Liver cancer is one of the most common cancers, and the incidence and mortality rate of liver cancer in China is the highest in the world, accounting for 55% of new cases and deaths worldwide each year, of which more than 80% are hepatocellular carcinoma (HCC) type. p53 is known as the “molecular police”, and its main biological functions are to maintain the stability of the cell genome, negatively It regulates cell growth and induces apoptosis. Studies have found that at least 50% of human malignant tumors have p53 gene alterations. With the in-depth understanding of the pathogenesis of hepatocellular carcinoma, there is more and more evidence that p53 is closely related to the process of hepatocarcinogenesis. In this paper, we review the expression and detection methods of p53 in hepatocellular carcinoma, as well as the relationship between p53 and clinical features of hepatocellular carcinoma and progress of gene therapy. Pan Xiaoping, Department of Interventional Vascular Surgery, Wuhai People’s Hospital 1 Expression of p53 in hepatocellular carcinoma In normal population and benign diseases, antibodies to p53 are rarely detected, while serum p53 antibodies are detected in most patients with malignant tumors, and the positive rate is about 7%-63%. Mutations in the p53 gene are present in more than 50% of hepatocellular carcinomas, and mutations and deletions of the p53 gene are found in 36% of progressive hepatocellular carcinomas, thus the gene is considered to be associated with hepatocellular carcinoma. Gong Ling et al. examined the expression of p53 in 40 hepatitis B-associated hepatocellular liver cancer tissues and their corresponding paraneoplastic tissues. The results showed that the positive expression of P53 protein was significantly higher in hepatocellular carcinoma tissues than in paraneoplastic liver tissues (P=0.047). Ren Yong et al. examined the expression of P53 protein in 49 HCC tissues, 21 paraneoplastic tissues, and 10 normal liver tissues, and the results showed that 53.1% of HCC tissues had positive expression of P53 protein. The positive expression of P53 protein in paraneoplastic tissues was 9.5%. The difference between the two was significant (P<0.01). 10 cases of normal liver tissues showed no P53 protein expression. Yu Hong et al. collected 62 cases of primary liver cancer tissues and corresponding paraneoplastic tissues, detected the expression of p53 and observed. The results showed that the expression of p53 in cancer tissues was significantly higher than that in paraneoplastic tissues and positively correlated with the degree of tumor differentiation (P<0.05); there was no difference between p53 expression and gender, age and tumor size. Zhang Zhipei et al. collected 42 cases of HCC paraffin tissues and detected the expression of mutant p53 in HCC tissues, and the analysis showed that the positive expression of mutant p53 was mainly localized in the nucleus, and the positive rate of mutant p53 in HCC tissues was 47. 62%. The positive rate of p53 antibodies in HCC tissues varied widely among studies, and Guan Yongsong et al. suggested that it might be related to the race and tumor stage of the patients included in the study, as well as to the site and type of p53 mutation. However, the overexpression of p53 protein in HCC tissues is certain, and p53 can be used as an important indicator to respond to the biological behavior of HCC. 2 Detection methods of p53 in hepatocellular carcinoma Usually sequencing of p53 gene in tumor tissues or showing mutated p53 protein in tumor cells by immunohistochemistry is the gold standard for detecting the presence of p53 gene mutation in tumors. The wild-type p53 oncogene product, P53 protein, has a short half-life (1-2h) and remains at low levels in normal cells, thus making it difficult to detect; whereas the P53 protein product expressed by the mutated p53 gene can be detected by immunohistochemistry due to its long half-life (2-12h), which is the most widely used in clinical practice to detect p53 gene mutations at the protein level. Chen Ke-he et al. used oligonucleotide microarray technology to detect the frequency and form of mutations in seven common mutation sites of p53 gene in hepatocellular carcinoma in China, and the results were verified by DNA sequencing. A total of 54 paraffin-embedded specimens of hepatocellular carcinoma were detected, and the mutation rate of p53 gene was 38.9% (21/54). p53 mutations mainly occurred in the 249 coding region; the results were validated by DNA sequencing, and the overlap rate between the two techniques was 100%. FASAY has higher sensitivity for p53 mutation detection compared to immunohistochemical assays. The FASAY technique is an allelic functional analysis technique for the detection of p53 mutations at the RNA level. Wu Xiaomou et al. used this technique in combination with DNA sequencing to detect structural mutations in p53 gene and the function of P53 protein in 28 clinical primary hepatocellular carcinoma surgical samples. The positive results of the FASAY assay were found in 15 cases, with a p53 gene mutation rate of 53.6%. cDNA sequencing of these 15 positive samples showed p53 gene mutations, while no gene mutations were detected in 13 FASAY negative samples. The findings suggest that FASAY is a sensitive technique for detecting structural and functional mutations in the p53 gene in HCC. Many studies have found a significant correlation between the presence of P53 antibodies and the accumulation of P53 protein and p53 mutations, so that the presence of p53 mutations can also be inferred from the relatively simple detection of P53 antibody status in serum. The authors agree that the FASAY technique can be used to screen for p53 mutations in HCC on a large scale and to study their transcriptional activity, ultimately contributing to the diagnosis, prognosis and treatment of HCC tumor patients. The serum p53 antibody assay is convenient, accurate and specific, and can be applied clinically as an auxiliary diagnosis. 3 Relationship between p53 and clinical characteristics of hepatocellular carcinoma Guan Yongsong et al. used ELISA to quantify the correlation between serum P53 antibody and gender, age, history of alcohol consumption, HbsAg, KPS score, pathological diagnosis, degree of tumor differentiation, cirrhosis, tumor growth pattern, tumor stage, vascular invasion, presence of extrahepatic metastasis, Child classification, serum albumin, AFP, serum ferritin The correlation between the tumor and the tumor was found. It was concluded that positive serum P53 antibody was associated with low tumor differentiation (P = 0.020), extrahepatic metastasis (P = 0.002), late tumor stage (P = 0.027), vascular invasion and other indicators representing poor biological characteristics of the tumor. Similar to the previous study. 3.1 Relationship between p53 and the degree of tumor differentiation and tumor stage Guan Yongsong et al. concluded that those with low pathological differentiation had a 66.7% positive rate of P53 antibody, which was significantly higher than those with high (25.0%) and intermediate (15.4%) differentiation. The P53 antibody positivity rate was higher in those with advanced tumor stage than in those with early stage. These results suggest that patients with positive serum P53 antibodies have poorly differentiated tumors, late stage, and high malignancy. Basic studies also found that the p53 gene mutation rate was higher in poorly differentiated hepatocellular carcinoma, and p53 gene mutations were more frequent in advanced tumor stages than in early stages. Gong Ling et al. concluded that the p53 positive expression rate was significantly higher in poorly differentiated hepatocellular carcinoma tissues than in those with high and medium differentiation (P=0.017). multifactorial analysis of Cox proportional risk model found clinical stage (P=0.028) to be an independent prognostic factor. 3.2 Relationship between p53 and tumor vasculature Experiments by Volpert et al. confirmed that p53 mutation increased the expression of vascular endothelial growth factor (VEGF) and significantly decreased angiogenesis suppressor (TSP), suggesting that p53 mutation plays an important role in tumor angiogenesis. Ren Yong's study also showed that p53 mutation was one of the causes of high VEGF expression. It can be seen that the angiogenesis of HCC tumors is closely related to their metastasis and influenced by VEGF expression. p53 can affect the angiogenesis of HCC by regulating the expression of VEGF. Saffroy and Guan Yongsong Song both concluded that tumors are more likely to invade blood vessels in serum P53-positive patients (P = 0.010). There was no significant difference in tumor length between P53-positive and negative patients (P>0.05 by rank sum test). 3.3 Relationship between p53 and AFP Saffroy found no correlation between P53 antibodies and AFP after analyzing 130 European patients with hepatocellular carcinoma. A further study by Guan Yongsong et al [11] found that among 41 patients with AFP less than the diagnostic criteria of 400 μg/L, 10 were positive for P53 antibodies. Molecular biology studies also found that mutations in the p53 gene may appear early in the hepatocellular carcinogenesis process, and gradually increase with tumor development. Therefore, we can take advantage of the high specificity of P53 antibody, which can complement AFP in the diagnosis of hepatocellular carcinoma and help to diagnose patients with AFP <400 μg/L; meanwhile, for patients with AFP >400 μg/L, positive P53 antibody can improve the certainty of hepatocellular carcinoma diagnosis. In addition, Shiota et al. analyzed 86 cases of HCC and found that P53 antibody positivity was associated with blood bilirubin and tumor number, not with tumor size. 4 p53 and gene therapy of hepatocellular carcinoma Gene therapy has opened a brand new way for the treatment of hepatocellular carcinoma, and p53 gene is the most relevant oncogene for human tumors. In recent years, people have replaced the normal wild-type p53 gene with the mutated p53 gene in tumor cells, showing a better potential of application. Finding efficient and directed vector systems is now the key to the clinical application of tumor gene therapy. 4.1 Viral vectors include adenovirus and retrovirus. Reiser et al. demonstrated that adenovirus-mediated gene transfer can effectively introduce the p53 gene into tumor cells, and Terence et al. used a receptor-mediated gene transfer system to transfect a wild-type p53-containing hepatocellular carcinoma cell line with mutated p53 and found that it significantly inhibited its growth. growth. Guo Ying et al. introduced p53 gene into hepatocellular carcinoma cell line -PLC/PRE/5 cells by expressing wtp53 recombinant adenoviral vector, and inhibited the growth of the cells by inducing apoptosis and cell cycle arrest. In the study of Shi Ming et al, high transfection rates of adenovirus into hepatocellular carcinoma cells BEL402, HLE and HuH7 were observed, indicating that adenovirus can effectively introduce the target gene into hepatocellular carcinoma cells and express it efficiently. 4.2 Liposome vector Zhu Guangyu et al. showed that using liposome as a vector has higher transfection efficiency than simply introducing genes, and at the same time, the amount of genes is proportional to the transfection efficiency within a certain range. At the same time, the host body does not show specific immune response due to exogenous viral gene, the expression time is longer than that of adenoviral vector, and both dividing and non-dividing cells can be transfected. The study of Lu Qin et al. further demonstrated that transferrin could enhance liposome-gene transfection. 4.3 PTD fusion protein system The PTD fusion protein system is considered to be a promising delivery vehicle. Ding Zhongyang et al. successfully constructed the p53 gene containing prokaryotic expression vector pTATHA/p53, induced expression in E. coli BL21(DE3) LysS and purified it. The purified p53 protein was immunized intraperitoneally in BALB/c mice, and a highly effective antiserum was prepared. This experiment laid the theoretical foundation for the application of PTD-p53 protein in the experimental study of hepatocellular carcinoma. In addition, Mu Hong et al. p53-cDNA eukaryotic expression plasmid p53-pcDNA3 was transfected on human-derived hepatocellular carcinoma cell line HepG2, and the transfection and transcription of exogenous p53-cDNA in HepG2-p53 cells were demonstrated by RNA in situ hybridization, and the successfully introduced p53-cDNA could induce apoptosis in HepG2 cells, which has good tumor gene therapy application prospects. An important mechanism of tumorigenesis is the inactivation of oncogenes and/or activation of oncogenes. Introducing the normal oncogene p53 into tumor cells to replace and compensate for the defective gene can fundamentally inhibit tumor growth. Oncogene p53 its will definitely play an important role in the diagnosis and treatment of liver cancer.