OBJECTIVETo investigate the mutation in mitochondrial DNA displacement-loop (mtDNA D-loop) region in oncocytoma and its relationship with tumorigenesis and tumor development.

METHODSThe mtDNA D-Loop region of 20 thyroid or renal oncocytomas and the adjacent normal tissues were amplified by PCR, and then sequenced. Five human fetal renal tissues were collected as matched controls.

RESULTSAmong the 20 oncocytomas, 21 mutations which focused on hypervariable region I (HVI) were found in 7 tumor tissues and 1 normal tissue with the mutation rates of 35% and 5%, respectively. At the same time, 191 polymorphisms were found in the 20 cases.

CONCLUSIONmtDNA D-loop region, especially HV I, is the mutational hotspot of oncocytomas, which may be closely related with mtDNA duplicating rate and the function of mitochondria.

Adenoma, Oxyphilic ; genetics ; Base Sequence ; DNA Mutational Analysis ; DNA, Mitochondrial ; genetics ; Female ; Humans ; Kidney Neoplasms ; genetics ; Male ; Middle Aged ; Mitochondria ; genetics ; Mutation ; Polymorphism, Genetic ; Thyroid Neoplasms ; genetics

Adenoma, Oxyphilic ; classification ; pathology ; Carcinoma, Renal Cell ; classification ; metabolism ; pathology ; Humans ; Kidney ; pathology ; Kidney Neoplasms ; classification ; genetics ; pathology ; therapy ; Molecular Biology ; methods ; trends

Objective: To explore clinicopathological features of low-grade oncocytic tumor (LOT) of the kidney and to analyze its relationship to hybrid oncocytic/chromophobe tumor (HOCT) of the kidney, renal oncocytoma (RO), and chromophobe renal cell carcinoma (chRCC). Methods: Seven LOTs were identified from the pathologic archives of two hospitals, including Xiangya Hospital (5 cases) and the Second Xiangya Hospital (2 cases) of Central South University between 2012 and 2019. Clinical data of the LOTs were collected. The tumor morphology was analyzed and immunohistochemistry was performed. Results: All LOTs occurred in adults, aged from 49 to 72 years (median 56.0 years, mean 60.7 years). The tumor size ranged from 2.5 to 6.0 cm (median 4.3 cm, mean 4.3 cm). There were three male and four female patients. Three cases occurred in the left kidney and four in the right. All the tumors were solitary lesions without the clinicopathologic background of Birt-Hogg-Dubé (BHD) syndrome or oncocytosis. Five patients had available follow-up data (follow-up period 23-95 months, median 69.0 months, mean 64.6 months) and all were alive without disease. Microscopically, all LOTs were well-circumscribed (7/7). Three LOTs were partly encapsulated. The tumors demonstrated a predominant growth pattern comprising prominently compact small nests surrounded by delicately branching thin-walled blood vessels, imparting an organoid architecture (7/7), but variable numbers of glandular or gland-like structures were often seen among the small nests (7/7). There were frequently areas with loose, edematous stroma, and the tumor cells exhibited reticular, trabecular, or single cell arrangements (6/7). Focal hemorrhage was also commonly present in both compact and loose areas (5/7). In addition, focally cystic formation and ossification occurred in the compact area of one case and in the loose area of another case. The tumor cells in LOT showed intermediate cytologic characteristics between RO and chRCC, including abundantly eosinophilic granular cytoplasm, ovoid to round nuclei with mostly smooth contours, discernable small nucleoli (RO features), frequently delicate perinuclear halos, and occasional binucleation (chRCC features). The tumors were typically CK7-positive and CD117-negative (7/7), and variable staining for PAX8 (5/7), P504s (2/7), and vimentin (1/7). They were negative for CK20, CD10 and FOXI1. All tumors retained SDHB immunostaining. Conclusions: LOT is a rare and indolent oncocytic renal tumor with homogeneously intermediate cytologic features between RO and chRCC. There are some clinicopathologic overlaps between LOT and sporadic HOCT. The distinctive morphology and immunophenotype of LOT suggest that it is potentially a distinct tumor entity.
Adenoma, Oxyphilic/pathology* ; Adult ; Biomarkers, Tumor/genetics* ; Carcinoma, Renal Cell/pathology* ; Female ; Forkhead Transcription Factors ; Humans ; Keratin-7 ; Kidney/pathology* ; Kidney Neoplasms/pathology* ; Male

OBJECTIVE: To assess the value of DNA methylation level of HYAL2 gene as a molecular marker for differential diagnosis of malignant and benign thyroid tumors. METHODS: DNA methylation of HYAL2 gene in tissue specimens of 190 patients with papillary thyroid cancer (PTC) and 190 age- and gender-matched patients with benign thyroid tumors was examined by mass spectrometry, and the protein expression of HYAL2 was detected immunohistochemically for another 55 pairs of patients. Logistic regression analysis was performed to calculate the odds ratio (OR) and evaluate the correlation of per 10% reduction in DNA methylation with PTC. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) was calculated to assess the predictive value of alterations in HYAL2 methylation. RESULTS: Hypomethylation of HYAL2_CpG_3 was significantly correlated with early-stage PTC (OR=1.51, P=0.001), even in stage I cancer (OR=1.42, P=0.007). Age-stratified analysis revealed a significantly stronger correlation between increased HYAL2_CpG_ 3 methylation and early-stage PTC in patients below 50 years than in those older than 50 years (OR: 1.89 vs 1.37, P < 0.05); ROC analysis also showed a larger AUC of 0.787 in younger patients. The results of immunohistochemistry showed that patients with PTC had significantly higher protein expressions of HYAL2 than patients with benign tumors. CONCLUSION The alterations of DNA methylation level of HYAL2 gene is significantly correlated with early-stage PTC, suggesting the value of DNA methylation level as a potential biomarker for differentiation of malignant from benign thyroid tumors.
Adenoma, Oxyphilic/genetics* ; Biomarkers, Tumor/metabolism* ; Cell Adhesion Molecules/metabolism* ; DNA Methylation ; GPI-Linked Proteins/metabolism* ; Humans ; Hyaluronoglucosaminidase/metabolism* ; Immunohistochemistry ; Middle Aged ; Thyroid Cancer, Papillary/pathology* ; Thyroid Neoplasms/pathology*

Objective: To investigate the clinicopathological, immunohistochemical and molecular characteristics of low grade oncocytic tumors (LOT) of the kidney with CK7+/CD117- staining pattern for enhancing the understanding of renal LOT. Methods: The clinical data, histological morphology and immunophenotypes of seven renal LOT cases diagnosed at the Department of Pathology, the First Affiliated Hospital, Zhejiang University School of Medicine from January 2017 to April 2021 were analyzed. The patients were followed up. Among the seven patients, five underwent high-throughput DNA targeted sequencing, and their molecular characteristics were analyzed. Results: The patients' age ranged 59-82 years, with an average of 70 years. There were 2 males and 5 females. The boundary of the tumor was clear. The tumor cells had homogeneous eosinophilic cytoplasm and round or oval nuclei, with a perinuclear halo. Small basophilic nucleoli were conspicuous (WHO/International Society of Urological Pathology grade 2). In the hypercellular areas, the tumor cells were mainly arranged in dense solid or nest. In the stroma, there were dilated veins, thick-walled arterioles and thick collagen fiber bundles that divided the cells into pseudonodules. In the sparsely cellular area, the tumor cells were arranged in the so-called "tissue culture" fashion. In addition, the stroma contained fresh hemorrhagic foci and lymphoid aggregates. High-throughput sequencing of 5 cases revealed that one case harbored mTOR gene missense mutation and another case harbored TSC1 frameshift mutation. Conclusions: LOT of the kidney is an indolent tumor with an overall good prognosis. Pathologists should not misdiagnose it as renal oncocytoma and chromophobe renal cell carcinoma.
Adenoma, Oxyphilic/pathology* ; Aged ; Aged, 80 and over ; Biomarkers, Tumor/genetics* ; Carcinoma, Renal Cell/pathology* ; Collagen ; Female ; Humans ; Immunohistochemistry ; Kidney/pathology* ; Kidney Neoplasms/pathology* ; Male ; Middle Aged ; Proto-Oncogene Proteins c-kit/metabolism* ; TOR Serine-Threonine Kinases

OBJECTIVETo study the expression and clinical significance of kidney injury molecule-1 (KIM-1) in primary and metastatic renal epithelial neoplasms.

METHODSA total of 136 cases of kidney neoplasms were retrospectively reviewed including 63 primary clear cell renal cell carcinomas (RCCs), 22 papillary RCCs, 13 chromophobe RCCs, 7 oncocytomas, 7 RCCs associated with Xp11.2 translocation/TFE3 gene fusions and 24 metastatic clear cell RCCs. Immunostaining for KIM-1 and kidney-specific-protein (Ksp)-cadherin were performed and the relationship to tumor stage and grade in clear cell RCCs was investigated.

RESULTSExpression of KIM-1 was detected in 77.8% (49/63) of clear cell RCCs, 90.9% (20/22) of papillary RCCs, 1/13 of chromophobe RCCs, 7/7 of RCCs associated with Xp11.2 translocation/TFE3 gene fusions and 87.5%(21/24) of the metastatic RCCs, but not detected in 7 cases of oncocytomas. A diffuse expression of KIM-1 was more frequently observed in Furhman nuclear grade III/IV clear cell RCCs (P = 0.010). Ksp-cadherin expression was mainly observed in chromophobe RCCs and oncocytomas.

CONCLUSIONSKIM-1 is a specific biomarker for injuried kidney proximal tubules and the corresponding neoplasms, and has a high specificity and sensitivity for primary or metastatic clear cell RCCs, papillary RCCs and RCCs associated with Xp11.2 translocation/TFE3 gene fusions. Combination of KIM-1 and Ksp-cadherin immunostaining can lead to a more precise histological classification of primary kidney epithelial neoplasms and improve the diagnostic accuracy of metastatic RCCs.

Adenoma, Oxyphilic ; metabolism ; pathology ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; genetics ; metabolism ; Bone Neoplasms ; metabolism ; secondary ; Cadherins ; metabolism ; Carcinoma, Papillary ; metabolism ; pathology ; Carcinoma, Renal Cell ; genetics ; metabolism ; pathology ; Chromosomes, Human, X ; Gene Fusion ; Hepatitis A Virus Cellular Receptor 1 ; Humans ; Kidney Neoplasms ; genetics ; metabolism ; pathology ; Lung Neoplasms ; metabolism ; secondary ; Membrane Glycoproteins ; metabolism ; Neoplasms, Glandular and Epithelial ; classification ; genetics ; metabolism ; pathology ; Receptors, Virus ; metabolism ; Retrospective Studies ; Translocation, Genetic