Sarcomatoid dedifferentiation in metastatic clear cell renal cell carcinoma and outcome on treatment with anti-vascular endothelial growth factor receptor tyrosine kinase inhibitors: a retrospective analysis.

INTRODUCTION: This study aimed to assess the efficacy of anti-vascular endothelial growth factor receptor tyrosine kinase inhibitors (anti-VEGFR-TKIs) in patients with metastatic clear cell renal cell carcinoma (m-ccRCC) with sarcomatoid dedifferentiation. PATIENTS AND METHODS: The files of all patients with m-ccRCC consecutively treated with first-line anti-VEGFR-TKIs at the authors' institution were retrospectively reviewed. Pathology slides from nephrectomy and metastasectomy were assessed for the presence and extent of sarcomatoid dedifferentiation. RESULTS: A total of 124 patients were included; nephrectomy and metastasectomy specimens were available in 117 and 35 patients, respectively. Thirty percent of the primary nephrectomy specimens had sarcomatoid features, and the median involvement of the sarcomatoid component was 21% (range, 1%-95%). Patients with an important sarcomatoid component, defined as ≥ 25% involvement of the tumor, had a very poor outcome: progression-free survival (PFS) and overall survival (OS) were 3 and 6 months, respectively, and no partial responses (PR) were observed. Patients without sarcomatoid dedifferentiation or with sarcomatoid involvement < 25% had a PFS of 12 months (P < .0001; hazard ratio [HR], 51; 95% CI, 12.58-207.3), an OS of 22 months (P < .0001, HR, 10.72; 95% CI, 3.56-32.25), and a PR rate of 50% (P = .0015). Patients with a sarcomatoid component ≥ 25% in the metastasectomy also had a poorer PFS and OS on anti-VEGFR-TKIs compared with patients with < 25% of sarcomatoid features at these sites. CONCLUSION: Patients with m-ccRCC whose tumors contain a component of sarcomatoid dedifferentiation of ≥ 25% of the total tumor volume have a very poor outcome when treated with anti-VEGFR-TKIs. Analysis of the extent of sarcomatoid features in resected metastases can provide additional prognostic information.

Keratin 19: a key role player in the invasion of human hepatocellular carcinomas.

OBJECTIVE: Keratin (K)19, a biliary/hepatic progenitor cell (HPC) marker, is expressed in a subset of hepatocellular carcinomas (HCC) with poor prognosis. The underlying mechanisms driving this phenotype of K19-positive HCC remain elusive. DESIGN: Clinicopathological value of K19 was compared with EpCAM, and α-fetoprotein, in a Caucasian cohort of 242 consecutive patients (167 surgical specimens, 75 needle biopsies) with different underlying aetiologies. Using microarrays and microRNA profiling the molecular phenotype of K19-positive HCCs was identified. Clinical primary HCC samples were submitted to in vitro invasion assays and to side population analysis. HCC cell lines were transfected with synthetic siRNAs against KRT19 and submitted to invasion and cytotoxicity assays. RESULTS: In the cohort of surgical specimens, K19 expression showed the strongest correlation with increased tumour size (p<0.01), decreased tumour differentiation (p<0.001), metastasis (p<0.05) and microvascular invasion (p<0.001). The prognostic value of K19 was also confirmed in a set of 75 needle biopsies. Profiling showed that K19-positive HCCs highly express invasion-related/metastasis-related markers (eg, VASP, TACSTD2, LAMB1, LAMC2, PDGFRA), biliary/HPC markers (eg, CD133, GSTP1, NOTCH2, JAG1) and members of the miRNA family 200 (eg, miR-141, miR-200c). In vitro, primary human K19-positive tumour cells showed increased invasiveness, and reside in the chemoresistant side population. Functionally, K19/KRT19 knockdown results in reduced invasion, loss of invadopodia formation and decreased resistance to doxorubicin, 5-fluorouracil and sorafenib. CONCLUSIONS: Giving the distinct invasive properties, the different molecular profile and the poor prognostic outcome, K19-positive HCCs should be considered as a seperate entity of HCCs.

Genome-wide microRNA expression analysis of clear cell renal cell carcinoma by next generation deep sequencing.

MicroRNAs (miRNAs), non-coding RNAs regulating gene expression, are frequently aberrantly expressed in human cancers. Next-generation deep sequencing technology enables genome-wide expression profiling of known miRNAs and discovery of novel miRNAs at unprecedented quantitative and qualitative accuracy. Deep sequencing was performed on 11 fresh frozen clear cell renal cell carcinoma (ccRCC) and adjacent non-tumoral renal cortex (NRC) pairs, 11 additional frozen ccRCC tissues, and 2 ccRCC cell lines (n = 35). The 22 ccRCCs patients belonged to 3 prognostic sub-groups, i.e. those without disease recurrence, with recurrence and with metastatic disease at diagnosis. Thirty-two consecutive samples (16 ccRCC/NRC pairs) were used for stem-loop PCR validation. Novel miRNAs were predicted using 2 distinct bioinformatic pipelines. In total, 463 known miRNAs (expression frequency 1-150,000/million) were identified. We found that 100 miRNA were significantly differentially expressed between ccRCC and NRC. Differential expression of 5 miRNAs was confirmed by stem-loop PCR in the 32 ccRCC/NRC samples. With respect to RCC subgroups, 5 miRNAs discriminated between non-recurrent versus recurrent and metastatic disease, whereas 12 uniquely distinguished non-recurrent versus metastatic disease. Blocking overexpressed miR-210 or miR-27a in cell line SKCR-7 by transfecting specific antagomirs did not result in significant changes in proliferation or apoptosis. Twenty-three previously unknown miRNAs were predicted in silico. Quantitative genome-wide miRNA profiling accurately separated ccRCC from (benign) NRC. Individual differentially expressed miRNAs may potentially serve as diagnostic or prognostic markers or future therapeutic targets in ccRCC. The biological relevance of candidate novel miRNAs is unknown at present.