BackgroundRecently, there have been a few reports of renal cell carcinoma (RCC) cases with anaplastic lymphoma kinase (ALK) gene fusion. In this study, we screened consecutively resected RCCs from a single institution for ALK protein expression by immunohistochemistry, and then we performed fluorescence in situ hybridization to confirm the ALK gene alteration in ALK immunohistochemistry-positive cases.MethodsWe screened 829 RCCs by ALK immunohistochemistry, and performed fluorescence in situ hybridization analysis using ALK dual-color break-apart rearrangement probe. Histological review and additional immunohistochemistry analyses were done in positive cases.ResultsOne ALK-positive case was found. Initial diagnosis of this case was papillary RCC type 2. This comprises 0.12% of all RCCs (1/829) and 1.9% of papillary RCCs (1/53). This patient was a 44-year-old male with RCC found during routine health check-up. He was alive without evidence of disease 12 years after surgery. The tumor showed a papillary and tubular pattern, and showed positivity for CD10 (focal), epithelial membrane antigen, cytokeratin 7, pan-cytokeratin, PAX-2, and vimentin.ConclusionsWe found the first RCC case with ALK gene rearrangement in Korean patients by ALK immunohistochemistry among 829 RCCs. This case showed similar histological and immunohistochemical features to those of previous adult cases with ALK rearrangement, and showed relatively good prognosis.

BackgroundTransmembrane protease serine 2-ETS related gene (TMPRSS2-ERG) gene fusion, the most common genetic alternation in prostate cancer, is associated with protein expression of the oncogene ERG. Recently, an immunohistochemical staining method using an anti-ERG antibody was shown to have a strong correlation with altered ERG protein expression.MethodsWe analyzed a total of 303 radical prostatectomy specimens (obtained from Korean prostate cancer cases) using a constructed tissue microarray and ERG immunohistochemical staining. Thereafter, we evaluated the association between ERG expression and clinicopathological factors.ResultsThe ERG-positive rate was 24.4% (74/303) and significantly higher ERG expression was observed in the subgroup with a lower Gleason score (p=0.004). Analysis of the histologic pattern of prostate adenocarcinomas revealed that tumors with discrete glandular units (Gleason pattern 3) displayed higher frequency of ERG expression (p=0.016). The ERG-positive rate was lower than that found (approximately 50%) in studies involving western populations. Other factors including age, tumor volume, initial protein-specific antigen level, a pathological stage and margin status were not significantly related with the ERG expression.ConclusionsERG immunohistochemical staining is significantly higher in tumors with well-formed glands and is associated with a lower Gleason score.

No abstract

No abstract

BackgroundClear cell papillary renal cell carcinoma (CCPRCC) is a recently established subtype of renal epithelial tumor. The aim of this study was to identify the diagnostic criteria of CCPRCC with an emphasis on immunohistochemical studies, and to report three cases with concurrent other-type renal cell carcinoma (RCC).MethodsA total of 515 RCC patients that consecutively underwent surgical resection at Seoul National University Hospital from 1 January 2010 to 31 December 2011 were screened. Each case was reviewed based on the histologic features and was evaluated immunohistochemically.ResultsA total of 15 CCPRCCs were identified, which composed 2.9% of the total RCCs. The mean age was 52 years, and the average tumor size was 1.65 cm. All 15 cases showed low nuclear grade, no lymph node metastasis and no distant metastasis. The CCPRCCs showed variable architectural patterns including cystic, trabecular, papillary, and acinar. All of the cases showed moderate to intense immunoreactivity for cytokeratin 7 (CK7). CD10 was negative or showed focal weak positivity. Three cases had concurrent other-type RCC, including a clear cell RCC and an acquired cystic disease-associated RCC.ConclusionsThe strong CK7 and negative or focal weak CD10 expression will be useful for the diagnosis of CCPRCC.