Relationship between expression of p53 protein and tumor subtype and grade in renal cell carcinoma

Our aim was to evaluate the overexpression of p53 protein, product of mutated TP53 gene, in histologic sections of the kidneys with renal cell carcinoma (RCC) and its association with tumor grade and subtype.

A total of 66 histologic sections of the kidneys of patients with the diagnosis of RCC were re-evaluated and tumor grade, tumor subtype, and p53 expression were determined.

Of the total 66 histologic sections with the diagnosis of RCC, 34 (51.5%), 27 (41%), and 5 (7.5%) were conventional, papillary, and chromophobe subtypes, respectively. Fifty-one (77.3%), 14 (21.2%), and 1 (1.5%) of tumors were grade 2, 3, and 4, respectively. Thirty (45.4%) sections were positive for p53 immunohistochemical staining. In 7 cases (20.6%) of the conventional tumors, p53 staining was positive, while 18 papillary (66.6%) and 5 chromophobe tumors (100%) had a positive staining for p53 (P < .001). Seventeen out of 51 grade 2 tumors (33.4%) and 12 out of 14 grade 3 tumors (85.7%) were positive for p53. The single case of grade 4 tumor was positive for p53 protein, too (P = .001).

Increased expression of p53 protein is rather prevalent in RCC. This factor is associated with tumor grade and subtype. According to our findings, it is generally accompanied by nonconventional subtypes and higher tumor grades.