Nowadays, it is generally accepted that cancer is a genetic disease. Tumour cells appear due to the accumulation of mutations in critical proto-oncogenes and tumour suppressor genes. Urothelial bladder cancer is a frequent oncological pathology, and therefore it is a significant social problem. The practical relevance of the study is due to the fact that the findings can significantly improve the efficiency of bladder cancer diagnosis. The purpose of the study was to consider all modern methods for diagnosing bladder cancer in one paper. As a research method, the analysis of scientific data obtained from the experimental study of bladder cancer was carried out. According to the data of the investigated sources, a fairly large number of scientists believe that bladder cancer (BC) is one of the most common tumours affecting the urinary tract. It is believed that important prognostic factors include the presence of vascular invasion and tumour complexes in the vessels, which increases the risk of the secondary neoplasm growth even at the pT1 stage. However, when assessing vascular invasion, pathologists often mistake the cracks formed around the tumour complexes for vessels. In this case, the study suggests conducting an immunohistochemical analysis for clear visualisation of blood vessels.