated with radiotherapy were retrospectively enrolled from January 2015 to December 2018. The treatment included radiotherapy combined with N or platinum-based induction chemotherapy and/or concurrent chemotherapy. The comparison of survival and toxicity between the two treatment modalities was evaluated using the log-rank and chi-squared tests. Overall survival (OS) was the primary endpoint. RESULTS: A total of 87 patients were included, of whom 32 and 55 were divided into the N group and the CRT group, respectively. No significant differences were noted in the survival rate between the N and the CRT groups (4-year OS rates, 37.1% vs. 40.7%, respectively; P = 0.735). Mild to moderate acute complications were common during the radiation period and mainly included mucositis and xerostomia. The majority of the acute toxic reactions were tolerated well. A total of 48 patients (55.2%) demonstrated late radiation injuries of grade ≥ 3, including 12 patients (37.5%) in the N group and 36 patients (66.5%) in the CRT group. The CRT group exhibited significantly higher incidence of severe late radiation injuries compared with that of the N group (P = 0.011). CONCLUSION: Radiotherapy combined with N did not appear to enhance treatment efficacy compared with CRT in patients with LR-NPC. However, radiotherapy combined with N may be superior to CRT due to its lower incidence of acute and late toxicities. Further studies are required to confirm the current findings.

Percutaneous endoscopic gastrostomy can improve survival outcomes in patients with N3 nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy.

OBJECTIVES: Our previous study revealed that percutaneous endoscopic gastrostomy (PEG) and intensive nutritional support may minimize body weight loss, maintain nutritional status, and offer better treatment tolerance for patients with locally advanced nasopharyngeal carcinoma (LA-NPC) during concurrent chemoradiotherapy (CCRT). This study aimed to further explore the potential long-term survival benefits of PEG in LA-NPC. METHODS: Between June 1, 2010 and June 30, 2014, a total of 133 consecutive LA-NPC patients who received prophylactic PEG (pPEG) feeding before the initiation of CCRT were included. Meanwhile, an additional 133 non-PEG patients, who were matched for age; sex; and tumor, node, and metastases stage, were selected as control cohort. The log-rank test was used to compare survival distributions between groups. Multivariate prognosis analysis was conducted using a Cox's proportional hazards regression model. RESULTS: After a median follow-up time of 81 months (range: 4-119 months), pPEG was not associated with significant survival benefits in the whole cohort. However, the N3 NPC patients who underwent PEG had significantly higher 5-year overall survival (OS) and progression-free survival (PFS) (84.0 and 76.0%, respectively) than those who did not undergo PEG (56.7 and 45.6%, respectively; p < 0.05). Univariate and multivariate analyses demonstrated that PEG was an independent factor for N3 survival. CONCLUSION: PEG can maintain the nutritional status and improve the rate of treatment completion for LA-NPC patients who underwent CCRT, and these advantages can transfer into survival benefits in N3 NPC. Further multicenter prospective clinical trials are warranted.

Administration of oral maintenance chemotherapy for 1 year following definitive chemoradiotherapy may improve the survival of patients with stage N3 nasopharyngeal carcinoma.

OBJECTIVES: This study aims to evaluate the effectiveness and the optimal maintenance period of oral chemotherapy using S1 following definitive chemoradiotherapy in patients with stage N3 nasopharyngeal carcinoma (N3-NPC). MATERIALS AND METHODS: A retrospective review was performed for N3-NPC treatment with maintenance chemotherapy (MC) [chemoradiotherapy (CRT)-MC] or without MC (CRT-non-MC) following definitive CRT between May 2014 and December 2017. Toxicities during MC were recorded. Overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS) and locoregional relapse-free survival (LRRFS) were compared between CRT-MC and CRT-non-MC cohorts. The optimal duration of using maintenance S1 (MC-S1) was also analyzed. RESULTS: A total of 304 patients with stage N3-NPC were identified, of whom 56 were treated with CRT-MC and 248 with CRT-non-MC. After a median follow-up of 48 months, significant differences in OS (74.9 vs. 91.7%; P = 0.003), PFS (60.7 vs. 83.7%; P = 0.001) and DMFS (68.8 vs. 85.5%; P = 0.015) were observed between the CRT-non-MC and CRT-MC groups. Skin hyperpigmentation, leukopenia and fatigue were common but not severe (grade 1-2) side effects of MC. The OS, DMFS and PFS were significantly higher for patients who received S1 administration over a period of ≥12 cycles compared with those who received <12 cycles (3-year OS, 100 vs. 87.5%, P = 0.018; 3-year PFS, 93.9 vs. 67.9%, P = 0.006; 3-year DMFS, 97.1 vs. 67.9%, P = 0.002). CONCLUSIONS: Using MC-S1 in patients with N3-NPC following definitive chemoradiotherapy achieved superior survival rate compared with the patients with non-MC. The side effects of MC-S1 were mild and tolerable. S1 should be maintained for ≥12 cycles.

Identifying the optimal candidates for locoregional radiation therapy in patients with de novo metastatic nasopharyngeal carcinoma.

BACKGROUND: To evaluate the value of locoregional radiation therapy (LRRT) in de novo metastatic nasopharyngeal carcinoma (mNPC) and identify suitable candidates for additional LRRT after palliative chemotherapy (PCT). METHODS: Patients with de novo mNPC received platinum-based chemotherapy for a minimum of four cycles with or without definitive LRRT via intensity-modulated radiation therapy (IMRT) were all candidates for this study. RESULTS: A total of 168 patients were included for this analysis. Additional LRRT was associated with significantly longer median OS (69.5 vs. 17.8 months, p < 0.001) when compared with PCT alone. However, this survival benefit of LRRT was only reflected in patients with oligometastatic diseases (90.8 vs. 17 months, p < 0.001), but not for those with polymetastatic disease (p = 0.86). CONCLUSIONS: Additional LRRT after PCT may only improve OS for oligometastatic patients. For patients with polymetastatic disease, intensive systemic treatment such as the combination of immunotherapy and adequate PCT might be necessary.

Modified reduced-volume intensity-modulated radiation therapy in non-metastatic nasopharyngeal carcinoma: A prospective observation series.

BACKGROUND AND PURPOSE: Although the efficacy of "reduced-volume intensity-modulated radiation therapy (IMRT)" in nasopharyngeal carcinoma (NPC) has been confirmed, two issues regarding the necessity of clinical target volume 1(CTV1) delineation and the optimal margin of CTV2 remained undetermined. The current series, utilized de-intensification technique that omitted the contouring of CTV1 and narrowed the margin of CTV2 from 10 mm to 8 mm, namely "modified reduced-volume IMRT" was initiated to evaluate the efficacy and feasibility of this renew technique in a prospective series. PATIENTS AND MATERIALS: Dosimetric analysis was performed in 40 non-metastatic NPC cases to evaluate whether our modification is feasible. Then this de-intensification technique was applied in non-metastatic NPC patients treated in our attending group since late 2014. Survival outcomes focused on local recurrence-free survival (LRFS) and local failure pattern were analyzed. RESULTS: Preliminary dosimetric evaluation of "modified reduced-volume IMRT" showed that the 60 Gy isodose curve generated naturally by this technique could well wrap the target area of CTV1. Subsequent observation series, which included a total of 471 patients and had a median follow-up time of 46.2 months(range,3.7-70.8 months), reported that 4-year estimated LRFS, regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS) and overall survival (OS) were 96.6%, 97.7%, 87.7% and 92.4%, respectively. All local recurrence lesions occurred within 95% isodose lines and were considered in-field failures. CONCLUSIONS: Our de-intensification technique "modified reduced-volume IMRT" was feasible and did not compromise therapeutic efficacy, well-designed multicenter prospective trials are needed for further research.

Oral Maintenance Chemotherapy Using S-1/Capecitabine in Metastatic Nasopharyngeal Carcinoma Patients After Systemic Chemotherapy: A Single-Institution Experience.

BACKGROUND: In this study, we retrospectively evaluated a series of metastatic nasopharyngeal carcinoma (mNPC) patients who received oral maintenance chemotherapy using S-1/capecitabine after systemic chemotherapy and local radiation therapy, and aimed to explore potential efficient treatment strategies for this subset of patients. PATIENTS AND METHODS: Thirty-seven patients with mNPC (19 newly diagnosed metastatic patients and 18 metastatic cases after definitive chemoradiotherapy) who received the treatment strategies mentioned above were analyzed. RESULTS: After a median follow-up time of 37 months, the 3-year progression-free survival and overall survival (OS) rates were 47.6% and 87.7%, respectively. The median time to progression was 27.6 months, while the median OS was not reached at time of last follow-up. The most common acute adverse events were hematological and gastrointestinal toxicity, and all were tolerable and curable. CONCLUSION: Oral maintenance chemotherapy using S-1/capecitabine in mNPC patients after systemic chemotherapy could yield a superb outcome. Further multicenter prospective clinical trials are warranted.

Maintenance chemotherapy using S-1 following definitive chemoradiotherapy in patients with N3 nasopharyngeal carcinoma.

BACKGROUND: Patients with N3 stage nasopharyngeal carcinoma (NPC) are at high risk for treatment failure. This study aims to assess the efficacy of maintenance chemotherapy (MC) using S-1 (MC-S1), a novel oral fluoropyrimidine agent, following definitive chemoradiotherapy (CRT) using intensity-modulated radiotherapy (IMRT) in patients with N3 nasopharyngeal carcinoma (N3-NPC). METHODS: A retrospective review was conducted for all N3-NPC treated with CRT with MC (CRT-MC) or without MC (CRT-non-MC) during 2014-2016. Toxicities with MC were recorded. Overall survival (OS), locoregional failure-free survival (LFFS) and distant metastasis free survival (DMFS) were compared between CRT-MC vs. CRT-non-MC cohorts. RESULTS: A total of 130 N3 patients were identified, of whom 21 (16.2%) were treated with CRT-MC, and 109 (83.8%) with CRT-non-MC. Patient characteristics did not significantly differ between the CRT-MC and CRT-non-MC groups, with the exception of the number of cycles of neoadjuvant chemotherapy. Following IMRT 69 patients achieved a complete response (CR) (CRT-MC: 10; CRT-non-MC: 59), 61 had a partial response (PR) (11 vs. 50), and none maintained stable disease (SD) or developed progression of disease (PD). After a median follow-up of 41 months for surviving patients, a significant differences in OS (76.3% vs. 95.2%, p = 0.046) and DMFS (70.3% vs. 90.5%, p = 0.043) but not LFFS (84.9% vs. 100%, p = 0.091) at 3 years were observed between the CRT-non-MC and CRT-MC groups. Skin hyperpigmentation, leucopenia, fatigue, neutropenia, anorexia and nausea were the common but not severe (grade 1-2) toxicities of MC. CONCLUSIONS: Using MC-S1 in N3-NPC patients following IMRT achieved superior survival to the CRT-non-MC patients. The toxicities of MC-S1 were mild and tolerable. Further clinical trials are required to evaluate the efficacy of MC-S1 in N3-NPC patients.

Stanniocalcin 2 (STC2) expression promotes post-radiation survival, migration and invasion of nasopharyngeal carcinoma cells.

Background: Stanniocalcin 2 (STC2) expression is upregulated under multiple stress conditions including hypoxia, nutrient starvation and radiation. Overexpression of STC2 correlates with tumor progression and poor prognosis. Purpose: We previously demonstrated that overexpression of STC2 in nasopharyngeal carcinomas (NPC) positively correlates with radiation resistance and tumor metastasis, two major clinical obstacles to the improvement of NPC management. However, it remains elusive whether STC2 expression is a critical contributing factor for post-radiation survival and metastasis of NPC cells. Materials and methods: Using the radiation resistant CNE2 cell line as a model, we examined the importance of STC2 expression for post-radiation survival, migration and invasion. Here, we report the establishment of STC2 knockout lines (CNE2-STC2-KO) using the CRISPR/Cas9-based genome editing technique. Results: Compared with the parental line, STC2-KO cells showed similar proliferation and morphology in normal culture conditions, and loss of STC2 did not compromise the cell tumorigenicity in nude mice model. However, STC2-KO lines demonstrated increased sensitivity to X-radiation under either normoxic or hypoxic conditions. Particularly, upon X-radiation, parental CNE2 cells only slightly whereas STC2-KO cells remarkably decreased the migration and invasion ability. Cell cycle analysis revealed that loss of STC2 accumulated cells in G1 and G2/M phases but decreased S-population. Conclusion: These data indicate that the expression of STC2, which can be stimulated by metabolic or therapeutic stresses, is one important factor to promote survival and metastasis of post-radiation NPC cells. Therefore, targeting STC2 or relative downstream pathways may provide novel strategies to overcome radiation resistance and metastasis of NPC.