| [Background] Hepatocellular carcinoma is one of the most commonmalignancies in China. It has the properties of rapid development, early metastasis and bad prognosis. At present, there are many limitations in investigating into its mechanism, diagnosis and treatment when it happens, so Zhu Wuling, a doctor of institution of digestive disease, Zhengzhou University, constructed complement deoxyribonucleic acid (cDNA) liberary of hepatocellular carcinoma by using suppressed subtractive hybridization (SSH) in order to find some new factors related to hepatocellular carcinoma in the molecular level. These clones were analyzed by Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR), and expressed sequence tag P02 (P02 EST) was found that had differential expression in the tissues of hepatocellular carcinoma and liver cirrhosis. Interestingly, sequence analysis identified that the cloned gene P02 was highly homologous with gene TCTP/TPT1. TCTP/TPT1 was widely expressed in a variety of species including plants, yeast, metazoans (including mammals). At the same time, it was a substantially conserved sequence, which suggested that it would have criticalphysiological functions in the normal cells. The protein product of TPT1 gene was called translationally controlled tumor protein (TCTP). Furthermore, P02 and TCTP had the same open reading frame (ORF), so the clone P02 was TCTP. But until now, the exact functions of TCTP/TPT1 are ill defined. In situ hybridization is that, according to base pair-match rule, using known base sequence with labeled nucleoacid as a probe hybridizes with nucleoacid detected and conform a two-hybrid system under some condition, then detect the two-hybrid system by histochemistry and immunohistochemistry, thus we can learn the unknown base sequence in situ, which is convenient and useful to detect the new genes and/or EST, especially when the antibodies of the new genes and/or EST are not accessible. So more and more researchers use ISH to detect the functions of genes and/or EST.[Aim] To investigate into the expression of hepatocellular carcinomasubtractive segment P02 in malignant tumors of digestive tract such as hepatocellular carcinomas, esophageal-carcinomas, gastric carcinomas, colorectal carcinomas and their normal tissues by in situ hybridization, elucidate the relationship between P02 and malignant tumors of digestive tract and develop the new diagnostic indicators or therapeutic targets.[Materials and methods] (1). All tissues came from the first, secondaffiliated hospital of zhengzhou university, the tumor hospital of He'nan, the No.4 hospital of zhengzhou, including 13 cases of hepatocellular carcinoma, 18 cases of esophageal -carcinoma, 16 cases of gastric carcinoma and 9 cases of colorectal-carcinoma. (2). The total RNA was extracted from hepatocellular carcinoma and got the PCR product by RT-PCR, then P02 probe was labeled by Dig random labeling technology and detected the sensitivity of P02 probe by using blot hybridization. All tissues were fixed in 2 % poly-formaldehyde (including 1/1000 DEPC) and embedded in paraffin and used for in situ hybridization. ( 3 ) . The data were analyzed by software SPSS 10.0, Fisher's exact test of probabilities and Kraskal-Wallis test were used for the data, and a =0.05 was considered the standard of significant difference.[Results] l.The sensitivity of P02 probe was 1.0 pg, which suggested that the probe was well and could be used to ISH.2. In liver cirrhosis tissues, positive straining for P02 were seen in liver cells and in hepatocellular carcinomas, positive straining were located in tumor cells. The positive rate of P02 in cirrhosis tissues and hepatocellular carcinoma were 25% and 92.3%, there was a significant difference between two groups (P<0.05) .3. In the normal tissues of esophagus, stomach, colorectal, positive staining were found in basic cells, and in esophageal-carcinoma, gastric carcinoma, and colorectal carcinoma tissues, positive staining were found in these tumor cells. Statistics...
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