Screening And Identification Of Relevant Genes Of Primary Retroperitoneal Liposarcoma

Primary retroperitoneal liposarcoma（PRPLS） is the most common retroperitonealsoft tissue sarcoma(RPS),which accounts for41%of the total incidence of RPS. PRPLSmainly appears around the kidney,with the ages concentrated between40to60yearsold.Owing to a large retroperitoneal cavity,patients experienced occult onset ofdisease,lacking of specific early symptoms and signs. When seeing a doctor, most of thempresents a palpable mass of complicated relation with adjacent organs, leading to a lowcomplete surgical resection rate. The tumor presents strong local aggressivity with highpostoperative local recurrence rate, in which the biggest problem of PRPLS clinicaltreatment lies. Although complete excision rate is improved in recent years with thedevelopment of surgical techniques and equipment, high postoperative recurrence rate isstill under control. Thus strengthening the basic research into PRPLS and understandingits biological characteristics is the key to solving this problem.Gene chip technology is a new type of gene function analytical techniques developedin the recent decade,which can detect expression profile of a series of genes in differenttissues or cells. Gene chip is characterized by high speed, high flux, intensification andlow cost, which has received extensive attention of the scientific community since birth. Itcan contrast gene expression spectrum characteristics between normal tissues or cells andtumor tissues or cells,providing insight into the mechanism of tumorigenesis, which contributes to early diagnosis, treatment and prognosis of the tumor.Therefore, testinggene expression differences between tumor tissues and normal tissues by gene chiptechnology is an effective method and strategy for tumor gene research. This study screensthe genes expressed differently between PRPLS and normal adipose tissues, so as toprovide valuable clues for further research into the genesis and development of PRPLS.Purpose:By detecting the genetic expression differences between PRPLS and normal adiposetissues using the gene chip technology,this study aims to find the candidate genesassociated with the genesis and development of primary retroperitoneal liposarcoma andprovide clues for the prevention and control research,.Method:1. Select two cases of surgically resected PRPLS specimens in our hospital, apply thegene chip technology to detect the whole genome sequence and analyze of thedifferences in gene expression in contrast to normal adipose tissues from patientsthemselves.2. Select another five cases of surgically resected PRPLS specimens in our hospital andnormal adipose tissues from patients themselves,apply the gene chip technology todetect seven upregulated genes and three downregulated genes and then use PCRtechnology to verify the result.3. Select35cases of surgically resected PRPLS specimens in our hospital in the past fiveyears and35cases of normal adipose tissues routinely surgically resected frompatients’ abdominal cavity in our department,and then use immunohistochemicaltechnology to verify the expression of the significantly up-regulated BIRC7genes andPTK7genes and significantly down-regulated TUSC5genes in PRPLS in contrast tonormal adipose tissues.Results:1. The gene chip reveals3828differently expressed genes between the two groups, including1837upregulated genes and1991downregulated genes,with a variety ofbiological processes such as cell proliferation, adhesion, apoptosis and signalpathways.etc. involved.2. Real time quantitative RT-PCR technology verified the mRNA expression of the10cases of samples. With GAPDH as the reference genes,the observation shows that thedifference ratio of the objective genes in all samples are consistent with the resultof the gene chip, illustrating the reliability of microarray results.3. Immunohistochemical results show the following result: Positive expression rateof BIRC7protein was71.43%(25/35)in PRPLS,while the counter rate in normalAdipose tissues was5.7%(2/35).The difference was statistically significant (X2=31.895, P <0.001); Positive expression rate of PTK7protein was77.14%(27/35)inPRPLS. while the counter rate in normal Adipose tissues was2.9%(1/35). Thedifference was statistically significant(X2=40.238，P<0.001)；Positive expression rate of TUSC5protein was65.71%(23/35) in normal adiposetissue, while the counter rate in PRPLS was14.29%(5/35). The difference wasstatistically significant (X2=19.286，P<0.001)Thus, BIRC7protein and PTK7protein expression was significantly higher inPRPLS than in normal adipose tissue，while TUSC5protein expression is just theopposite.ConclusionWe screen the genes closely related to the genesis and development of primaryretroperitoneal liposarcoma using gene expression profile chip and confirms that PRPLSgenesis and development is the complex process of various biological malfunctionresulting from abnormal expression of multiple cancer related genes. Comprehensiveanalysis of the expression of these abnormal genes can help illustrate some mechanisms ofthe genesis and development of PRPLS from the molecular level, providing potentialmolecular markers and target genes for the basic research and early clinical diagnosis,prevention and treatment.