Immunohistochemical application of S100A1 in renal oncocytoma, oncocytic papillary renal cell carcinoma, and two variants of chromophobe renal cell carcinoma

S100A1 is a calcium-binding protein and a member of the S100 family. Recently, S100A1 immunohistochemistry may be an available marker in the differential diagnosis between renal oncocytoma and chromophobe renal cell carcinoma (RCC). However, there are no reports on S100A1 expression in oncocytic papillary RCC that has been recently identified. In this article, we immunohistochemically examined the expression of S100A1 protein in 18 renal tumors including 4 renal oncocytoma, 10 chromophobe RCCs, and 4 oncocytic papillary RCCs. All the cases of renal oncocytoma and oncocytic papillary RCC showed a positive reaction for S100A1 with cytoplasmic pattern. In chromophobe RCC, 3 of 4 tumors with typical variant and 4 of 6 tumors in eosinophilic variant were completely negative for S100A1. Finally, S100A1 immunohistochemistry may be useful in distinguishing renal oncocytoma from chromophobe RCC, but it may be of no use in the differential diagnosis between renal oncocytoma and oncocytic papillary RCC.     

C-kit expression in renal oncocytomas and chromophobe renal cell carcinomas

C- kit encodes the membrane-bound tyrosine kinase KIT, whose expression has been identified in several types of human neoplasms. Recently, KIT has been reported to be a marker for chromophobe renal cell carcinoma (RCC) and renal angiomyolipoma. However, expression of this molecule has not been adequately studied in other renal tumors, particularly oncocytoma, which may morphologically resemble chromophobe RCC. In this study, we analyzed c- kit messenger RNA (mRNA) levels in 17 chromophobe RCCs and 20 renal oncocytomas obtained from complementary DNA (cDNA) microarrays. Furthermore, comprehensive immunohistochemical analysis of KIT protein using a monoclonal antibody was performed in 226 renal tumors including chromophobe RCC (n=40), oncocytoma (n=41), clear-cell RCC (n=40), renal angiomyolipoma (n=29), and papillary RCC (n=21) on tissue microarrays (TMAs) and was compared with immunostaining results from 25 chromophobe RCCs and 30 oncocytomas using standard sections. The staining intensity was semiquantitatively graded on a 3-tier scoring system. All chromophobe RCCs and oncocytomas showed significant overexpression of c- kit mRNA. The average increase of mRNA compared with normal kidney tissue was 7.4-fold for chromophobe RCCs and 7.4-fold for oncocytomas. Immunohistochemical expression of KIT was found in most chromophobe RCCs (95% in TMAs and 96% in conventional sections) and oncocytomas (88% in TMAs and 100% in conventional sections) but was infrequently observed in renal angiomyolipomas (17%), papillary RCCs (5%), and clear-cell RCCs (3%). Furthermore, the average KIT immunoreactivity in TMAs was stronger in chromophobe RCC (1.93) and oncocytoma (2.07) than in other subtypes of renal tumors tested, including angiomyolipomas (0.17), papillary RCCs (0.05), and clear-cell RCCs (0.03). In conclusion, we found a significant elevation of c- kit mRNA by cDNA expression microarrays and overexpression of KIT protein by immunohistochemistry not only in chromophobe RCCs but also in oncocytomas. In contrast, immunohistochemical expression of KIT was not detected in most other types of renal cell tumors evaluated. The differential expression of c- kit in these renal tumors may have diagnostic and therapeutic implications.     

Claudin-7 is highly expressed in chromophobe renal cell carcinoma and renal oncocytoma

Claudin-7 has recently been suggested to be a distal nephron marker. We tested the possibility that expression of claudin-7 could be used as a marker of renal tumors originating from the distal nephron. We examined the immunohistochemical expression of claudin-7 and parvalbumin in 239 renal tumors, including 179 clear cell renal cell carcinoma (RCC)s, 29 papillary RCCs, 20 chromophobe RCCs, and 11 renal oncocytomas. In addition, the methylation specific-PCR (MSP) of claudin-7 was performed. Claudin-7 and parvalbumin immunostains were positive in 3.4%, 7.8% of clear cell RCCs, 34.5%, 31.0% of papillary RCCs, 95.0%, 80.0% of chromophobe RCCs, and 72.7%, 81.8% of renal oncocytomas, respectively. The sensitivity and specificity of claudin-7 in diagnosing chromophobe RCC among subtypes of RCC were 95.0% and 92.3%. Those of parvalbumin were 80.0% and 88.9%. The expression pattern of claudin-7 was mostly diffuse in chromophobe RCC and was either focal or diffuse in oncocytoma. All of the cases examined in the MSP revealed the presence of unmethylated promoter of claudin-7 without regard to claudin-7 immunoreactivity. Hypermethylation of the promoter might not be the underlying mechanism for loss of its expression in RCC. Claudin-7 can be used as a useful diagnostic marker in diagnosing chromophobe RCC and oncocytoma.     

Cytokeratin expression in adrenocortical neoplasia: an immunohistochemical and biochemical study with implications for the differential diagnosis of adrenocortical, hepatocellular, and renal cell carcinoma.

The immunostaining patterns of adrenocortical tumors are not clearly defined, primarily due to their inconsistent expression of cytokeratins (CK). To address this issue and to investigate whether adrenocortical tumors can be immunohistochemically differentiated from histologically similar tumors arising from the kidney and liver, we studied four normal adrenal glands, two adrenocortical adenomas (ACAs), 31 adrenocortical carcinomas (ACCs), 37 renal cell carcinomas (RCCs), and 33 hepatocellular carcinomas (HCCs) with anti-CK antibodies AE1, CAM 5.2, UCD/PR10.11, 35BH11, PKK1, and Ks19.1, as well as antibodies to vimentin (VIM), epithelial membrane antigen (EMA), and HMFG-2. Normal adrenal cortical cells showed variable staining with all anti-CK antibodies on fixed and frozen sections. In contrast, only one of two fixed ACAs stained with a single anti-CK, although both neoplasms reacted with multiple anti-CK antibodies on frozen sections. Similarly, 20 of 31 fixed ACCs contained VIM, but only one tumor stained for CK; frozen sections of this and another, previously negative tumor, however, stained with most of the anti-CK antibodies tested. One-dimensional Western immunoblot analysis confirmed the presence of CKs 18 and 19 in two examples of normal adrenal cortex, one ACA, and the ACC immunohistochemically positive on fixed and frozen sections, with CK 19 identified in the ACC that was positive on frozen section alone. All fixed HCCs and most RCCs stained with multiple anti-CK antibodies (33 and 34 cases, respectively), with a proportion of tumors positive for VIM (six and 22 cases, respectively), EMA (seven and 30 cases, respectively), and HMFG-2 (15 and 28 cases, respectively). The results suggest that CK expression is diminished in most adrenocortical tumors to levels too low to be recognized following the deleterious effects of fixation. While the immunohistochemical absence of CK, EMA, and HMFG-2 in fixed sections in the majority of ACCs is distinctive, sufficient phenotypic overlap exists such that differentiation between RCC and HCC may not be possible in an individual case.     

New and emerging renal tumour entities

In this review, we discuss new and emerging renal cell carcinoma (RCC) entities, including anaplastic lymphoma kinase (ALK) RCC, oncocytic variant of chromophobe RCC, atrophic kidney-like renal tumour, biphasic alveolosquamoid RCC, tubulocystic RCC, thyroid-like follicular carcinoma of the kidney, succinate dehydrogenase-deficient RCC, Birt–Hogg–Dubé syndrome-associated renal tumour, hereditary leiomyomatosis/renal cell carcinoma associated RCC, tuberous sclerosis-associated RCC, PTEN hamartoma tumour syndrome, clear cell papillary RCC, acquired cystic disease-associated RCC, Xp11.2 RCC, t(6;11) RCC and renal hemangioblastoma. These tumours have clinical, pathological and genetic features distinct from other common RCCs and therefore are important to recognize. Some of them have been recognized as distinct histological subtypes in the 2016 World Health Organization Classification. However, further studies are needed to elucidate their clinicopathologic features and molecular mechanisms.     

Genetic and epigenetic alterations during renal carcinogenesis

Renal cell carcinoma (RCC) is not a single entity, but comprises a group of tumors including clear cell RCC, papillary RCC and chromophobe RCC, which arise from the epithelium of renal tubules. The majority of clear cell RCCs, the major histological subtype, have genetic or epigenetic inactivation of the von Hippel-Lindau (VHL) gene. Germline mutations in the MET and fumarate hydratase (FH) genes lead to the development of type 1 and type 2 papillary RCCs, respectively, and such mutations of either the TSC1 or TSC2 gene increase the risk of RCC. Genome-wide copy number alteration analysis has suggested that loss of chromosome 3p and gain of chromosomes 5q and 7 may be copy number aberrations indispensable for the development of clear cell RCC. When chromosome 1p, 4, 9, 13q or 14q is also lost, more clinicopathologically aggressive clear cell RCC may develop. Since renal carcinogenesis is associated with neither chronic inflammation nor persistent viral infection, and hardly any histological change is evident in corresponding non-tumorous renal tissue from patients with renal tumors, precancerous conditions in the kidney have been rarely described. However, regional DNA hypermethylation on C-type CpG islands has already accumulated in such non-cancerous renal tissues, suggesting that, from the viewpoint of altered DNA methylation, the presence of precancerous conditions can be recognized even in the kidney. Genome-wide DNA methylation profiles in precancerous conditions are basically inherited by the corresponding clear cell RCCs developing in individual patients: DNA methylation alterations at the precancerous stage may further predispose renal tissue to epigenetic and genetic alterations, generate more malignant cancers, and even determine patient outcome. The list of tumor-related genes silenced by DNA hypermethylation has recently been increasing. Genetic and epigenetic profiling provides an optimal means of prognostication for patients with RCCs. Recently developed high-throughput technologies for genetic and epigenetic analyses will further accelerate the identification of key molecules for use in the prevention, diagnosis and therapy of RCCs.     

Alpha-methylacyl-CoA racemase as a marker in the differential diagnosis of metanephric adenoma.

Metanephric adenoma (MA), a well-described renal neoplasm, usually behaves in a benign fashion. It may have areas that are morphologically similar to papillary renal cell carcinoma (RCC) type, or epithelial (tubular predominant) type Wilms' tumor. Prior immunohistochemical studies of MA have reported variable staining patterns. Alpha-methylacyl-CoA racemase (AMACR), a molecular marker for prostate carcinoma, has subsequently been found to be overexpressed in breast, colorectal and ovarian cancers, among others. Recent microarray analysis of renal tumors has shown an increase of AMACR mRNA levels in papillary RCC but not in other subtypes. We investigated the utility of immunohistochemical staining for AMACR, cytokeratin 7(CK7), CD57 and WT1 to differentiate between the above-mentioned three neoplasms. Immunohistochemical stains were performed on paraffin-embedded tissue sections from 25 papillary RCC, 10 MAs and eight Wilms' tumors. AMACR was positive in one (10%) of 10 MAs and 24 (96%) of 25 papillary RCC, while it was negative in all Wilms' tumors. CK7 was positive in 20 of 25 papillary RCCs, focally positive in one Wilms' tumor and was negative in all MAs. CD57 was positive in all six MAs that were stained, focally positive in one of 25 papillary RCC and one of eight Wilms' tumors. WT1 was positive in seven of 10 MAs, three of 25 papillary RCCs and all eight Wilms' tumors. In conclusion, diffuse and strong immunoreactivity for AMACR may be useful in differentiating papillary RCC from MA but a panel which includes AMACR, CK7 and CD57 is better in this differential diagnosis. AMACR is not helpful in differentiating MA from Wilms' tumor, but CD57 is helpful in this differential diagnosis. WT1 may be useful in separating Wilms' tumor from MA and papillary RCC but is not helpful in differentiating MA from papillary RCC.     

p63, CK7, PAX8 and INI-1: an optimal immunohistochemical panel to distinguish poorly differentiated urothelial cell carcinoma from high-grade tumours of the renal collecting system

Carvalho J C, Thomas D G, McHugh J B, Shah R B & Kunju L P
(2012) Histopathology  60, 597–608
p63, CK7, PAX8 and INI‐1: an optimal immunohistochemical panel to distinguish poorly differentiated urothelial cell carcinoma from high‐grade tumours of the renal collecting system Aims: High‐grade, poorly differentiated, infiltrative carcinomas involving the renal sinus region often pose challenging differential diagnostic considerations, specifically differentiation of urothelial carcinoma (UC) from renal cell carcinoma (RCC) subtypes. Accurate classification, especially the distinction of UC from RCC, is critical, as therapeutic approaches differ. Methods and results: Cluster analysis was performed on immunohistochemical data from 18 invasive UCs, six CDCs, two RMCs, 18 type 2 papillary renal cell carcinomas (PRCCs) and 20 high‐grade clear cell renal cell carcinomas (CRCCs) using a broad panel of traditional and novel immunohistochemical markers. The initial analysis with all antibodies segregates almost all the RCCs (45 of 46, 98%) from all the UCs based on the lack of expression of p63 in all (100%) RCCs, along with predominant strong expression of paired box gene 8 (PAX8) and vimentin, predominant lack of expression of high molecular weight cytokeratin (HMCK) and CK7 and variable expression of RCC, CD10, CA1X and PAX2. All the UCs cluster together with strong, diffuse reactivity for p63, predominant reactivity for CK7 and high molecular weight kininogen (HMWK), and absent to minimal staining with PAX8, RCC antigen, PAX2, alpha‐methylacyl‐CoA racemase (AMACR), carbonic anhydrase IX (CAIX) and vimentin. After removing antibodies with significant overlap and/or minimal impact, a second analysis with a limited panel including p63, CK7, vimentin, integrase interactor 1 (INI‐1) and PAX8 was performed. Again, the majority of UCs cluster into one group and p63 positivity separates all UCs from RCCs. Conclusions: Lack of INI‐1 expression, noted exclusively in RMCs, segregates RMCs into a separate cluster. PAX8 is rarely positive (17%) in UC, is commonly expressed in CDC, RMC, PRCC and CRCC and is superior to PAX2.     

Expression profiling of renal epithelial neoplasms: a method for tumor classification and discovery of diagnostic molecular markers

The expression patterns of 7075 genes were analyzed in four conventional (clear cell) renal cell carcinomas (RCC), one chromophobe RCC, and two oncocytomas using cDNA microarrays. Expression profiles were compared among tumors using various clustering algorithms, thereby separating the tumors into two categories consistent with corresponding histopathological diagnoses. Specifically, conventional RCCs were distinguished from chromophobe RCC/oncocytomas based on large-scale gene expression patterns. Chromophobe RCC/oncocytomas displayed similar expression profiles, including genes involved with oxidative phosphorylation and genes expressed normally by distal nephron, consistent with the mitochondrion-rich morphology of these tumors and the theory that both lesions are related histogenetically to distal nephron epithelium. Conventional RCCs underexpressed mitochondrial and distal nephron genes, and were further distinguished from chromophobe RCC/oncocytomas by overexpression of vimentin and class II major histocompatibility complex-related molecules. Novel, tumor-specific expression of four genes-vimentin, class II major histocompatibility complex-associated invariant chain (CD74), parvalbumin, and galectin-3-was confirmed in an independent tumor series by immunohistochemistry. Vimentin was a sensitive, specific marker for conventional RCCs, and parvalbumin was detected primarily in chromophobe RCC/oncocytomas. In conclusion, histopathological subtypes of renal epithelial neoplasia were characterized by distinct patterns of gene expression. Expression patterns were useful for identifying novel molecular markers with potential diagnostic utility.     

Immunohistochemical analysis of monoclonal antibodies to renal antigens. Application in the diagnosis of renal cell carcinoma.

Four mouse monoclonal antibodies reacting with renal proximal epithelium were characterized on normal adult tissues, fetal kidneys, and various malignancies. These four antibodies were found to react with renal cell carcinomas (RCCs) but not with a variety of other tumors. Three antibodies react only with some primary RCCs and not with metastatic RCCs. The fourth antibody, RC 38, reacts with 46 of 47 primary RCCs tested and with 8 of 13 RCC metastases. No reaction was seen with 179 tumors of various origin, which indicates that this antibody is very useful in diagnosing RCC.     

Immunohistochemical characterization of renal tumors in patients with Birt‐Hogg‐Dubé Syndrome

Birt‐Hogg‐Dubé syndrome (BHD) is an autosomal dominant disorder associated with a germline mutation of folliculin (FLCN). The affected families are at a high risk for developing multiple renal cell carcinomas (RCC). Little is known about the immunostaining patterns of mutant FLCN‐associated RCCs. We investigated 32 RCCs obtained from 17 BHD patients. The studied tumors included chromophobe RCCs (n = 15), hybrid oncocytic/chromophobe tumors (HOCT) (n = 14) and clear cell RCCs (n = 3). Almost all chromophobe RCCs and HOCTs revealed positive staining for S100A1, Ksp‐cadherin and CD82. They stained either focally or diffusely for CK7, and were negative for CA‐IX. All clear cell RCCs were positively stained for CA‐IX and negative for CK7. These data confirmed that mutant FLCN‐associated oncocytic and clear cell RCCs exhibited generally similar immunostaining patterns compared to their sporadic counterparts. Frequent positive staining for S100A1, Ksp‐cadherin and CD82 in chromophobe RCCs and HOCTs indicated that these two types were relatively similar rather than distinctively different in their patterns of immunoreactivity. Characteristic peri‐nuclear halos and polygonal cells with clear cytoplasm, which often misleads pathologists into the diagnosis of clear cell RCC, should be carefully examined using an immunohistochemical panel including CA‐IX, Ksp‐cadherin, CD82 and CK7.     

Can renal oncocytoma be differentiated from its renal mimics? The utility of anti-mitochondrial,caveolin 1, CD63 and cytokeratin 14 antibodies in the differential diagnosis

Among the epithelial renal tumours with eosinophilic cytoplasm, the main differential diagnostic problem arises between renal oncocytomas (ROs) and eosinophilic variants of chromophobe renal cell carcinomas (RCCs). We investigated the possible role of anti-mitochondrial (AMA), anti-caveolin 1 (CAV1), anti-CD63 (CD63) and anti-cytokeratin 14 (CK14) antibodies in the differential diagnosis of eosinophilic epithelial tumours and applied the Muller and Mowry modification of Hale's colloidal iron stain (HCI). Thirty-five ROs and 77 eosinophilic RCCs (27 chromophobe, 28 clear cell and 22 papillary RCCs) were included in this study. Apical and/or polar CD63 immunostaining (94%) and diffuse AMA (91%) and CAV1 (88%) immunostainings were the characteristics of ROs, whereas diffuse CD63 immunostaining (96%) and diffuse-peripheral AMA (96%) and CAV1 (92%) immunostainings were characteristic immunohistochemical features of eosinophilic chromophobe RCCs. We showed CK14 antibody not to be useful in the differential diagnosis of the eosinophilic epithelial renal tumours. The staining localisations with AMA, CAV1 and CD63 antibodies were significantly different between tumour groups. AMA had 96% sensitivity and 94% specificity, whereas CAV1 had 92% sensitivity and 97% specificity in diagnosing chromophobe RCCs. With HCI staining, ROs, showing apical and/or polar staining, could be differentiated from chromophobe RCCs, showing diffuse cytoplasmic staining. HCI had fairly low (69%) sensitivity and 100% specificity, whereas CD63 had 95% sensitivity and 100% specificity to diagnose ROs. We recommend using CD63 as the best marker of choice for distinguishing ROs from eosinophilic chromophobe RCCs when standard diagnostic criteria are not helpful.     

Papillary renal cell carcinoma with prominent spindle cell stroma - tumor mimicking mixed epithelial and stromal tumor of the kidney: Clinicopathologic,morphologic, immunohistochemical and molecular genetic analysis of 6 cases

Papillary renal cell carcinoma (PRCC) is currently a well-studied type of RCC. In addition to PRCC type 1, there are a number of other subtypes and variants of PRCCs which have been reported. We describe a series of 6 PRCCs with papillary, micropapillary and/or tubulopapillary architecture and prominent spindle cell stroma, resembling stroma in mixed epithelial and stromal tumor of the kidney (MESTK) or sarcomatoid RCC.Clinicopathologic, morphologic, immunohistochemical and molecular features were analyzed.All patients were males with an age range of 44–98 years (mean 65.3, median 65.5 years). Tumor size ranged from 2.4–11.4 cm (mean 5.8, median 4.5 cm). Follow-up data were available for 4 patients, ranging from 3 to 96 months (mean 42.75, median 36 months). Epithelial cells were mostly cylindrical with eosinophilic cytoplasm, showing nuclear grade 2 and 3 (ISUP/WHO).In all cases, loose to compact prominent stroma composed of spindle cells, without malignant mesenchymal heterologous elements was detected. No atypical mitoses were found, while typical mitoses were rare in both epithelial and stromal components.Epithelial cells were positive for CK7, AMACR, and vimentin in all cases, while negative for TFE3, HMB45, desmin, CD34, and actin. The stroma was positive for vimentin, actin and focally for CD34, while negative for CK7, AMACR, TFE3, HMB45, and desmin. Estrogen and progesterone receptors were completely negative. FH and SDHB expression was retained in all analyzable cases. Proliferative index was barely detectable in stromal component and low in epithelial component, ranging 0 to 5% positive stained cells/high power field.Copy number variation was variable with no distinct pattern. No mutations in CDKN2A, BAP1, MET were detected.PRCC with MESTK-like features is a distinct variant of PRCC mimicking MESTK. Our findings add to the body of literature on ever expanding variants of PRCCs. Both epithelial and stromal components lacked true Müllerian features, which was also proven by immunohistochemistry.     

Useful markers for differential diagnosis of oncocytoma, chromophobe renal cell carcinoma and conventional renal cell carcinoma

Renal oncocytoma, conventional RCC (granular cell type) and chromophobe RCC have different prognosis. Sometimes differentiation between them is difficult in HandE slides. In a 5-year study of 128 renal tumors, we selected 76 cases [30 conventional RCC (CRCC), 16 papillary RCC, 21 chromophobe RCC (ChRCC), 8 oncocytoma, 1 collecting duct carcinoma (cdc)] and staining with Hale's colloidal iron, CK7, CK8, CK18, CK19, CK20, Vimentin, EMA, CD10 and RCC marker were done. No significant difference was seen between renal tumor subtypes with CK8, CK18, CK19, CK20 and EMA. The most useful markers were Vimentin, CK7, CD10, RCC marker and Hale's colloidal iron. Hale's colloidal iron staining with diffuse reticular fine cytoplasmic pattern was present in ChRCCs, but was absent in other subtypes and oncocytomas. Vimentin, CK7, CD10, RCC marker and Hale's colloidal iron can be used for the differential diagnosis of problematic epithelial tumors of kidney (CRCC, ChRCC and oncocytoma) - i.e. ChRCC: Vimentin, CD10 and RCC marker - negative, CK7 - positive and positive diffuse fine reticular cytoplasmic pattern of Hale's colloidal iron; oncocytoma: Vimentin, CK7, RCC marker and CD10 - negative and Hale's colloidal iron - negative; CRCC: CK7 - negative, Vimentin, CD10 and RCC marker - positive and Hale's colloidal iron - negative.     

Nucleophosmin expression in renal cell carcinoma and oncocytoma

The objective of this study was to investigate nucleophosmin/B23 (NPM) expression in renal cell carcinomas (RCC) and renal oncocytomas. The expression of NPM was studied by immunohistochemical methods on 59 RCCs, 9 oncocytomas, and 19 tumour-negative renal tissues. The expression was assessed relative to various clinicopathological variables and histological subtypes, to determine its potential role as a prognostic and diagnostic marker. All tumours showed nuclear staining, and a minority also exhibited cytoplasmic immunoreactivity. Two patterns of nuclear staining were observed: nuclear staining with a prominent nucleolus (nucleolar staining) and nuclear staining without a prominent nucleolus. There were significant differences, in both nuclear staining and cytoplasmic NPM expression, between oncocytomas and chromophobe RCCs (p < 0.001) and clear cell RCCs (p < 0.001). Cytoplasmic NPM expression was markedly lower in RCCs than in oncocytomas. A statistically significant correlation was discovered between nucleolar staining and nuclear grade (p < 0.001, r = 0.5). No relationship was found between cytoplasmic expression of NPM and any of the clinicopathological parameters or survival. NPM might be a useful immunohistochemical marker for differential diagnosis between oncocytoma and chromophobe RCC. In addition, increased nucleolar NPM expression in RCCs appears to be associated with tumour progression.     

青少年肾细胞癌的临床病理及分子遗传学研究

目的 探讨青少年肾细胞癌的临床病理特征、遗传学改变、鉴别诊断及预后.方法 对46例青少年肾细胞癌进行光镜观察及免疫组织化学染色,随访并复习相关文献.对46例肿瘤进行von Hippel-Lindau(VHL)基因区域杂合性缺失(LOH)及VHL基因突变筛查.结果 共诊断19例Xp11.2易位/TFE3基因融合相关性肾癌(Xp11 RCC)、9例透明细胞癌、17例乳头状肾细胞癌(PRCC)和1例不能分类肾细胞癌.19例Xp11 RCC均TFE3阳性,而TFEB阴性.8例肿瘤具有巢状和乳头状结构形态类似t(X;17)ASPL-TFE3型肾癌,6例肿瘤组织学类似t(X;1)PRCC-TFE3型肾癌,4例肿瘤形态像透明细胞癌,1例肿瘤组织学形态文献中未被检索到,表现为细胞核呈毛玻璃样,核仁不明显,可见核沟,肿瘤间质见大量黏液.LOH及VHL突变检测结果显示,仅1例透明细胞癌和1例2型PRCC存在LOH,并且该2型PRCC的VHL基因的一个剪切位点存在胚系突变,553+5 G→C.其余45例均未检测出VHL突变.统计学分析表明TFE3阳性肾细胞癌比TFE3阴性肾细胞癌更倾向于高病理分期(pT3/pT4),并且预后较差(P=0.035).结论 青少年肾细胞癌表现出不同的组织学形态以及分子遗传学背景.其中Xp11 RCC为最常见的肾癌亚型.TFE3阳性肾细胞癌的预后要差于TFE3阴性肾细胞癌.     

Expression of serine protease matriptase in renal cell carcinoma: correlation of tissue microarray immunohistochemical expression analysis results with clinicopathological parameters

Serine protease matriptase (matriptase) cleaves and activates proteins implicated in the progression of cancer and represents a potential therapeutic target. Immunohistochemical analysis of matriptase was performed in tissue microarrays of 168 renal cell carcinomas (RCCs). All subtypes of RCC showed significant immunohistochemical expression of matriptase. In contrast, no expression occurred in areas of RCC with sarcomatous differentiation (SRCC) and in normal collecting tubules. The matriptase scores were significantly higher in papillary RCC (341+/-28) and clear cell RCC with granular cell differentiation (GRCC; 324+/-27) than in other histologic subtypes of RCC. In GRCC, matriptase scores were correlated with TNM staging and nuclear grading. Matriptase was overexpressed in all subtypes of RCC, and matriptase scores could distinguish between conventional clear cell RCC, GRCC, and SRCC.