Pathology and Genetics in Renal Cell Cancer

Targeting the nuclear factor-kappaB rescue pathway has promising future in human renal cell carcinoma therapy

Metastatic renal cell carcinoma (RCC) remains refractory to therapies. The nuclear factor-kappaB (NF-kappaB) transcription factor is involved in cell growth, cell motility, and vascularization. We evaluated whether targeting NF-kappaB could be of therapeutic and prognostic values in human RCC. The activation of the NF-kappaB pathway in human RCC cells and tumors was investigated by Western blot. In vitro, the effects of BAY 11-7085 and sulfasalazine, two NF-kappaB inhibitors, on tumor cell growth were investigated by cell counting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and fluorescence-activated cell sorting. Their specificity toward NF-kappaB was analyzed by Western blot, confocal microscopy, NF-kappaB small interfering RNA, and NF-kappaB transcription assay. In vivo, the effects of BAY 11-7085 on the growth of human RCC tumors were investigated in nude mice. A tissue microarray (TMA) containing 241 cases of human RCC with 12 to 22 years of clinical follow-up and corresponding normal tissues was built up to assess prognostic significance of activated NF-kappaB. NF-kappaB is constitutively activated in cultured cells expressing or not the von Hippel-Lindau (VHL) tumor suppressor gene as a consequence of Akt kinase activation and in tumors. In vitro and in vivo NF-kappaB inhibition blocked tumor cell growth by inducing cell apoptosis. On the TMA, NF-kappaB activation was correlated with tumor dimension but was not found to be an independent prognostic factor for patient survival. This report provides strong evidence that the mechanisms responsible for the intrinsic resistance of RCC cells to apoptosis converge on NF-kappaB independently of VHL expression and that targeting this pathway has great anticancer potential.

Chromophobe renal cell carcinoma: comprehensive analysis of 104 cases from multicenter European database

OBJECTIVES

To analyze the clinical behavior of chromophobe renal cell carcinoma (CRCC), we retrospectively evaluated the data from six European centers. In 1985, CRCC was identified as a new RCC histologic subtype. Because of its low frequency, only few large CRCC series are available.

METHODS

We created a renal cancer database including 3228 patients who underwent surgery between 1986 and 2002 in six European centers. The relevant clinical and pathologic data were extracted from the clinical charts at each institution and collected into a unique database.

RESULTS

Of the 3228 patients, 104 (3.2%) affected by CRCC were identified. The mean age at diagnosis was 57.6 years (range 22 to 83). Of the 104 patients, 51 (49%) were men and 53 (51%) were women. The mean tumor size was 6.4 +/- 3.6 cm. An incidental diagnosis accounted for 61.5% of the cases. Radical nephrectomy was performed in 88 patients (85%). After a median follow-up of 38 months (mean 44, range 1 to 153), no local recurrence was observed. The 5-year overall survival rate for CRCC was 81%. Of the 104 patients, 5 (4.8%) and 9 (8.6%) died of unrelated causes and renal cancer, respectively.

CONCLUSIONS

Our series confirmed a favorable outcome for the CRCC subtype with little local aggressiveness and a low propensity for progression and death from cancer.

Parathyroid hormone-related protein in human renal cell carcinoma

Parathyroid hormone-related protein (PTHrP), a polyprotein discovered in 1987, plays crucial roles not only in development and in various physiological events associated with normal life, but also in a number of pathological conditions such as cancer. PTHrP appears as the major causative agent in humoral hypercalcemia of malignancy (HHM) associated to a broad range of tumors. However, this is only one aspect of the multiple facets of PTHrP in cancer biology. Indeed, the complex growth factor-like properties of PTHrP has shed new light onto potential roles of this peptide in the regulation of tumor growth and invasion. Initial studies in breast, prostate and lung cancer and recent results in renal cell carcinoma (RCC) suggest such roles and highlight the therapeutic potential of PTHrP-targeting strategies in human cancer including RCC. In this review, the role of PTHrP in RCC tumorigenesis and its potential as a therapeutic target will be discussed.