Multi-colour FISH on preoperative renal tumour biopsies to confirm the diagnosis of uncertain renal masses

[Biomarkers for renal cell tumours]

During the last three decades, renal tumours have become increasingly well differentiated on the basis of their histopathological and molecular features. This subtyping has increasingly impacted clinical practice because more therapeutic options are available in organ-confined and metastatic renal cell tumours. The knowledge of the underlying molecular alterations is essential to develop molecular targeted therapies and to select the most effective systemic therapy for each patient. This manuscript gives an overview of the molecular differentiation on the one hand, and on diagnostic, prognostic and predictive biomarkers on the other hand.

Application of Chromosome Microarray Analysis for the Differential Diagnosis of Low-grade Renal Cell Carcinoma With Clear Cell and Papillary Features

Clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) are the 2 most common RCCs. However, some RCCs can have both clear cell and papillary features, including clear cell papillary RCC (ccpRCC). They can be a diagnostic challenge in daily practice. Accurate diagnosis of these tumors is important for both patient prognosis and appropriate treatment. Fourteen RCCs with papillary architecture, clear cytoplasm and low Fuhrman grade were analyzed by SNP-based chromosome microarray (CMA). Seven cases had pathologic features of ccpRCC, and all had normal genomic profiles except one that had copy neutral loss of heterozygosity (cnLOH) of chromosome 3 and loss of one copy of the X chromosome. The remaining 7 cases also had papillae and clear cytoplasm. Two of these cases showed losses of chromosome 3 which are typically found in ccRCC. One had a gain of chromosome 7, which is commonly seen in pRCC. The remaining 4 had no alterations of chromosome 3 or 7. However, 3 of these 4 had monosomy 8, which are consistent with RCC with monosomy 8. The remaining case had no copy number alterations. This study shows that low-grade RCC with papillae and clear cell phenotype represents a heterogeneous group, including ccpRCC, ccRCC, pRCC, and RCC with monosomy 8. CMA analysis can be useful for the differential diagnosis of these neoplasms.

Adult Renal Neoplasms: Cytology, Immunohistochemistry, and Cytogenetic Characteristics

Tissue sampling of renal masses is traditionally performed using percutaneous sonographic or CT guidance core biopsy (CB) with or without touch preparation cytology and/or fine-needle aspiration cytology (FNAC). The combined used of CB and FNAC is expanding in clinical practice, especially in small renal masses and plays a pivotal role in therapeutic decision making. Grouping the renal neoplasms in differential diagnostic groups helps in choosing specific immunohistochemical markers and reaching an accurate diagnosis.

Diagnostic accuracy of image-guided biopsies in small (<4 cm) renal masses with implications for active surveillance: a systematic review of the evidence

OBJECTIVE:

To determine the safety and diagnostic accuracy of renal tumour biopsies in a defined population of small renal masses (SRMs) only <4 cm using 3 × 2 table, intention to diagnose approach. 3 × 2 table approach examines indeterminate results as a separate category rather than pushing these through traditional 2 × 2 table (four-cell matrix) approach.

METHODS:

A highly sensitive search was performed in the Cochrane Library, Database of Abstracts of Reviews of Effects; MEDLINE and MEDLINE in Process, EMBASE and conference proceedings (1966-2016) for the acquisition of data on the diagnostic accuracy and complications of RTB in patients with SRM <4 cm. Methodological quality and risk of bias was assessed using QUADAS-2. Test characteristics were calculated using conventional 2 × 2 contingency table analysis excluding non-diagnostic biopsies, and an intention-to-diagnose approach with a 3 × 2 table for pooled estimates of the sensitivity and specificity.

RESULTS:

A total of 20 studies were included with a total sample size of 974. The pooled estimates for sensitivity and specificity of RTB based upon univariate analysis using 2 × 2 table observed sensitivity 0.952 [confidence interval (CI) 0.908-0.979] and specificity 0.824 (CI 0.566-0.962). Using the 3 × 2 table and intention-to-diagnose principle, sensitivity 0.947 (CI 0.925-0.965) and specificity 0.609 (CI 0.385-0.803) decreased.

CONCLUSION:

RTB in SRMs (<4 cm) is associated with a high diagnostic sensitivity but poor specificity when non-diagnostic results are included by a 3 × 2 table for analysis (intention to diagnose approach). Risk of non-diagnostic results and poor quality of research need addressing through future studies, preferably by a well-designed prospective study appropriately powered for diagnostic accuracy using valid reference standards.

ADVANCES IN KNOWLEDGE:

A comprehensive synthesis of literature on image-guided biopsies in SRMs using a different methodology and study design.

Clinical Utility of Fluorescence In Situ Hybridization (FISH) for Deletion of Chromosome 3p in the Work-up of Renal Masses

Chromosome 3p deletion is a well-established genetic aberration in clear cell renal cell carcinoma (RCC). We aimed to evaluate the clinical utility of 3p fluorescence in situ hybridization (FISH) on formalin-fixed paraffin-embedded tissue in surgical pathology specimens. 3p:3q <0.8 was established as the cut-off for 3p loss. The 2015 Medicare allowable billing rates were used to estimate the cost. Over 2.5 years (2013 to 2015), 3p FISH was performed on 18 cases per year. Among tested cases, 70% (30/43) were nephrectomies and 30% (14/43) metastases. 3p loss was detected in 44% (19/43) of cases, with a higher rate of loss in radical compared with partial nephrectomies (71% vs. 15%; P=0.003). A definitive RCC subtype was assigned in 65% (28/43) of cases. More partial nephrectomies had a definitive subtype assigned, compared with radical nephrectomies (92% vs. 59%; P=0.04), possibly related to more high-grade, high-stage tumors in submitted radical nephrectomies. Tested nephrectomies were most commonly diagnosed as clear cell (41%) or clear cell papillary RCC (32%). Half of unclassifiable RCCs had 3p loss (53%, 8/15). Annual 3p FISH costs were $3446.64, with 79% of costs from ancillary studies attributable to immunostains. 3p FISH was performed infrequently in nephrectomy specimens and was not cost prohibitive. RCC cases that are unclassifiable by morphology and other ancillary tests, but which have 3p FISH deletion may merit a comment in the pathology report, raising the possibility of clear cell RCC, as the oncologic approach may be altered despite the lack of a definitive RCC subtype.

A molecular pathology method for sequential fluorescence in situ hybridization for multi-gene analysis at the single-cell level

Multi-gene detection at the single-cell level is desirable to enable more precise genotyping of heterogeneous hematology and oncology samples. This study aimed to establish a single-cell multi-gene fluorescence in situ hybridization (FISH) method for use in molecular pathology analyses. Five fluorochromes were used to label different FISH gene probes, and 5 genes were detected using a five-color FISH protocol. After the first hybridization, the previous FISH probe set was stripped, and a second set of five-color FISH probes was used for rehybridization. After each hybridization, the fluorescence signals were recorded in 6 fluorescence filter channels that included DAPI, Spectrum Green^™, Cy3^™ v1, Texas Red, Cy5, and PF-415. A digital automatic relocation procedure was used to ensure that exactly the same microscopic field was studied in each stripping and hybridization cycle. By using this sequential stripping and rehybridization strategy, up to 20 genes can be detected within a single nucleus. In conclusion, a practical molecular pathology method was developed for analyzing multiple genes at the single-cell level.

Surgical histopathology for suspected oncocytoma on renal mass biopsy: a systematic review and meta-analysis

To estimate the proportion of oncocytic renal neoplasms diagnosed on renal mass biopsy (RMB) confirmed on surgical pathology, a systematic review of MEDLINE, Embase, and the Cochrane databases (1997 to 1 July 2016) was conducted quantifying all cases of reported oncocytic renal neoplasms on RMB suggestive of an oncocytoma. In addition, institutional data was assessed to identify additional cases. Concordance with surgical histopathology (positive predictive value [PPV]) was evaluated for patients undergoing surgery by performing a meta-analysis. In all, 10 RMB series, including institutional data, were included in the meta-analysis with 205 RMBs identifying oncocytic renal neoplasms and 46 (22.4%) proceeding to surgery. One additional study identified two neoplasms not captured by the primary RMB series for a total of 48 unique lesions included in the analysis. Surgical pathology showed oncocytoma (64.6%), chromophobe renal cell carcinoma (RCC; 12.5%), other RCC (12.5%), hybrid oncocytic/chromophobe tumour (6.3%), and other benign lesions (4.2%). PPV of oncocytoma on RMB was 67% (95% confidence interval 34-94%) with significant heterogeneity between studies (I² = 71.8%, P < 0.01). Risk of bias was judged to be low for four of the 10 series. Confidently diagnosing a localised renal mass as a benign lesion, such as an oncocytoma, has implications for the ultimate management strategy a patient will undergo. RMB was found to be unreliable in confidently diagnosing a localised renal mass as an oncocytoma, with one in four found to be RCC on surgical pathology. Patients and physicians should be aware of the uncertainty in diagnosis when considering management strategies.

Diagnostic Accuracy and Risks of Biopsy in the Diagnosis of a Renal Mass Suspicious for Localized Renal Cell Carcinoma: Systematic Review of the Literature

PURPOSE

Clinical practice varies widely on the diagnostic role of biopsy for clinically localized renal masses suspicious for renal cell carcinoma. Therefore, we performed a systematic review of the available literature to quantify the accuracy and rate of adverse events of renal mass biopsy.

MATERIALS AND METHODS

MEDLINE®, Embase® and the Cochrane databases were searched (January 1997 to May 2015) for relevant studies. The systematic review process established by the Agency for Healthcare Research and Quality was followed. Nondiagnostic biopsies were excluded from diagnostic accuracy calculations.

RESULTS

A total of 20 studies with 2,979 patients and 3,113 biopsies were included in the study. The overall nondiagnostic rate was 14.1% with 90.4% of those undergoing surgery found to have malignancy. Repeat biopsy led to diagnosis in 80% of patients. The false-positive rate was low (4.0%), histological and renal cell carcinoma subtype concordance was substantial, and Fuhrman upgrading notable (16%) from low grade (1 to 2) to high grade (3 to 4). Core biopsy was highly sensitive (97.5%, CI 96.5-98.5) and specific (96.2%, CI 90.7-100) when a diagnostic result was obtained, but most patients (∼80%) did not undergo surgery after a benign biopsy. Among patients undergoing extirpation 36.7% with a negative biopsy had malignant disease on surgical pathology (negative predictive value 63.3%, CI 52.4-74.2). Direct complications included hematoma (4.9%), clinically significant pain (1.2%), gross hematuria (1.0%), pneumothorax (0.6%) and hemorrhage (0.4%).

CONCLUSIONS

Diagnostic accuracy was generally high for biopsy of localized renal masses with a low complication rate, but the nondiagnostic rate and negative predictive value were concerning. Renal mass sampling should be used judiciously as further research will determine its true clinical utility.

Systematic Review and Meta-analysis of Diagnostic Accuracy of Percutaneous Renal Tumour Biopsy

CONTEXT

The role of percutaneous renal tumour biopsy (RTB) remains controversial due to uncertainties regarding its diagnostic accuracy and safety.

OBJECTIVE

We performed a systematic review and meta-analysis to determine the safety and accuracy of percutaneous RTB for the diagnosis of malignancy, histologic tumour subtype, and grade.

EVIDENCE ACQUISITION

Medline, Embase, and Cochrane Library were searched for studies providing data on diagnostic accuracy and complications of percutaneous core biopsy (CB) or fine-needle aspiration (FNA) of renal tumours. A meta-analysis was performed to obtain pooled estimates of sensitivity and specificity for diagnosis of malignancy. The Cohen kappa coefficient (κ) was estimated for the analysis of histotype/grade concordance between diagnosis on RTB and surgical specimen. Risk of bias assessment was performed (QUADAS-2).

EVIDENCE SYNTHESIS

A total of 57 studies recruiting 5228 patients were included. The overall median diagnostic rate of RTB was 92%. The sensitivity and specificity of diagnostic CBs and FNAs were 99.1% and 99.7%, and 93.2% and 89.8%, respectively. A good (κ = 0.683) and a fair (κ = 0.34) agreement were observed between histologic subtype and Fuhrman grade on RTB and surgical specimen, respectively. A very low rate of Clavien ≥ 2 complications was reported. Study limitations included selection and differential-verification bias.

CONCLUSIONS

RTB is safe and has a high diagnostic yield in experienced centres. Both CB and FNA have good accuracy for the diagnosis of malignancy and histologic subtype, with better performance for CB. The accuracy for Fuhrman grade is fair. Overall, the quality of the evidence was moderate. Prospective cohort studies recruiting consecutive patients and using homogeneous reference standards are required.

PATIENT SUMMARY

We systematically reviewed the literature to assess the safety and diagnostic performance of renal tumour biopsy (RTB). The results suggest that RTB has good accuracy in diagnosing renal cancer and its subtypes, and it appears to be safe. However, the quality of evidence was moderate, and better quality studies are required to provide a more definitive answer.

Subtyping of renal cortical neoplasms in fine needle aspiration biopsies using a decision tree based on genomic alterations detected by fluorescence in situ hybridization

OBJECTIVES

To improve the overall accuracy of diagnosis in needle biopsies of renal masses, especially small renal masses (SRMs), using fluorescence in situ hybridization (FISH), and to develop a renal cortical neoplasm classification decision tree based on genomic alterations detected by FISH.

PATIENTS AND METHODS

Ex vivo fine needle aspiration biopsies of 122 resected renal cortical neoplasms were subjected to FISH using a series of seven-probe sets to assess gain or loss of 10 chromosomes and rearrangement of the 11q13 locus. Using specimen (nephrectomy)-histology as the 'gold standard', a genomic aberration-based decision tree was generated to classify specimens. The diagnostic potential of the decision tree was assessed by comparing the FISH-based classification and biopsy histology with specimen histology.

RESULTS

Of the 114 biopsies diagnostic by either method, a higher diagnostic yield was achieved by FISH (92 and 96%) than histology alone (82 and 84%) in the 65 biopsies from SRMs (<4 cm) and 49 from larger masses, respectively. An optimized decision tree was constructed based on aberrations detected in eight chromosomes, by which the maximum concordance of classification achieved by FISH was 79%, irrespective of mass size. In SRMs, the overall sensitivity of diagnosis by FISH compared with histopathology was higher for benign oncocytoma, was similar for the chromophobe renal cell carcinoma subtype, and was lower for clear-cell and papillary subtypes. The diagnostic accuracy of classification of needle biopsy specimens (from SRMs) increased from 80% obtained by histology alone to 94% when combining histology and FISH.

CONCLUSION

The present study suggests that a novel FISH assay developed by us has a role to play in assisting in the yield and accuracy of diagnosis of renal cortical neoplasms in needle biopsies in particular, and can help guide the clinical management of patients with SRMs that were non-diagnostic by histology.

Significance of chromosome 9p status in renal cell carcinoma: a systematic review and quality of the reported studies

Defining the prognosis of renal cell carcinoma (RCC) using genetic tests is an evolving area. The prognostic significance of 9p status in RCC, although described in the literature, remains underutilised in clinical practice. The study explored the causes of this translational gap. A systematic review on the significance of 9p status in RCC was performed to assess its clinical applicability and impact on clinical decision-making. Medline, Embase, and other electronic searches were made for studies reporting on 9p status in RCC. We collected data on: genetic techniques, pathological parameters, clinical outcomes, and completeness of follow-up assessment. Eleven studies reporting on 1,431 patients using different genetic techniques were included. The most commonly used genetic technique for the assessment of 9p status in RCC was fluorescence in situ hybridization. Combined genomic hybridisation (CGH), microsatellite analysis, karyotyping, and sequencing were other reported techniques. Various thresholds and cut-off values were used for the diagnosis of 9p deletion in different studies. Standardization, interobserver agreement, and consensus on the interpretation of test remained poor. The studies lacked validation and had high risk of bias and poor clinical applicability as assessed by two independent reviewers using a modified quality assessment tool. Further protocol driven studies with standardised methodology including use of appropriate positive and negative controls, assessment of interobserver variations, and evidenced based follow-up protocols are needed to clarify the role of 9p status in predicting oncological outcomes in renal cell cancer.

Fluorescence in situ hybridization (FISH): an increasingly demanded tool for biomarker research and personalized medicine

Extensive studies of the genetic aberrations related to human diseases conducted over the last two decades have identified recurrent genomic abnormalities as potential driving factors underlying a variety of cancers. Over the time, a series of cutting-edge high-throughput genetic tests, such as microarrays and next-generation sequencing, have been developed and incorporated into routine clinical practice. Although it is a classical low-throughput cytogenetic test, fluorescence in situ hybridization (FISH) does not show signs of fading; on the contrary, it plays an increasingly important role in detecting specific biomarkers in solid and hematologic neoplasms and has therefore become an indispensable part of the rapidly developing field of personalized medicine. In this article, we have summarized the recent advances in FISH application for both de novo discovery and routine detection of chromosomal rearrangements, amplifications, and deletions that are associated with the pathogenesis of various hematopoietic and non-hematopoietic malignancies. In addition, we have reviewed the recent developments in FISH methodology as well.

Potential role of genetic markers in the management of kidney cancer

CONTEXT

Kidney cancer is not a single entity but comprises a number of different types of cancer that occur in the kidney including renal cell tumours as the most common type. Four major renal cell tumour subtypes can be distinguished based on morphologic and genetic characteristics. To individualise therapy and to improve the prognosis in patients with renal cell tumours, accurate subtyping, definition of individual course of disease, and the prediction of therapy response are necessary.

OBJECTIVE

To discuss the potential role of genetic markers in the management of kidney cancer.

EVIDENCE ACQUISITION

A Medline search was conducted to identify original articles, review articles, and editorials addressing the role of genetic alterations in kidney cancer management. Keywords included kidney neoplasms, genetics, SNP, gene expression, miRNA, classification, diagnosis, drug therapy, prognosis, and therapy. The articles with the highest level of evidence were identified and critically reviewed. This review is the result of an interactive peer-reviewing process by an expert panel of co-authors.

EVIDENCE SYNTHESIS

Each subtype is characterised by specific genetic, epigenetic, and expression patterns that potentially can be used to subclassify renal cell tumours in cases of ambivalent histopathology. Molecular signatures and single alterations in primary tumours are associated with aggressiveness and prognosis. Germline polymorphisms in specific genes encoding for metabolizing enzymes, efflux transporters, and drug targets seem to be associated with toxicity and response in patients receiving targeted therapy.

CONCLUSIONS

Significant advances have been achieved in the molecular analysis of renal cancer. Validation of findings is greatly needed to implement genetic markers in the management of renal cancer. This should lead to improved diagnosis, prognosis, and personalised therapy in this heterogeneous disease.