Primary collision tumors of the kidney composed of oncocytoma and papillary renal cell carcinoma: A review

To characterize small renal cell carcinoma using diffusion relaxation correlation spectroscopic imaging and apparent diffusion coefficient based histogram analysis: a preliminary study

PURPOSE

To study the capability of diffusion-relaxation correlation spectroscopic imaging (DR-CSI) on subtype classification and grade differentiation for small renal cell carcinoma (RCC). Histogram analysis for apparent diffusion coefficient (ADC) was studied for comparison.

MATERIALS AND METHODS

A total of 61 patients with small RCC (< 4 cm) were included in the retrospective study. MRI data were reviewed, including a multi-b (0-1500 s/mm2) multi-TE (51-200 ms) diffusion weighted imaging (DWI) sequence. Region of interest (ROI) was delineated manually on DWI to include solid tumor. For each patient, a D-T2 spectrum was fitted and segmented into 5 compartments, and the volume fractions VA, VB, VC, VD, VE were obtained. ADC mapping was calculated, and histogram parameters ADC 90th, 10th, median, standard deviation, skewness and kurtosis were obtained. All MRI metrices were compared between clear cell RCC (ccRCC) and non-ccRCC group, and between high-grade and low-grade group. Receiver operator curve analysis was used to assess the corresponding diagnostic performance.

RESULTS

Significantly higher ADC 90th, ADC 10th and ADC median, and significantly lower DR-CSI VB was found for ccRCC compared to non-ccRCC. Significantly lower ADC 90th, ADC median and significantly higher VB was found for high-grade RCC compared to low-grade. For identifying ccRCC from non-ccRCC, VB showed the highest area under curve (AUC, 0.861) and specificity (0.882). For differentiating high- from low-grade, ADC 90th showed the highest AUC (0.726) and specificity (0.786), while VB also displayed a moderate AUC (0.715).

CONCLUSION

DR-CSI may offer improved accuracy in subtype identification for small RCC, while do not show better performance for small RCC grading compared to ADC histogram.

Actual encounters of the kidney kind: Exploring 48 cases of renal collision tumors through the lens of literature

Multiple tumors of different lineages merging into a single mass, termed collision tumors, are considered a rare phenomenon in the kidney. Tumor components, or partners, may be malignant (including metastatic disease), borderline, or benign. We report the largest cohort to date of 48 cases. The cases were identified from the archives of three institutions in the last 16 years, including 43 (90%) with 2 tumor partners (dyad) and 5 (10%) with 3 partners (triad), totaling 101 individual neoplasms. The majority of cases involved immunohistochemical workup, and 5 underwent FISH or molecular studies. Forty (83%) cases featured a malignant entity, including all triads. Twenty dyads and two triads were composed entirely of malignant tumors. The most common malignant partner was clear cell renal cell carcinoma (RCC) (N = 19) followed by papillary RCC (N = 17). Nine (19%) cases featured borderline entities, including 5 multilocular cystic neoplasms of low malignant potential and 6 clear cell papillary renal cell tumors. Twenty one (44%) cases contained a benign partner, including 6 benign dyads. Papillary adenoma (N = 13) and oncocytoma (N = 8) were most common. Epithelial tumors were present in all 48 cases, and non-epithelial neoplasms in 9 cases (19%). Our cohort includes many novel combinations and collision partners with rare entities such as SDH-deficient RCC, TFE3-rearranged RCC, eosinophilic solid and cystic RCC, and acquired cystic disease associated RCC. A comprehensive literature review and analysis of collision tumor phenomenon in kidney placed these cases in context suggesting that collision tumors of the kidney are more common than previously recognized.

The potential of Lycium barbarum miR166a in kidney cancer treatment

Predator species of animal can absorb plant microRNA that can regulate target gene expression and physiological function across species. The herb Lycium barbarum, a traditional Chinese medicine, has a wide range of antitumor effects. However, there are no reports on the effects of microRNA derived from it on the cross-border regulation of renal cell carcinoma (RCC). We performed in vitro and in vivo experiments to explore the role and mechanism of the L. barbarum-derived microRNA miR166a (Lb-miR166a) in cross-border regulation of RCC. Our mRNA sequencing analysis showed that Lb-miR166a regulates the expression of various genes in tumor cells, including 1232 upregulated genes and 581 downregulated genes, which were enriched to 1094 Gene Ontology entries and 43 Kyoto Encyclopedia of Genes and Genomes pathways. In vitro cell experiments confirmed that Lb-miR166a can inhibit the proliferation of RCC cells, promote the apoptosis of tumor cells, and inhibit the invasion and metastasis of tumor cells by regulating the expression of related genes. Furthermore, our in vivo tumor-bearing experiment showed that subcutaneous tumor formation volume decreased in Lb-miR166a mice, along with the number of liver metastases. This study elucidates the role and mechanism of Lb-miR166a in RCC treatment (Fig. 1). Our results further mechanistically confirm the antitumor properties of L. barbarum. Our study may contribute to the clinical development of a targeted drug for RCC treatment.

Renal collision tumours: three additional case reports

Background

Multiple kidney tumours are frequently seen in hereditary syndromes and familial diseases. Renal collision tumours (RCT) are characterized by the simultaneous existence of different and unrelated tumour types within the same location in the kidney, forming a single, heterogenous lesion. RCT are uncommon histological entities with distinctive features. The most frequent subtypes include clear cell renal cell carcinoma (CCRCC), papillary renal cell carcinoma (PRCC), chromophobe renal cell carcinoma (CRCC), and collecting duct carcinoma (CDC).

Case presentation

Here, we report three sporadic cases of RCT successfully treated by nephrectomy and confirmed by histological analysis. The first case was of a 64-year-old man diagnosed with RCT composed of a stage 2 nucleolar grade 3 CCRCC and a stage 1a nucleolar grade 2 type 1 PRCC. The second case was of a 68-year-old woman diagnosed with a combined nucleolar grade 2 type 1 PRCC and an angiomyolipoma (non-assessed stage), while the third case was of a 59-year-old woman diagnosed with a combined stage 1a nucleolar grade 3 CCRCC and a stage 1b CDC.

Conclusions

Due to the rarity of RCT, there are no standard guidelines for their management. Hence, the prognosis is considered to be associated with the most aggressive component, possibly the tumour with the highest nucleolar grade and stage. The histogenesis of RCT remains debated, and increase in knowledge regarding this can help enable the development of targeted therapies for advanced or metastatic tumours.

Calbindin S100A16 Promotes Renal Cell Carcinoma Progression and Angiogenesis via the VEGF/VEGFR2 Signaling Pathway

Purpose

Recent research has indicated that the calcium-binding protein S100A16 promotes carcinogenesis and tumor growth in several forms of cancer. The objective of this study was to examine the relationship between S100A16 and renal cell cancer.

Methods

By using The Cancer Genome Atlas (TCGA) database, the differentially expressed gene S100A16 was identified, and its appearance and link to the prognosis of persons with renal cancer were confirmed. Cox regression was used in multivariate analysis, and a nomogram was developed for internal validation. The correlation between S100A16 and immune cells was analyzed in the TIMER database. Moreover, the potential mechanism of action was investigated utilizing GO and KEGG enrichment analyses. Proliferation, migration, and angiogenesis were investigated in vitro, and the involvement of S100A16 in the undesirable biological events of renal cell carcinoma (RCC) was further explored.

Results

S100A16 was the differentially expressed molecule identified through database screening. Malignant tissues showed higher S100A16 expression than noncancerous tissues, and S100A16 expression was mostly localized in the cytoplasm. According to the TCGA and KM-plotter datasets, patients with RCC and low S100A16 expression had superior OS, PFI, and DSS. The C-index of the nomogram was 0.754 (0.726–0.782), and the accuracy of the prediction model was high. The TIMER database shows that the expression of S100A16 is associated with immune infiltration and may play an important role in promoting tumor cell immune escape in the RCC tumor microenvironment. S100A16 may influence the biological processes of RCC via the VEGF/VEGFR2 signaling route and PI3K-Akt signaling pathway and through P53 alteration and cell cycle according to the gene enrichment technique. In vitro cytological experiments demonstrated that S100A16 knockdown can inhibit the proliferation and migration of renal cancer cells and the expression levels of VEGF, VEGFR2, and phosphorylated AKT within renal cancer cells, thereby inhibiting angiogenesis in renal cancer cells and resulting in a poor prognosis of RCC.

Conclusion

A decrease in S100A16 expression may dramatically increase the OS, PFI, and DSS of patients with RCC and may thus be used as a biomarker for predicting RCC. It may be associated with the immune infiltration of RCC and play a crucial role in the immune evasion of tumor cells within the RCC microenvironment. Intervention of s100a16 can promote the progression and angiogenesis of renal cell carcinoma through the VEGF/VEGFR2 signal transduction pathway and lead to poor prognosis of renal cell carcinoma. These findings suggest a potential target for the development of anticancer strategies for renal cancer.

High-Resolution Ultrasonography of Renal Oncocytoma Presenting with Symptomatic Hematuria and Urinary Bladder Clot Retention-A Rare Occurrence

Renal oncocytomas are asymptomatic, benign tumors often encountered incidentally on various imaging modalities. Renal oncocytomas comprise 5–7% of primary renal neoplasms and are derived from cells of the distal renal tubule. We present a case report of renal oncocytoma in a 22-year-old male having right-sided flank pain and symptomatic gross hematuria with a giant urinary bladder clot retention. The tumor was excised, and the patient underwent laparoscopic partial nephrectomy. Typical features of renal oncocytoma were observed upon histopathological examination of the resected specimen. The patient was catheterized, and bladder irrigation with clot retraction was performed.

Histone Methyltransferase G9a Promotes the Development of Renal Cancer through Epigenetic Silencing of Tumor Suppressor Gene SPINK5

Background

Renal cell carcinoma (RCC) accounts for approximately 2–3% of malignant tumors in adults, while clear cell renal cell carcinoma accounts for 70–85% of kidney cancer cases, with an increasing incidence worldwide. G9a is the second histone methyltransferase found in mammals, catalyzing lysine and histone methylation. It regulates gene transcription by catalyzing histone methylation and interacting with transcription factors to alter the tightness of histone-DNA binding. The main purpose of this study is to explore the role and mechanism of G9a in renal cell carcinoma.

Methods

Firstly, we investigated the expression of G9a in 80 clinical tissues and four cell lines. Then, we explored the effect of G9a-specific inhibitor UNC0638 on proliferation, apoptosis, migration, and invasion of two renal cancer cell lines (786-O, SN12C). In order to study the specific mechanism, G9a knocking down renal cancer cell line was constructed by lentivirus. Finally, we identified the downstream target genes of G9a using ChIP experiments and rescue experiments.

Results

The results showed that the specific G9a inhibitor UNC0638 significantly inhibited the proliferation, migration, and invasion of kidney cancer in vivo and in vitro; similar results were obtained after knocking down G9a. Meanwhile, we demonstrated that SPINK5 was one of the downstream target genes of G9a through ChIP assay and proved that G9a downregulate the expression of SPINK5 by methylation of H3K9me2. Therefore, targeting G9a might be a new approach to the treatment of kidney cancer.

Conclusion

G9a was upregulated in renal cancer and could promote the development of renal cancer in vitro and in vivo. Furthermore, we identified SPINK5 as one of the downstream target genes of G9a. Therefore, targeting G9a might be a new treatment for kidney cancer.

Renal Tumors with Oncocytic and Papillary Features: A Phenotypic and Genotypic Study

The occurrence of kidney oncocytic lesions with an admixed papillary component is not unusual in routine pathology practice. These neoplasms with dual morphology are classically recognized as collision tumors with variable malignant potential. Using immunohistochemistry, we investigated fluorescent in situ hybridization and next generation sequencing of the genetic and phenotypic profiles in the two components of 11 kidney tumors with colliding oncocytic and papillary features. The oncocytic component was CD117 positive, CK7 negative, and AMACR negative; the papillary component was CK7 positive, AMACR positive, and CD117 negative in all cases. Fluorescence in situ hybridization (FISH) results were inconsistent. Next generation sequencing (NGS) analysis demonstrated that the mutations identified in the two tumor components were identical and displayed an allelic frequency of approximately 50%, strongly suspicious for genetic polymorphisms. The two oncocytic and papillary tumor counterparts shared the same genetic profile and did not harbor pathogenic mutations. Clinical confirmation of the biological benign features of these tumors is required. The term collision tumor is not suitable for these neoplasms, and we propose the term oncopapillary tumor for this histological entity.

Tumor heterogeneity: does it matter?

Introduction: It has long been recognized that tumors are composed of a mosaic of cells and numerous methods have been developed to detect tumor heterogeneity, including in situ hybridization, multi-regional sampling, cytological assays, and whole genome and single cell sequencing. Using these methods, heterogeneity has been observed at the genetic, epigenetic, and phenotypic level in numerous cancers. With the advent of deep sequencing technology, we now appreciate a greater complexity of distinct genotypes and phenotypes that drive the biological behavior of cancer. Despite decades of progress in detecting tumor heterogeneity, the question remains: to what extent does it matter? Areas covered: This review explores the evidence for and against the importance of tumor heterogeneity in three main areas: prognostication, development of targeted therapeutics and tumor resistance; summarizing current understanding before evaluating ongoing experimental and clinical developments. Expert opinion: Theoretical understanding and in vitro detection of intratumour heterogeneity promises much but is yet to translate into meaningful clinical benefit. However, the recent emergence of a host of technological innovations and upcoming clinical trials may soon change the landscape of this field.