Most bladder cancer comes from urothelial cells. About 75% of the patients are non muscle invasive bladder cancer (NMIBC), and 25% of the patients are muscle invasive bladder cancer (MIBC). With the development of medical technology, the treatment and survival prognosis of bladder cancer patients have not changed. The human p53 gene is composed of 11 exons and 10 introns, which is located in the 31 band 17 p13.1 of the short arm 1 region of chromosome 17. The full length of its cDNA is 2074 BP. It has a single open reading frame. The first exon does not encode. There is a promoter P1 at the upstream 400 BP and a promoter P2 at the downstream 1 KB. The two exons encode 5, respectively These domains are highly conserved in evolution. P53 gene can be divided into wild type and mutant type. For mutant p53, there are deletion mutation, point mutation, frameshift mutation and gene rearrangement. However, wild-type p53 is a normal gene and its half-life is very short, so it is difficult to detect it by immunohistochemistry. The spatial conformation of the mutant p53 protein was changed, the half-life was prolonged, and it was easy to be detected by immunohistochemistry.
P53 can be used as a powerful transcription factor in cells. When DNA damage occurs, p53 can be activated by different signal pathways and remain stable. It can enhance the transcription of downstream genes and cause cell cycle arrest, apoptosis or senescence, so as to maintain the integrity of cell genome and remove damaged cells. These biological effects depend on different stress signals and cell types.
It has been reported that p53 plays a role in many cancers such as cholangiocarcinoma, liver cancer and gastric cancer. However, there are few studies on the prognosis of muscle invasive bladder cancer based on large sample data. In this study, about half of the samples had p53 gene mutations, missense mutations and truncated mutations. A small number of samples had missense mutations and truncated mutations at the same time, and the mutation rate was high. The expression of p53 was negatively correlated with TNM stage, distant metastasis, lymph node metastasis and clinical stage (P < 0.05), but positively correlated with lymphatic invasion and pathological grade (P < 0.05), but not with mutation (P > 0.05). Survival analysis showed that p53 gene mutation had no effect on disease-free survival and overall survival of bladder cancer patients (P > 0.05). The above results are similar to those of P. gontro and other scholars. Our study agreed that p53 mutation has little effect on predicting the recurrence of early bladder cancer. However, more research results are not consistent with the results of this study, such as thorstenh et al. They believe that p53 mutation can be used as a prognostic indicator of bladder cancer, which is inconsistent with the results of this study. The reason for this difference may be that most of the samples in this study have muscle layer infiltration, and the clinical stage of the patients is mainly in the late stage. The difference of samples leads to the inconsistency of results. And the related mechanism is worthy of our in-depth study.
P53 is a classic tumor suppressor gene. In many kinds of cancer research, it has been shown that p53 gene is related to the prognosis of patients. In the study of bladder cancer, its correlation is controversial. J. G. Lorenzo Romero and his team studied 115 patients with bladder cancer. Their results showed that p53 gene mutation can be used as a prognostic and therapeutic decision-making factor. In this study, the survival analysis of patients with p53 mutation and patients without p53 mutation showed that there was no difference in overall survival and disease-free survival (P > 0.05). So far, there is no sufficient evidence that p53 can be used as an independent prognostic factor for bladder cancer. In this study, multivariate Cox analysis showed that lymph node metastasis and invasion and distant metastasis were independent adverse factors affecting the prognosis of bladder cancer (P < 0.05), which was consistent with the results of many literatures.