Immunohistochemical Study for p53 and hsc70 in Transitional Cell Carcinoma of the Urinary Bladder: Correlation with Histologic Grade, Clinical Stage and DNA Ploidy Pattern

Cho, Hyuni; Cho, Sung Jin; Kim, Han Kyeom; Chae, Yang Seok

Abstract

Transitional cell carcinoma of the urinary bladder is the most common cancer of the genitourinary tract in Korea and its prognosis is determined by the histologic grade and clinical stage present at initial diagnosis. Recently, an extensive search for a more objective and reproducible method to evaluate the proliferation activity of cancer cells has been done. The p53 gene is located on the short arm of the chromosome 17 and acts as a cancer suppressor gene. Mutant p53 gene induces malignant transformation. Recent studies reveal that the level of mutant p53 protein is elevated in some human tumor and many diverse transformed cell lines. Heat shock proteins(HSPs) are present constitutively in normal cells, where they play an important role in normal cell metabolism. In mammalian cells, they are induced by a variety of physical and chemical stimuli. A protein that belongs to the hsp70 family, called hsc70, is only slightly heat inducible and is found at a higher level in growing cells than in the resting cells. The mutant p53 protein binds with hsc70 and the p53-hsc70 complex has functional significance in the transforming capacity of the mutant p53. We investigated the correlation between the p53 and hsc70 by immunohistochemical methods and with better defined prognostic indicators such as histologic grade, clinical stage, and DNA ploidy pattern in 42 transitional cell carcinomas of the urinary bladder. The results are summarized as follows. p53 expression rate was higher in the DNA aneuploid group than in the DNA diploid group(p=0.061), but there was no significant difference in the histologic grade(p=0.861) or clinical stage(p=0.154). The higher the hsc70 expression rate was, the poorer the tumor differentiation(p=0.000) and the deeper the invasion(p=0.001). The aneuploid group showed a higher hsc70 expression rate than the diploid group(p=0.017). 27 of 42(64.3%) carcinomas showed positivity of both p53 and hsc70. Though statistically insignificant, their correlation showed a relatively low correlation coefficient (P=0.059). In conclusion, we suspect that p53 and hsc70 are closely correlated to each other by comparing the results of this immunohistochemical study, and hsc70 will be a useful prognostic marker in transitional cell carcinomas of the urinary bladder after sufficient follow up studies are performed.