The Significance Of TSER And MSI With The Survival In Stage â…¡ And â…¢ Colorectal Cancer Accepting Adjuvant Chemotherapy After Completely Surgical Operation

BackgroundThe colorectal cancer is the most frequently tumor in digestive system.In recent years,the incidence of colorectal cancer increased year by year. With the adjuvant chemotherapy by the 5-Fu/Lv,the effectiveness and survival of patients have been greatly improved. But still some patients show primary stage or the secondary drug-fast with 5-Fu,which can caused the disease recidivation or progress.Therefore it is important for those patients to seek the reason of drug-fast and the marker of prognosis in molecular biology.Thymidylate synthetase (TS) is a rate-limiting enzyme of thymidine(dTMP).It is not only a vital role in the cell cycle from the G1 telophase to S early but also a target enzyme for 5-Fu. Thymidylate synthetase gene is located in the eighteenth chromosome(18p11.32),and the transcriptional start site stands in the upper reaches of initiation codon ATG about 160-180bp.The interactive transcriptional factor is regulated by the untranslated region gene, for example:the enhancer,the promotor, and so on.It have been discovered that the thymidylate synthetase gene enhancer (TSER) which has a tandem repetitive sequence(TRS) about 28bp is side in the upper reaches of initiation codon ATG about 400bp.And the TRS influences the transcription of TS gene, the stability and translation of TSmRNA.It is elucidated that the tumor cell who expresses much thymidylate synthetase is not sensltive with 5-Fu.Microsatellite is a simple repeat sequence which is less than 10bp in the genome.The repeat sequence is usually 2-6bp, such as:(CG)n,(GT)n,(CAG)n, and so on. Microsatellite instability(MSI) is that when the DNA reproduces the simple repeat sequence appears amplification or deletion.It was observed in the Hereditary non-multiple polyp colon cancer (HNPCC). Later the instability was observed in many tumor,such as Lung cancer, breast cancer, esophagus cancer, stomach cancer, carcinoma of urinary bladder, prostate gland cancer,and so on.MSI is connection with the colorectal cancer, especially the HNPCC. HNPCC is 5%～15% in the colorectal cancer,but the MSI incidence rate is quitely high,abou 70.00%～90.00%.But the rate is low in the sporadic colorectal cancer,about 10.00%～15.00%.It has been discovered that the patients with MSI have a better prognosis than the ones without MSI.ObjectiveTo detect the TSER and MSI, elucidate the connection among TSER,MSI and the prognosis of the stageⅡandⅢcolorectal cancer with adjuvant chemotherapy after completely surgical operation,in order to find a new orientation and method to guide the individualized treatment for the patients.MethodsCollection of 2004.1-2004.12 the stageⅡandⅢcolorectal cancer patient's clinical data and paraffin-embedded tumor specimen,and all of which had been diagnosed and treated in our hospital,a total of 76 cases. All the tumor had been completely resected and all the patients had accepted a adjuvant chemotherapy by 5-Fu/Lv at least 6 cycles.All the specimens are cut into slices at 3-5 um by section razor and the sections are mounted on the glass slide.The tumor and the normal tissues are separated by microdissection on laser. We achieve the DNA from the tumor and the normal tissues by the cell lysate and protease K, amplify the TSER and MS gene by the polymerase chain reaction (PCR), and detect the product by capillary electrophoresis.In accordance with the result of TSER and MS, the patients are divided into different groups to analyse the connection among the TSER and MS with clinical data, progression-free survival and overall survival.Application SPSS13.0 statistical software to analyze the experimental data,α= 0.05 as the test standard. The data were analyzed byχ2 test and Kaplan-Merie Survival Analysis, Log-Rank test of significant difference.Results1. We detected the polymorphism of TSER and MS in 76 patients with the stageⅡandⅢcolorectal cancer. The TSER genetypes are only 2R/2R and 3R/3Rin the tumor or the normal, separately.30 cases (39.5%) are the 2R/2R type and 46 cases (60.5%) are the 3R/3R type in the tumor,but the rate are 75%(57/76)and25% (19/76)in the normal.And 30 cases (39.5%) are MSI-H,28 (36.8%)caces are MSI-L,18(33.7) caces are MSS.2. We evaluated the polymorphism of TSER and MS in above 76 patients. It is not significative bentween TSER and the sex or age or stage or location of tumor or differential. And there is a marked difference between MSI with the stage and location of tumor,but no difference in sex,age,and the differential of tumor.3. There is not a significative difference in TSER with the disease-free survival and overall survival.The same result is discovered in MSI.But a significative difference is observed that the famale patients who with MSI-H have a longer time in the disease-free survival and overall survival than the ones with MSI-L and MSS.The same ruselt is in the patients younger than 60.Conclusions1. There are two types (2R/2R and 3R/3R)in tumor and normal.2. The type of TSER and MSI don't predict the disease-free survival and overall survival of the patients with stageⅡandⅢcolorectal cancer.3. The stage,the number of biopsy lymph nodes and the grade of histology are available and independent factors to predict the prognosis.