Basic science and research in renal cell carcinoma: from workbench to bedside

Nucleic acid-based marker approaches to urologic cancers

There are numerous molecular modifications known to occur in cancer. New nucleic acid-based biomarkers provide a unique approach to patient management in urologic oncology. Malignant transformation of a normal cell requires a series of epigenetic and genetic changes or "hits." Epigenetics produced by deoxyribonucleic acid methylation, adding a methyl group to the fifth position of cytosine within CpG dinucleotides, are important players in deoxyribonucleic acid repair, genome instability, and regulation of chromatin structure. Genetic alterations in cancer can include mutations, chromosome deletions, insertions, amplifications, and translocations. In addition, the modifications of telomeres are critical to the maintenance of chromatin structure, transcription, and cell function in cancer. We review only nucleic acid-based molecular biomarkers in urologic oncology that can assist the clinician in establishing the diagnosis of disease, or that can predict the behavior of the disease or the patient's survival.

Detection of circulating tumor cells in patients with renal cell carcinoma by reverse transcriptase polymerase chain reaction for G250/MNCA-9: results of a prospective trial

OBJECTIVES

Radical nephrectomy displays the standard procedure for patients with localized renal cell carcinoma. The transperitoneal approach is often favored compared to the retroperitoneal approach because of the early ligation of the renal vessels, thereby tumor cell shedding by manipulation of the tumor is thought to be avoided. The aim of our study was to investigate the influence of the surgical technique on intraoperative tumor cell shedding. Furthermore, we evaluated the clinical course of the patients being operated on with either method in terms of complications, postoperative recovery, and hospital stay.

METHODS

A total of 55 consecutive patients with renal tumors suspicious for malignancies were evaluated for this study. Peripheral blood samples were obtained from 44 patients at admission, intraoperatively (before and after kidney removal), and before discharge. Ribonucleic acid was extracted, converted to complementary deoxyribonucleic acid, and reverse transcriptase polymerase chain reaction (RT-PCR) with primers specific for G250/MNCA-9 was performed. Data regarding the clinical course of the patients were analyzed retrospectively by reviewing patient files.

RESULTS

The clinical course for patients undergoing retroperitoneal nephrectomy was statistically different compared to the transperitoneal approach group regarding operating time and duration of drains, favoring the retroperitoneal approach group. Evaluation of MNCA-9 RT-PCR revealed no difference according to operative technique, tumor-nodes-metastasis, or clinical tumor stage. Despite this result, we found positive RT-PCR signals for MNCA-9 in patients with transitional cell cancer of the renal pelvis and benign renal lesions.

CONCLUSIONS

There is no clinical relevant difference between the transperitoneal and retroperitoneal approaches for radical nephrectomy. Furthermore, the retroperitoneal approach does not bear the risk of intraoperative tumor cell shedding by the handling of the tumor.

Second-line strategies for metastatic renal cell carcinoma: classics and novel approaches

OBJECTIVES

Renal cell carcinoma is an aggressive malignancy with a high propensity for both early and metachronous regional and distant metastasis. While surgical resection is the mainstay of therapy for patients with localized disease, the prognosis for patients with distant metastasis is poor with a 5-year survival rate of less than 10%. Response rates to first-line immunotherapy or immunochemotherapy range from 10-35%; responses achieved are predominantly partial remissions of short duration. Until today, there is no standard therapeutic procedure for the growing number of patients who relapse following first-line therapy and desire further active treatment.

MATERIALS AND METHODS

This article reviews classic and recent publications about second- and third-line approaches, their potential efficacy and toxicity.

RESULTS

Several novel approaches have raised well-founded hope. Especially the application of monoclonal antibodies targeting VEGF signalling as well as different receptor tyrosine kinase inhibitors have the potential to change the face of second-line treatment of patients with metastatic RCC. Both groups of agents are focused in current phase III trials, either as mono- and/or combination therapy.

CONCLUSIONS

Until today, second-line treatment of patients with metastatic RCC progressing under therapy with biological response modifiers remains an unresolved issue. The results of ongoing clinical trials evaluating novel targeted approaches can be expected with suspense.

Application of retinoids in the treatment of renal cell carcinoma–a futile effort?

The therapeutic benefit of adding retinoids such as all-trans retinoic acid (RA), 9-cis-RA or 13-cis-RA to established single-agent or combination immuno/chemotherapy regimens for the treatment of metastatic renal cell carcinoma (RCC) has been extensively investigated during the last decade. However, at present results are contradictory and their application controversial. Moreover, recent studies indicated a significantly higher incidence of toxic side-effects in patients treated with retinoids in addition to established bio/chemotherapy. This Commentary summarizes preclinical and clinical trials investigating efficacy and toxicity of retinoids in the treatment of RCC.