Study Of Intestinal Flora Differences Between Small Cell Lung Cancer Patients And Healthy People

Research Background and Objective: Small Cell Lung Cancer(SCLC)accounts for approximately 14% of lung cancer.It is a highly invasive tumor.SCLC is characterized by high growth fraction,a rapid doubling time,and easy to develop widespread metastases.SCLC has poor prognosis.Most patients were diagnosed at the stage of extensive disease(ED).SCLC is highly sensitive to initial radiotherapy and chemotherapy.The objective response rate is high in the near future,but after treatment,more than 90% of patients have recurrence and metastases in the short term.There are a large number of symbiotic microorganisms in the intestinal tract of the human body,which are more than 1000 kinds.Many studies have shown that the symbiotic microorganisms in the body intestinal tract candirectly involve in the various metabolic processes of the host,play anunique and important role,and produce a variety of beneficial to body health.Under normal circumstances,intestinal flora,the body and the external environment maintain a relative balance to maintain the health of the body.If the balance is broken,the body will appear the alteration of intestinal flora,which will cause disease.Studies have shown that the alteration of intestinal flora is related to the occurrence of a variety of diseases.Current studies focus on the relationship between gastrointestinal tract tumor and intestinal flora at home and abroad.In this study,by comparing the intestinal flora differences between patients first diagnosed with SCLC and healthy people,the pathogenic factors of SCLC are analyzed from the perspective of microecology,which provides a new strategy for the diagnosis,prevention and treatment of SCLC.Method:1.Clinical fecal specimens collection: 14 patients first pathologically diagnosed with SCLC in the Second Affiliated Hospital of Dalian Medical University were enrolled.Fresh fecal samples were collected before the first cycle of chemotherapy and labeled as 1-14.14 healthy people were matched,screening age,sex,smoking index,living area and other factors.At the same time,fresh stool specimens were collected and labeled as 15-28.Thecollected samples were stored at-80 ? as soon as possible.The first group was specimens 1-7 and 15-21.The second group was specimens 8-14 and 22-28.2.Intestinal bacteria DNA extraction: Intestinal bacteria in SCLCpatients and healthy people was extracted by fecal DNA kit.3.The changes of intestinal flora were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis(PCR-DGGE).Conducting PCR on intestinal bacteria,then performing DGGE.The PCR amplification of bacteria analyzed by DGGE fingerprinting.Cut the bands with significant differences in sequencing to determine the classification of bacteria.4.Results analysis: Quantity One software and SPSS19.0 software were used to analyze the results.Result:1.DNA extraction and PCR amplification:14 patients first diagnosed with SCLC and healthy people were extracted intestinal bacteriaDNA.DNA concentrations are different in different stool specimens.The intestinal bacteria DNA bands were amplified by PCR.2.Intestinal flora analysis in SCLC group and healthy group:(1)Intestinal flora analysis inthe first group: The diversity index and abundanceof the healthy group are higher than those of the SCLC group,but the difference is not significant(P>0.05).Similarity clustering analysis was performed using UPGAMA.The results show that SCLC group and healthy group are not divided into two clusters.There is no significant difference between the two groups.(2)Intestinal flora analysis inthe second group: The diversity index and abundanceof the healthy group are higher than those of the SCLC group,but the difference is not significant(P>0.05).Similarity clustering analysis was performed using UPGAMA.The results show that SCLC group and healthy group are not divided into two clusters.There is no significant difference between the two groups.(3)Intestinal flora analysis in SCLC group(1-14)and healthy group(15-28): The diversity index and abundance of the healthy group are higher than those of the SCLC group,the difference in diversity index is statistically significant(P<0.05),but the difference in abundance is not significant(P>0.05).(4)Sequencing results analysis: Cutting the strips with obvious changes in DGGE spectra,brightness of band 1,3,7 and 8 are higher in SCLC group than in healthy group;brightness of band 2,4,5,6 and 9 are higher in SCLC group than in healthy group.The results show that the homology of band 1,3 with Eubacterium xylanophilumisis 98% and 97%respectively;the homology of band 2,6 withPrevotella copriis 91% and 97%respectively;the homology of band 4 withBlotia sp.is 93%;the homology of band 5 with Dialister succinatiphilus is92%;the homology of band 7 with Eubacterium eligens is 100%;the homology of band 8 withClostridium sp.is 99%;the homology of band 9 with Pseudobutyrivibrio ruminisis 100%.3.Intestinal flora analysis in SCLC group: According to stage,age and smoking index,14 patients with SCLC were divided into different groups.The results show that the diversity index and abundanceof the limited disease are lower than that of the extensive disease,but the difference is not significant(P>0.05);the diversity index and abundance of age>60 years group are higher than age?60 years group,but the difference is not significant(P>0.05);the diversity index and abundance of smoking index>692.857 group are higher than smoking index ? 692.857 group,but the difference is not significant(P>0.05).Conclusion:1.Intestinal flora is different between SCLC patients and healthy people,the difference in diversity index is significant,but the difference in abundance is notsignificant.2.The increase ofEubacterium xylanophilum,Eubacterium eligens and Clostridium sp.are positively correlated with the occurrence of SCLC.The decrease of Prevotella copri and Pseudobutyrivibrio ruminis are positively correlated with the occurrence of SCLC.3.There is no significant correlation between the structure of SCLC patients intestinal microflora and stage,age,smoking index.