Review of renal carcinoma associated with Xp11.2 translocations/TFE3 gene fusions with focus on pathobiological aspect

The concept of Xp11.2 renal cell carcinoma (RCC) was recently established as a tumor affecting 15% of RCC patients <45 years. Many patients present with advanced stage with frequent lymph node metastases. Histologically, Xp11.2 RCC is characterized by mixed papillary nested/alveolar growth pattern and tumor cells with clear and/or eosinophilic, voluminous cytoplasm. Neoplastic cells show intense nuclear immunoreactivity to TFE3, while focal immunostaining for melanocytic markers, including melanosome-associated antigen or Melan A in some cases, are also noted. Alpha smooth muscle actin and TFEB are consistently negative. Ultrastructurally, the ASPL-TFE3 RCC variant contains rhomboid crystals in the cytoplasm, similar to that observed in alveolar soft part sarcoma. The fusion of the TFE3 gene with several different genes, including ASPL(17q25), PRCC(1q21), PSF(1q34), NonO (Xq12) and CLTC (17q23) have been identified to date. The behavior of Xp11.2 RCC in children and young adults is considered as indolent even when diagnosed at advanced stage, including lymph node metastasis. However, Xp11.2 RCC in older patients behaves in a more aggressive fashion. Therapy includes nephrectomy with extended lymphadenectomy. There may be a role for new protease inhibitors in advanced inoperable disease. Further research is required to correlate clinical behavior with the expanding genetic spectrum of this tumor, and to establish standard therapy protocols for primary and metastatic lesions.     

Autophagy in Xp11 translocation renal cell carcinoma: from bench to bedside

Molecular and Cellular Biochemistry - Xp11 translocation renal cell carcinoma (tRCC) characterized by the rearrangement of the TFE3 is recently identified as a unique subtype of RCC that urgently...     

Immunohistochemical identification of intracytoplasmic lumens by cytokeratin typing may differentiate renal oncocytomas from chromophobe renal cell carcinomas

Renal oncocytomas and chromophobe renal cell carcinomas (RCCs) share a common phenotype and both originate from the intercalated cells of the collecting duct. This makes it very difficult to differentiate between the two tumors immunohistochemically. Therefore, we studied the results of immunohistochemistry focusing on certain characteristic structures that are occasionally present in renal oncocytomas. We carried out Hale's colloidal iron staining and immunohistochemistry for various cytokeratins (cytokeratins 7, 8, 10, 10/13, 14, 18, 19 and 20, and AE1/AE3) in four oncocytomas and six chromophobe RCCs. In addition, one renal oncocytoma and one chromophobe RCC were studied using electron microscopy. Two renal oncocytomas and one chromophobe RCC were completely unstained by colloidal iron. There was no evident difference between the immunohistochemical characteristics of oncocytomas and those of chromophobe RCCs. However, in all four renal oncocytomas we identified intracytoplasmic ring-like positive reactions for some cytokeratins (at least 3 antigens of cytokeratins 7, 8 and 19, and AE1/AE3), which corresponded ultrastructurally to the intracytoplasmic lumens (ICLs). In contrast, no such structures were found in any of the chromophobe RCCs using the antibodies employed. Therefore, immunohistochemical identification of ICLs by cytokeratin typing may be useful for differentiating between renal oncocytomas and chromophobe RCCs and be more sensitive in this respect than colloidal iron staining.     

Review of sarcomatoid renal cell carcinoma with focus on clinical and pathobiological aspects

In sarcomatoid renal cell carcinoma (RCC), it is generally accepted that the sarcomatoid portion is derived from metaplastic transformation of carcinoma. Sarcomatoid RCCs account for about 1-8% of all renal tumors. Macroscopically, tumors generally form encapsulated masses and show invasive growth. Sarcomatoid RCCs originate from all subtypes of RCCs, including conventional, papillary, chromophobe, and collecting duct carcinomas. With regard to the growth pattern of the sarcomatoid component, malignant fibrous histiocytomatous, fibrosarcomatous and unclassified sarcomatous patterns are frequently seen. Immunohistochemically, sarcomatoid RCCs are generally positive for AE1/AE3, epithelial membrane antigen (EMA) and vimentin and negative for desmin, actin and S-100. Little is know about genetic alterations in sarcomatoid RCCs. Further studies are therefore needed to identify the key gene involved in sarcomatoid transformation of RCCs.     

Sodium butyrate induces cell death by autophagy and reactivates a tumor suppressor gene DIRAS1 in renal cell carcinoma cell line UOK146

Sodium butyrate (SB), a histone deacetylase inhibitor, is emerging as a potent anti-cancer drug for different types of cancers. In the present study, anti-cancer activity of SB in Xp11.2 (TFE3) translocated renal cell carcinoma cell line UOK146 was studied. Anti-proliferative effect of SB in renal cell carcinoma (RCC) cell line UOK146 was evaluated by MTT assay and morphological characteristics were observed by phase contrast microscopy which displayed the cell death after SB treatment. SB induces DNA fragmentation and change in nuclear morphology observed by increased sub-G1 region cell population and nuclear blebbings. Cell cycle arrest at G2/M phase was found after SB treatment. UOK146 cell line shows autophagy mode of cell death as displayed by acridine orange staining and flow cytometry analysis. LC3-II, a protein marker of autophagy, was also found to be upregulated after SB treatment. A tumor suppressor gene DIRAS1 was upregulated after SB treatment, displaying its anti-cancer potential at molecular level. These findings suggest that SB could serve as a novel regulator of tumor suppressors and lead to the discovery of novel therapeutics with better and enhanced anti-cancer activity.     

Sarcomatoid acquired cystic disease-associated renal cell carcinoma

In this article, we report a rare case of hitherto undescribed acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) with sarcomatoid change. A 78-year-old woman had been receiving hemodialysis for fourteen years at the time when a renal tumor was encountered on the follow-up examination of the kidney. Microscopically, oncocytic cuboidal cells proliferated with tubular, cribriform or papillary growth patterns, and atypical columnar cells with abundant cytoplasm proliferated with papillary configuration. Oxalate crystal deposition was observed in the stroma and the tumor focally resembled translocation type (TFE3) RCC. Sarcomatous neoplastic cells were also seen. The cytoplasm of oncocytic and sarcomatous neoplastic cells was diffusely positive for anti-mitochondrial antibody and the ultrastructural examination detected many mitochondria in the cytoplasm of oncocytic carcinoma cells and sarcomatous neoplastic cells. The loss of chromosomes 1p, 2q11-22, 9 and 14 was observed using comparative genomic hybridization analysis. We thus report here a case of hitherto undescribed ACD-associated RCC intermingled with oncocytic cells, translocation type RCC-like area and sarcomatoid change. This is the sixth case of sarcomatoid RCC arising in end-stage kidney disease.     

Localization of X chromosome short arm markers relative to synovial sarcoma- and renal adenocarcinoma-associated translocation breakpoints

A series of thirteen different DNA markers was mapped relative to papillary renal cell carcinoma- and synovial sarcoma-associated translocation breakpoints in Xp11.2 using a panel of tumor-derived somatic cell hybrids in conjunction with Southern blot analysis. Our results indicate that the two translocation breakpoints differ from each other and that the chromosomal break in t(X; 1)-positive papillary renal cell carcinoma is located between the markers PFC-TIMP-OATL1-SYP-TFE3 and DXS226-DXS146-DXS255-OATL2-DXS14. In addition, our current breakpoint analysis has resulted in a revision of the regional localization of the proximal Xp marker DXS226.     

Expression and Functional Characterization of the BNIP3 Protein in Renal Cell Carcinomas

BNIP3 (Bcl-2/adenovirus E1B 19-kDa interacting protein 3) is a BH3-only protein that regulates apoptosis and autophagy. BNIP3 plays also an important role in hypoxia-induced cell response and is regulated by HIF1. Here, we studied a possible association of BNIP3 expression and the prognosis of patients with renal cell carcinomas (RCCs) and examined the functional relevance of BNIP3 in the regulation of cell survival and apoptosis of renal carcinoma cells. BNIP3 expression was determined by immunohistochemistry in RCC tumor tissue samples of 569 patients using a tissue microarray. Functional characterization of BNIP3 in renal carcinoma cells indicates prosurvival effects. In human RCC tumor samples, high cytoplasmic BNIP3 expression was associated with high-grade RCCs and regional lymph node metastasis. BNIP3 expression correlated negatively with disease-specific survival. Multivariate Cox regression analysis retained BNIP3 expression as an independent prognostic factor in patients without distant metastasis. Together, our studies imply that BNIP3 regulates cell survival in RCCs and its expression is an independent prognostic marker in patients with localized RCCs.     

Review of chromophobe renal cell carcinoma with focus on clinical and pathobiological aspects

In recent years, the concept of chromophobe renal cell carcinoma (RCC) has been established. Chromophobe RCCs account for about 4-6% of all renal tumors. Macroscopically, the cut surface of the tumor is generally grey-beige in color. Histologically, there are two variants (typical and eosinophilic). In the typical variant, large tumor cells with architecture of a compact tubulo-cystic pattern proliferate. The cytoplasm is abundant and shows a fine reticular translucent pattern. The cell border is thick, prominent and eosinophilic. In the eosinophilic variant, tumor cells are smaller and markedly eosinophilic, and a perinuclear halo is often seen. Histochemically, the tumor cells generally show a diffuse and strong reaction for Hale's colloidal iron staining. Ultrastructurally, tumor cells contain many cytoplasmic microvesicles (150-300 nm). In chromosomal analysis, a low chromosome number is characteristic of chromophobe RCCs, due to the frequent occurrence of a combined loss of chromosomes 1, 2, 6, 10, 13, 17, and 21. In differential diagnosis, histological distinction from oncocytomas, which share a common phenotype (intercalated cells of the collecting duct system), is most important. In this diagnostic setting, recent studies have given rise to several problems. Firstly, some cases of coexistent chromophobe RCC and oncocytoma (so-called renal oncocytosis) or cases of oncocytoma with metastasis have recently been reported. Secondly, the existence of chromophobe adenoma, which is the benign counterpart of chromophobe RCC, and an oncocytic variant of chromophobe RCC has recently been suggested. Therefore, further studies are needed to elucidate the relationship between chromophobe RCCs and oncocytomas, to confirm whether chromophobe adenoma actually exists or not, and to identify the key gene that causes chromophobe RCCs.     

Molecular study of a new family with hereditary renal cell carcinoma and a translocation t(3;8)(p13;q24.1)

An alternative model has been proposed for the development of clear-cell renal cell carcinoma (RCC) in families where chromosome 3 translocations segregate with the disease. In this model, the existence of a translocation involving chromosome 3 would favour the non-disjunctional loss of the derivative chromosome carrying the 3p segment. Additionally, subsequent somatic mutations in the VLH gene, located in 3p25-26, would inactivate this tumour suppressor gene. In the present work, we describe a new family with two clear-cell RCC affected members and a t(3;8)(p13;q24.1) translocation in two consecutive generations. We observed loss of the derivative chromosome carrying the 3p segment (der(8)) and somatic mutation of the VHL gene in the left-kidney tumoral tissue of the proband. His right-kidney tumour carried a different VHL mutation and loss of heterozygosity (LOH) was not detected. The mother of the proband was also clear-cell RCC-affected but the tumoral tissue analysed did not carry any VHL gene mutations. Another member of the family, a maternal aunt, had a papillary RCC and did not carry this translocation, the LOH on 3p or the VHL somatic mutations. Haplotype analysis of the three affected members revealed that they did not inherit a common region on 3p, confirming the different genetic origin of both tumour types. Finally, the presence of RCC in other non-available members of the family highlights the overall risk for RCC in families with chromosome 3 translocations. In the present work, we have confirmed the proposed mechanism for the development of clear-cell RCC in this family, although we cannot discard the existence of other genes, in addition to VHL, being involved in hereditary RCC.     

Alterations of the WNT7A Gene in Clear Cell Renal Cell Carcinomas

WNT7A (wingless-type MMTV integration site family, member 7A) is a known tumor suppressor gene of non-small cell lung carcinomas (NSCLC) and is frequently inactivated due to CpG-island hypermethylation in human cancers. The members of WNT family are involved in cell signaling and play crucial roles in cancer development. In the present work hypermethylation of the WNT7A gene was detected in 66% (29/44) of analyzed clear cell renal cell carcinomas (RCCs) using methyl-specific PCR (MSP). Moreover, bisulfite sequencing confirmed intensive hypermethylation of the 5′-CpG island of the WNT7A gene. Methylation analysis revealed positive correlations between tumor stage, Fuhrman nuclear grade and WNT7A hypermethylation. Additionally, restoration of WNT7A gene expression in the A498 cell line by 5-aza-2′-deoxycytidine treatment confirmed a direct contribution of hypermethylation in silencing of the WNT7A gene. High frequency of loss of heterozygosity (LOH) was demonstrated on chromosome 3p25 in regions surrounding the WNT7A gene. The frequent down-regulation of WNT7A gene expression was detected in 88% (15/17) of clear cell RCCs. We have also shown that the WNT7A gene possesses tumor suppression function by colony-formation and cell proliferation assays in RCC cell lines. In summary, the WNT7A gene is inactivated by genetic/epigenetic alterations in clear cell RCC and demonstrates tumor suppressor properties.     

PRCC‐TFE3 regulates migration and invasion of translocation renal cell carcinomas via activation of Drp1‐dependent mitochondrial fission

PRCC‐TFE3 translocation renal cell carcinomas (tRCC) is a common subtype of TFE3 tRCCs in which TFE3 fusions are indicated as oncogenes to promote tumor development. PRCC‐TFE3 fusions are often accumulated in the nucleus and related to poorer outcomes and higher stages (III/IV). In this study, we found that PRCC‐TFE3 could positively regulate expression of both dynamin‐related protein 1 (Drp1) and fission protein 1, and alter distribution of mitochondria, which could promote cell migration and invasion independent of matrix metalloproteinase‐2 (MMP‐2) and MMP‐9. Together, our findings showed a new mechanism for PRCC‐TFE3 tRCC cell migration and invasion by alteration of mitochondrial dynamics. Thus, targeting dysregulated Drp1‐dependent mitochondrial fission may provide a novel strategy for suppressing the progression of PRCC‐TFE3 tRCC.     

Incontinentia pigmenti (type 1) and X;5 translocation.

The authors present a 5-year-old girl with total absence of speech, dysmorphic features, pigmented lesions on the legs, an abnormal EEG and otherwise normal intelligence representing a mild form of type 1 Incontinentia pigmenti associated with an (X;5) (p11.2;q35.2) apparently balanced translocation prenatally diagnosed. The seven previous translocation type 1 IP patients are reviewed and all have the same Xp11 breakpoint. Somatic cell hybrids have been made to further study this breakpoint and further define the putative type 1 IP gene.     

Review of papillary renal cell carcinoma with focus on clinical and pathobiological aspects

Recent studies have shown that papillary renal cell carcinoma (RCC) is clinically and genotypically a distinct entity. Papillary RCCs account for about 10-15% of renal parenchymal neoplasms. Macroscopically, the cut surface is yellow or brown in color and large tumors frequently show cystic change. Hemorrhage and necrosis are common. Histologically, Delahunt and Eble have classified papillary RCCs into type 1 (small cells, single layer) and type 2 (large cells, pseudostratification) according to the cytoplasmic volume and thickness of the lining cells. In chromosomal analysis, gain of chromosomes 7 and 17, loss of Y chromosome and additional gains (chromosome 3q, 8p, 12q, 16q and 20q) are frequently found in type 1 papillary RCCs, but the chromosomal aberration of type 2 papillary RCCs seems to be more heterogenous than that of type 1 papillary RCCs. Mutations of MET proto-oncogenes in some cases of both hereditary and sporadic papillary RCCs have recently been detected. Furthermore, all hereditary and sporadic papillary RCCs with MET proto-oncogene show type 1 histological features. Type 1 papillary RCCs generally seem to have a favorable prognosis, but type 2 tumors have a worse prognosis than do type 1 tumors. Papillary RCCs with involvement of the X chromosome and cancer syndrome with predisposition to cutaneous/uterine leiomyomas and papillary RCCs, the histological features of which are basically different from those of usual papillary RCCs, have also been recently reported. Since papillary RCCs seem to constitute clinically, histologically, and even genetically more heterogenous groups than previously thought, further investigations are needed to characterize the subtype of papillary RCC.     

Renal FNA-based typing of renal masses remains a useful adjunctive modality: evaluation of 31 renal masses with correlative histology

Objectives:  Given the advances in renal imaging modalities in the recent years, a greater number of renal cell carcinomas (RCCs) with tumour size of <3 cm are being detected radiologically. Consequently, there is a pressing need for accurate typing of RCCs which, in turn, will aid in selection of cases of nephron-sparing surgery.
Methods:  A total of 31 cases of renal masses with available fine needle aspiration (FNA) material and concomitant histopathology details were retrieved. They included 27 RCCs (17 clear cells, eight papillary and two chromophobe), one oncocytoma, one liposarcoma and two benign lesions – one xanthogranulomatous pyelonephritis (XPN) and one benign cyst. Two investigators reviewed all FNA material. The degree of concordance between cytological typing and histological typing was assessed.
Results:  There was excellent agreement between the FNA typing and the final diagnosis, with correct classification in 28 of 31 cases. Among the three discordant cases, two were RCCs. The first was a papillary RCC (PRCC) that was misdiagnosed on FNA as clear cell RCC. Another case that was typed as a PRCC on final histopathology was diagnosed 'suspicious cells' on FNA. The third case was an XPN that was misdiagnosed on FNA as RCC with necrosis.
Conclusions:  There is an excellent concordance (90.3%) between the FNA diagnosis and the final histological diagnosis, especially in RCCs. There is a tendency for misdiagnosis with PRCC. Lesions with extensive necrosis and relatively insufficient diagnostic material on FNA specimens must be interpreted with caution. Better concordance might be observed with more extensive sampling.