Downregulation of AC092894.1 promotes oxaliplatin resistance in colorectal cancer via the USP3/AR/RASGRP3 axis.

BACKGROUND: Oxaliplatin resistance is a complex process and has been one of the most disadvantageous factors and indeed a confrontation in the procedure of colorectal cancer. Recently, long non-coding RNAs (lncRNAs) have emerged as novel molecules for the treatment of chemoresistance, but the specific molecular mechanisms mediated by them are poorly understood. METHODS: The lncRNAs associated with oxaliplatin resistance were screened by microarray. lncRNA effects on oxaliplatin chemoresistance were then verified by gain- and loss-of-function experiments. Finally, the potential mechanism of AC092894.1 was explored by RNA pull-down, RIP, and Co-IP experiments. RESULTS: AC092894.1 representation has been demonstrated to be drastically downregulated throughout oxaliplatin-induced drug-resistant CRC cells. In vivo and in vitro experiments revealed that AC092894.1 functions to reverse chemoresistance. Studies on the mechanism suggested that AC092894.1 served as a scaffold molecule that mediated the de-ubiquitination of AR through USP3, thereby increasing the transcription of RASGRP3. Finally, sustained activation of the MAPK signaling pathway induced apoptosis in CRC cells. CONCLUSIONS: In conclusion, this study identified AC092894.1 as a suppressor of CRC chemoresistance and revealed the idea that targeting the AC092894.1/USP3/AR/RASGRP3 signaling axis is a novel option for the treatment of oxaliplatin resistance.

Higher Levels of Tumour-Infiltrating Lymphocytes (TILs) are Associated with a Better Prognosis, While CDK5 Plays a Different Role Between Nonmetastatic and Metastatic Colonic Carcinoma.

OBJECTIVE: We investigated the prognostic value of cyclin-dependent kinase 5 (CDK5) in a true population-based cohort of patients with colon cancer. METHODS: 1. Immunohistochemical (IHC) staining was used to retrospectively analyse the expression of CDK5 in colon cancer tissue samples of 296 patients. The χ2 test, Kaplan-Meier method and Cox proportional regression model were used to analyse the difference between the patients with differential expression of CDK5 and with different stages (metastatic and nonmetastatic); 2. The number of tumour-infiltrating lymphocytes (TILs) in tumour sections was determined, and its relationship with prognosis was explored. RESULTS: 1. Among 296 patients stained for CDK5, 18 cases (6.09%) showed negative expression, 77 cases (26.01%) showed weak expression (+1), 124 cases (41.89%) showed medium positive expression (2+), and 77 cases (26.01%) showed strong positive expression (3+). The expression of CDK5 was neither related to mismatch repair nor TILs (p > .05). In non-metastatic patients, longer progression-free survival (PFS) and cancer-specific survival (CSS) were observed in patients with high CDK5 expression (2+ or 3+) than low CDK5 expression (- or 1+), while in metastatic disease, the opposite was true (p < .001). 2. TILs in 226 patients were detected in the study. Among them, 115 cases (50.88%) showed a low number of TILs (TILs-L), and 111 cases (49.12%) showed a high number of TILs (TILs-H). Patients with a TIL ratio greater than .2 had a significantly better CSS (p < .001) or PFS (p = .008) than patients with a lower TIL ratio. By multivariate analysis, TILs-H was a protective factor for CSS, however failed to reach a significant difference (hazard ratio: .59, 95% CI: .33∼1.06, p = .079), and so was the PFS (HR: .65, 95% CI: .29∼1.43, p = .279). CONCLUSION: High expression of CDK5 indicates a good prognosis in nonmetastatic colon cancer, while it is the opposite in metastatic colon cancer, and the expression of CDK5 is unrelated to TILs. Patients with TIL-H have a better prognosis, with a proper cut-off value of 20% for colon cancer.

Estrogen receptor-negative/progesterone receptor-positive and her-2-negative breast cancer might no longer be classified as hormone receptor-positive breast cancer.

BACKGROUND: The single progesterone receptor (PR)-positive phenotype (estrogen receptor (ER)-/PR + , sPR positive) is an infrequent and independent biological entity. However, the prognosis of patients with sPR-positive and her-2-negative phenotype is still controversial, and it is not always easy to decide treatment strategies for them. METHODS: Patients during 2010-2014 were identified from Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier method was used to evaluate cancer-specific survival (CSS). The propensity score matching (PSM) method was used to balance differences of characteristics in groups. The Life-Table method was used to calculate 5-year CSS rates and the annual hazard rate of death (HRD). RESULTS: A total of 97,527 patients were included, and only 745 (0.76%) patients were sPR-positive phenotype. The majority of sPR-positive breast cancer were basal-like subtype. Survival analysis showed that the sPR-positive breast cancer had similar prognosis comparing to double hormonal receptor-negative (ER-/PR-, dHoR-negative) breast cancer, and had the highest HRD during the initial 1-2 years of follow-up, then maintained the HRD of almost zero during the late years of follow-up. CONCLUSIONS: The patients with sPR-positive and her-2-negative breast cancer, similar to dHoR-negative breast cancer, had a worse survival, and could benefit from chemotherapy significantly. However, the escalating endocrine therapy was not recommended for sPR-positive patients. The patients with sPR positive should be excluded from future clinical trials concerning endocrine therapy.

Resection of primary lesion with chemotherapy improves the survival of patients with metastatic colorectal neuroendocrine carcinoma.

OBJECTIVE: To evaluate the effect of resection of primary lesion and chemotherapy on survival of patients with metastatic colorectal neuroendocrine carcinoma (CRNEC). METHODS: Clinical data of 393 patients with metastatic CRNECs between January 2010 and December 2016 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database, including 171 patients who received resection of primary lesion and 221 patients who did not undergo surgery. With the propensity score matching method 172 non-operated patients were selected as controls. Kaplan-Meier method and Log-rank test were used to evaluate the survival differences, while the prognostic factors were analyzed by Cox proportional-hazards model. Metastatic CRNEC patients from January 2001 to December 2021 in Affiliated Jinhua Hospital, Zhejiang University School of Medicine were selected for validation. RESULTS: Compared with non-operated patients, patients who received resection had longer cause-specific survival ( P<0.05). Patients with resected positive lymph nodes>8 had a poorer prognosis compared to those with resected positive lymph nodes≤8 ( P<0.05). Multivariate analysis showed that gender, location of primary lesion and treatments were independent risk factors for cause-specific survival in patients with metastatic CRNEC (all P<0.05). For metastatic CRNEC patients with resection of primary lesion, rectal neuroendocrine carcinoma, positive resected lymph nodes≤8 and resection of primary lesion combined with chemotherapy were associated with better cause-specific survival (all P<0.05). CONCLUSIONS: Patients with metastatic CRNEC may benefit from resection of primary lesion, and resection of primary lesion combined with chemotherapy might be the better strategy for metastatic CRNECs. The number of positive lymph nodes resected is correlated with the prognosis of patients.

Propofol Affects EGF's Activity in Intestinal Cell by Down-Regulating EGFR-Mediated Intracellular Signaling.

Propofol is a commonly used anesthetic drug in clinic. In recent years, a series of non-anesthetic effects of propofol have been discovered. Studies have shown that propofol has many effects on the intestine. Epidermal growth factor (EGF) is one of the most important growth factors that could regulate intestinal growth and development. In the current study, we studied the effect of protocol on the biological activity of EGF on intestinal tissue and cell models. Through flow cytometry, indirect immunofluorescence and Western-blot and other technologies, it was found that propofol reduced the activity of EGF on intestinal cells, which inhibited EGF-induced intestinal cell proliferation and changed the cell behavior of EGF. To further explore the potential mechanism by which propofol down-regulated epidermal growth factor receptor (EGFR)-induced signaling, we carried out a series of related experiments, and found that propofol may inhibit the proliferation of intestinal cells by inhibiting the EGFR-mediated intracellular signaling pathway. The current research will lay the theoretical and experimental basis for further study of the effect of propofol on the intestine.

p.L105Vfs mutation in a family with thymic neuroendocrine tumor combined with MEN1: a case report.

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder arising from mutations of the MEN1 tumor suppressor gene on chromosome 11q13; MEN1 is characterized by the development of neuroendocrine tumors, including those of the parathyroid, gastrointestinal endocrine tissue and anterior pituitary. Additionally, thymic neuroendocrine tumors in MEN1 are also rarely reported. CASE PRESENTATION: This case report observed a family that presented with MEN1 p.L105Vfs mutation, and two of the family members had been diagnosed with thymic neuroendocrine tumor combined with MEN1. To the best of our knowledge, this is the first time such a mutation in the MEN1 gene has been reported. The proband presented with thymic neuroendocrine tumor, parathyroid adenoma and rectum adenocarcinoma. The son of the proband presented with thymic neuroendocrine tumor, gastrinoma, hypophysoma and parathyroid adenoma. Genetic testing revealed the frameshift mutation p.L105Vfs, leading to the identification of one carrier in the pedigree (the patient's younger sister). The proband then underwent parathyroidectomy at the age of 26 years (in 1980) for a parathyroid adenoma. Subsequently, the patient underwent thymectomy, radiotherapy and chemotherapy. The patient is now 64 years old, still alive and still undergoing Lanreotide therapy. CONCLUSION: Thymic neuroendocrine MEN1 is rare, but it accounts for almost 20% of MEN1-associated mortality. Consequently, we should focus on regular clinical screening of the thymus in MEN1 patients.

Combining serum miRNAs, CEA, and CYFRA21-1 with imaging and clinical features to distinguish benign and malignant pulmonary nodules: a pilot study : Xianfeng Li et al.: Combining biomarker, imaging, and clinical features to distinguish pulmonary nodules.

BACKGROUND: Our study was designed to improve the accuracy of determining whether pulmonary nodules are benign or malignant. METHODS: We evaluated the clinical and imaging features and serum markers: neuron specific enolase (NSE), carcino-embryonic antigen (CEA), cytokeratin fragment antigen 21-1 (CYFRA 21-1), miRNA-21-5p, and miR-574-5pof in 39 patients with pathology information. Factors that differed significantly between those with benign versus malignant pulmonary nodules were used to establish a prediction model for identifying malignant nodules. RESULTS: The studied nodules were 51.3% malignant and 48.7% benign. Age, smoking status, nodule diameter, history of emphysema, vascular sign, burr sign, CYFRA21-1, CEA, miRNA-21-5p, and miRNA-574-5p differed significantly between the benign and malignant nodule groups. Serum levels of CYRFA21-1 and CEA could be used to distinguish between malignant and benign nodules with a positive predictive value (PPV) of 80.0%, a negative predictive value (NPV) of 84.2%, and an area under the receiver operating characteristics curve (AUC) of 0.863. Using the serum levels of miRNA-21-5p and miRNA-574-5p, the PPV was 55%, the NPV was 84.2%, and the AUC was 0.797. When all four serum markers were combined, the PPV was 80%, the NPV was 89.5%, and the AUC was 0.921. We established a prediction model for malignant nodules, including clinical features, imaging features, and serum markers. In cross-validation, the ratio of discriminant conformance was 95%. CONCLUSIONS: Serum levels of miRNA-21-5p and miRNA-574-5p are significantly higher in patients with malignant nodules than in patients with benign nodules and are potential serum biomarkers. Our prediction model could improve malignant nodule diagnosis.

Retrospective analysis of the impact of dose delay and reduction on outcomes of colorectal cancer patients treated with FOLFIRI­based treatment.

Objectives: To determine the relationship between chemotherapy dose delay/reduction with progression-free survival (PFS) and overall survival (OS) in colorectal cancer patients treated with FOLFIRI based first-line chemotherapy in real-world retrospectively study. Methods: We identified 144 eligible patients with advanced CRC who received FOLFIRI as first-line based treatment. The study protocol was submitted to the institutional review board and was exempted. Dose delay was defined as an average delay of more than 3 days (>3 days vs. ≤3 days) from the intended date. Dose reduction (actual dose/standard dose * 100%) ≤85% was considered as chemotherapy reduction in the chemotherapy dose relative to the standard (mg/m2) regimen for all cycles. Relative dose intensity (RDI) ≤80% was described as chemotherapy reduction. OS and PFS were measured using Kaplan-Meier and Cox proportional hazard models. Results: There were 114 patients with chemotherapy dose delay (dose delay >3 days). PFS of patients without dose delay had better survival than patients with dose delay (p = 0.002). There were 28.47% patients treated with dose reduction of 5-Fu. PFS and OS were better in patients without 5-Fu dose reduction than in patients with 5-Fu dose reduction with p values of 0.024 and <0.001, respectively. Patients with high 5-FU RDI had better PFS than patients with low 5-FU RDI (p < 0.001). While, there was no statistical difference in OS between the two groups. Then we stratified the analysis by age. In <65 years cohort, both PFS and OS were better in patients with high 5-Fu RDI than in those with low 5-Fu RDI (p < 0.001, p = 0.005, respectively). But, in ≥65 years cohort, OS were better in patients with low 5-Fu RDI than in those with high 5-Fu RDI (p = 0.025). Moreover, both dose reduction and RDI of irinotecan had no statistically significant difference in both PFS and OS. Conclusion: In the advanced colorectal cancer patients who received FOLFIRI based treatment as first-line regimen, chemotherapy dose delay and reduction dose of 5-Fu were associated with worse survival, especially among patients younger than 65 years.

The predictive model for risk of chemotherapy-induced thrombocytopenia based on antineoplastic drugs for solid tumors in eastern China.

Chemotherapy-related thrombocytopenia (CIT) is a significant adverse event during chemotherapy, which can lead to reduced relative dose intensity, increased risk of serious bleeding and additional medical expenditure. Herein, we aimed to develop and validate a predictive nomogram model for prediction of CIT in patients with solid tumor. From Jun 1, 2018 to Sep 9, 2021, a total of 1541 patients who received 5750 cycles of chemotherapy were retrospectively enrolled. Cox regression analysis was performed to identify predictive factors to establish the nomogram model for CIT. The incidence of chemotherapy-induced thrombocytopenia was 21.03% for patient-based and 10.26% for cycles of chemotherapy. The top five solid tumors with CIT are cervix, gastric, bladder, biliary systemic, and ovarian. The incidence of chemotherapy dose delays in any cycle because of CIT was 5.39%. Multivariate analysis showed that tumor site, treatment line, AST, oxaliplatin, and capecitabine were significantly associated with CIT. Moreover, we established a nomogram model for CIT probability prediction, and the model was well calibrated (Hosme-Lemeshow P = 0.230) and the area under the receiver operating characteristic curve was 0.844 (Sensitivity was 0.625, Specificity was 0.901). We developed a predictive model for chemotherapy-induced thrombocytopenia based on readily available and easily assessable clinical characteristics. The predictive model based on clinical and laboratory indices represents a promising tool in the prediction of CIT, which might complement the clinical management of thrombocytopenia.

The impact of age on outcomes of breast cancer in different hormone receptor and HER2 groups.

OBJECTIVE: The aim of the current study was to explore the association between age and outcomes in breast cancer. METHODS: Patients during 2010-2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) and breast cancer-specific death (BCSD) were taken as endpoints. The restrict cubic spline graph (RCS) was used to explore the relationship between age and outcomes in patients, and the cumulative incidence of BCSD and non-BCSD was calculated using the Gray method. Age-specific gene expression profiles were studied using RNA sequence data from the Cancer Genome Atlas (TCGA) database to explore whether there were young age-related gene or gene sets. RESULTS: A total of 142,755 patients with breast cancer were included. The hazard ratio (HR) of OS for Patients with stage I-III breast cancer was roughly stable before 53 years old and increased significantly after that, and the HR of BCSD for these patients showed a U-shaped distribution when plotted against age, with patients younger than 50 years and patients older than 70 years experiencing the worst survival. Further stratified analysis according to molecular subtype revealed that the U-shaped distribution of the HR of BCSD with was only found in the Hormone receptor-positive/HER2-negative (HoR+/HER2-) subgroup. The cumulative incidence plots showed that young age was associated with worse BCSD in the breast cancer patients with stage I-III and HoR+/HER2- subgroup. In stage IV breast cancer, there was a linearity of the relationship between poor OS and increasing age. We failed to find any differentially expressed age-specific genes between 20-40 years and 41-60 years groups in 258 patients with stage I-III and HoR+/HER2- subtype. CONCLUSION: Young age could predict worse BCSD of patient with stage I-III and HoR+/HER2- breast cancer. The escalating therapy was recommended to young age breast cancer with stage I-III and HoR+/HER2- subtype.

A Prediction Model for Chemotherapy-Induced Thrombocytopenia Based on Real-World Data and a Close Relationship Between AST/ALT Ratio and Platelet Count in Patients with Solid Tumors.

Objective: Chemotherapy-induced thrombocytopenia (CIT) can lead to chemotherapy dose delay or reduction, and even serious bleeding. This study aimed to develop a CIT-predicting model based on the laboratory indices of cancer patients undergoing chemotherapy. Material and Methods: From Jun 1, 2017 to Dec 30, 2021, a total of 2043 patients who had received 7676 cycles of chemotherapy were retrospectively enrolled. A logistic regression analysis was performed to identify predictive factors, on the basis of which a nomogram model for predicting CIT was established. A bootstrapping technique was applied for internal validation. A generalized additive mixed model (GAMM) was constructed to analyze the trends in the changes of aspartate aminotransferase (AST), ratio of AST to alanine transaminase (ALT) (AST/ALT ratio), and platelet (PLT) count in patients with solid tumors. P values ≤0.05 were considered statistically significant. Results: The patient-based incidence of CIT was 20.51% and the cycle-based incidence was 10.01%. The multivariate analysis showed that AST level, AST/ALT ratio, and total bilirubin (Tbil), white blood cell (WBC), platelet (PLT), hemoglobin (Hb) levels were significantly associated with the risk of CIT. The GAMM analysis showed that PLT level was inversely associated with AST/ALT ratio and AST level, more significantly with AST/ALT ratio. And both exhibited statistically predictive abilities for CIT. The model achieved an area under the receiver operating characteristic curve (AUC) of 0.793, a sensitivity of 0.543 and a specificity of 0.930. Conclusion: The AST/ALT ratio was inversely associated with the CIT risk in cancer patients. The GAMM model based on laboratory indices presented a high accuracy in predicting the risk of CIT, and a potential to be translated into clinical management.

An R-Based Landscape Validation of a Competing Risk Model.

The Cox proportional hazard model is widely applied for survival analyses in clinical settings, but it is not able to cope with multiple survival outcomes. Different from the traditional Cox proportional hazard model, competing risk models consider the presence of competing events and their combination with a nomogram, a graphical calculating device, which is a useful tool for clinicians to conduct a precise prognostic prediction. In this study, we report a method for establishing the competing risk nomogram, that is, the evaluation of its discrimination (i.e., concordance index and area under the curve) and calibration (i.e., calibration curves) abilities, as well as the net benefit (i.e., decision curve analysis). In addition, internal validation using bootstrap resamples of the original dataset and external validation using an external dataset of the established competing risk nomogram were also performed to demonstrate its extrapolation ability. The competing risk nomogram should serve as a useful tool for clinicians to predict prognosis with the consideration of competing risks.

Competing Nomogram for Late-Period Breast Cancer-Specific Death in Patients with Early-Stage Hormone Receptor-Positive Breast Cancer.

BACKGROUND: More than half of early breast cancer recurrences occur after 5 years from the initial diagnosis. An individualized estimate of the risk of late-period breast cancer-specific death (LP-BCSD) after 5 years of endocrine therapy (ET) can improve decision-making for extended endocrine therapy (EET). MATERIALS AND METHODS: A total of 147,059 eligible patients with breast cancer who survived 5+ years after diagnosis between 1990 and 2007 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses based on the competing risk regression model were used to evaluate predictive factors for high risk of LP-BCSD or late-period non-breast cancer-specific death (LP-non-BCSD). Significant factors were used to build a nomogram to individualize estimates of LP-BCSD or LP-non-BCSD. RESULTS: The 5- and 10-year LP-BCSD rates were 5.7% and 10.1%, respectively, and the 5- and 10-year LP-non-BCSD rates were 6.7% and 15.5%, respectively. Young age, black race, single marital status, poor differentiation, large tumor size, lymph node metastasis, and estrogen receptor-positive/progesterone receptor-negative (ER+/PR-) status were independent predictive factors for high risk of LP-BCSD. Age was the most important factor for predicting high risk of LP-non-BCSD. The nomograms, which were based on significant factors identified by the competing risk regression model. A risk score system based on the competing risk nomogram was established to describe the relative risk of LP-BCSD and LP-non-BCSD. CONCLUSION: This study explored the novel endpoint of LP-BCSD for further clinical trials. The risk score system might be highly useful for patient counseling, especially in discussing EET options with elderly or comorbid patients.

A Case Report: Cutaneous Metastasis of Advanced Rectal Cancer with BRAF Mutation.

Cutaneous metastasis of rectal cancer is rare and typically indicates widespread disease and poor prognosis. We report an exceedingly rare case of BRAF-mutated MSS rectal cancer with metastasis to the skin. A 53-year-old woman presented with stage IV unresectable adenocarcinoma of the rectum and received chemotherapy and molecularly targeted agents. Six months later she developed a focal skin nodule in the left groin. During treatment with four cycles of FOLFIRI plus bevacizumab, the skin nodules gradually increased in size, involving the skin of the left thigh. A portion of the rash was bleeding and painful. The biopsy specimen was consistent with a mucinous adenocarcinoma of rectal origin and expressed reduced CDX-2. Palliative treatment with FOLFIRI plus cetuximab and vemurafenib was initiated. The cutaneous nodules decreased in size but were not stable. The patient had severe electrolyte disturbances and depression and opted for palliative care.

The Effect of Adjuvant Treatment in Small Node-negative HER2-positive Breast Cancer: Which Subgroup Will Benefit?

BACKGROUND: We conducted this study to evaluate whether patients with T1a/b, node-negative (N-), human epidermal growth factor receptor 2-positive (HER2+) breast cancers benefited from adjuvant therapy, and explored better treatment strategies for these patients. PATIENTS AND METHODS: Patients with T1a/b, N-, HER2+ breast cancers during 2000 through 2004 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The Gray test was used to evaluate breast cancer-specific death (BCSD) and non-BCSD. To identify patients more suitable for chemotherapy, subgroup analyses were conducted according to tumor size and estrogen receptor (ER) status, and plots of hazard rate of death (HRD) were drawn to present the changes of BCSD. RESULTS: A total of 2940 patients with T1a/b, N-, HER2+ breast cancers were included; more patients in the T1b group received chemotherapy compared with the T1a group (65.18% vs. 29.30%; P < .001). Patients receiving chemotherapy did not benefit from it (5-year incidences of BCSD: 1.00% in the non-chemotherapy group vs. 1.18% in the chemotherapy group; P = .853). Compared with those in the T1a group, patients in the T1b group had similar prognosis (P = .532), whereas ER status was significantly associated with survival (P = .048). HRD had a peak in years 2 to 5, which was more obvious in the ER- group. CONCLUSION: Chemotherapy, which is mainly decided by tumor size, fails to render survival benefits for patients with T1a/b, N-, HER2+ breast cancers. ER status, rather than tumor size, is important for clinicians to make adjuvant treatment decisions. The peak of BCSD occurs 2 to 5 years after diagnosis, and an at least 5-year follow-up is recommended for these patients.

Netrin­1 interference potentiates epithelial­to­mesenchymal transition through the PI3K/AKT pathway under the hypoxic microenvironment conditions of non­small cell lung cancer.

Netrin­1 is overexpressed in several types of cancer. However, whether netrin­1 can potentiate hypoxia­induced tumor progression in lung cancer has not been reported to date. Thus, the objective of the present study was to investigate whether netrin­1 regulates cancer cell migration and invasion under hypoxic conditions in lung cancer and explore the underlying mechanism. A three­dimensional microfluidic chip was used to observe real­time changes in cancer cells, and cobalt chloride (CoCl2) was used to simulate a hypoxic microenvironment. Netrin­1 siRNA was employed in the A549 and PC9 cell lines to downregulate the expression of netrin­1. Microfluidic chip, wound healing and Transwell assays were used to examine cell migration and invasion. The expression levels of E­cadherin and vimentin were detected by western blotting. The data demonstrated that netrin­1 mediated epithelial­to­mesenchymal transition (EMT) of A549 and PC9 cells in vitro, which may be associated with the phosphoinositide 3 kinase/AKT pathway. This effect of netrin­1 on the EMT was not observed in the normoxic microenvironment. In this retrospective study, netrin­1 concentrations were evaluated in serum obtained from patients with non­small cell lung cancer (NSCLC) and compared with healthy control samples by quantitative enzyme­linked immunosorbent analysis. The serum concentration of netrin­1 was found to be significantly higher in NSCLC patients compared with that in healthy donors. Taken together, the findings of the present study highlight a novel role for netrin­1 in tumor development under hypoxia in NSCLC and provide further evidence for the use of netrin­1 as a therapeutic target.