Rola Saleeb

Malignancies arising in allograft kidneys, with a first reported translocation RCC post-transplantation: A case series.

BACKGROUND The increased risk of malignancy in the post-renal transplant population has been well documented. Renal carcinoma is more common in this population, usually arising in native kidneys. Rarely, tumors arise in the transplanted kidney. Our case series reports four cases of malignancy in allograft kidneys, one of which is a first reported case of translocation RCC in a transplanted kidney. METHODS The renal transplantation database (1584 patients) at St. Michaels Hospital was reviewed for malignancies arising in allograft kidneys: reports and pathology slides were reviewed. RESULTS Four cases of malignancies arising in the allograft kidney were identified among our kidney transplant population. One patient developed a high grade urothelial carcinoma in the donor kidney post BK virus infection. The other 3 cases were renal cell carcinomas: one clear cell renal cell carcinoma, one translocation renal cell carcinoma, and one papillary renal cell carcinoma. The translocation renal cell cancer had confirmed TFE3 protein over-expression by immunohistochemistry. Molecular testing of the tumors in all 4 cases identified two separate genetic profiles, favored to represent tumors arising from donor tissues along with infiltrating recipient lymphocytes. DISCUSSION Previous reports suggested that epithelial malignancies in allograft kidneys are rare. We identified 4 such tumors in 1584 transplant patients. Further, we identified the first reported case of translocation RCC in an allograft kidney. While the rate of malignancy in allograft kidneys is low, screening of the donor kidneys by ultrasound and/or urine cytology may be of use in detecting these lesions.

An integrated genomic analysis of papillary renal cell carcinoma type 1 uncovers the role of focal adhesion and extracellular matrix pathways

Papillary renal cell carcinoma (pRCC) is the second most common RCC subtype and can be further classified as type 1 (pRCC1) or 2 (pRCC2). There is currently minimal understanding of pRCC1 pathogenesis, and treatment decisions are mostly empirical. The aim of this study was to identify biological pathways that are involved in pRCC1 pathogenesis using an integrated genomic approach. By microarray analysis, we identified a number of significantly dysregulated genes and microRNAs (miRNAs) that were unique to pRCC1. Integrated bioinformatics analyses showed enrichment of the focal adhesion and extracellular matrix (ECM) pathways. We experimentally validated that many members of these pathways are dysregulated in pRCC1. We identified and experimentally validated the downregulation of miR‐199a‐3p in pRCC1. Using cell line models, we showed that miR‐199a‐3p plays an important role in pRCC1 pathogenesis. Gain of function experiments showed that miR‐199a‐3p overexpression significantly decreased cell proliferation (p = 0.013). We also provide evidence that miR‐199a‐3p regulates the expression of genes linked to the focal adhesion and ECM pathways, such as caveolin 2 (CAV2), integrin beta 8 (ITGB8), MET proto‐oncogene and mammalian target of rapamycin (MTOR). Using a luciferase reporter assay, we further provide evidence that miR‐199a‐3p overexpression decreases the expression of MET and MTOR. Using an integrated gene/miRNA approach, we provide evidence linking miRNAs to the focal adhesion and ECM pathways in pRCC1 pathogenesis. This novel information can contribute to the development of effective targeted therapies for pRCC1, for which there is none currently available in the clinic.

Malignancies in a renal transplant population: The St. Michael's Hospital experience

Introduction: Previous publications have shown an increased incidence of various malignancies amongst renal transplant populations. The objective of this study was to analyze the rate and types of malignancies occurring in the St. Michaels Hospital renal transplant population and to determine whether our results were comparable to those previously published. Methods: After approval by the hospitals research ethic board, review of the records and pathology of the 1584 patients in the renal transplant clinic database patients was performed. The reports dated back to the year 1970. Results: Amongst the 1584 renal transplant patients, 106 patients with 132 dysplastic and malignant posttransplant lesions were identified. The highest incidence amid the malignancies was in nonmelanoma skin malignancies squamous cell carcinoma (SCC), basal cell carcinoma, and Kaposi sarcoma, with a total of 32 patients having 54 separate tumors (2.02% of all patients, 43.2% of tumors). Following skin tumors in incidence were genitourinary (28 tumors), gastrointestinal tract (GIT) lesions (8 adenocarcinomas, 14 dysplastic lesions, 1 low grade neuroendocrine tumor/carcinoid), posttransplant lymphoproliferative disorders (PTLDs) (10 cases), gynecologic (6 carcinomas), cervical/anal/vulvar dysplasia and invasive (SCCs) (4), and thyroid (3 papillary tumors). Nine patients had tumors of multiple sites/types. With respect to outcome, 14 patients died of malignancy, with the highest mortality being in the GIT malignancies (six patients). Second in mortality were the PTLD and skin tumor groups. Discussion: Information on the incidence and outcome of various malignancies in renal transplant patients is important in designing guidelines for the follow-up of these patients regarding tumor screening and prevention. The rate of malignancies in our group is comparable to that reported in other centers.

Integrated Phenotypic/Genotypic Analysis of Papillary Renal Cell Carcinoma Subtypes: Identification of Prognostic Markers, Cancer-related Pathways, and Implications for Therapy

BACKGROUND Two histologic subtypes are recognized for papillary renal cell carcinoma (PRCC). Studies have shown that the subtypes differ in characteristic genetic alterations and clinical behavior. Clinically, the subtypes are managed similarly. OBJECTIVES To analyze the biological differences between the two PRCC histological subtypes, in order to further guide their clinical management. DESIGN, SETTING, AND PARTICIPANTS PRCC cohort consisting of 317 patients from the Cancer Genome Atlas database and our institution. Patients were stratified according to histologic criteria as type 1, type 2, or not otherwise specified (NOS). Gene and miRNA expression data for the cohort were examined via unsupervised and supervised clustering. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Significant molecular signatures for each subtype were used to unravel the implicated molecular pathways via bioinformatics analysis. Survival was compared between the subtypes. Newly discovered biomarkers were used to further stratify survival of patients in the NOS category. RESULTS AND LIMITATIONS Tumor genotyping revealed two distinct PRCC subtypes. The top molecular pathways enriched in PRCC1 were WNT, Hedgehog, and Notch signaling (p=0.001-0.01); highlighting an embryonic developmental theme to the pathogenesis of this subtype. PRCC2 showed enrichment in the mTOR, VEGF (p=7.49E-09) and HIF (p=7.63E-05) signaling pathways. Overall survival and disease-free survival significantly differed between the types. ABCC2 expression was identified as a significant prognostic biomarker for the NOS group in univariate (log rank p<0.0001; hazard ratio [HR] >11.63) and multivariate analysis (p=0.003; HR >2.12). ABCC2 expression and its effect on survival should be further validated at the protein level. CONCLUSIONS The classical PRCC types 1 and 2 have two distinct genotypes. We unraveled pathways that indicate that the two types could potentially respond differently to current therapies. We also identified biomarkers that stratify tumors within the PRCC NOS category into prognostic subgroups. Our findings highlight the need for molecular markers to accurately subtype PRCC and guide clinical management. PATIENT SUMMARY The two types of papillary renal cancer are treated similarly. We show that the two types have a different genetic makeup, and hence they should be considered two different tumors. There is a different biology underlying each tumor type that can potentially affect the way they respond to treatment. We uncovered genes that can be tested for to guide therapy in some problematic cases for which it hard to define the tumor type.

Clear cell papillary renal cell carcinoma as part of histologically discordant multifocal renal cell carcinoma: A case report and review of literature.

BACKGROUND Multifocal renal cell carcinoma of different histological subtypes within a single kidney is rare. We report a recently classified clear cell (tubulo) papillary renal cell carcinoma as part of an unusual case of multifocal renal cell carcinoma of discordant histological subtypes. RESULTS A 57 year-old-man was found to have multiple renal tumors and cysts on imaging and underwent a laparoscopic left radical nephrectomy. Pathological review showed multifocal renal cell carcinoma (clear cell (tubulo) papillary, clear cell and papillary renal cell carcinomas and papillary adenomas). Morphology of clear cell papillary renal cell carcinoma was supported by immunohistochemical profile (CK7+, HMWK+, CAIX+, AMACR-, CD10-, TFE3-). CONCLUSIONS This is the first report of clear cell papillary renal cell carcinoma as part of multifocal renal cell carcinoma of different histological subtypes. Related lineage of clear cell renal cell carcinoma and papillary renal cell carcinoma is supported by the highest prevalence of their combination within multifocal renal cell carcinoma of different histological subtypes along with their molecular interconnection. Clear cell papillary renal cell carcinoma may be uniquely placed between clear cell and papillary renal cell carcinomas since it shows morphological features intermediate between clear cell and papillary renal cell carcinoma along with overlapping but unique immunohistochemical profile. Clear cell papillary renal cell carcinoma may be molecularly related to clear cell and papillary renal cell carcinomas since the tumors overexpress markers of HIF pathway activation with normal/elevated VHL mRNA expression and some tumors show losses of chromosome 3. Due to the overlapping morphology, it is possible that cases of clear cell papillary renal cell carcinoma may have been misclassified as papillary or clear cell renal cell carcinoma in the literature, incorrectly increasing their reported prevalence. Identification of multifocal RCCs may be related to the extent of pathological sampling.

A miRNA-based classification of renal cell carcinoma subtypes by PCR and in situ hybridization

Renal cell carcinoma (RCC) constitutes an array of morphologically and genetically distinct tumors the most prevalent of which are clear cell, papillary, and chromophobe RCC. Accurate distinction between the typically benign-behaving renal oncocytoma and RCC subtypes is a frequent challenge for pathologists. This is critical for clinical decision making. Subtypes also have different survival outcomes and responses to therapy. We extracted RNA from ninety formalin-fixed paraffin-embedded (FFPE) tissues (27 clear cell, 29 papillary, 19 chromophobe, 4 unclassified RCC and 11 oncocytomas). We quantified the expression of six miRNAs (miR-221, miR-222, miR-126, miR-182, miR-200b and miR-200c) by qRT-PCR, and by in situ hybridization in an independent set of tumors. We developed a two-step classifier. In the first step, it uses expression of either miR-221 or miR-222 to distinguish the clear cell and papillary subtypes from chromophobe RCC and oncocytoma (miR-221 AUC: 0.96, 95% CI: 0.9132–1.014, p < 0.0001 and miR-222 AUC: 0.91, 95% CI: 0.8478–0.9772, p < 0.0001). In the second step, it uses miR-126 to discriminate clear cell from papillary RCC (AUC: 1, p < 0.0001) and miR-200b to discriminate chromophobe RCC from oncocytoma (AUC: 0.95, 95% CI: 0.8933–1.021, p < 0.0001). In situ hybridization showed a nuclear staining pattern. miR-126, miR-222 and miR-200b were significantly differentially expressed between the subtypes by in situ hybridization. miRNA expression could distinguish RCC subtypes and oncocytoma. miRNA expression assessed by either PCR or in situ hybridization can be a clinically useful diagnostic tool to complement morphologic renal tumor classification, improving diagnosis and patient management.

Modulating ATP binding cassette transporters in papillary renal cell carcinoma type 2 enhances its response to targeted molecular therapy

Papillary renal cell carcinoma (PRCC) is the most common nonclear cell RCCs and is known to comprise two histological subtypes. PRCC2 is more aggressive and is molecularly distinct from the other subtypes. Despite this, PRCCs are treated together as one entity, and they show poor response to the current therapies that do not target pathways implicated in their pathogenesis. We have previously detected ABCC2 (an ABC transporter), VEGF, and mTOR pathways to be enriched in PRCC2. In this study, we assess the therapeutic potential of targeting these pathways in PRCC2. Twenty RCC cell lines from the Cancer Cell Encyclopedia were compared to the Cancer Genome Atlas PRCC cohort (290), to identify representative PRCC2 cell lines. Cell lines were further validated in xenograft models. Selected cell lines were treated in vitro and in vivo (mice models) under five different conditions, untreated, anti‐VEGF (sunitinib), ABCC2 blocker (MK571), mTOR inhibitor (everolimus) and sunitinib + MK571. Sunitinib +ABCC2 blocker group showed a significant response to therapy compared to the other treatment groups both in vitro (P ≤ 0.0001) and in vivo (P = 0.0132). ABCC2 blockage resulted in higher sunitinib uptake, both in vitro (P = 0.0016) and in vivo (P = 0.0031). Everolimus group demonstrated the second best response in vivo. The double‐treatment group showed the highest apoptotic rate and lowest proliferation rate. There is an urgent need for individualized therapies of RCC subtypes that take into account their specific biology. Our results demonstrate that combined targeted therapy with sunitinib and ABCC2 blocker in PRCC2 has therapeutic potential. The results are likewise potentially significant for other ABCC2 high tumors. However, the results are preliminary and clinical trials are needed to confirm these effects in PRCC2 patients.

Melanotic MiT family translocation neoplasms: Expanding the clinical and molecular spectrum of this unique entity of tumors

MiT family translocation tumors are a group of neoplasms characterized by translocations involving MiT family transcription factors. The translocation renal cell carcinomas, TFE3 (Xp11.2) and TFEB (t6;11) are known members of this family. Melanotic Xp11 translocation renal cancer is a more recently described entity. To date only 14 cases have been described. It is characterized by a distinct set of features including a nested epithelioid morphology, melanin pigmentation, labeling for markers of melanocytic differentiation, lack of labeling for markers of renal tubular differentiation, predominance in a younger age population and association with aggressive clinical behavior. There are noted similarities between that entity and TFE3 associated PEComas. There are no cases reported of equivalent melanotic TFEB translocation renal cancer. We report 2 rare cases of melanotic translocation renal neoplasms. The first is a melanotic TFE3 translocation renal cancer with an indolent clinical course, occurring in a patient more than 3-decades older than the usual average age in which such tumors have been described. The other case is, to our knowledge, the first reported melanotic TFEB translocation cancer of the kidney. Both cases exhibit the same H&E morphology as previously reported in melanotic translocation renal cancers and label accordingly with HMB45 and Melan-A. While the TFE3 melanotic tumor lacked any evidence of renal tubular differentiation, the TFEB melanotic cancer exhibited some staining for renal tubular markers. Based on the unique features noted above, these two cases expand the clinical and molecular spectrum of the melanotic translocation renal cancers.