Our findings suggest that specific miRNAs are involved in metastasis and have an impact on the progression of the ccRCC. Furthermore, we identified specific miRNAs characterising very aggressive tumours with early metastasis. In addition, we determined candidate markers associated with survival of the patients. Thus, it seems possible to use miRNAs for prediction of progression to distant metastasis and prognosis analysing the primary tumour.

An interesting group of papers in this section is headed by two papers on synchronous bilateral renal tumours, one from an international group of authors and one from Germany. The large series of patients are examined carefully by both groups, and the findings should be useful for all who are interested in this area. Authors from the UK examine the role of lactate dehydrogenase as a prognostic factor for testicular cancer. They found that it had limited sensitivity, specificity and positive predictive value for detecting relapse, with false‐positive elevations being common. OBJECTIVE To present a multicentre experience and the largest cohort to date of nonmetastatic (N0M0) synchronous bilateral renal cell carcinoma (RCC), as because it is rare the single‐institutional experience is limited. PATIENTS AND METHODS We retrospectively studied 10 337 patients from 12 urological centres to identify patients with N0M0 synchronous bilateral RCC; the clinicopathological features and cancer‐specific survival were compared to a cohort treated for N0M0 unilateral RCC. RESULTS In all, 153 patients had synchronous bilateral solid renal tumours, of whom 135 (88%) had synchronous bilateral RCC, 118 with nonmetastatic disease; 91% had nonfamilial bilateral RCC. Bilateral clear cell RCC was the major histological subtype (76%), and papillary RCC was the next most frequent (19%). Multifocality was found in 54% of bilateral RCCs. Compared with unilateral RCC, patients did not differ in Eastern Cooperative Oncology Group performance status (ECOG PS) and T classification, but bilateral RCCs were more frequently multifocal (54% vs 16%, P < 0.001) and of the papillary subtype (19% vs 12%), and less frequently clear cell RCC (76% vs 83%, P = 0.005). For the outcome, patients with nonmetastatic synchronous bilateral RCC and unilateral RCC had a similar prognosis (P = 0.63); multifocality did not affect survival (P = 0.60). Multivariate analysis identified ECOG PS, T classification, and Fuhrman grade, but not laterality, as independent prognostic factors for cancer‐specific survival. CONCLUSIONS Patients with N0M0 synchronous bilateral RCC and N0M0 unilateral RCC have a similar prognosis. The frequency of a familial history for RCC (von Hippel‐Lindau disease or familial RCC) was significantly greater in bilateral synchronous than in unilateral RCC. The significant pathological findings in synchronous bilateral RCC are papillary subtype and multifocality.

MiRNAs are deregulated in metastatic primary ccRCC and could be promising prognostic markers for an early prediction of metastasis. Alterations in miRNA expression characterize distant metastases of different metastatic sites. Furthermore, our study suggests a functional role of miR-30c in metastasis. The miRNAs could be a helpful tool for individual follow-up prediction and personalized therapy selection.

Epithelial-mesenchymal transition (EMT) is regulated by interaction of carcinoma and stromal cells and crucial for progression of urinary bladder carcinoma (UBC). Therefore, the influence of activated fibroblasts on the expression of E-cadherin repressors as well as EMT and invasion in UBC was investigated. A correlative analysis of the immunohistochemical expression of fibroblast (ASMA, S100A4, FAP, SDF1, PDGFRβ) and EMT (Snail, Slug, Zeb1, E-cadherin) markers was performed on 49 UBC cases of different stages. The impact of distinguishable growth factor stimulated fibroblasts on invasion, EMT, and E-cadherin repressor expression was investigated in an invasion model. In situ, invasiveness was significantly correlated to the loss of membranous E-cadherin (E-cad_m) and increased Snail, Slug, Zeb1 in tumour cells, as well as to increased ASMA, S100A4, and PDGFRβ in stromal cells. A significant correlation to nodal metastasis could be evidenced for the loss of E-Cad_m, and for an increase in S100A4 and PDGFRβ. Comparison of stromal and EMT markers revealed significant correlations of ASMA to Snail and Slug; of S100A4 to the loss of E-cad_m and Zeb1; and of PDGFRβ to the loss of E-Cad_m, Slug and Zeb1. In vitro, TGFβ1 induced myofibroblasts were the strongest attractants, while aFGF or TGFβ1/aFGF stimulated fibroblasts were the most potent EMT inductors. As shown here for the first time, distinct sub-populations of fibroblasts are to various extents associated with EMT and tumour progression in UBC. These relevant findings might be the basis for the identification of new diagnostic markers and therapeutic targets selectively affecting tumour supporting CAF effects.

The metastatic potential and biology of these small nodules are not yet known. To lower the risk of local recurrence the results of our study suggest that nephron sparing surgery might be advisable in patients with renal cell carcinoma 20 mm. or less in diameter.

Long-term survival rates of metachronous, bilateral renal cell carcinoma are moderate. von Hippel-Lindau disease, a family history of renal cell carcinoma, multifocal first renal cell carcinoma and young patient age are independent risk factors for contralateral renal cell carcinoma. These risk factors support close and extended abdominal surveillance following nephrectomy for unilateral renal cell carcinoma. Patients with a longer primary-free interval have a more favorable prognosis.

Core biopsy of renal lesions is accurate enough for histopathological evaluation and determination of therapeutic procedure. Additionally, biopsy could be used for identifying benign renal lesion for observation.

Data suggest that specific chromosomal alterations in clear cell renal cell carcinoma can be used to predict metastasis and cancer specific survival in patients with clear cell renal cell carcinoma. It seems possible to design a combined fluorescence in situ hybridization assay based on these genetic targets for outcome prediction, which can be used for routine diagnostics.