| Early diagnosis of gastric cancer -A study on detecting telomerase activity in small samples of patients with gastric cancerObjective To investigate the diagnostic significance of the detection of telomerase in gastroscopic biopsy tissues from patients with gastric cancer and precancer diseases .Methods The techniques of telomeric repeat amplification protocol (TRAP)-based telomerase polymerase chain reaction(PCR)-enzyme-linked immunosorbent assay (ELISA) and TRAP-sliver staining were employed to detect telomerase activity in 43 samples of biopsy from patients with gastric cancer,52 samples of biopsy from patients with precancer diseases,15 samples of biopsy from healthy people.Results First,the positive rate and levels of telomerase activity in 36 biopsy samples of gastric cancer groups were same as that in 7 biopsy samples from suspecting gastric cancer patients (p>0.05),but were significantly higher than that in normal contrai group (p<0.001) .The sensitivity ,specificity and accuracy of detection of telomerase activity were 88.9%,77.2%,84.5% respectively. The positive likelihood rate and negative likelihood rate were 3.90,0.144 ,respectively. Second ,the significant difference in positive rates and levels of telomerase activity were not found between different pathological types:adenocarcinoma,mucinous adenocarcinoma and poorly differentiated cancer,and it was found that there was no significant difference between different differentiation groups (p>0.05).Third,the positive rate of telomerase activity detected in TRAP-PCR-ELISA was higher than that detected in TRAP-silver staining,but the significant difference was not found . It was found that samples with low absorbing value detected in the quantified way would show weak positive with less ladder bands or vague ladder bands if detected in the latter way. Finally ,to detect telomerase activity in 52 samples from patients with precancer diseases showed that there was no significant difference between chronic atrophic gastric with intestinal metaplasia and chronic atrophic gastric with middle-high hyperplasia ,the positive rate of telomerase activity in the two groups was obviously higher than that in sight atrophic gastritis and sight atrophic gastritis with sight hyperplasia.Althouh the positive rate of telomerase activity in gastric hyperplatic polyps,sight atrophic gastritis and sight atrophic gastritis with sight hyperplasia were higher than that in normal control group,it was not found there was no significant difference between them .Conclusion Telomerase may be sensitive and specific tumor markers of gastric cancer .Compared with TRAP-silver staining,TRAP-PCR-ELISA was convenient ,objective and cost less time .Combined with pathological detection ,it is possible to raise the earlydiagnostic rates of gastric cancer specially ,precancer diseases . |
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