Objective The aim of this study was to evaluate the compliance of breast cancer screening among high-risk population in Chinese cities and analyze its related factors. Methods The data of 399,869 high-risk breast cancer patients in the urban cancer early diagnosis and treatment project carried out in 20 provinces in China from 2013 to 2018 were used for data analysis.All participants who met the research conditions of the Urban Cancer Early Diagnosis and Treatment Project were received a risk assessment questionnaire to assess the risk of cancer,and it was recommended that people whose assessment results were at high risk of breast cancer undergo corresponding screening(breast ultrasound and/or mammography).Chi-square tests were used to compare the differences in breast cancer screening participation rates among groups of different characteristics;Multivariate logistic regression models were used to explore the potential factors related to breast cancer screening participation rates. Results Among the 399,869 high-risk groups of breast cancer,221,268 participants received breast cancer screening,with a participation rate of 55.3%.According to the regional classification standards of the National Bureau of Statistics,breast cancer screening in the eastern China(55.7%,81,999/147,209),central(59.9%,76,368/127,594),and western(50.3%,62,901/125,066)regions.The participation rates were significant difference(χ²=2347.3,P＜0.001).The results of multivariate logistic regression analyses showed that 50~59 years old,still smoking,and currently quit smoking,an education with high school degree or above,secondhand smoke exposure,menopausal,reproductive history,a history of benign breast diseases,family history of breast or ovarian cancer were more likely to accept breast cancer screening.High-risk populations who were 60~74 years old,ethnic minorities,often participate in physical exercise,and had a history of breastfeeding were less likely to receive breast cancer screening. Conclusion The overall participation rate of screening of high-risk breast cancer populations in 20 provinces in China is low.Age,education,Ethnicity smoking,exposure to second-hand smoke physical activity,menopause,history of childbirth,breastfeeding history,benign breast disease,family history of breast or ovarian cancer are important factors related to breast cancer screening compliance.

Objective The objective of this study was to analyze the screening status of the urban cancer early diagnosis and treatment project in Hubei province from 2018 to 2019. Methods The evaluation data and clinical screening data of the urban cancer early diagnosis and treatment project in Hubei province from 2018 to 2019 were summarized,the high-risk rate,population screening participation rate and positive detection of various cancers were analyzed. Results A total of 39,575 people were assessed from 2018 to 2019,and the overall high risk rate was 47.31%.The high risk rates of various cancer types were lung cancer(21.10%),female breast cancer(19.01%),esophagus cancer(9.60%),gastric cancer(13.76%),liver cancer(11.22%),and colorectal cancer(17.38%).The detection rates of positive lesions were lung(6.13%),female breast(20.04%),liver(6.38%),upper gastrointestinal tract(0.42%),and colorectum(5.02%). Conclusion The combined screening mode of the urban cancer early diagnosis and treatment project will help reduce the incidence and mortality of malignant tumors in the long run.In order to improve the screening effect of the project,it is necessary to further increase the population's awareness of cancer prevention and enhance the screening compliance of the 50~64 age group.

Objective The aim of this study was to understand the impact of the coronavirus disease(COVID-19)pandemic on the early diagnosis and treatment project for cancer in Beijing,and to explore management strategies for related work under the new normal of epidemic prevention and control. Methods Based on the 2018-2019 Beijing Urban Cancer Early Diagnosis and Treatment Project,cluster sampling was used to recruit Beijing registered residents aged 40 to 74 years old from 6 urban areas in Beijing to conduct a cancer risk assessment questionnaire survey.Subjects relevant clinical examinations were performed in designated hospitals.Among them,Project Year 2018 corresponded to November 23,2018-November 22,2019(before the pandemic),and Project Year 2019 corresponded to November 23,2019-December 23,2020(during the pandemic).The Chi-square test was used to compare differences in the questionnaires evaluation,clinical examination,result entry,and the compliance with clinical examinations in various districts and cancer species before and during the pandemic. Results Overall,21,026 and 6,663 residents were included in the study in Project Year 2018 and 2019,respectively.Compared with the rates in Project Year 2018,the completion rate of questionnaire evaluation decreased from 100.1% to 60.4%,the completion rate of clinical examination tasks decreased from 101.4% to 57.5%,and the result entry rate decreased from 99.2% to 88.2%,and the participation rate in the examination decreased from 87.3% to 80.8% in project Year 2019.All rates,differences mentioned above were statistically significant differences(P＜0.001). Conclusion The coronavirus disease(COVID-19)pandemic has a greater impact on the Beijing Urban Cancer Early Diagnosis and Treatment Project.In the future,efforts should be made to change the work model of cancer prevention and control in the context of normalized response to the pandemic,so that epidemic prevention and control may go hand in hand with the chronic diseases management.

Objective The objective of this study was to evaluate the compliance of breast cancer screening among high-risk population in urban areas of Henan province from 2013 to 2019 and explore possible influencing factors. Methods The urban residents aged 40~74 years old in Henan province were selected for cancer risk factor survey and breast cancer risk assessment.For people at high risk of breast cancer,breast ultrasound examination was performed for those aged 40~45 years old,and breast ultrasound combined with X-ray photography(molybdenum target)examination for those over 45 years old.The participation rate of breast cancer screening among people with different characteristics was compared and further analyzed its influencing factors. Results A total of 29,111 cases of breast cancer high-risk population that met the research requirements were included in the study,of which 13,760 cases were screened for breast cancer,and the overall participation rate was 47.27%.There were significant regional and time differences in the participation rate of breast cancer screening:the participation rates in the highest and lowest cities were 74.24% and 40.00%,respectively;the overall screening participation rate from 2013 to 2014 was the lowest 40.66% and the highest 51.05% from 2017 to 2018.The multivariate logistic regression analyses suggested:45~64 years old,with junior high school degree or above,smoking or smoking in the past,drinking or drinking in the past,lack of physical exercise,menarche age ＜12 years,menopause,history of fertility,history of benign breast disease,a family history of breast cancer,and a family history of ovarian cancer were more willing to accept breast cancer screening. Conclusion The overall participation rate of breast cancer screening among high-risk population of urban breast cancer in Henan province is less than 48%.The measures should be taken for specific populations to improve the overall compliance of breast cancer screening in the future.

Objective Esophageal cancer is one of the most common malignant tumors of the digestive tract,and Hebei province is located in the high-incidence area of esophageal cancer.This study aims to analyze the latest epidemic trends and characteristics of esophageal cancer in Hebei province from 2011 to 2016. Methods Statistical analysis was performed on the incidence and death data of esophageal cancer in 27 tumor registries of Hebei province.The incidence and mortality were analyzed by urban and rural,gender,and age group.The age-standardized rate was calculated using China′s 2000 census population and Segi′s World population.The grey model was used to predict the mortality of Cixian and Shexian,where were high-incidence areas. Results A total of 14,905 cases of esophageal cancer and 9,933 deaths of esophageal cancer from 2011 to 2016 were reported in Hebei province.The crude incidence was 21.73/100,000 and the mortality was 14.48/100,000.The incidence and mortality of esophageal cancer were both higher in men than those in women,and higher in rural areas than those in urban areas.The incidence and mortality of esophageal cancer in Hebei province had a downward trend(P＜0.001).The incidence and mortality in the high-incidence areas of Cixian and Shexian showed a long-term downward trend.It was predicted that the mortality of esophageal cancer would continue to decline in the next ten years. Conclusion The incidence and mortality of esophageal cancer in Hebei province are steadily declining,but the disease burden is still heavy.The primary prevention,early detection and early treatment of esophageal cancer should pay more attention to rural residents and male population.

Objective The aim of this study was to analyze the current status of incidence and mortality of brain tumors in 2015 and the trend of changes from 2006 to 2015 in Jiangsu province. Methods The data year 2015 from 35 cancer registries collected and quality-controlled from Jiangsu provincial center for disease control and prevention in 2018 were used and data of brain tumor were extracted to calculate the incidence(mortality)of urban and rural,gender and age groups,and the Chinese population standard estimating the incidence and mortality of brain tumors in the province based on indicators such as the conversion rate(abbreviated as Chinese standard rate),the World population standardized rate(abbreviated as the World standard rate),the cumulative incidence or mortality(0~74 years old)and other indicators.Combined with the demographic data,the incidence and mortality of brain tumors in the whole province were estimated.The province′s tumor registration data from 2006 to 2015 were summarized,sorted out,and calculated the average annual change percentage(AAPC)of the standardized incidence and mortality in the past 10 years by Joinpoint software. Results In 2015,the province′s cancer registry covered a total of 38,761,144 people(15,168,594 people in urban areas,and 23,592,550 people in rural areas).The mortality to incidence ratio of brain tumors was 0.67,proportion of morphological cerification was 41.42%,and proportion of death cerification only was 1.46%.It is estimated that the number of new cases of brain tumors in the province was 5,452,the crude incidence was 7.16/100,000,the Chinese standard rate was 4.79/100,000,the World standard rate was 4.79/100,000,and the cumulative incidence of 0~74 years old was 0.51%.It is estimated that there were 2,446 new cases of brain tumors in urban areas,and the Chinese standard rate was 4.99/100,000;the estimated new cases of brain tumors in rural areas are 3 006,and the Chinese standard rate was 4.65/100,000.The province′s estimated brain tumor deaths were 3,626 cases,the crude mortality was 4.76/100,000,the Chinese standard rate was 3.09/100,000,the World standard rate was 3.13/100,000,and the cumulative mortality rate between 0 and 74 years old was 0.32%.There were 1,429 deaths from brain tumors in urban areas,and the Chinese standard rate was 2.86/100,000;there were 2,197 deaths from brain tumors in rural areas,and the Chinese standard rate was 3.27/100,000.The Chinese standard rate of brain tumor incidence in urban areas and women showed a significant upward trend,with an average annual increase of 1.918% and 3.149%.The Chinese standard rate of brain tumor mortality in rural areas as a whole and in women showed a significant downward trend,with an average annual decrease of 1.587% and 1.882%. Conclusion Brain tumors are common malignant tumors in my country,and early screening,prevention and control of brain tumors should be strengthened.

Objective The objective of this study was to analyze the incidence and death of upper gastrointestinal cancer in the cancer registration areas of Shanxi province in 2016,and to provide evidence for prevention and control of upper gastrointestinal cancer. Methods The cancer registration data reported by 12 tumor registration areas of Shanxi in 2016 were sorted out and stratified by urban and rural areas and gender.The number of cases and deaths,the crude incidence and mortality,the cumulative rate(0~74 years old),age-specific incidence and mortality were calculated.The incidence and mortality were standardized by the 2000 China Census standard population composition(ASR China)and Segi′s World standard population composition(ASR World). Results In 2016,there were 2 940 new cases of upper gastrointestinal cancer and 2,135 deaths in the cancer registration areas of Shanxi province.The crude incidence of upper gastrointestinal cancer was 60.13/100,000(80.53/100,000 in male and 38.97/100,000 in female;39.38/100,000 in urban areas and 74.17/100,000 in rural areas),the population standardization rate in China was 41.91/100,000,the population standardization rate in World was 42.97/100,000,and the cumulative incidence rate for 0~74 years old was 5.61/100,000.The crude rate of death from upper gastrointestinal cancer of Shanxi in 2016 was 43.67/100,000(58.56/100,000 in males and 28.21/100,000 in females;31.67/100,000 in urban areas and 51.78/100,000 in rural areas),the standardized mortality rate in China was 29.94/100,000,the standardized mortality rate in World was 30.52/100,000,the cumulative mortality rate of 0~74 years old was 3.62/100,000.Overall,incidence and mortality of upper gastrointestinal cancer in rural areas were higher than those in urban areas.The incidence and mortality of upper gastrointestinal cancer in males were higher than females.After 40 years old,the incidence of upper gastrointestinal cancer was on the rise.The incidence peaks in the 80-year-old age group were in urban areas and 65-year-old in rural areas.The mortality of upper gastrointestinal cancer was at a low level before the 45-year-old age group,and then gradually increased with increasing age,and peaked in the 85+ years old age group. Conclusion Upper gastrointestinal cancer is the most common malignant tumor that threatens the health of residents in Shanxi province.Male population,people in rural areas,middle-aged and elderly population are the focus of cancer prevention and control in Shanxi province.Upper digestion cancer should be carried out in a targeted manner of cancer prevention and treatment work according to urban-rural and gender differences.

Objective The objective of this study was to investigate the morbidity,mortality characteristics and prevalence trends of lung cancer in the tumor registration areas of Yunnan province from 2011 to 2016,and to provide suggestion for the prevention and treatment of lung cancer. Methods The incidence and death cases of lung cancer in the tumor registration areas of Yunnan province from 2011 to 2016 were collected and sorted out.The incidence,mortality,standardized incidence,standardized mortality,the cut-off rate,the cumulative rate(0-74 years old),and annual percentage of trend change(annual percentage change,APC)of lung cancer were analyzed. Results The crude incidence of lung cancer in Yunnan cancer registration areas from 2011 to 2016 was 42.05/100,000,the China standard rate was 28.38/100,000,the World standard rate was 28.21/100,000,the cumulative rate(0~74 years old)was 3.48%,and the truncated age-standardized rate was 55.38/100,000.The male incidence was 58.52/100,000,the China standard rate was 40.53/100,000,and the female incidence was 25.11/100,000,the China standard rate was 16.62/100,000.The incidence in urban areas was 44.14/100,000,the China standard rate was 28.11/100,000,and the incidence in urban area was 39.40/100,000,the China standard rate was 29.02/100,000.The mortality of lung cancer in Yunnan cancer registration areas from 2011 to 2016 was 33.16/100,000,the China standard rate was 28.33/100,000,the World standard rate was 21.64/100,000,the cumulative rate(0~74 years old)was 2.61%,and the truncated age-standardized rate was 38.96/100,000.The male mortality was 47.47/100,000,the China standard rate was 32.32/100,000.The female mortality was 18.44/100,000,the China standard rate was 11.71/100,000.The mortality in urban areas was 34.54/100,000,the China standard rate was 21.28/100,000,and the mortality in rural areas was 31.47/100,000,the China standard rate was 22.81/100,000.The age-specific incidence and mortality rate were at a low level in the 0-34 years old group,and increased rapidly after 35-years old group.There was no statistical significant difference between the total number of lung cancer and the trend of incidence in urban areas and rural areas from 2011 to 2016(P＞0.05),but the annual percent change in incidence of lung cancer among women in rural areas was 10.6%,and the annual percent change in standardized incidence was 9.8%.The crude incidence and standardized incidence of women in rural areas showed an upward trend(P＜0.05). Conclusion The incidence and mortality of lung cancer in Yunnan cancer registration areas from 2011 to 2016 were generally lower than that in the national and the western regions,and the annual change in incidence and mortality of rural women showed an upward trend.It is recommended to continue to expand the coverage of early diagnosis and treatment of lung cancer,and actively carry out tobacco control activities.

Objective The aim of this study was to analyze 10 years survival status of gastric cancer and its influencing factors in three cities of Liaoning province. Methods Four hundred cases of gastric cancer randomly selected from the tumor incidence report database in three cities of Liaoning province from 2000 to 2002 were actively followed up to obtain the diagnosis,treatment and survival status of the patients.The life table method was used to calculate the observed survival rate(OSR),and the Ederer II method was used to calculate the relative survival rate(RSR).The multivariate Cox model was used to analyze the factors affecting survival. Results The 10-year OSR,RSR and T₅₀ of gastric cancer in the three cities of Liaoning province were 14.3%,19.1%,and 12.3 months,respectively.The 10-year OSR,RSR and T₅₀(41.6%,53.7% and 69.0 months)of stage Ⅰ~Ⅱ cases were significantly higher than those of stage Ⅲ(9.1%,14.1% and 14.7 months)and stage Ⅳ(3.0%,4.1% and 6.1 months).The 10-year OSR,RSR and T₅₀(20.8%,27.7% and 20.8 months)of patients treated with surgery were significantly higher than those of non-operative cases(2.6%,3.9% and 4.9 months).The 10-year OSR,RSR and T₅₀(21.1%,23.2% and 14.0 months)in the 0~64 years old group were significantly higher than those in the 65+ years old group(8.9%,15.7% and 10.4 months).There were no significant differences in the 10-year OSR,RSR and T₅₀ between males and females.The results of multivariate analysis showed that diagnosis staging,treatment methods and age had significant impact on the 10-year relative survival rate of gastric cancer. Conclusion The 10-year relative survival rate of gastric cancer(19.1%)in three cities of Liaoning province was lower than that of Europe and America(25.4%~30.7%)and Korea(48.7%)in the same period.The low rate of early diagnosis and standardized diagnosis and treatment may be the main reasons.

Objective The objective of this study was to analyze the incidence and mortality of cancer in the cancer registration areas of Hainan province in 2016,and provide a basis for cancer prevention and control. Methods The data on incidence and mortality and population data in 6 cancer registration areas that met the quality control requirements were collected through the China Cancer Registry Platform.According to the classification of urban and rural areas,gender,and age,the incidence(mortality),the age-standardized incidence(mortality)by Chinese standard population(ASR China),the age-standardized incidence(mortality)by World Segi′s standard population(ASR World),the composition ratio,and cumulative incidence(mortality)rate between 0 and 74 years old,and the top ten cancer incidence and mortality were calculated in Hainan province. Results In 2016,the number of new cases of malignant tumors in Hainan province was 5,569,the incidence was 269.64/100,000(313.59/100,000 for males and 221.11/100,000 for females),Chinese standard population was 227.27/100,000,and the World segi′s standard population was 221.26/100,000,the cumulative incidence rate of 0~74 years old was 25.54%.The cancer with the highest incidence was liver cancer,followed by lung cancer,colorectal cancer,gastric cancer,and breast cancer.The number of death from malignant tumors was 2,651,the mortality was 128.36/100,000(173.73/100,000 for males and 78.25/100,000 for females),Chinese standard population was 105.96/100,000,and the World segi′s standard population was 104.69/100,000,and the cumulative mortality rate of 0~74 years old was 12.14%.The cancer with the highest mortality was liver cancer,followed by lung cancer,gastric cancer,colorectal cancer,and esophagus cancer. Conclusion There is a heavy burden of cancer in Hainan province in 2016,and there are significant differences between urban and rural areas and between men and women.Liver cancer ranks first in the incidence and death of cancer in Hainan province.We should focus on the prevention and treatment of cancer and carry out relevant prevention and treatment measures according to its risk factors.

Objective The objective of this study was to analyze the morbidity and mortality of esophageal cancer in 2016 and the prevalence trend from 2012 to 2016 in Inner Mongolia cancer registration areas. Methods The data of esophageal cancer in Inner Mongolia cancer registration areas from 2012 to 2016 were collected.According to the stratification of urban and rural areas,gender,age,the incidence and mortality,standardized rate,cumulative rate,age-specific rate,and annual percentage change(APC)of esophageal cancer were calculated. Results In 2016,a total of 1,311 new cases and 791 deaths of esophageal cancer were reported in Inner Mongolia cancer registration areas.The crude incidence of esophageal cancer was 19.06/100,000,the age-standardized incidence rate by Chinese standard population(ASIRC)was 13.32/100,000,the age-standardized incidence rate by World standard population(ASIRW)was 13.66/100,000,and the cumulative rate(0~74 years old)was 1.65%.The mortality of esophageal cancer was 13.71/100,000,the age-standardized mortality rate by Chinese standard population(ASMRC)was 9.33/100,000,the age-standardized mortality rate by World standard population(ASMRW)was 9.55/100,000,and the cumulative incidence rate(0~74 years old)was 1.14%.In terms of time trends,the incidence and mortality of esophageal cancer changed steadily,with a slight downward trend.The APC was-0.42% and-0.46%,respectively,and the change trend was not statistically significant(P＞0.05). Conclusion The morbidity and mortality of esophageal cancer in Inner Mongolia cancer registration areas are higher than the national average,and prevention and control measures such as health education and early screening of the population should be further strengthened.

Objective The objective of this study was to explore the correlation between the expression of LAYN gene in thyroid cancer tissues and clinical prognosis,and its influence on infiltration of immune cell,so as to provide a basis for further research on potential molecular mechanism. Methods The genes related to thyroid cancer were collected from Oncomine and GEPIA databases,and analyzed the differences of the expression of LAYN gene between thyroid cancer tissues and normal tissues.The GEPIA database was used to analyze the correlation between the LAYN gene and the clinical stage,and prognosis of patients with thyroid cancer.The combination of ImmucellAI and TIMER2.0 tools was used to analyze the relationship between the LAYN gene and CD4⁺T cells and CD8⁺T cells infiltration abundance in thyroid cancer tissues.Combination with the STRING database was used to analyze the LAYN expression related proteins.Real-time fluorescent quantitative PCR(RT-qPCR)was used to further verify and detect the expression of LAYN in thyroid cancer tissues and adjacent tissues,thyroid cancer cell lines SW579,TPC-1 and thyroid epithelial TEC cells. Results The results of Oncomine,GEPIA and STRING database showed that compared with normal thyroid tissues,LAYN gene was low expressed in thyroid cancer tissues(P＜0.05).The LAYN gene was related to the clinical TNM staging of thyroid cancer(P＜0.05),and the LAYN gene was low expressed in tumor issues of patients with stage Ⅲ/Ⅳ.The overall survival(OS)of patients in the high expression of LAYN gene group was poor,while the disease free survival(DFS)was better(P＜0.05).In thyroid cancer tissues,the infiltration abundance of CD4⁺T cells and CD8⁺T cells was low,and the infiltration abundance of CD4⁺T cells and CD8⁺T cells was positive correlation with the expression of LAYN gene(P＜0.05).In addition,the proteins related to the expression of LAYN were PNRC1,MAGEH1,HAPLN1,SMOC1,PRSS12,HMMR,NF2,TLN2,TLN1 and TLE2.The verification results of RT-PCR showed that LAYN was low expressed in thyroid cancer and thyroid cancer SW579 and TPC-1 cell lines(P＜0.05). Conclusion The LAYN gene is low expressed in thyroid cancer tissues,and it is related to the clinical TNM staging and prognosis of patients with thyroid cancer.It can be used as a molecular marker for prognostic judgment.The underlying mechanism of this gene may play a role in affecting the abundance of infiltrating immune cells.This study provides a theoretical basis for studying the pathogenesis of thyroid cancer and the development of targeted drugs.

“Drug reuse” or “drug relocation” is a hot topic in the field of oncology.It refers to finding a marketed drug with anticancer activity that is not a cancer indication,and combining it with conventional cancer treatments with a view to bringing survival benefits to patients.Simvastatin is commonly used clinically to treat hyperlipidemia and prevent cardiovascular diseases.Many studies have found that simvastatin has great potential for the treatment of colorectal cancer.Many clinical studies have tried to use simvastatin as an adjuvant drug for the treatment of metastatic colorectal cancer.

Programmed cell death protein-1(PD-1)plays a negative role in regulating immune response by interacting with programmed cell death protein ligand-1(PD-L1),which promotes tumor cell immune escape.Immunotherapy targeting PD-1/PD-L1 has become a new model of tumor therapy.At present,surgery and radiotherapy and chemotherapy are still the main treatment for colorectal cancer,but the survival rate has not been significantly improved.Studies have shown that PD-1/PD-L1 inhibitors alone or combined with radiotherapy,chemotherapy and surgery have achieved considerable results in colorectal cancer,and related clinical trials are ongoing.This article reviews the molecular biological mechanism of PD-1/PD-L1 signaling pathway and the relationship between the expression of PD-L1 and the chemoradiotherapy and prognosis of colorectal cancer,and introduces the clinical research progress of PD-1/PD-L1 inhibitors in colorectal cancer.

Androgen deprivation therapy(ADT)has always been a representative therapy for advanced prostate cancer.When prostate cancer progresses to castration resistant prostate cancer(CRPC),ADT resistance also emerges.Currently,docetaxel is the first cytotoxic chemotherapy drug approved for CRPC.In addition,abiraterone,enzalutamide and other drugs have also been approved by FDA,and these drugs have shown good survival benefits.In this article,we reviewed the clinical trials and survival benefits of these therapies,and discussed emerging drugs in this field.This review will describe the current status of CRPC drug treatment and provide references for clinical medication.

Lung squamous cell carcinoma accounts for 20%~30% of lung cancer,causing about 400,000 deaths worldwide every year.The prognosis of patients with lung squamous cell carcinoma is poor,because patients often have advanced to advanced stage when they are diagnosed.There are many factors that affect the prognosis of lung squamous cell carcinoma,such as gender and smoking.This study reviewed the effects of own factors(smoking status,gender,age,BMI and complications),tumor factors(subsites and metastasis status)and treatment factors on the prognosis of lung squamous cell carcinoma.

The occurrence,development and invasion of tumors are closely related to epigenetic changes.5-Methylcytosine(5-mC),a product of cytosine methylation,is an important epigenetic regulator.Hydroxymethylation is one of the important processes of 5-mC demethylation,and its product 5-hydroxymethylcytosine(5-hmC)is also involved in the epigenetic regulation of genes.Multiple studies at domestic and foreign suggest that the changes of 5-hmC level and distribution are closely related to embryonic development and tumorigenesis.This article reviews the research progress of 5-hmC and its abnormality in tumor and its relationship with tumor.