Among the 11 non-responders 7 (64%) were wild-type, 2 (18%) were p53 mutated and 2 (18%) VHL1 mutated.No significant associations were found among RCC histotype, mutation variants and response to therapies.
We examined 33 patients with renal cell carcinoma and 29 with bladder cancer; heterozygosity in the p53 gene was lost in 60% (6 of 10 cases) and 73% (8 of 11 cases) of the renal and bladder tumors, respectively.
The results obtained in the present study suggest that the p53 pathway is altered in a tissue/disease-specific manner and that therapeutic strategies targeting this pathway should be investigated to determine whether the tumour suppressive function of p53 can be rescued in RCC.
Recently, we found that the increase of TGase 2 expression is required for p53 depletion in RCC by transporting the TGase 2 (1-139 a.a)-p53 complex to the autophagosome, through TGase 2 (472-687 a.a) binding p62.
To investigate the prognostic value of DNA ploidy, Ki-67 index and p53 expression in relation to disease-related survival in a consecutive series of patients with renal cell carcinoma (RCC).
The specimens of tumours (T) and clinically normal tissues (N) adjacent to them were collected from 41 patients with RCC. mRNA expression levels of p53 isoforms were detected using RT-PCR followed by nested PCR.
In in vitro studies, depletion of PARG1by siRNA in human RCC cell lines inhibited their proliferation through inducing G1 cell cycle arrest via upregulation of p53 and subsequent p21<sup>Cip1/Waf1</sup>, which are mediated by increased RhoA-ROCK activities.
The evasion of p53 function (possibly through the expression of HDMX) is an essential element in the development of resistance to VEGF-targeted therapy in RCC.
Remarkably, cells of normal kidney epithelium also caused partial p53 repression in cell fusion experiments, suggesting that RCC-specific p53 repression may be based on an unknown dominant mechanism also acting in normal kidney tissue.
This study shows that mutation of the p53 tumour suppressor gene does not correlate with the specific loss of DNA sequences at chromosome 17 in chromophobe RCCs, nor can it be used as a prognostic parameter for RCCs in general.
Quantification of tumors cells with TP53 gene alterations showed a significant increase in the metastases compared to the primary RCCs, and, strikingly, the xenografts were similar to the metastases and not to the primary RCCs from which they were derived.Using laser-microdissection of p53-expressing tumor cells, we identified TP53-mutated tumor cells in the xenografts derived from the primary RCC, and in a lung metastasis later developed in one patient.
Mass spectrometry analysis revealed that streptonigrin binds to the N-terminus of TGase 2 (amino acids 95⁻116), which is associated with inhibition of TGase 2 activity in vitro and with p53 stabilization in RCC.
Tumor progression in renal cell carcinoma (RCC) can be explained by a multistep model, in which the activation of certain oncogenes such as c-neu and c-fos appear to be early events in tumorigenesis, while the expression of p53 and pan-ras are found in advanced stages.
Destruction of HIF-1alpha by p53 was corroborated in the present study by using pVHL-deficient RCC4 (renal carcinoma) cells, supporting the notion of a pVHL-independent degradation process.
MDM2 expression, combined with increased p53 expression, is associated with reduced survival in several cancers, but is particularly of interest in renal cell carcinoma (RCC) where evidence suggests the presence of tissue-specific p53/MDM2 pathway defects.