Cytogenetic abnormalities in renal oncocytic neoplasms

Molecular pathology of renal oncocytoma: a review

Differentiating renal oncocytoma from its renal cell carcinoma (RCC) mimics, particularly chromophobe RCC, can be difficult, especially when limited tissue is available for evaluation and requires sophisticated microscopic, ultrastructural and immunohistochemical evaluation. In this review, the relevant literature has been reviewed, and supporting data obtained by applying modern microarray-based technologies are discussed with a focus on molecular pathology of renal oncocytoma. The high resolution whole-genome DNA-microarray based analyses excluded with all certainty the occurrence of small specific alterations. Renal oncocytomas are characterized by variable chromosomal patterns. The number of genes selected by global gene expression analyses and their usefulness in the diagnostic pathology based on immunohistochemical evaluation is far below the expectations. The conflicting staining patterns, together with the poor specificity of proposed antibodies, leads us to believe that these candidate immunomarkers might not help in the separation of these tumors. Applying DNA based tools might help in the diagnosis of renal oncocytoma with uncertain histology. However, only the combination of all available techniques could give reliable information.

The Evolving Concept of Renal Neoplasia: Impact of Emerging Molecular and Electron Microscopic Studies

The classification of renal tumors has evolved from one that initially encompassed only 2 types of tumors, i.e., clear and granular cell carcinomas, to the markedly expanded recent classification that incorporates new entities, some of which are primarily defined by specific molecular abnormalities. Despite these advances, a single tumor category, clear cell carcinoma, still incorporates the majority (approximately 70%) of renal tumors. It is, however, postulated that this single category is likely to encompass several different tumor types that are, at present, undifferentiated. Electron microscopic studies have been pivotal in defining the spectrum of oncocytoma-chromophobe renal cell carcinoma. Cytoplasmic eosinophilia found in some renal cell carcinomas currently classified as clear cell type is under intense study. Tumors that have recently emerged from this group include tumors with translocations involving chromosome Xp11.2, carcinomas associated with neuroblastoma and epithelioid angiomyolipoma. The spectrum of renal tumors seen in younger patients is wider than among older patients, with rare and unusual tumors being more likely seen in younger patients. The author concludes that although the routine application of electron microscopy to kidney tumor diagnosis may not be practical, systematic ultrastructural studies of these tumors may aid in the definition of new entities.

High Incidence of Chromosome 1 Abnormalities in a Series of 27 Renal Oncocytomas: Cytogenetic and Fluorescence In Situ Hybridization Studies

Context.—It has recently been shown by cytogenetics that there is a high incidence of chromosome 1 abnormalities in renal oncocytomas.

Objective.—To confirm the cytogenetic results by fluorescence in situ hybridization (FISH) analysis.

Design.—Nine additional cytogenetic analyses were added to those reported in our recent study, with a total of 27 tumors studied, which makes it the largest series of renal oncocytomas studied to date by cytogenetics and/or FISH. We used the LSI 1p36/LSI 1q25 Dual Color Probe Set to make the analyses.

Results.—In this study, combined cytogenetics and FISH showed loss of chromosome arm 1p1 in 48% of renal oncocytomas. By FISH, deletion of 1p36.3 was observed in 59% of renal oncocytomas, whereas by cytogenetics, abnormality in chromosome 1 was seen in 32% of tumors. However, the incidence of chromosome 1 abnormalities among 9 bilateral tumors was much higher than in single tumors (88% vs 28%, respectively). Loss of only the 1p36.3 site occurred in 2 renal oncocytomas with translocation of chromosome 1, as shown by cytogenetics. Concordance between the 2 techniques, when they were used simultaneously to detect chromosome 1p1 abnormality, was 82%.

Conclusions.—This study further confirmed our prior results demonstrating the widespread occurrence of chromosome 1 abnormalities in renal oncocytomas. Although no abnormalities in chromosome 1 in tumors with normal karyotypes were detected by FISH using the current set of probes, a much higher incidence of such abnormalities was found in bilateral tumors, suggesting that genetic alterations related to the development of renal oncocytoma reside in this region.

Losses of 1p and chromosome 14 in renal oncocytomas

We performed cytogenetic analyses of 8 renal oncocytomas to identify chromosomal regions involved in the tumorigenesis of oncocytomas. All cases showed chromosomal findings corresponding to established cytogenetic subsets of renal oncocytomas: 3 cases with normal karyotypes, 1 case with rearrangement of 11q, and 4 cases with losses of chromosome 14. In the latter cytogenetic subgroup, monosomy 14 was additionally accompanied by either monosomy 1 in 2 cases or loss of 1p in a third case, providing insights in the cytogenetic evolution of this subgroup.

Oncocytic renal neoplasms: diagnostic considerations

Advances in our understanding of renal neoplasia have resulted in recognition of numerous tumors that are composed predominantly of cells with abundant eosinophilic cytoplasm. This article discusses the features of renal oncocytoma (including oncocytosis), chromophobe renal cell carcinoma (RCC), and clear cell RCC; explores the relationship between renal oncocytoma and chromophobe RCC; briefly discusses other tumors with abundant eosinophilic cytoplasm; and emphasizes the differential diagnosis of such tumors.

The genetics of renal oncocytosis: a possible modelfor neoplastic progression

Renal oncocytosis is a rare condition characterized by the presence of numerous oncocytomas and oncocytic changes in the renal tubules. Other than oncocytomas associated with the Birt-Hogg-Dube (BDH) syndrome, the genetics of oncocytosis is not known. Whether oncocytomas and oncocytosis are similar to BDH syndrome, in which the tumors diploid (as most oncocytomas are), or show chromosomal losses may be significant regarding the observation that in oncocytosis, there frequently is morphological evidence of progression to chromophobe carcinoma. Here we report on the case of a 69-year old male who underwent a staged procedure of partial nephrectomy on the left side and right radical nephrectomy for multiple renal tumors. The tumors were studied by routine hematoxylin and eosin morphology, immunohistochemistry, cytogenetics, and loss of heterozygosity analysis. Both kidneys had numerous oncocytic neoplasms morphologically progressing from oncocytomas to hybrid tumors with chromophobe carcinoma. Genetic studies demonstrated progression from normal cytogenetics to chromosomal losses similar to those in some oncocytomas and in chromophobe carcinomas. The genetics of this apparently nonfamilial oncocytoma differs from that of BDH syndrome and is characterized by losses involving chromosomes 1, 14, 21, and Y. To our knowledge, this is the first report of the genetic and cytogenetic findings in oncocytosis not related to BDH syndrome and may suggest a possible model of progression from oncocytoma to chromophobe renal cell carcinoma.

Renal oncocytomas with 11q13 rearrangements: cytogenetic, molecular, and immunohistochemical analysis of cyclin D1

Two groups of renal oncocytomas have been cytogenetically defined by the loss of one or both of chromosomes Y and 1 or by structural rearrangement involving 11q12~q13. We report five renal oncocytomas with structural chromosomal rearrangements involving 11q13 with previously unreported partner chromosomes (namely, 1, 6, and 7). For two of the five cases, a t(6;11)(p21;q13) translocation was revealed; the others had t(1;11)(p13;q13), t(7;11)(q11.2;q13), and t(5;11)(q35; q13). Fluorescence in situ hybridization confirmed translocation of CCND1 at 11q13 to partner chromosomes 5, 6, and 7. Overexpression of cyclin D1, the protein product of CCND1, was detected in three of the five cases (60%) by means of immunohistochemical staining of formalin-fixed, paraffin-embedded tumor sections. In three cases for which fresh tissue was available, Southern blot analysis using the MDL-5 probe for the BCL1 breakpoint did not reveal rearrangement of BCL1. In addition, six consecutive renal oncocytomas diagnosed at our institution between 1999 and 2002 whose karyotypes did not show 11q13 translocations were all negative for cyclin D1 overexpression under immunohistochemical analysis. The findings of CCND1 rearrangement with FISH and correlation with cyclin D1 overexpression under immunohistochemical analysis suggest that cyclin D1 alterations play a role in the subset of renal oncocytomas with 11q translocations, although other genes may also be involved.

Cytogenetic Analysis of a Series of 13 Renal Oncocytomas

PURPOSE

Only about 50 renal oncocytomas have been studied cytogenetically. They fall into 3 categories, namely 1-normal karyotype, 2-monosomy 1, often with Y chromosome loss, and 3-structural abnormalities of 11q13. Additional abnormalities may occur with transformation to chromophobe renal cell carcinoma, although exactly which one is unclear. We expanded the oncocytoma data base to shed light on changes that characterize transformation.

MATERIALS AND METHODS

A total of 14 oncocytomas from 12 patients were collected in 2(1/2) years. One tumor failed to grow but 13 were successfully karyotyped.

RESULTS

Seven tumors (53.8%), including 2 from 1 kidney, had normal karyotypes or abnormalities characteristic of normal kidney tissue. A total of 6 tumors from 5 individuals (46.2%) had chromosome 1 abnormalities. Monosomy 1 was detected in 2 single tumors and in both tumors in a bilateral case. Structural anomalies resulting in loss of the short arm of chromosome 1 were found in an additional 2 patients. Other abnormalities, including Y chromosome loss and monosomy 14, were observed but no abnormalities of 11q13 were seen.

CONCLUSIONS

Our series confirms that 1p loss is the most common anomaly in oncocytoma. Additional studies are required to understand the transformation potential of this usually benign tumor, identify the putative 1p tumor suppressor gene and determine whether karyotypically normal tumors have molecular abnormalities of 1p.

The basic biology and immunobiology of renal cell carcinoma: considerations for the clinician

These are indeed exciting times in the study of RCC. No longer should the clinician view RCC as a single entity, nor should the researcher pose basic questions without considering the biologic diversity of this tumor. The success of novel targeted therapeutic strategies will depend on the systematic study of genetic and epigenetic events and their relationship to aberrant protein expression and function, and an understanding of the permissive microenvironment that allows the tumor to be sustained. These studies must be correlated in a rigorous fashion to clinical parameters and outcomes. Progress against this elusive tumor will require a continuous translational dialogue between laboratory and clinical investigators.

Analysis of kidney tumors by comparative genomic hybridization and conventional cytogenetics

Comparative genomic hybridization (CGH) and conventional cytogenetic karyotyping were used to screen for losses and gains of DNA sequences along chromosomes in ten renal tumors (RCC) of different histologic types (clear-cell RCC, papillary RCC, and one oncocytoma). Loss of 3p was the most common change in clear-cell RCC. All papillary tumors, either adenomas or carcinomas revealed gains of chromosomes 7 and 17q without limitation to size and grade. Homozygotic loss of the pseudoautosomal Xp or Yp region was detected in three RCC tumors. A dicentric (Y;14) was present as the sole chromosome abnormality in the oncocytoma. Both techniques showed concordant results in tumors with homogeneous karyotype. However, in tumors with several composite clones some discrepancies were observed, especially in cases of clear-cell RCC where chromosomal abnormalities present in a low number of metaphases could not be detected by CGH.

Renal oncocytoma: diagnostic and therapeutic aspects

Renal oncocytoma is one of the most unusual benign lesions, which presents as a complicated mass resulting in a diagnostic and therapeutic dilemma. A new case of renal oncocytoma in a 13-year-old boy is presented. The clinocopathologic features of this rare entity are discussed, with special emphasis on diagnosis and treatment. There are no specific presumptive clinical and laboratory findings, including tumor markers, ploidy analysis, and imaging techniques that distinguish oncocytoma from other renal masses. The most important diagnostic aid is to bear this entity in mind when a child presents with an unexplained renal mass. Frozen section biopsies followed by partial nephrectomy are mandatory for the appropriate treatment after excluding bilateral or multifocal occurrence.

Oncocytoid renal cell carcinoma after neuroblastoma: a report of four cases of a distinct clinicopathologic entity

Four children who developed oncocytoid renal cell carcinoma (RCC) after neuroblastoma are reported. One patient had multiple, bilateral RCCs. The mean age at time of diagnosis of RCC was 8.8 years (range, 5-13 years). The mean interval between neuroblastoma and RCC was 7.15 years (range, 3.1-11.5 years). The histologic findings of these RCCs did not fit within the spectrum of known renal epithelial neoplasms. Most of the neoplastic cells in all cases had eosinophilic, oncocytoid cytoplasm and were arranged in solid and papillary growth patterns. A subset of cells with reticular cytoplasm was also present. Immunohistochemical studies demonstrated keratins 8 and 18 in all neoplasms and keratin 20 in two cases. DNA ploidy analysis revealed that two of three neoplasms assessed were aneuploid. Cytogenetic studies revealed 45, XX, add or dup (7)(q32q36) in one neoplasm, and 83-89, XXXX, -1 ,-3, del (3)(q11.1q2?1), der(4)t(4;?22) (q32;q11.2), -14, -22 in a second tumor. Microsatellite polymerase chain reaction analysis detected no abnormalities in one neoplasm and allelic imbalance of chromosomes 2p31-32.2, 8p22, 9p22-24, 13q22, 20q13, and 22q11 in a second tumor. In case 4, two different RCCs excised 6 months apart were analyzed. The initial neoplasm showed allelic imbalance of chromosomes 2q31-32.2, 5q22, 5q31, 10p13-14, 13q22, 14q31, and 20q13. The subsequent neoplasm showed allelic imbalance of chromosomes 3p21.3, 14q31, and 20q13. The common presence of 14q31 and 20q13 abnormalities suggests that these two neoplasms were genetically related. In aggregate, these findings are distinctive, are not found in known types of RCC, and support the morphologic impression that oncocytoid RCC after neuroblastoma is a distinct clinicopathologic entity.

Cytogenetic analysis of 11 renal oncocytomas: further evidence of structural rearrangements of 11q13 as a characteristic chromosomal anomaly

We carried out cytogenetic analysis on 11 renal oncotytomas by using G-banding and DAPI-banding techniques. Four of our tumors exhibited structural rearrangements affecting chromosome 11 at band q13. Together with another case previously described by us, our tumors constitute the largest series of renal oncocytomas displaying translocations involving 11q13. A review of the literature disclosed only 6 similar oncocytomas, 1 tumor with a t(9;11)(p23;q12), 2 tumors with a nearly identical t(9;11)(p23;q13), and 3 tumors with a t(5;11)(q35;q13). Therefore, our findings provide further cytogenetic evidence that genes located on 11q12-13 may be involved in the tumorigenesis of renal oncocytomas.

Familial renal oncocytoma: clinicopathological study of 5 families

PURPOSE

We analyzed familial renal oncocytoma to provide a foundation for studies aimed at defining genes involved in the pathogenesis of renal oncocytoma.

MATERIALS AND METHODS

We describe 5 families with multiple members affected with renal oncocytoma. Tumors were analyzed pathologically, and affected and nonaffected members were screened clinically and genetically.

RESULTS

We identified 12 affected male and 3 affected female (ratio 4:1) individuals in the 5 families. In affected family members renal oncocytomas were often multiple and bilateral. No metastatic disease was observed. Most renal oncocytomas were detected incidentally in asymptomatic individuals or during screening of asymptomatic members of renal oncocytoma families. One identical twin pair was affected with bilateral multiple renal oncocytomas.

CONCLUSIONS

Renal oncocytoma may be inherited in some families.

Lack of genetic changes at specific genomic sites separates renal oncocytomas from renal cell carcinomas

Morphological similarities between renal oncocytomas and 'oncocytic' renal cell carcinomas (RCCs) make a differential diagnosis in many cases difficult. A series of 41 renal oncocytomas has been analysed by microsatellite markers from chromosomes 1, 2, 3p, 6q, 8p, 9, 10, 13q, 14q, 17, and 21, alterations of which are known to be involved specifically in non-papillary and chromophobe RCCs. Only eight of the 41 renal oncocytomas showed loss of heterozygosity (LOH). LOH at chromosomes 1 and 14 occurred in four tumours each and at chromosomes 2, 8, and 9 in one tumour each. Combined LOH at chromosomes 1, 9, and 14 and also at chromosomes 1 and 14 occurred in one case each. No LOH was seen at any other genomic sites. The lack of combination of LOH at specific chromosomal sites differentiates renal oncocytomas from other renal cell tumours with overlapping phenotypes. Applying the microsatellite assay described here, the diagnosis can be established within 2 days, from fresh as well as from paraffin-embedded material.

Renal oncocytoma with t(5;12;11), der(1)1;8) and add(19): "true" oncocytoma or chromophobe adenoma?

Renal oncocytomas reveal a considerable (cyto)genetic heterogeneity. At least 2 genetic subsets are currently recognized, characterized by (1) translocations involving breakpoint 11q13 and (2) the combined loss of chromosomes 1 and X/Y. We present a case of oncocytoma revealing a 3-way translocation involving breakpoint 11q13, a der(1)t(1;8) and an add(19). The der(1) resulted in loss of chromosome 1 sequences. Using fluorescence in situ hybridization, the 11q13 breakpoint of the present case proved to be slightly different from the one observed previously in 3 cases of renal oncocytoma. Whether the 11q13 breakpoint observed in our case resides in or near another gene remains to be elucidated.

Fine mapping of the human renal oncocytoma-associated translocation (5;11)(q35;q13) breakpoint

Recent cytogenetic analysis of a series of human renal oncocytomas revealed the presence of a recurring chromosomal translocation (5;11)(q35;q13) as sole anomaly in a subset of the tumors. The molecular characterization of this translocation was initiated using two primary t(5;11)-positive renal oncocytomas and a panel of somatic cell hybrids derived from one of these tumors, in conjunction with fluorescence in situ hybridization (FISH) and Southern blot analysis. The breakpoint in chromosome band 11q13 could be located within a genomic interval of at maximum 400 Kb immediately centromeric to the BCL1 locus.

Involvement of the chromosomal region 11q13 in renal oncocytoma: case report and literature review

Renal oncocytomas comprise a cytogenetically heterogeneous group of tumors consisting potentially of cytogenetic distinguishable subgroups. Review of the literature revealed loss of chromosome 1 and Y as a possible anomaly for at least one subset oncocytomas. The frequent finding of rearrangements involving chromosome 11 band q13 characterizes another subset of oncocytomas. We report the cytogenetic and pathological features of a renal oncocytoma diagnosed in a 72-year-old woman and found a t(9;11)(p23;q13) as a consistent abnormality. This supports the idea that translocations involving 11q13 define a further subset of oncocytoma.

Comparative genomic hybridization for genetic analysis of renal oncocytomas

Renal oncocytomas are uncommon tumors of the kidney that are considered to be of low malignant potential. Neither conventional cytogenetic nor restriction fragment length polymorphism analyses have identified consistent genetic alterations in their genomic DNA. The purpose of the present study was to identify the genetic alterations associated with the development of renal oncocytomas. We studied 13 renal oncocytomas by using comparative genomic hybridization, and we identified loss of genetic material from chromosomes 1 and/or 14 in six of these tumors. These alterations may represent early genetic events in the development of these tumors.

The t(1;12)(p36;q13) in a renal oncocytoma

A new chromosome rearrangement, t(1;12)(p36;q13), is added to the cytogenetic changes found in renal oncocytomas. The breakpoint in 12q is cytogenetically different from those of the MAR region, and molecularly HMGIC located in 12q15 on the basis of 3' RACE experiments does not seem to be directly involved.

Loss of heterozygosity studies indicate that chromosome arm 1p harbors a tumor supressor gene for renal oncocytomas

We carried out a complete genome scan for loss of heterozygosity (LOH) in four renal oncocytomas by using highly polymorphic CA repeat microsatellite loci. Three of the four tumors exhibited LOH for chromosome arm 1p, and the oncocytomas of both female patients lost Xq. Therefore, these chromosome arms may harbor tumor suppressor genes involved in the etiology of this disease. Although the genomes of ontocytomas are relatively stable, two different microsatellite loci in one tumor were mutated by + or - 2 nt. Similar alterations in CA repeats that are probably due to spontaneous mutation have been observed in renal cell carcinomas.

Chromosomal changes in renal oncocytomas. Evidence that t(5;11)(q35;q13) may characterize a second subgroup of oncocytomas

Many of the reported oncocytomas have different chromosome abnormalities, indicating that they comprise a cytogenetically heterogenous group of tumors consisting of potentially cytogenetic subgroups. We have performed cytogenetic studies on nine renal oncocytomas. Clonal abnormalities were present in eight tumors. The findings most observed were the loss of the Y chromosome, and abnormalities of chromosomes 1 and 22. We also observed telomeric associations (tas) in two tumors and structural aberrations of chromosomes 9p and 19q, as well as monosomy 10. In two cases we found a similar reciprocal t(5;11)(q35;q13) in two cases. Review of the literature disclosed one other oncocytoma with a t(5;11) (q35;q13). This suggests that t(5;11)(q35;q13) defines a (second) subset of oncocytomas apart from the subgroup specifically associated with the loss of chromosomes 1 and Y.

Cytogenetic analysis of epithelial renal-cell tumors: relationship with a new histopathological classification

Renal-cell carcinomas (RCC) are clinically, histologically and cytogenetically very heterogeneous. The present histological WHO classification shows no clear correlation between histologic subtypes and specific chromosomal abnormalities. In 1986, a new classification was proposed by Thoenes and Störkel based on the cell type from which the tumor arises. They distinguish 5 cell types: clear-cell, chromophilic, chromophobic, ductus Bellini and oncocytic. Results of 105 primary tumors show that, in this new classification, there is a correlation between different subtypes of renal-cell tumor and specific chromosomal abnormalities at a microscopic and/or molecular level. The clear-cell compact type shows structural aberrations of chromosomes I, 3, 4, 5q, 6, 10q, 11q and 12q, together with polysomy of chromosomes X, 4, 5, 7, 10, 12, 15, 16, 19, 20, 21 and 22, monosomy of chromosomes 3, 8, 9, 13, 14, and loss of Y. The main characteristics of the chromophilic tubulo-papillary type are trisomies 7 and 17, and loss of the Y-chromosome. Chromophobic carcinoma seems to be correlated with, inter alia, polysomy 7, trisomies 12, 16, 18, 19, structural abnormalities of 11q, and telomeric associations. Oncocytomas do not reveal any specific chromosomal anomaly, except for trisomy 7. Loss of heterozygosity on 3p is only found in the clear-cell compact type. Some specific chromosomal abnormalities correlate with a particular grade of the tumor. These correlations support the hypothesis that specific chromosomal abnormalities play a role in the histogenesis and oncogenesis of RCC. They may be important for tumor diagnosis and clinical prognosis.

Molecular differential pathology of renal cell tumours

Recent application of molecular cytogenetic techniques to the evaluation of renal cell tumours revealed four subtypes, each with a characteristic combination of genetic alterations within the chromosomal and mitochondrial DNA. The most common, nonpapillary renal cell carcinomas are characterized by the loss of chromosome 3p sequences, rearrangement of the chromosome 5q region and loss of the chromosome 14q sequences. Papillary renal cell tumours can be divided into two groups. Tumours with a combined trisomy of chromosomes 7 and 17 as well as loss of the Y chromosome are papillary renal cell adenomas. Tumours with additional trisomies such as trisomy 16, 20 or 12 are papillary renal cell carcinomas. Chromophobe renal cell carcinomas show a combination of allelic losses, which do not occur in other types of renal tumours. In addition, they have a rearrangement in the mitochondrial DNA. Renal oncocytomas are benign tumours marked by normal or abnormal karyotypes with balanced or unbalanced translocations and an altered restriction pattern of the mitochondrial DNA. Although the major cytological characteristics of renal cell tumours, such as clear, granular, chromophobe and oncocytic cell phenotypes correspond to nonpapillary, papillary and chromophobe renal cell carcinomas and renal oncocytomas, there are many cases with overlapping phenotype. Therefore, a classification of renal cell tumours based on specific genetic alterations is proposed.