Ferroptosis-dependent breast cancer cell-derived exosomes inhibit migration and invasion of breast cancer cells by suppressing M2 macrophage polarization.

Aim: Ferroptosis, a novel type of iron-dependent cell death, plays a vital role in breast cancer progression. However, the function of ferroptosis-induced cancer cell-derived exosomes in breast cancer remains unclear. In this study, we attempted to investigate the impact of breast cancer cells-derived exosomes induced by ferroptosis on the polarization of macrophages and the progression of breast cancer. Methods: Erastin was used to induce ferroptosis and breast cancer cell-derived exosomes were identified by transmission electron microscopy. Western blot, quantitative reverse transcription PCR, immunofluorescence, flow cytometry, and ELISA were used to determine the role of exosomes in macrophage polarization. Transwell assays were used to detect breast cancer cell migration, and invasion. Results: Our results showed that erastin promoted ferroptosis in breast cancer cells with increased Fe2+ level and ROS production. Breast cancer cell-derived exosomes induced by ferroptosis were successfully isolated and verified to be internalized by macrophages. In addition, ferroptosis-induced breast cancer cell-derived exosomes (Fe-exo) remarkably diminished M2 marker, Arg-1 expression. The ratio of CD206+ macrophages was significantly decreased after Fe-exo treatment. CD206 protein expression and Arg-1 level were dramatically reduced in M2 macrophages incubated by Fe-exo. Moreover, autophagy PCR array showed that the expression of 84 autophagy-related genes were altered after macrophages were incubated by Fe-exo. Furthermore, macrophages incubated by Fe-exo repressed the migration and invasion of breast cancer cells. Conclusion: Ferroptosis-dependent cancer cell-derived exosomes inhibited M2 polarization of macrophages, which in turn inhibited migration and invasion of breast cancer cells. This study provides novel therapeutic strategies for patients with breast cancer.

Predictors of lymph-node metastasis in surgically resected T1 colorectal cancer in Western populations.

BACKGROUND: The risk of lymph-node metastasis (LNM) in T1 colorectal cancer (CRC) has not been well documented in heterogeneous Western populations. This study investigated the predictors of LNM and the long-term outcomes of patients by analysing T1 CRC surgical specimens and patients' demographic data. METHODS: Patients with surgically resected T1 CRC between 2004 and 2014 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Patients with multiple primary cancers, with neoadjuvant therapy, or without a confirmed histopathological diagnosis were excluded. Multivariate logistic-regression analysis was used to identify the predictors of LNM. RESULTS: Of the 22,319 patients, 10.6% had a positive lymph-node status based on the final pathology (nodal category: N1 9.6%, N2 1.0%). Younger age, female sex, Asian or African-American ethnicity, poor differentiation, and tumor site outside the rectum were significantly associated with LNM. Subgroup analyses for patients stratified by tumor site suggested that the rate of positive lymph-node status was the lowest in the rectum (hazard ratio: 0.74; 95% confidence interval: 0.63-0.86). CONCLUSION: The risk of LNM was potentially lower in Caucasian patients than in API or African-American patients with surgically resected T1 CRC. Regarding the T1 CRC site, the rectum was associated with a lower risk of LNM.

Inhibition of DNA­PK by gefitinib causes synergism between gefitinib and cisplatin in NSCLC.

Lung cancer has the highest incidence and mortality rates among the malignant tumor types worldwide. Platinum­based chemotherapy is the main treatment for advanced non­small­cell lung cancer (NSCLC), and epidermal growth factor receptor­tyrosine kinase inhibitors (EGFR­TKIs) have greatly improved the survival of patients with EGFR­sensitive mutations. However, there is no standard therapy for treating patients who are EGFR­TKI resistant. Combining EGFR­TKIs and platinum­based chemotherapy is the most popular strategy in the clinical practice. However, the synergistic mechanism between EGFR­TKIs and platinum remains unknown. Therefore, the aim of the present study was to determine the synergistic mechanism of gefitinib (an EGFR­TKI) and cisplatin (a main platinum­based drug). MTT assay, apoptosis analysis, tumorsphere formation and an orthotropic xenograft mouse model were used to examine the combination effects of gefitinib and cisplatin on NSCLC. Co­immunoprecipitation and immunofluorescence were used to identify the underlying mechanism. It was found that gefitinib could selectively inhibit EGFR from entering the nucleus, decrease DNA­PK activity and enhance the cytotoxicity of cisplatin on NSCLC. Collectively, the results suggested that inhibition of DNA­dependent protein kinase by gefitinib may be due to the synergistic mechanism between gefitinib and cisplatin. Thus, the present study provides a novel insight into potential biomarkers for the selection of combination therapy of gefitinib and cisplatin.

Renovated filter filled with poly-3-hydroxybutyrateco-hydroxyvalerate and granular activated carbon for simultaneous removal of nitrate and PPCPs from the secondary effluent.

Reclaimed water is in huge demand in water-deficient cities. However, nitrogen, pharmaceuticals and personal care products (PPCPs) are frequent contaminants in reclaimed water that are probable to bring environmental risks. To develop a technology for safe reclaimed water production, in this study, a renovated filter that integrates solid-phase denitrification (SPD) with biodegradable polymer poly-3-hydroxybutyrate-co-hydroxyvalerate (PHBV) and granular activated carbon (GAC) adsorption (SPD-GAC filter) was proposed and applied to remove nitrogen and target PPCPs (metoprolol and diclofenac) simultaneously. The influences of different ratio of the filled PHBV and GAC, and the hydraulic retention time (HRT) on the removal performances were investigated. The results showed that the filter with PHBV/GAC = 1 (25 cm PHBV/25 cm GAC) simultaneously achieved an average NO3--N removal efficiency of about 95% with no accumulation of ammonia and nitrite, and an average removal efficiency of PPCPs of about 80%. Compared with PHBV-based SPD system, the integrated SPD-GAC filter significantly improved the control of carbon release and the PPCP removals. SPD-GAC filter also exhibited a strong tolerance for the variation of influent NO3--N loading rate, achieving a highest denitrification rate of 0.76-0.82 g N·(L·d)-1. The integrated SPD-GAC filter proves to be a promising technology for the simultaneous removal of nitrogen and PPCPs from the secondary effluent.

Is Primary Tumor Excision and Specific Metastases Sites Resection Associated With Improved Survival in Stage â £ Colorectal Cancer? Results From SEER Database Analysis.

OBJECTIVE: We aimed to explore the prognostic value of primary tumor and specific metastases excision on survival among patients with stage IV colorectal cancer (CRC) in the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Patients with stage IV CRC were selected using SEER database between 2010 and 2013. Survival rate was calculated according to the Kaplan-Meier method, and differences between curves were tested by the log-rank test. Cox proportional hazards model was used in the multivariable analysis. RESULTS: Included in this study were 27 878 patients with distant metastatic CRC. Among the single organ site of metastatic CRC, patients with solitary metastasis of lung showed the highest median overall survival (OS). Both primary and metastatic sites surgical resection for patients with liver, lung, and simultaneous liver and lung metastases had better median OS. Age younger than 65 years, Asian and Pacific Islander, distal colon and rectum, and palliative primary tumor and metastatic lesions resection were associated with better OS after multivariate analysis. Palliative primary tumor and metastatic lesions resection had a significant survival benefit compared with nonsurgical group in selected patients. CONCLUSION: These findings support the use of preemptive surgery in the management of highly selected metastatic CRC patients.

Impact of Site-Specific Metastases on Surgical Value and Survival among Metastatic Colorectal Cancer Patients.

We aimed to explore the potential prognostic impact of the metastatic site on the management approach and prognosis of stage IV colorectal cancer patients with synchronous metastases. Synchronous metastatic colorectal cancer patients reported to the Surveillance, Epidemiology, and End Results Program database between 2010 and 2013 were included in this study. Overall survival (OS) was compared between patients with different treatment options using risk-adjusted Cox proportional hazard regression models. Overall, 17,776 patients with stage IV colorectal cancer were identified. Of these patients, 2,052 (11.5%) underwent surgical resection for tumors at both the primary and metastatic sites. Patients who underwent surgical resection of both primary and metastatic sites with liver, lung, and simultaneous liver and lung metastases had a longer median OS (P < 0.001) than patients who underwent nonsurgical treatments. Cox regression analysis revealed that surgical resection of both primary and metastatic sites was associated with a significantly enhanced OS (P < 0.001). Colorectal cancer patients with hepatic or pulmonary metastases, who underwent metastasectomy, even in selected patients with both hepatic and pulmonary metastases after multidisciplinary evaluation, could have a better survival benefit than patients who underwent nonsurgical treatments.

[Comparison of Polycaprolactone and Poly-3-hydroxybutyrate-co-3-hydroxyvalerate for Nitrogen Removal].

Two types of biodegradable polymers, polycaprolactone (PCL) and poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), were used as a denitrification slow-release carbon source and a microbial carrier. By comprehensively comparing their performances in denitrification, carbon release, surface morphology, and material composition as well as their microbial community characteristics, the PHBV was determined as the better performer. It had a shorter denitrification start time, a higher denitrification rate, a lower residual organic matter concentration, and a more stable and sustained denitrification performance than PCL. This is because its surface was rough and contained large amounts of hydrophilic groups such as C-O and C=O, which is easily attached and degraded by microorganisms. As a result, the microorganisms on its surface were diverse. The dominant ones were identified with heterotrophic denitrification potentials, such as Thiothrix, Pseudomonas, Zoogloea, Flavobacterium, and Dechloromonas. Therefore, PHBV is suitable as a carbon source medium for tertiary nitrogen removal.

Trends of incidence and survival in patients with gastroenteropancreatic signet ring cell carcinoma: an analysis from the Surveillance, Epidemiology, and End Results program.

BACKGROUND: The epidemiology and clinical outcome of gastroenteropancreatic signet ring cell carcinoma (SRC) were not well illustrated. We aimed to explore the long-term epidemiology and predictors affect the overall survival (OS) of patients with SRC in gastrointestinal tract and pancreas. METHODS: Annual age-adjusted incidence, OS and survival trend of patients with gastroenteropancreatic SRC were evaluated in the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2014. Multivariate Cox hazards regression model were used to identify predictive factors of the entity disease. RESULTS: Of the 24,613 patients in the cohort, 54.0% (13,295) were male gender. The age-adjusted incidence of SRC from January 2000 to December 2014 was decreased slightly. This trend appeared across all stages, grades and all the tumor locations, excerpt for esophagus and appendix. In regard to the incidence of SRC in gastrointestinal tract and pancreas, the stomach carried a higher incidence than other sites. Different primary site, stage and grade, and age of clinical diagnosis as well as time period of diagnosis were all found to have the significant median OS by multivariable analysis. Five years' OS of gastroenteropancreatic SRC was improving gradually between 2000-2014. In subgroups stratified by tumor stages and grades, the most pronounced improvement of survival over the same interval was observed in the early-stage and well differentiation SRC. CONCLUSIONS: SRC in a heterogeneous US population tended to carry the poor prognosis with a high proportion of distant metastasis. The poor prognosis of SRC was mainly caused by high tumor stages and poor differentiation at diagnosis.

Non-functional pancreatic neuroendocrine tumours: emerging trends in incidence and mortality.

BACKGROUND: Our aim was to determine the epidemiology and recent changes in the trends of non-functional pancreatic neuroendocrine tumours (NF-pNETs) at the population level. In addition, we explored the risk factors that are associated with survival duration. METHODS: Cases were identified form the Surveillance, Epidemiology, and End Results (SEER) Programme database from 2000 to 2014. Data on incidence and incidence-based (IB) mortality for NF-pNET were obtained from this database. Secular trends in age-adjusted incidence and IB mortality were determined by using the Joinpoint Regression program. Data analyses were performed using chi-square tests, Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: Overall, 4766 patients diagnosed with NF-pNET with a median age of 59 years were identified through our descriptive criteria. Caucasian patients accounted for the majority of the study population, and the proportion of patients with distant disease significantly decreased during our study period. Overall, there was an increase in incidence and IB mortality for NF-pNET; however, the rate of increase decreased during the recent years. In addition, the incidence trends of NF-pNET located in the pancreatic head significantly increased, and rates fo increase in IB mortality for NF-pNET in the pancreatic tail decreased in recent years. Additionally, the 1-, 5-, and 10-year survival rates were 79.0, 51.8, 38.1%, respectively. Furthermore, patient age, tumour grade, stage at diagnosis, tumour size, tumour site and resection were associated with mortality. CONCLUSION: Despite increases in incidence and IB mortality, the rate of change in IB mortality for NF-pNET has decreased in recent years. Survival duration displayed a secular increase during the overall period, and the prognosis and survival duration of patients were closely related to the time of diagnosis, age of the patients and size and location of the tumour. Appropriate treatment adjustments based on tumour stage may thus facilitate improvements in patient outcomes.

Genome-Wide Profiling of Prognostic Alternative Splicing Signature in Colorectal Cancer.

Background: This study was to explore differential RNA splicing patterns and elucidate the function of the splice variants served as prognostic biomarkers in colorectal cancer (CRC). Methods: Genome-wide profiling of prognostic alternative splicing (AS) events using RNA-seq data from The Cancer Genome Atlas (TCGA) program was conducted to evaluate the roles of seven AS patterns in 330 colorectal cancer cohort. The prognostic predictors models were assessed by integrated Cox proportional hazards regression. Based on the correlations between survival associated AS events and splicing factors, splicing networks were built. Results: A total of 2,158 survival associated AS events in CRC were identified. Interestingly, most of these top 20 survival associated AS events were adverse prognostic factors. The prognostic models were built by each type of splicing patterns, performing well for risk stratification in CRC patients. The area under curve (AUC) of receiver operating characteristic (ROC) for the combined prognostic predictors model could reach 0.963. Splicing network also suggested distinguished correlation between the expression of splicing factors and AS events in CRC patients. Conclusion: The ideal prognostic predictors model for risk stratification in CRC patients was constructed by differential splicing patterns of 13 genes. Our findings enriched knowledge about differential RNA splicing patterns and the regulation of splicing, providing generous biomarker candidates and potential targets for the treatment of CRC.

Trends of incidence and survival in patients with gastrointestinal mucinous adenocarcinoma.

The epidemiology and clinical outcome of gastrointestinal mucinous adenocarcinoma (MA) are not well illustrated. The present study aimed to explore the evolving epidemiology and prognostic factors that affect the survival of patients with MA in the gastrointestinal tract. A retrospective and population-based study was conducted to determine the annual age-adjusted incidence, overall survival (OS) and survival trend of gastrointestinal mucinous MA using nationally representative data from the Surveillance, Epidemiology, and End Results (SEER) program between 2000 and 2014. A Kaplan-Meier curve and a Cox proportional regression model were used to evaluate prognostic factors for this disease. Of the 51632 cases, females accounted for 50.5% (26058). The annual incidence of MA steadily decreased from 2000 to 2014. This trend occurred across all stages, grades and sites, apart from the appendix. In the SEER 18 registry grouping (2000-2014), the highest incidence was 3.333 per 100,000 persons for the colon. The median OS varied significantly between different primary sites, stages, grades, and age of clinical diagnosis, and the time period of diagnosis, according to a multivariable analysis. The five-year OS of gastrointestinal MA improved gradually between 2000 and 2014. The improvement in survival over the same interval was more pronounced in the subgroup of distant gastrointestinal MA. All sites along the alimentary tract, with the exception of the appendix, showed a decrease in the incidence of MA. Improved survival rates were observed for most of the gastrointestinal tract, especially for patients with advanced stage disease. MA in the upper gastrointestinal tract was less frequent but had poorer survival than colorectal MA. Clinicians should consider the primary tumour site when making therapeutic guidelines and treatment decisions for gastrointestinal MA.

TNM Staging of Colorectal Cancer Should be Reconsidered According to Weighting of the T Stage: Verification Based on a 25-Year Follow-Up.

The gradient monotonicity of existing tumor, node, metastases staging systems for colorectal cancer is unsatisfactory. Our proposed T-plus staging system strengthens weighting of the T stage. In this study, applicability of the T-plus staging system was verified with data of a Chinese colorectal cancer center.Records of 2080 nonmetastatic, advanced cancer patients undergoing colorectal cancer surgery from 1985 to 2011 were reviewed for T, N stage pathology and follow-up information. Using overall and disease-specific survival data, the 7th edition tumor, node, metastases staging system and the T-plus staging system were compared for stage homogeneity and discrimination and gradient monotonicity.For gradient monotonicity, the T-plus staging system was superior for both colon and rectal cancer. With Kaplan-Meier survival curves, the T-plus staging system discriminated among different stages, and the corresponding survival was inversely associated with the stage. However, for the 7th edition tumor, node, metastases staging system, stage IIIa had a better prognosis than stage II for rectal cancer and stage I for colon cancer. For homogeneity within the same stage and discrimination between different stages, the 2 staging systems were similar for colorectal cancer, but the T-plus system was clearly better for colon cancer.The T-plus staging system provides good gradient monotonicity. For future colorectal cancer staging systems, we propose replacement of lymph node status as the criterion to discriminate colorectal cancer stage II and stage III with greater weighting of the T stage.

Clinicopathologic distribution of KRAS and BRAF mutations in a Chinese population with colorectal cancer precursor lesions.

Investigating the clinical features and corresponding histomorphologic and molecular profiles of precursor lesions of colorectal cancer in a natural population provides new insights into the nature of colorectal cancer, uncovers new screening markers and establishes new prevention strategies for colorectal cancer. In this study, 4302 patients with at least one colorectal polyp from a large colorectal cancer screening program were evaluated and genetic mutations in either KRAS or BRAF were detected in 495 patients. The population-based mutation rates of KRAS and BRAF genes in colorectal polyps within this Chinese patient population were 21.8% and 12.1% respectively. Interestingly, considerable variability in the KRAS and BRAF mutations rates were found among different types of polyps. In a multivariate analysis, presence of villous histology and high-grade dysplasia was associated with KRAS mutations (OR, 3.0; 95% CI, 1.7-5.4 and OR, 3.5; 95% CI 1.9-6.5, respectively), while serrated adenomas and hyperplastic polyps were associated with BRAF V600E mutations (OR, 20.6; 95% CI, 8.2-51.8 and OR, 11.9; 95% CI 4.9-29.0, respectively). KRAS mutations may, in part, drive the histologic progression of adenomas toward a villous histology and higher grades of dysplasia. Mutant BRAF may, in part, drive the histologic progression of adenomas toward serrated histology. Dysplasia may arise from hyperplastic polyps, resulting in the formation of serrated adenomas and potentially the development of colorectal carcinoma.

Young patients (≤ 35 years old) with colorectal cancer have worse outcomes due to more advanced disease: a 30-year retrospective review.

An appropriate cutoff of age and the impact of age on colorectal cancer outcomes remain unclear and need to be explored, particularly in China.In total, 2460 colorectal cancer patients were studied retrospectively. All patients were divided into 6 groups according to their ages at the time of diagnosis: ≤ 30, 31 to 35, 36 to 40, 41 to 45, 46 to 50, and ≥ 50 years. A suitable cutoff age for defining young adult colorectal cancer was explored according to the distribution of survival in each group. Clinical characteristics and prognosis between the young adult group and the older group were then compared.According to the survival curves for each group, 35 years old was considered a suitable cutoff age for defining young adult colorectal cancer. There were 140 (5.7%) and 2320 (94.3%) cases in the young adult and older groups, respectively. The proportion of stage III-IV tumors was significantly higher in the young adult group (69.3%) than in the older group (46.4%) (P  =  0.000). The univariate analysis showed that the 5-year overall survival (OS) rate and the 10-year OS rate in the young adult group were 48.9% and 38.6%, respectively, whereas in the older group, they were 63.6% and 56.9%, respectively. The young adult group had a worse prognosis (P  =  0.000). The multivariate analysis showed that age was not an independent prognostic factor (relative risk 0.787, P  =  0.062). After adjusting for tumor stage, the hazard proportion of death in the young adult group increased by 27.6%, but this difference was not significant (P  =  0.053). Stratified analyses showed that the young adults with stage IV tumors had a worse survival rate (P  =  0.046).Patients ≤ 35 years who were diagnosed with colorectal cancer had a worse prognosis because of a higher proportion of advanced stage tumors. When stage-to-stage analysis was performed, it was found that young adult colorectal cancer patients had a worse outcome only if they had stage IV tumors.

Feasibility and accuracy of sentinel lymph node biopsy in clinically node-positive breast cancer after neoadjuvant chemotherapy: a meta-analysis.

Sentinel lymph node biopsy (SLNB) has replaced conventional axillary lymph node dissection (ALND) in axillary node-negative breast cancer patients. However, the use of SLNB remains controversial in patients after neoadjuvant chemotherapy (NAC). The aim of this review is to evaluate the feasibility and accuracy of SLNB after NAC in clinically node-positive patients. Systematic searches were performed in the PubMed, Embase, and Cochrane Library databases from 1993 to December 2013 for studies on node-positive breast cancer patients who underwent SLNB after NAC followed by ALND. Of 436 identified studies, 15 were included in this review, with a total of 2,471 patients. The pooled identification rate (IR) of SLNB was 89% [95% confidence interval (CI) 85-93%], and the false negative rate (FNR) of SLNB was 14% (95% CI 10-17%). The heterogeneity of FNR was analyzed by meta-regression, and the results revealed that immunohistochemistry (IHC) staining may represent an independent factor (P = 0.04). FNR was lower in the IHC combined with hematoxylin and eosin (H&E) staining subgroup than in the H&E staining alone subgroup, with values of 8.7% versus 16.0%, respectively (P = 0.001). Thus, SLNB was feasible after NAC in node-positive breast cancer patients. In addition, the IR of SLNB was respectable, although the FNR of SLNB was poor and requires further improvement. These findings indicate that IHC may improve the accuracy of SLNB.

Neuroendocrine differentiation is a prognostic factor for stage II poorly differentiated colorectal cancer.

Neuroendocrine differentiation (NED) in colorectal cancer is an indistinct phenomenon and may define a new cancer subtype, especially in the poorly differentiated colorectal cancer (PDCRC). The clinical features of PDCRC with NED remain controversial, thus confusing the implementation of individualized treatment. This study included 171 patients who underwent surgery from 2000 to 2011 and had pathology-confirmed PDCRC. Each sample was examined by immunohistochemistry for the biological markers of NED, synaptophysin (Syn), and chromogranin (CgA). Patients with Syn(+) and/or CgA(+) cells were classified as NED(+); otherwise, they were NED(-). Data were collected for patients who were followed up for at least two years. NED(+) staining was present in 71 (41.5%) patients. The median survival time was 36.9 months. No survival differences existed between the NED(-) and NED(+) groups (P > 0.05). However, stage II NED(+) patients had a significantly worse prognosis than NED(-) patients (P = 0.018). For the NED(+) group, the median survival was 38.56 months, and the 5-year survival was 65%. For the NED(-) group, the median survival was 53.18 months, and the 5-year survival was 90%. NED is a common event in primary PDCRC. For stage II PDCRC, NED(+) indicates a poor prognosis.

Cancer-associated fibroblasts from invasive breast cancer have an attenuated capacity to secrete collagens.

Normal fibroblasts produce extracellular matrix (ECM) components that form the structural framework of tissues. Cancer-associated fibroblasts (CAFs) with an activated phenotype mainly contribute to ECM deposition and construction of cancer masses. However, the stroma of breast cancer tissues has been shown to be more complicated, and the mechanisms through which CAFs influence ECM deposition remain elusive. In this study, we found that the activated fibroblast marker α-smooth muscle actin (α-SMA) was only present in the stroma of breast cancer tissue, and the CAFs isolated from invasive breast cancer sample remained to be activated and proliferative in passages. To further assess the difference between CAFs and normal breast fibroblasts (NFs), MALDI TOF/TOF­MS was used to analyze the secretory proteins of primary CAFs and NFs. In total, 2,903 and 3,023 proteins were identified. Mass spectrum quantitative assay and data analysis for extracellular proteins indicated that the CAFs produce less collagens and matrix-degrading enzymes compared with NFs. This finding was confirmed by western blot analysis. Furthermore, we discovered that reduced collagen deposition was present in the stroma of invasive breast cancer. These studies showed that although CAFs from invasive breast cancer possess an activated phenotype, they secreted less collagen and induced less ECM deposition in cancer stroma. In cancer tissue, the remodeling of stromal structure and tumor microenvironment might, therefore, be attributed to the biological changes in CAFs including their protein expression profile.

Clinical characteristics and prognosis of young patients with colorectal cancer in Eastern China.

AIM: To explore the clinical characteristics and prognosis of young patients with colorectal cancer patients in Eastern China. METHODS: A total of 1335 patients with colorectal cancer treated from December 1985 to December 2005 at the Second Affiliated Hospital of Zhejiang University School of Medicine were studied retrospectively. The patients were divided into two groups, a younger group (aged ≤ 30 years) and an older group (aged > 30 years), and comparison was made in the clinical characteristics and prognosis between the two groups. Chi-square test was used for data analysis of all categorical variables, and overall survival (OS) was calculated by the Kaplan-Meier method. A multivariate analysis was performed using the Cox model. RESULTS: There were 42 (3.1%) and 1293 (96.9%) cases in the younger group and older group, respectively. Univariate analysis showed that the 5- and 10-year OS in the younger group were 33.9% and 26.1%, respectively, and those in the older group were 60.1% and 52.2%, respectively. Younger group had poor survival (χ(2) = 14.146, P = 0.000). Multivariate analysis revealed that age was not a dependent factor for prognosis (OR = 0.866, 95%CI: 0.592-1.269, P = 0.461). Stratified analysis indicated that in stage III and IV disease, the 5- and 10-year OS were 24.6% and 14.8% in the younger group, and 40.4% and 33.3% in the older group, respectively, with a significant difference between the two groups (χ(2) = 5.101, P = 0.024). In the subgroup of radical surgery, the 5- and 10-year OS were 44.3% and 34.2% in the younger group, and 69.6% and 60.5% in the older group, with a difference being significant between the two groups (χ(2) = 7.830, P = 0.005). CONCLUSION: Compared with older patients, the younger patients have lower survival, especially in the subgroups of stage III and IV disease and radical surgery.