Investigation of tumour supressor protein p53 in renal cell carcinoma patients

P53 and survivin expression in renal cell carcinoma

Objective

Mutation of p53 is detected in more than 50% of human cancers, expression of p53 has a potential prognostic value in patients with renal cell carcinoma (RCC). Survivin is a member of the inhibitor of apoptosis protein family, its overexpression is observed in many malignancies, including RCC. The aim of the study was to estimate a correlation between survivin and p53 expression in tumor samples and the histologic type of a tumor, tumor stage, tumor grade, and survival of patients.

Materials and Methods

Tumor samples were collected from surgical specimens of 90 patients who underwent radical or partial nephrectomy for RCC between November 2017 and July 2020. Tumors were staged according to the UICC (The Union for International Cancer Control) TNM classification system and histopathologically graded according to Fuhrman nuclear grade system. Histopathological diagnosis was confirmed with standard light microscopic evaluation, using hematoxylin and eosin staining and standard p53 and survivin antibodies.

Results

Positive p53 staining was observed in 36.7% of tumor specimens and 24.4% were survivin positive. There was a statistically significant correlation between p53 or survivin expression and histologic subtype of clear cell RCC as well as Type I and II of papillary RCC. There was a statistically significant correlation between p53 expression and tumor size, stage, and grade. The p53 or survivin expression was related to lower overall survival.

Conclusion

The results of this study suggest that p53 overexpression and survivin positivity in RCC patients could be associated with poor prognosis. Thus, these proteins could be used as prognostic markers in RCC.

VHL missense mutations in the p53 binding domain show different effects on p53 signaling and HIFα degradation in clear cell renal cell carcinoma

Clear cell Renal Cell Carcinoma (ccRCC) formation is connected to functional loss of the von Hippel-Lindau (VHL) gene. Recent data identified its gene product, pVHL, as a multifunctional adaptor protein which interacts with HIFα subunits but also with the tumor suppressor p53. p53 is hardly expressed and rarely mutated in most ccRCC. We showed that low and absent p53 expression correlated with the severity of VHL mutations in 262 analyzed ccRCC tissues. In contrast to nonsense and frameshift mutations which abrogate virtually all pVHL functions, missense mutations may rather influence one or few functions. Therefore, we focused on four VHL missense mutations, which affect the overlapping pVHL binding sites of p53 and Elongin C, by investigating their impact on HIFα degradation, p53 expression and signaling, as well as on cellular behavior using ccRCC cell lines and tissues. TP53 mRNA and its effector targets p21, Bax and Noxa, were altered both in engineered cell lines and in tumor tissues which carried the same missense mutations. Two of these mutations were not able to degrade HIFα whereas the remaining two mutations led to HIFα downregulation, suggesting the latter are p53 binding site-specific. The selected VHL missense mutations further enhanced tumor cell survival, but had no effects on cell proliferation. Whereas Sunitinib was able to efficiently reduce cell proliferation, Camptothecin was additionally able to increase apoptotic activity of the tumor cells. It is concluded that systematic characterization of the VHL mutation status may help optimizing targeted therapy for patients with metastatic ccRCC.

Gelsolin, NF-κB, and p53 expression in clear cell renal cell carcinoma: Impact on outcome

OBJECTIVES

To examine the prognostic significance of Gelsolin, NF-κB, and p53 in clear cell renal cell carcinoma (CRCC), which has an unpredictable behavior and tendency for recurrence and metastasis.

MATERIALS AND METHODS

Immunohistochemistry was performed on 100 consecutive cases of CRCC using antibodies against Gelsolin, NF-κB, and p53. Tumors were grouped by nuclear grade (NG) as low NG (NG1, 2) or high NG (NG3, 4), and by pathological stage as localized (pT1, 2) or locally invasive (pT3, 4). Clinical stage was grouped as early stage (stage I, II) or late stage (stage III, IV). Evaluation was based on cytoplasmic (NF-κB(Cyt)) and nuclear (NF-κB(Nuc)) expression for NF-κB, nuclear expression for p53, membranous and cytoplasmic expression for Gelsolin.

RESULTS

Gelsolin expression correlated with high NG (p = 0.001), metastasis (p = 0.003), late stage (p = 0.008), and cancer death (p = 0.001). NF-κB(Cyt) expression correlated with high NG (p = 0.002), perirenal invasion (p = 0.010), local invasion (p = 0.020), and late stage (p= 0.003). NF-κB(Nuc) expression failed to predict the prognosis of CRCC. p53 expression correlated with high NG (p = 0.045), lymphovascular invasion (p = 0.05), metastasis (p = 0.001), late stage (p = 0.028), and cancer death (p = 0.034). However, only Gelsolin was found to correlate with disease-specific survival, (p = 0.006), and neither NF-κB nor p53 showed such relation.

CONCLUSION

Expressions of Gelsolin, NF-κB(Cyt), and p53 associated with aggressive behavior of CRCC, while Gelsolin expression specifically indicated poor disease-specific survival. The results of the present study served to determine biomarkers for predicting high-risk patients with CRCC, expected to show aggressive phenotype.