Overexpression of KIT (CD117) in chromophobe renal cell carcinoma and renal oncocytoma

KIT expression has not been studied substantially in renal tumors. We analyzed the immunohistochemical expression for KIT in 256 conventional renal cell carcinomas (RCCs), 29 chromophobe RCCs, 25 papillary RCCs, 6 collecting duct RCCs, 6 unclassified RCCs, 7 renal oncocytomas, 20 urothelial carcinomas, 7 nephroblastomas, and 23 angiomyolipomas. We found that 24 chromophobe RCCs (83%) and 5 renal oncocytomas (71%) revealed membranous immunoreactivity for KIT while none of the RCCs of other types expressed KIT immunohistochemically. Sporadic cases of urothelial carcinoma and nephroblastoma were focally positive for KIT. All angiomyolipomas were negative. Genomic DNA extracted from the chromophobe RCCs and renal oncocytomas was submitted for polymerase chain reaction and direct sequencing of the juxtamembrane (exons 9 and 11) and tyrosine kinase (exons 13 and 17) domains. No mutation was found. Our results demonstrate that KIT could be a useful immunophenotypic marker for chromophobe RCC and renal oncocytoma; therefore, it has value for the precise classification of renal cortical epithelial tumors. However, the therapeutic relevance of KIT overexpression in these tumors is uncertain owing to the lack of mutations that would lead to constitutive activation of the protein.     

C-kit expression in renal oncocytomas and chromophobe renal cell carcinomas

C- kit encodes the membrane-bound tyrosine kinase KIT, whose expression has been identified in several types of human neoplasms. Recently, KIT has been reported to be a marker for chromophobe renal cell carcinoma (RCC) and renal angiomyolipoma. However, expression of this molecule has not been adequately studied in other renal tumors, particularly oncocytoma, which may morphologically resemble chromophobe RCC. In this study, we analyzed c- kit messenger RNA (mRNA) levels in 17 chromophobe RCCs and 20 renal oncocytomas obtained from complementary DNA (cDNA) microarrays. Furthermore, comprehensive immunohistochemical analysis of KIT protein using a monoclonal antibody was performed in 226 renal tumors including chromophobe RCC (n=40), oncocytoma (n=41), clear-cell RCC (n=40), renal angiomyolipoma (n=29), and papillary RCC (n=21) on tissue microarrays (TMAs) and was compared with immunostaining results from 25 chromophobe RCCs and 30 oncocytomas using standard sections. The staining intensity was semiquantitatively graded on a 3-tier scoring system. All chromophobe RCCs and oncocytomas showed significant overexpression of c- kit mRNA. The average increase of mRNA compared with normal kidney tissue was 7.4-fold for chromophobe RCCs and 7.4-fold for oncocytomas. Immunohistochemical expression of KIT was found in most chromophobe RCCs (95% in TMAs and 96% in conventional sections) and oncocytomas (88% in TMAs and 100% in conventional sections) but was infrequently observed in renal angiomyolipomas (17%), papillary RCCs (5%), and clear-cell RCCs (3%). Furthermore, the average KIT immunoreactivity in TMAs was stronger in chromophobe RCC (1.93) and oncocytoma (2.07) than in other subtypes of renal tumors tested, including angiomyolipomas (0.17), papillary RCCs (0.05), and clear-cell RCCs (0.03). In conclusion, we found a significant elevation of c- kit mRNA by cDNA expression microarrays and overexpression of KIT protein by immunohistochemistry not only in chromophobe RCCs but also in oncocytomas. In contrast, immunohistochemical expression of KIT was not detected in most other types of renal cell tumors evaluated. The differential expression of c- kit in these renal tumors may have diagnostic and therapeutic implications.     

Carbonic anhydrase IX expression in renal neoplasms: correlation with tumor type and grade

Carbonic anhydrase IX (CAIX), a hypoxia-induced protein, is expressed in some renal tumors. We evaluated its immunohistochemical expression in 317 primary and 42 metastatic renal neoplasms (186 clear cell, 52 papillary, 35 chromophobe, 47 unclassified, and 15 Xp11.2 translocation renal cell carcinomas [RCCs]; 26 oncocytomas; 2 metanephric adenomas; 1 urothelial carcinoma; 1 mixed epithelial and stromal tumor; and 1 angiomyolipoma); 7 neoplasms were unknown as to whether they were primary or metastatic. We also correlated expression with tumor type and grade. Variable staining was seen in clear cell, papillary, unclassified, and Xp11.2 translocation carcinomas. One chromophobe carcinoma had focal expression. No staining was seen with other tumors. An association was found between high expression and clear cell vs non-clear cell carcinomas with all cases (P < .01) and primary (P < .01) cases. An association between CAIX expression and grade (P < .01) in primary clear cell carcinomas was found. CAIX expression is more common in clear cell RCC than other renal tumor types and is associated with grade.     

Nucleophosmin expression in renal cell carcinoma and oncocytoma

The objective of this study was to investigate nucleophosmin/B23 (NPM) expression in renal cell carcinomas (RCC) and renal oncocytomas. The expression of NPM was studied by immunohistochemical methods on 59 RCCs, 9 oncocytomas, and 19 tumour-negative renal tissues. The expression was assessed relative to various clinicopathological variables and histological subtypes, to determine its potential role as a prognostic and diagnostic marker. All tumours showed nuclear staining, and a minority also exhibited cytoplasmic immunoreactivity. Two patterns of nuclear staining were observed: nuclear staining with a prominent nucleolus (nucleolar staining) and nuclear staining without a prominent nucleolus. There were significant differences, in both nuclear staining and cytoplasmic NPM expression, between oncocytomas and chromophobe RCCs (p < 0.001) and clear cell RCCs (p < 0.001). Cytoplasmic NPM expression was markedly lower in RCCs than in oncocytomas. A statistically significant correlation was discovered between nucleolar staining and nuclear grade (p < 0.001, r = 0.5). No relationship was found between cytoplasmic expression of NPM and any of the clinicopathological parameters or survival. NPM might be a useful immunohistochemical marker for differential diagnosis between oncocytoma and chromophobe RCC. In addition, increased nucleolar NPM expression in RCCs appears to be associated with tumour progression.     

Chromosomal abnormalities in renal cell carcinoma variants detected by Urovysion fluorescence in situ hybridization on paraffin-embedded tissue

Urovysion fluorescence in situ hybridization (UVFISH) identifies malignant cells in urine by detecting specific urothelial carcinoma-related chromosomal abnormalities. Some renal carcinomas (RCCs) share overlapping chromosomal aberrations with urothelial carcinoma. Malignant renal cells that are shed in urine can potentially cause a positive UVFISH result. We evaluated UVFISH in RCCs to determine its potential applicability to the diagnosis and grading of RCCs. Paraffin blocks from 39 RCCs (25 clear cell, 9 papillary, 2 chromophobe, and 3 sarcomatoid) and 15 controls (5 renal oncocytomas and 10 urothelial carcinomas) were tested. Of the RCCs, 15 (40%) were UVFISH-positive (9/25 [40%] clear cell, 3/9 [30%] papillary, 1/2 [50%] chromophobe, and 2/3 [67%] sarcomatoid carcinoma) and 24 (60%) were negative. Of the 15 controls, 8 (～50%) were UVFISH-positive (2/5 [40%] oncocytomas and 6/10 [60%] urothelial carcinomas) and 7 (～50%) were UVFISH-negative. Polysomy of chromosome 17 showed a statistically significant correlation with RCC subtype, being absent in most of the clear cell RCCs (P = .0096) compared with other RCCs. Polysomy of chromosome 7 was more frequent in high-grade than low-grade RCC (P = .0197) and more likely in high-grade clear cell than low-grade clear cell RCC (P = .0120). In conclusion, we showed that RCC has overlapping chromosomal abnormalities with urothelial carcinoma and can cause a positive UVFISH result. This has implications for the interpretation of Urovysion in patients whose urine contains malignant cells but who have negative cystoscopy and a concomitant renal mass. The chromosomal abnormalities observed in RCC are not distinct from those in urothelial carcinoma; therefore, UVFISH cannot distinguish these tumor types, nor can it type or grade RCC.     

青少年肾细胞癌的临床病理及分子遗传学研究

目的 探讨青少年肾细胞癌的临床病理特征、遗传学改变、鉴别诊断及预后.方法 对46例青少年肾细胞癌进行光镜观察及免疫组织化学染色,随访并复习相关文献.对46例肿瘤进行von Hippel-Lindau(VHL)基因区域杂合性缺失(LOH)及VHL基因突变筛查.结果 共诊断19例Xp11.2易位/TFE3基因融合相关性肾癌(Xp11 RCC)、9例透明细胞癌、17例乳头状肾细胞癌(PRCC)和1例不能分类肾细胞癌.19例Xp11 RCC均TFE3阳性,而TFEB阴性.8例肿瘤具有巢状和乳头状结构形态类似t(X;17)ASPL-TFE3型肾癌,6例肿瘤组织学类似t(X;1)PRCC-TFE3型肾癌,4例肿瘤形态像透明细胞癌,1例肿瘤组织学形态文献中未被检索到,表现为细胞核呈毛玻璃样,核仁不明显,可见核沟,肿瘤间质见大量黏液.LOH及VHL突变检测结果显示,仅1例透明细胞癌和1例2型PRCC存在LOH,并且该2型PRCC的VHL基因的一个剪切位点存在胚系突变,553+5 G→C.其余45例均未检测出VHL突变.统计学分析表明TFE3阳性肾细胞癌比TFE3阴性肾细胞癌更倾向于高病理分期(pT3/pT4),并且预后较差(P=0.035).结论 青少年肾细胞癌表现出不同的组织学形态以及分子遗传学背景.其中Xp11 RCC为最常见的肾癌亚型.TFE3阳性肾细胞癌的预后要差于TFE3阴性肾细胞癌.     

Expression of CD138 (Syndecan-1) in renal cell carcinoma is reduced with increasing nuclear grade.

CD138/Syndecan-1 is a cell-surface heparan sulfate proteoglycan expressed on most epithelial cells, and decreased CD138 expression is associated with increased invasive and metastatic potential in carcinomas. CD138 expression has not been investigated previously in renal neoplasms. Formalin-fixed, paraffin-embedded tissue sections of 50 renal cell carcinomas (RCCs) (40 clear-cell RCCs of various nuclear grades, 10 of which harbored metastases; 6 papillary RCCs, 4 chromophobe RCCs) and 4 oncocytomas were stained immunohistochemically for CD138 using the monoclonal antibody B-B4 (CD138). Staining intensity and distribution were scored and results related to histologic type, nuclear grade, and local stage (pT). Immunoreactivity was membranous in all clear-cell RCCs, chromophobe RCCs, and oncocytomas and was located at the basal aspect of cytoplasm in papillary RCCs. In clear-cell RCCs, the extent of CD138 immunoreactivity decreased with increasing nuclear grade (P<0.001). No significant correlation was found between CD138 immunoreactivity and histologic type (P=0.2) or local stage (P=0.7). Metastatic foci showed a mild to moderate decrease in intensity compared with primary tumor. Decreased expression of CD138 may have a role in more aggressive behavior of clear-cell RCC.     

CD10 is a diagnostic and prognostic marker in renal malignancies

AIMS: To determine the diagnostic and prognostic value of CD10 immunoreactivity in renal cell carcinomas (RCCs) and transitional cell carcinomas (TCCs). METHODS AND RESULTS: CD10 expression was investigated in primary (n = 180) and metastatic (n = 58) RCCs and upper urinary tract TCCs (n = 53) using a tissue microarray technique. One hundred and fifty-four of 172 (90%) evaluable primary and 48/56 (86%) evaluable metastatic RCCs expressed CD10. Extensive immunoreactivity (positivity of >50% cancer cells) decreased with rising tumour grade in conventional RCCs [G1/G2 72/81 (89%), G3/G4 33/48 (69%); P = 0.009]. Chromophobe RCCs showed a significantly lower overall and extensive immunoreactivity compared with conventional tumours (P < 0.001). In papillary RCCs immunoreactivity of more than 10% of cancer cells for CD10 was seen more often in type 2 (7/8, 88%) compared with type 1 (5/12, 42%; P =0.054) tumours. In conventional RCCs, pure apical membranous staining was associated with low tumour stage (P = 0.003), low grade (P = 0.004) and improved prognosis on univariate analysis (P = 0.031). TCCs were less frequently stained (51%). Extensive staining, however, was associated with high-stage tumours (P = 0.024), high-grade (P = 0.073) tumours, and was associated with shorter disease-free survival in univariate analysis (P = 0.003). CONCLUSIONS: CD10 proved to be an additional marker for renal malignancies with predominantly diagnostic potential.     

Different immunohistochemical patterns of Fhit protein expression in renal neoplasms.

BACKGROUND: The FHIT gene on human chromosome 3p14.2 is deleted in a variety of malignant tumors, including clear cell renal carcinomas (RCCs) resulting in a loss of expression of Fhit protein. The Fhit expression in specific subtypes of renal carcinomas has not been characterized. We have investigated the association of Fhit expression with particular subtypes of renal tumors to determine the role and specificity of this putative tumor suppressor gene in renal neoplasia. MATERIAL AND METHODS: The immunohistochemical expression of Fhit was tested in normal kidneys and in 109 renal neoplasms consisting of 51 clear cell RCCs, 26 papillary RCCs, two chromophobe carcinomas, six oncocytomas, four pelvic transitional cell carcinomas and 20 Wilms' tumors from formalin fixed and routinely processed tissue. RESULTS: Normal renal tubules expressed Fhit strongly and consistently. The majority (78%) of clear cell RCCs showed reduced or absent expression of Fhit, whereas the majority (74%) of papillary carcinomas, all chromophobe renal cell carcinomas, and oncocytomas were strongly positive. Sixty-eight percent of low-grade (G1 plus G2) but only 9% of high-grade (G3 plus G4) clear cell carcinomas were Fhit negative. Wilms' tumors demonstrated focal staining in the epithelial component in 8 of 20 cases (40%). CONCLUSIONS: The loss of Fhit expression in a high percentage of clear cell RCCs with conservation of Fhit in other types of tumors supports the proposed role of FHIT alterations in the genesis of clear cell carcinomas in contrast to other types of renal epithelial tumors. FHIT expression may play a role in epithelial differentiation of nephroblastomas (Wilms' tumors).     

Expression of kidney-specific cadherin in chromophobe renal cell carcinoma and renal oncocytoma

Kidney-specific cadherin (Ksp-cad) recently was proposed to differentiate chromophobe renal cell carcinoma (RCC) from oncocytoma based on a finding of Ksp-cad expression in 97% of chromophobe RCCs but only 3% of oncocytomas. However, another study showed no difference in Ksp-cad immunoreactivity between these 2 tumors. We attempted to evaluate Ksp-cad expression in renal tumors using expression microarrays and immunohistochemical analysis. Ksp-cad messenger RNA (mRNA) levels were examined in 158 renal tumors, including 15 chromophobe RCCs and 15 oncocytomas. Immunohistochemical analysis was performed on tissue microarrays containing 125 renal tumors, including 36 chromophobe RCCs and 41 oncocytomas. Ksp-cad mRNA compared with normal kidney tissue was 89% in chromophobe RCC and 64% in oncocytoma. Furthermore, 31 of 36 chromophobe RCCs and 31 of 41 oncocytomas showed Ksp-cad immunoreactivity. Ksp-cad was present in chromophobe RCCs and oncocytomas at mRNA and protein levels, providing strong evidence that Ksp-cad immunohistochemical analysis cannot be used in differentiating these tumors.     

The diagnostic utility of MOC31, BerEP4, RCC marker and CD10 in the classification of renal cell carcinoma and renal oncocytoma: an immunohistochemical analysis of 328 cases

AIMS: To demonstrate the diagnostic utility of MOC31, BerEP4, renal cell carcinoma marker (RCC Ma) and CD10 in the classification of RCC and renal oncocytoma, based upon a comprehensive immunohistochemical analysis. METHODS AND RESULTS: Immunohistochemistry was performed on 328 samples consisting of 256 clear cell/conventional, 27 papillary, 28 chromophobe, five collecting duct, five unclassified RCCs and seven renal oncocytomas using antibodies MOC31, BerEP4 and antibodies against cytokeratins (KL-1, CAM5.2, 34betaE12, cytokeratin 7), RCC Ma, epithelial membrane antigen, E-cadherin, CD10, CD15 and vimentin. Multivariate analysis showed that MOC31, BerEP4, RCC Ma and CD10 have discriminatory value. MOC31 and BerEP4 chiefly labelled distal tubules of normal kidney while RCC Ma and CD10 labelled the proximal tubules. Twenty-three chromophobe RCCs (82%) were reactive for MOC31, while only four clear cell RCCs and three papillary RCCs were positive for this marker. Clear cell RCCs were characterized by a high positive rate for CD10 (82%) and a low positive rate for BerEP4 (27%). Papillary RCCs frequently coexpressed RCC Ma and BerEP4 (51%). All renal oncocytomas were negative for MOC31 and CD10. CONCLUSIONS: MOC31 has diagnostic merit in discerning chromophobe RCC. The CD10+/BerEP4- profile and RCC Ma+/BerEP4+ profile achieve moderate sensitivity and good specificity for clear cell RCC and papillary RCC, respectively. The non-reactivity for both MOC31 and CD10 is helpful in distinguishing renal oncocytoma from RCC. When properly selected, antibodies have immunohistochemical diagnostic utility for the classification of renal cortical epithelial tumours.     

Bellini duct carcinoma: further evidence for this rare variant of renal cell carcinoma

Bellini duct carcinomas have recently been identified as a new entity in the spectrum of renal cell carcinomas and 10 cases have now been reported. The present paper adds detailed clinical and morphological data on six new cases. In addition, immunohistological and electronmicroscopical results support the origin of these tumours from the renal collecting ducts, especially the papillary ducts (Bellini ducts). A set of immunohistological reactions, including reactions to cytokeratins 13 and 19, vimentin and UEA-1 was found to facilitate the differential diagnosis of Bellini duct carcinomas from other renal cell carcinomas and infiltrating urothelial carcinomas of renal pelvis.     

Mutation of the p53 tumour suppressor gene occurs preferentially in the chromophobe type of renal cell tumour

Genomic DNA from 30 non-papillary and 20 chromophobe renal cell carcinomas (RCCs), 30 papillary renal cell tumours, and 20 renal oncocytomas was screened for the presence of mutations in exons 5–8 of the p53 tumour suppressor gene by polymerase chain reaction–single strand conformation polymorphism analysis and direct DNA sequencing. Mutations leading to an amino acid change were found only in 6 out of 20 chromophobe RCCs. Microsatellite analysis of chromophobe RCCs revealed the loss of one allele at chromosome 17p in 14 out of 18 informative cases. No mutation of the p53 gene was found in five sarcomatous RCCs or in seven tumours of stage IV. This study shows that mutation of the p53 tumour suppressor gene does not correlate with the specific loss of DNA sequences at chromosome 17 in chromophobe RCCs, nor can it be used as a prognostic parameter for RCCs in general. © 1997 John Wiley & Sons, Ltd.     

Expression of GLUT1 in primary renal tumors: morphologic and biologic implications

This study aimed to assess whether glucose transporter 1 (GLUT1) is useful in prognostication or differential diagnosis of renal tumors. GLUT1 immunostain for 228 renal tumors showed a membranous or cytoplasmic pattern. The membranous pattern was seen in 86.2% of 145 clear cell renal cell carcinomas (RCCs) and 100% of 11 transitional cell carcinomas (TCCs) but in no oncocytomas, other subtypes of RCC, or sarcomatoid areas of RCCs. The cytoplasmic pattern was seen in 55.2% of 145 clear cell RCCs, 38% of papillary RCCs (11/29), 13% of chromophobe RCCs (2/16), 22% of oncocytomas (5/23), and 82% of TCCs (9/11). Western blot showed a markedly increased GLUT1 protein content in clear cell RCCs compared with a low level in papillary RCCs and normal kidney specimens. GLUT1 expression in clear cell RCC was not significantly correlated with patient survival, tumor grade, or tumor stage. GLUT1 may be a novel target for immunotherapy and a useful marker in the differential diagnosis and classification of renal tumors.     

Microsatellite allelotyping differentiates chromophobe renal cell carcinomas from renal oncocytomas and identifies new genetic changes

AIMS: The diagnosis of renal oncocytomas (ROs) and chromophobe renal cell carcinomas (RCCs) based on histological features is often uncertain. To assess the value of genetic analysis in their differential diagnosis we analysed 27 ROs and 21 chromophobe RCCs by microsatellite allelotyping. METHODS AND RESULTS: Markers at the short and long arms of chromosomes specifically involved in the genetic changes of the four main types of renal cancers were selected. Allelic changes were identified by automated sequencing. Allelic changes at chromosome 1p occurred in 8/26 (31%) and at chromosome 14q in 4/27 (15%) ROs. Loss of heterozygosity (LOH) at chromosomes 1, 2, 6, 10, 13, 17 and 21 were seen in 90%, 90%, 96%, 86%, 85%, 90% and 72% of the chromophobe RCCs, respectively. Alterations of at least three of these chromosomal sites were detected in each chromophobe RCC. In addition, we found recurrent LOH at chromosomes 9p23 (43%), 18q22 (30%), 5q22 (28%) and 8p (28%) in chromophobe RCCs. CONCLUSIONS: Chromophobe RCCs can be differentiated from ROs by analysing specific chromosomal regions with microsatellites.