Frequent allelic changes at chromosome 7q34 but lack of mutation of the BRAF in papillary renal cell tumors

We have analyzed the BRAF locus on chromosome 7q34 with microsatellites for allelic changes and exons 11 and 15 of the BRAF with sequencing for mutations in 50 kidney cancers including 20 papillary, 15 conventional and 15 chromophobe renal cell carcinomas (RCC). Allelic changes at the BRAF locus were seen in 16 of the 20 papillary, 3 of the 15 conventional RCCs and 2 of the 15 chromophobe RCCs. Sequencing failed to disclose mutations in exons 11 and 15 of the BRAF gene in any of the tumors. Our data indicate that BRAF mutation does not play a role in the development of renal cell tumors.     

Expression of heparanase in renal cell carcinomas: implications for tumor invasion and prognosis

PURPOSE: Heparanase activity has been detected in many malignant tumors, showing a correlation with the metastatic potential. The present study was undertaken to investigate the expression of heparanase and its prognostic significance in renal cell carcinomas (RCC). EXPERIMENTAL DESIGN: Nineteen RCCs and 6 nonneoplastic renal tissues were analyzed for heparanase mRNA expression by real-time PCR. Heparanase protein expression was semiquantitatively investigated by immunohistochemistry in 70 RCCs. Involvement of heparanase in the invasiveness of RCC cell lines, 786-O and Caki-2 cells, was examined by down-regulating the gene expression with small interfering RNA (siRNA) using the Matrigel invasion assay. RESULTS: The expression level of heparanase mRNA was significantly higher in clear cell RCCs than in papillary RCCs, chromophobe RCCs, and nonneoplastic renal tissues. Heparanase was predominantly immunolocalized to cell surface and cytoplasm of clear cell RCCs and mean expression levels of heparanase were significantly higher in clear cell RCCs than in papillary and chromophobe RCCs. The protein expression levels were positively correlated with primary tumor stage, distant metastasis, and histologic grade. Targeting of heparanase mRNA expression in 786-O and Caki-2 cells with siRNA down-regulated the mRNA expression and inhibited the Matrigel invasion by these cells, whereas nonsilencing siRNA showed no effect. Multivariate Cox analysis revealed that elevated heparanase expression was a significant and an independent predictor of disease-specific survival (odds ratio, 8.814; P = 0.019). CONCLUSIONS: These data suggest that heparanase plays an important role in invasion and metastasis and silencing of the gene might be a potential therapeutic target in clear cell RCCs.     

Inactivation of BHD in sporadic renal tumors

Studies of families with Birt-Hogg-Dubé syndrome (BHD) have recently revealed protein-truncating mutations in the BHD gene, leading to tumorigenesis of the skin and of different cell types of kidney. To additionally evaluate the role of BHD in kidney tumorigenesis, we studied 39 sporadic renal tumors of different cell types: 7 renal oncocytomas, 9 chromophobe renal cell carcinomas (RCCs), 11 papillary RCCs, and 12 clear cell RCCs. We screened for BHD mutations and identified a novel somatic mutation in exon 13: c.1939_1966delinsT in a papillary RCC. We performed loss of heterozygosity (LOH) analysis on 28 matched normal/tumor sets, of which 10 of 28 (36%) demonstrated LOH: 2 of 6 (33%) chromophobe RCCs, 5 of 6 (83%) papillary RCCs, 3 of 12 (25%) clear cell RCCs, but 0 of 4 renal oncocytomas. BHD promoter methylation status was examined by a methylation-specific PCR assay of all of the tumors. Methylation was detected in 11 of 39 (28%) sporadic renal tumors: 2 of 7 (29%) renal oncocytomas, 1 of 9 (11%) chromophobe RCCs, 4 of 11 (36%) papillary RCCs, and 4 of 12 (33%) clear cell RCCs. Five tumors with methylation also exhibited LOH. Mutation and methylation were absent in 9 kidney cancer cell lines. Our results showed that somatic BHD mutations are rare in sporadic renal tumors. The alternatives, LOH and BHD promoter methylation, are the two possible inactivating mechanisms involved. In conclusion, unlike other hereditary kidney cancer-related genes (i.e., VHL and MET), which are cell type-specific, BHD is involved in the entire spectrum of histological types of renal tumors, suggesting its major role in kidney cancer tumorigenesis.     

Evolving classification of renal cell neoplasia

The development of consensus classifications for renal epithelial neoplasia in 1996 and 1997 led to the recognition of renal adenoma, renal oncocytoma and metanephric adenoma/adenofibroma as benign tumors and conventional (clear cell) renal cell carcinoma (RCC), papillary RCC, chromophobe RCC and collecting duct carcinoma as malignant morphotypes. While the overwhelming majority of renal adenomas and metanephric adenomas are benign, malignant transformation of both types have been described and genetic predictors of malignant transformation are as yet unknown. The main groups of malignant renal tumors are associated with characteristic genetic changes; conventional RCC (-3p), papillary RCC (+7, +17, -Y), chromophobe RCC (hypodiploid). Recent studies have also shown focal loss of heterozygosity of 3p segments in papillary and chromophobe RCC, indicating that 3p mutations are not confined to the conventional RCC morphotype and suggesting the presence of an important tumor suppressor gene at this site. Sarcomatoid metaplasia may occur in any morphotype and this is associated with a poor prognosis. More recently additional varieties of conventional RCC (multilocular cystic RCC), collecting duct carcinoma (medullary renal carcinoma) and papillary RCC (Types 1 and 2), each showing a characteristic morphology, have been recognized.     

Evolving classification of renal cell neoplasia

The development of consensus classifications for renal epithelial neoplasia in 1996 and 1997 led to the recognition of renal adenoma, renal oncocytoma and metanephric adenoma/adenofibroma as benign tumors and conventional (clear cell) renal cell carcinoma (RCC), papillary RCC, chromophobe RCC and collecting duct carcinoma as malignant morphotypes. While the overwhelming majority of renal adenomas and metanephric adenomas are benign, malignant transformation of both types have been described and genetic predictors of malignant transformation are as yet unknown. The main groups of malignant renal tumors are associated with characteristic genetic changes; conventional RCC (-3p), papillary RCC (+7, +17, -Y), chromophobe RCC (hypodiploid). Recent studies have also shown focal loss of heterozygosity of 3p segments in papillary and chromophobe RCC, indicating that 3p mutations are not confined to the conventional RCC morphotype and suggesting the presence of an important tumor suppressor gene at this site. Sarcomatoid metaplasia may occur in any morphotype and this is associated with a poor prognosis. More recently additional varieties of conventional RCC (multilocular cystic RCC), collecting duct carcinoma (medullary renal carcinoma) and papillary RCC (Types 1 and 2), each showing a characteristic morphology, have been recognized.     

Identification of anaplastic lymphoma kinase fusions in renal cancer: Large-scale immunohistochemical screening by the intercalated antibody-enhanced polymer method

BACKGROUND:

Several promising molecular‐targeted drugs are used for advanced renal cancers. However, complete remission is rarely achieved, because none of the drugs targets a key molecule that is specific to the cancer, or is associated with “oncogene addiction” (dependence on one or a few oncogenes for cell survival) of renal cancer. Recently, an anaplastic lymphoma kinase (ALK) fusion, vinculin‐ALK, has been reported in pediatric renal cell carcinoma (RCC) cases who have a history of sickle cell trait. In this context, ALK inhibitor therapy would constitute a therapeutic advance, as has previously been demonstrated with lung cancer, inflammatory myofibroblastic tumors, and anaplastic large cell lymphomas.

METHODS:

Anti‐ALK immunohistochemistry was used to screen 355 tumor tissues, using the intercalated antibody‐enhanced polymer (iAEP) method. The cohort consisted of 255 clear cell RCCs, 32 papillary RCCs, 34 chromophobe RCCs, 6 collecting duct carcinomas, 10 unclassified RCCs, 6 sarcomatoid RCCs, and 12 other tumors.

RESULTS:

Two patients (36‐ and 53‐year‐old females) were positive for ALK as determined by iAEP immunohistochemistry. Using 5′‐ rapid amplification of complementary DNA ends, we detected TPM3‐ALK and EML4‐ALK in these tumors. The results of this study were confirmed by fluorescence in situ hybridization assays. The 2 ALK‐positive RCCs were unclassified (mixed features of papillary, mucinous cribriform, and solid patterns with rhabdoid cells) and papillary subtype. They comprised 2.3% of non–clear cell RCCs (2 of 88) and 3.7% of non–clear cell and nonchromophobe RCCs (2 of 54).

CONCLUSIONS:

The results of this study indicate that ALK fusions also exist in adult RCC cases without uncommon backgrounds. These findings confirm the potential of ALK inhibitor therapy for selected cases of RCC. Cancer 2012. © 2012 American Cancer Society.     

Vascular cell adhesion molecule 1 predicts cancer-free survival in clear cell renal carcinoma patients.

PURPOSE: Vascular cell adhesion molecule 1 (VCAM1) is a cell surface glycoprotein implicated in various pathophysiologic conditions. We measured VCAM1 expression levels in tumor tissues and evaluated its significance and prognostic use in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: We used real-time quantitative PCR to examine the VCAM1 expression levels of a total of 485 sporadic renal tumors, including 429 clear cell, 21 papillary, 17 chromophobe, 11 oncocytomas, and 7 collecting duct carcinomas. We retrospectively examined the relationship of this expression to various clinicopathologic variables and the von Hippel-Lindau alteration status. We evaluated its significance with respect to patient survival rates using the Cox regression model combined with the split-sample method. RESULTS: Compared with normal kidney samples (n = 43), VCAM1 was significantly up-regulated in clear cell RCC and papillary RCC, whereas it was down-regulated in chromophobe RCC and oncocytoma. In clear cell RCC, VCAM1 expression levels were apparently high in patients asymptomatic at presentation and in patients with small tumor size, low-stage, low-grade, microvascular invasion-negative, and von Hippel-Lindau alteration-positive tumors. Univariate analyses showed that VCAM1 high expression is strongly associated with better outcomes in clear cell and papillary RCCs. Further, Cox multivariate analysis models combined with the split-sample method revealed that this association is significant only in cancer-free survival for patients with clear cell RCC after curative surgical resection. CONCLUSIONS: VCAM1 expression levels were found to be histologically subtype specific in renal tumors. Determination of the VCAM1 expression level as a biomarker can provide useful prognostic information for patients with clear cell RCC.     

Treatment outcome and survival associated with metastatic renal cell carcinoma of non-clear-cell histology.

PURPOSE: To define outcome data for patients with metastatic renal cell carcinoma (RCC) with histology other than clear-cell type, including collecting duct (or medullary carcinoma), papillary, chromophobe, and unclassified histologies. PATIENTS AND METHODS: Sixty-four patients with metastatic non-clear-cell RCC histology were the subjects of this retrospective review. Included in the analysis were 22 (8%) of 286 patients from a clinical trials database, 19 of 1,166 patients from a surgery database, and 23 of 357 patients from a pathology database. RESULTS: The prevalent histology was collecting duct, present in 26 (41%) patients. The number of patients with chromophobe and papillary histologies was 12 (19%) and 18 (28%), respectively. Eight (12%) of the patients had tumors that could not be classified for specific tumor histology. Among the 43 patients treated with 86 systemic therapies, including 37 cytokine therapies, two patients (5%) were observed to have a partial response. The median overall survival time was 9.4 months (95% confidence interval, 8 to 14 months). The survival was longer for patients with chromophobe tumors compared with collecting duct or papillary histology, and this group included four patients with survival of greater than 3 years. CONCLUSION: RCC consists of a heterogeneous group of tumors including clear-cell, papillary, chromophobe, collecting duct, and unclassified cell types. Non-clear-cell histologies constitute less than 10% of patients in general populations of patients with advanced RCC treated on clinical trials. Metastatic non-clear-cell RCC is characterized by a resistance to systemic therapy and poor survival, with the survival for patients with chromophobe tumors longer than that for patients with metastatic collecting duct or papillary RCC. Treatment with novel agents on clinical trials is warranted.     

Overexpression of KIT in chromophobe renal cell carcinoma

We analysed gene-expression profiles in 15 surgical specimens of conventional, papillary, and chromophobe renal cell carcinomas (RCCs) using high-density oligonucleotide arrays. From about 12,000 genes targeted by the array, 67 were upregulated specifically in each histological type of RCC. The oncogene KIT was one of the genes whose expression was upregulated specifically in chromophobe RCCs. Immunohistochemical analysis demonstrated the KIT gene product on the cell membrane of chromophobe RCC in all cases, although it was not detected in conventional RCCs or non-neoplastic kidneys except for weak staining in the cytoplasm of renal tubules. These results suggest that each histological subtype of RCC has a unique gene-expression profile, and in particular indicates for the first time that KIT could be a useful marker for chromophobe RCC. As overexpression of KIT might be involved in tumor growth, KIT could be a new therapeutic target in this special type of RCC.     

Molecular genetics and immunohistochemistry characterization of uncommon and recently described renal cell carcinomas

Renal cell carcinoma (RCC) compromises multiple types and has been emerging dramatically over the recent several decades. Advances and consensus have been achieved targeting common RCCs, such as clear cell carcinoma, papillary RCC and chromophobe RCC. Nevertheless, little is known on the characteristics of several newly-identified RCCs, including clear cell (tubulo) papillary RCC, Xp11 translocation RCC, t(6;11) RCC, succinate dehydrogenase (SDH)-deficient RCC, acquired cystic disease-associated RCC, hereditary leiomyomatosis RCC syndrome-associated RCC, ALK translocation RCC, thyroid-like follicular RCC, tubulocystic RCC and hybrid oncocytic/chromophobe tumors (HOCT). In current review, we will collect available literature of these newly-described RCCs, analyze their clinical pathologic characteristics, discuss their morphologic and immunohistologic features, and finally summarize their molecular and genetic evidences. We expect this review would be beneficial for the understanding of RCCs, and eventually promote clinical management strategies.     

100例小肾癌螺旋CT多期扫描分析

目的评价螺旋CT多期扫描在小肾癌诊断和鉴别诊断中的价值。方法回顾性分析100例经病理证实的小肾癌（≤3．0cm）在螺旋CT多期（平扫、皮髓、排泄）扫描时的表现。结果100例小肾癌患者中,左肾38例,右肾62例,肿瘤长径为1．0-3．0 cm,平均2．5 cm。根据WHO 2004年公布的肾肿瘤组织学分型,透明细胞癌76例,多房性透明细胞癌4例,乳头状癌9例,嫌色细胞癌4例,未归类癌7例。上述各亚型小肾癌有其特征性的CT表现,透明细胞癌呈不均匀（因出血、坏死、囊变）而富血供;多房性透明细胞癌呈多房囊性肿块,囊壁和间隔薄而均匀,且无膨胀性结节;乳头状癌呈不均匀而少血供;嫌色细胞癌呈较均匀而少血供,未归类癌与透明细胞癌相似,但更具侵袭性生长。结论常见小肾癌各亚型螺旋CT多期扫描时有其特征性的表现,有助于鉴别诊断,各亚型应分别与肾嗜酸细胞瘤、囊性肾瘤、复杂性肾囊肿、肾少脂肪血管平滑肌脂肪瘤、肾浸润性泌尿上皮癌等病变相鉴别。     

Oncofetal protein IMP3: a novel molecular marker that predicts metastasis of papillary and chromophobe renal cell carcinomas

BACKGROUND: Whether an oncofetal protein, IMP3, can serve as a prognostic biomarker to predict metastasis for patients with localized papillary and chromophobe subtypes of renal cell carcinomas (RCCs) was investigated. METHODS: The expression of IMP3 in 334 patients with primary papillary and chromophobe RCC from multiple medical centers was evaluated by immunohistochemistry. The 317 patients with localized papillary and chromophobe RCCs were further evaluated for outcome analyses. RESULTS: IMP3 was significantly increased in a subset of localized papillary and chromophobe RCCs that subsequently metastasized. Patients with localized IMP3-positive tumors (n=33; 10%) were over 10 times more likely to metastasize (risk ratio [RR], 11.38; 95% confidence interval [CI], 5.40-23.96; P<.001) and were nearly twice as likely to die (RR, 1.91; 95% CI, 1.13-3.22; P=.016) compared with patients with localized IMP3 negative tumors. The 5-year metastasis-free and overall survival rates were 64% and 58% for patients with IMP3-positive localized papillary and chromophobe RCCs compared with 98% and 85% for patients with IMP3 negative tumors, respectively. In multivariable analysis adjusting for the TNM stage and nuclear grade, patients with IMP3-positive tumors were still over 10 times more likely to progress to distant metastasis (RR, 13.45; 95% CI, 6.00-30.14; P<.001) and were still nearly twice as likely die (RR, 1.95; 95% CI, 1.15-3.31; P=.013) compared with patients with IMP3-negative tumors. CONCLUSIONS: IMP3 is an independent prognostic biomarker that can be used to identify a subgroup of patients with localized papillary and chromophobe RCC who are at high risk for developing distant metastasis.     

Deletion of chromosome 3p14.2-p25 involving the VHL and FHIT genes in conventional renal cell carcinoma

Loss of heterozygosity (LOH) at chromosome 3p and inactivation of the VHL gene are associated with the development of conventional renal cell carcinomas (RCCs). Recently, it was suggested that LOH at the FHIT gene at 3p14.2 is an early event in the development of RCC and is characteristic for all types of RCC. We have analyzed 88 conventional, 30 papillary, and 22 chromophobe RCCs for LOH at the VHL and FHIT regions and at other loci on chromosome 3p. A continuous deletion of 3p14.2-p25 harboring the VHL and FHIT genes occurred in 96% of the conventional RCCs but only in 10% of the papillary RCCs and 18% of the chromophobe RCCs. Our data indicate that LOH at chromosome 3p14.2-p25 is specific for conventional RCC and that loss of one allele of both the VHL and FHIT genes occurs in early stage of tumorigenesis.     

Expression of cyclin D1, D3, E,and p27 in human renal cell carcinoma analysed by tissue microarray

Aberrations in the G1/S transition of the cell cycle have been observed in many malignancies and seem to be critical in the transformation process. Few studies have delineated the presence of G1/S regulatory defects and their clinical relevance in renal cell carcinoma (RCC). Therefore, we have examined the protein contents of cyclin D1, D3, E, and p27 in 218 RCCs, using tissue microarray and immunohistochemistry. The results from a subset of tumours were confirmed by Western blotting and immunohistochemical staining of regular tissue sections. Interestingly, low protein contents of cyclin D1 and p27 were associated with high nuclear grade, large tumour size, and poor prognosis for patients with conventional tumours. We further observed substantial differences in the pattern of G1/S regulatory defects between the different RCC subtypes. The majority of both conventional and papillary cases expressed p27; however, chromophobe tumours generally lacked p27 staining. In addition, conventional RCCs often expressed high cyclin D1 protein levels, while papillary RCCs exhibited high cyclin E. In summary, we have shown that G1/S regulatory defects are present in RCC and are associated with clinico-pathological parameters. The pattern of cell cycle regulatory defects also differed between RCC subtypes.     

Molecular cytogenetic characterization shows higher genetic homogeneity in conventional renal cell carcinoma compared to other kidney cancers

In this study seven primary kidney tumors out of 13 were cytogenetically characterized by comparative genomic hybridization (CGH) on the surgical specimens as well as by spectral karyotyping (SKY) analysis after short-term culturing. In two of the seven cases only a normal karyotype was identified. Non-clonal aberrations were observed in four of the seven cases. Overall numerical alterations were more frequent than structural changes. The two structural alterations identified constituted of a deletion of the short arm of chromosome 3 in a conventional renal cell carcinoma (RCC), and a ring chromosome derived from chromosome 8 in a papillary RCC. By CGH gains of copy number were revealed on chromosomes 3, 5, 7, 8q, and 20, while the losses encompassed 3p and 17p. In the papillary RCCs only gains were found. Comparison between SKY and CGH data suggests that the conventional RCCs are genetically more homogeneous than the other types of kidney cancer. In the two papillary RCCs, trisomies of chromosomes 7 and 17 were typical findings. In the transitional cell carcinoma different findings by CGH and SKY would suggest that these tumors constitute a heterogeneous population of tumor cells which could represent different steps of somatic evolution of tumors.     

Prognostic utility of the recently recommended histologic classification and revised TNM staging system of renal cell carcinoma: a Swiss experience with 588 tumors

BACKGROUND: A new, internationally accepted histologic classification of renal cell carcinoma (RCC) and a new edition of the TNM staging system were introduced in 1997. In the latter, there was a dramatic change in the pT classification of organ-confined renal cancer in which the break point between category pT1 and pT2 was increased from 2.5 cm to 7 cm. METHODS: To study the significance of the new pT classification and the new recommendations for histologic classification, 588 nephrectomy specimens were reevaluated to define morphologic prognostic parameters in RCC. pT classification (TNM 1997), histologic subtype, histologic tumor grade, presence of necrosis, and sarcomatoid differentiation were assessed. RESULTS: The histopathologic review according to the new classification revealed 487 conventional (clear cell) (83%), 64 papillary (11%), 31 chromophobe (5%), and 6 collecting duct (1%) RCCs. Clinical follow-up was available for 470 RCCs. The new pT classification (1997) was strongly correlated with patient survival (P < 0.0001). Histologic grade, presence of necrosis, and sarcomatoid differentiation provided independent prognostic information on the clear cell subtype of renal cancer. Sarcomatoid differentiation, but not tumor necrosis, portended a dismal prognosis for patients with papillary RCC. Chromophobe RCC was associated with a significantly better prognosis than clear cell RCC (P = 0.05). Papillary RCC with scanty cytoplasm and small cells (type 1) behaved less aggressively than papillary tumors with eosinophilic cytoplasm and large cells (type 2; P < 0.001). CONCLUSIONS: Accurate histologic classification according to the new recommendations has implications because the prognostic importance of other histologic features that are of independent significance varies with tumor subtype. The data suggest that the new pT classification allows good separation of prognostic groups of patients with renal cancer.     

The expression of hypoxia-inducible factor 1alpha is a favorable independent prognostic factor in renal cell carcinoma.

PURPOSE: Renal cell carcinoma (RCC) is the most common malignancy of the kidney composed of specific tumor types. The sporadic conventional RCCs are, in contrast to the other RCC types, characterized by a high rate of von Hippel-Lindau (VHL) mutations and hypermethylation. The majority of these tumors lack functional VHL protein (pVHL) that leads to increased hypoxia-inducible factor 1alpha (HIF-1alpha) expression. The pVHL is the physiologic regulator of the activity of HIF-1alpha by targeting it to the proteasome for degradation under normoxia. Both pVHL and HIF-1alpha target other genes that are important for cancer survival and proliferation. Expression of HIF-1alpha has been linked to poor prognosis in different malignancies, although few studies have been done on the relation between HIF-1alpha and clinical variables in RCC. EXPERIMENTAL DESIGN: HIF-1alpha protein expression was analyzed in tumor tissue from 92 patients with RCC. HIF-1alpha was quantified by Western blot relative to a positive control. RESULTS: The HIF-1alpha protein was expressed as two bands which strongly correlated (r = 0.906, P < 0.001); therefore, they were added and the sum evaluated against clinicopathologic variables. There was no association between HIF-1alpha and gender, stage, grade, tumor size, or vein invasion. Conventional RCCs had significantly higher HIF-1alpha expression compared with papillary and chromophobe RCCs and kidney cortex. In conventional RCC, HIF-1alpha was an independent prognostic factor. CONCLUSION: HIF-1alpha levels varied significantly between the different RCC types. In conventional RCC, HIF-1alpha was an independent prognostic factor. These data indicate that HIF-1alpha is involved in tumorogenesis and progression of RCC. Evaluation of other HIF target gene products and correlation to angiogenesis seems warranted.