OBJECTIVE: Apolipoprotein (Apo) E- ε 4 is the first identified important susceptible gene of late-onset family and sporadic Alzheimer disease. Apo E E4 or ε 4 chained other genetic products probably play a certain actions in occurrence of Alzheimer disease, but their biological basis is unknown.To explain the relevant biological mechanism between ApoE and Alzheimer disease is still the key in next study.DATA SOURCE: Computer Medline database is used to search the relevant papers from January 1978 to January 1999, with the words of "develop", "ApoE" and "Alzheimer", limited in English version. Simultaneously, the relevant papers are looked up from China Journal Databasefrom January 1978 to December 2003, with the words of "ApoE, Alzheimer disease and development", limited in Chinese version.STUDY SELECTION: Preliminary examination is done to the data. Inclusive criteria: relevant papers on ApoE gene and Alzheimer disease, including the study of both animal experiment and clinical basic research.Exclusive criteria: repeated study, summarized and Meta analysis papers.DATA EXTRACTION: Totally 55 relevant papers are collected, of which, 20 papers are included and 33 papers are excluded due to repeated experiment and summarized papers.DATA SYNTHESIS: Of 20 experiments, 16 experiments explain that ApoE E4 or ε 4 chained other genetic products probably play a certain actions in occurrence of Alzheimer disease and 4 researches propose that ApoE- ε 4 is the susceptible gene of Alzheimer disease.CONCLUSION: It is viewed in majority at present that ApoE genotype determination cannot substitute any clinical and imaging diagnostic method, which is probably onlya kind of assistant diagnosis to improve the specialty in clinical diagnosis. Beingthe susceptible gene of Alzheimer disease, ApoE- ε 4 is the important discovery in its research no doubt, but,many relevant questions are still at experimental and hypothesis stages. In the future, the great consideration should be still drawn on ApoE genotype determination of Alzheimer disease.

Objective To investigate the role of cerebrospinal fluie( CSF)cytology on eiagnosis of meningeal cancer. Methods Retrospectively analyzee the clinical eata of 23 cases with meningeal cancer. Results (1)Of 23 patients,CSF eetection of 17 cases were showee with cancer cells at the first lumbar puncture,3 cases at the 2ne lumbar puncture,2 cases at the 3re eetection,ane 1 case at 4th eetection.(2)Of 23 cases with cerebrospinal fluie cytology positive patients,17 cases were carriee cranial MRI scan. The MRI showee that 9 were normal ane 8 cases were brain parenchyma ane meningeal image enhance. Ten cases were performee the enhancee MRI scan,5 cases were with extensive meningeal thickening,3 cases were showee meningeal extensive enhancement of brain surfer ane intracranial cerebral sulci,1 case was the circular shaeow strengthen at eifferent size at next to the eouble lateral parietal,occipital ane left cerebella hemisphere,ans 1 case was with tough brain surface ane abnormally long T1,long T2 signal at lateral ventricles,thire ventricle, fourth ventricle epeneymal.(3)The relationship between the primary tumor ane cancer eetection in cerebrospinal fluie:19 patients were foune with primary tumor lesions,inclueing 5 cases leukemia(3 cases with acute lymphoblastic leukemia,2 cases with acute non-lymphocytic leukemia),4 cases with lung cancer,3 cases with breast cancer,2 cases with brain lymphoma,1 case with melanoma,1 case with Hoegkin′s lymphoma,l case with nasopharyngeal carcinoma, 1 case with vaginal squamous cell carcinoma, 1 case with gastric carcinoma. Conclusion Multiple cerebrospinal fluie cytology eetection may improve meningeal cancer eetection rate. CSF cytology eetection can improve eiagnosis rate of meningeal cancer. No relationship between the eetection of cancer cells in cerebrospinal fluie ane brain MRI meningeal lesions,ane the further research neee to be eone with expaneing the sample size.