Diagnostic utility of renal cell carcinoma marker in cytopathology

PAX-2 is a helpful marker for diagnosing metastatic renal cell carcinoma: comparison with the renal cell carcinoma marker antigen and kidney-specific cadherin

CONTEXT

The diagnosis of metastatic renal cell carcinoma (RCC) remains problematic.

OBJECTIVE

To evaluate the role of PAX-2, a renal tubular cell transcription factor, in the diagnosis of metastatic RCC. PAX-2 expression in metastatic RCC was compared with that of the renal cell carcinoma marker antigen (RCCM) and kidney-specific cadherin (KSC), which are 2 known markers for RCC.

DESIGN

Immunostaining for PAX-2, RCCM, and KSC was performed on consecutive tissue sections of 95 metastatic RCCs (77 clear cell, 8 papillary, 5 sarcomatoid, and 5 collecting duct) and 183 metastatic tumors other than RCC.

RESULTS

For PAX-2, positive immunoreactivity was detected in 77% clear cell, 75% papillary, 100% collecting duct, and 0% sarcomatoid metastatic RCCs. For RCCM, positive immunoreactivity was detected in 49% clear cell, 75% papillary, 0% collecting duct, and 0% sarcomatoid metastatic RCCs. For KSC, only 2 metastatic clear cell RCCs (3%) were positive. In combination, all markers were positive in 0% of cases; all markers were negative in 23% of cases (17 clear cell, 1 papillary, and for all 5 sarcomatoid); and at least 1 marker was positive in 76% of cases (PAX-2 only in 28% of cases [21 clear cell, 1 papillary, and 5 collecting duct] and RCCM only in 3% of cases [2 clear, 1 papillary]). Of 183 metastatic tumors other than RCC, 14 were positive for PAX-2 (nodal metastasis of carcinoma of colon [1], breast [1], endometrium [1], and ovary [1]; and omental metastasis of carcinoma of uterus or ovary [10]).

CONCLUSIONS

PAX-2 is a sensitive and specific marker for metastatic RCC. The diagnostic yield would be marginally increased by adding RCCM, but not KSC, as an immunomarker.

The utility of Pax-2 as an immunohistochemical marker for renal cell carcinoma in cytopathology

Pax-2 is a homeogene expressed during kidney development. Its expression in renal cell carcinoma (RCC) has been previously evaluated in histologic samples with a high sensitivity and specificity. Here, we investigated the utility of Pax-2 immunohistochemistry (IHC) for RCC in cytologic material, in comparison with a variety of other neoplasms. Pax-2 IHC was performed on cell block sections of 33 RCCs (14 primary, 19 metastatic) and 35 non-RCC malignancies, including 26 carcinomas, five mesenchymal tumors, one neuroblastoma, two melanomas, and one lymphoma, from fine-needle aspirations and body fluids. The presence or absence of nuclear staining and its intensity and distribution in positive cases were evaluated. Of 33 RCCs, Pax-2 was positive in 20 (61%) and negative in 13 (39%). All staining was nuclear, with an admixture of weakly or strongly staining nuclei. Only an endometrial adenocarcinoma was positive in the non-RCC group. The sensitivity and specificity of Pax-2 IHC for RCC were 61 and 97%, respectively. Pax-2 is a moderately sensitive and highly specific marker for RCC in cytologic material, with a lower sensitivity compared with tissue sections, likely due to a patchy expression pattern, and should be included in the immunohistochemical work-up of malignancies.

Utility of antiphosphorylated H2AX antibody (gamma-H2AX) in diagnosing metastatic renal cell carcinoma

The differential diagnosis of metastatic renal cell carcinoma (RCC) includes, although is not limited to, hepatocellular carcinoma (HCC) and adrenocortical carcinoma (ACC) due to overlapping morphology. Immunohistochemical markers, including RCC marker (RCC-Ma) have been employed with varying success in the differential diagnosis of RCC. Our preliminary tissue microarray study demonstrated that gamma-H2AX, an antibody that specifically reacts with phosphorylated histone H2AX, stained many primary RCC strongly and did not stain HCC or ACC, prompting us to evaluate its utility in these tumors and to compare it with RCC-Ma. Seventy-one cases of metastatic RCC, 18 HCC, and 21 ACC were stained with gamma-H2AX and RCC-Ma and the sensitivity and specificity of each marker was compared. RCC-Ma demonstrated a membranous pattern of staining in 70% of RCC cases (50/71), and none of the ACC or HCC (100% specificity for RCC). Nuclear staining by gamma-H2AX had a similar sensitivity of 70% for RCC but a lower specificity of 77%, as it was seen in 1 of 18 HCC (5%) and 8 of 21 (38%)ACC. In metastatic RCC, 83% (39/47) of tumors with a higher nuclear grade stained with gamma-H2AX, compared with 46% (11/24) of low nuclear grade (equivalent of Fuhrman 2 and lower) tumors. RCC-Ma had a similar rate of staining in low and high-grade tumors, 75% (18/24) and 68% (32/47), respectively. More importantly, of RCCs that were negative for RCC-Ma, 14 of 21 (67%) were positive for gamma-H2AX. The results suggest gamma-H2AX is a useful adjunct in diagnosis of metastatic RCC when RCC-Ma is negative and in higher grade RCC, which are often a diagnostic challenge. A nuclear pattern of staining of gamma-H2AX has a comparable sensitivity with RCC-Ma, and the interpretation is easier and more reliable. RCC-Ma is 100% specific for RCC, but only when a membranous pattern of staining is interpreted as positive.

Immunocytochemical typing of primary tumors on fine-needle aspiration cytologies of lymph nodes

The aim of this study was to analyze the role of immunocytochemistry as an ancillary method on routine FNACs of enlarged lymph nodes, using different markers. In a validating cohort study all patients had confirmatory histological and/or clinical follow-up. 10 FNACs were analyzed for the differentiation of Non-Hodgkin Lymphoma (NHL) from metastatic carcinoma (MC), 30 cases to identify the sites of metastatic unknown primary tumors and 16 cases were checked to confirm clinical suspicion of a specific MC. Accuracy to differentiate NHL from MC was 100%, 92.3% to identify a primary tumor site of MC, and 100% to confirm a clinical suspicion of a specific MC. In 7 cases, the site of the primary tumor remained clinically unknown. Application of immunocytochemical markers on the same slide used for microscopic diagnosis is a useful tool in the routine assessment of FNACs of lymph nodes.

Expression of Renal Cell Carcinoma Antigen (RCC) in Renal Epithelial and Nonrenal Tumors

Antibody to renal cell carcinoma (RCC) antigen, a normal human proximal brush border antigen, has recently become commercially available and reported to be highly specific and a relatively sensitive marker for RCC. Of the nonrenal tumors occasional carcinomas have been reported to express RCC, notably breast carcinoma. Using tissue microarrays, we investigated the use of RCC on a large number of renal epithelial neoplasms (RENs) and nonrenal tumors, especially those potentially confused with REN. Three tissue microarrays containing 241 REN samples, 192 samples of a wide variety of neoplasms and 170 adrenal tumor samples, respectively, were stained with RCC monoclonal antibody. RCC expression was scored for staining intensity and percentage expression. Out of 241 REN, 173 were positive for RCC (sensitivity 72%): clear cell 72%, papillary 95%, chromophobe 91%, unclassified 85%, oncocytoma 75%, sarcomatoid 20%, and metastatic RCC 40%. The overall immunostaining intensity was consistently much higher in papillary and clear cell RCC than in other tumors. Seventy-six out of 362 nonrenal tumor samples demonstrated either focal or diffuse expression for RCC (specificity 79%). These included: adrenocortical neoplasms 37/170 (22%), colonic 11/29 (37.5%), breast 9/27 (33%), prostate 5/18 (27.7%), ovary 2/17 (11.7%), melanoma 3/18 (16.6%), lung 3/21 (14.2%), and parathyroid 3/3 (100%). RCC expression was seen equally among adrenal adenoma and carcinoma group. Eight out of 28 (28.5%) normal adrenal cores also stained for RCC. RCC is a relatively useful marker in the differential diagnosis of REN only if used in a panel with other positive and negative markers. RCC does not reliably differentiate REN, especially classic clear cell type, from adrenocortical neoplasms, which are frequently confused due to close anatomic proximity and similar morphology. RCC also does not reliably differentiate subtypes of renal epithelial neoplasms.

[Expression of CD10 and renal cell carcinoma marker in clear cell renal cell carcinoma: analysis on tissue arrays]

OBJECTIVES

CD10 and renal cell carcinoma (RCC) marker antibodies react against proteins of the epithelium of the renal proximal tubule, being expressed by renal cell carcinomas. The frequence and pattern of expression of both markers are analysed in a series of clear cell renal cell carcinomas.

METHOD

Two tissue arrays were used, which were composed of cylinders obtained with a 16G needle from 40 paraffin blocks that corresponded to clear cell renal cell carcinomas. The labeled streptavidin-biotin technique was performed (LSAB2, Dako) using CD10 and RCC monoclonal antibodies (Novocastra), testing different antigen retrieval methods for RCC. Immunoreactivity was evaluated as + (isolated cells or focal staining); ++ (moderate) and +++ (extense).

RESULTS

Thirty cases (75%) were positive for CD10: 12 +; 5 ++ and 13 +++. The best antigen retrieval method for RCC was a double enzyme digestion (trypsin + protease). Twenty cases (50%) were positive for RCC: 7 +; 5 ++ and 8 +++. Four cases out of the 20 immunoreactive for RCC were negative for CD10. The 16 remaining cases also expressed CD10.

CONCLUSIONS

CD10 and RCC are often expressed by clear cell renal cell carcinomas, and they may be useful markers to suggest a renal origin of carcinomas. RCC is less sensitive than CD10. Staining for both of them is usually focal, and thus sensitivity of these techniques decreases when small samples are investigated, such as tissue arrays. The antigen retrieval method is essential for RCC immunohistochemical detection, obtaining the best results with the use of proteolytic enzymes.

The usefulness of immunohistochemical markers in the differential diagnosis of renal neoplasms

Histologic subtyping of RCC has been shown to be of prognostic value; therefore, it is important to classify malignant epithelial tumors of the kidney correctly and also to differentiate them from benign ones. Overlapping morphologic features of renal tumors sometimes make histologic subtyping difficult. The accurate diagnosis and classification of RCC are based on cytoarchitectural features and require correlation with immunophenotype and cytogenetic characteristics. RCC Ma and CD10, two markers with relative renal specificity, have been used to confirm a diagnosis of suspected RCC and can facilitate the accurate diagnosis of metastatic RCC, in particular, in FNA. Although CCRCC and PRCC share most immunomarkers, CK7 and AMACR expression can be helpful in the differential diagnosis of challenging histologic variants of the two. In addition, E-cadherin aids in the distinction between types 1 and 2 PRCC. Useful markers in the differential diagnosis between ChRCC and CCRCCare CK7, RCC Ma, CD10, VIM, CD117, parvalbumin, and E-cadherin. We propose CK7/CK20/CD15 as a useful primary immunopanel to differentiate ChRCC from ONC reliably.

Monocytes promote natural killer cell interferon gamma production in response to the endogenous danger signal HMGB1

Substantial attention has been paid to the role of the toll-like receptor (TLR) ligands of late and their role in regulating the innate immune response. They serve as exogenous danger signals important in informing and driving the distal adaptive immune response to pathogens. Less clear has been the role of the nominal endogenous danger signals released and recognized in stressed cells following genotoxic or metabolic stress as occurs in progressively growing tumors. HMGB1 (high-mobility group B1) is a nuclear protein well characterized for its ability to modify DNA access to transcriptional proteins that is released from necrotic cells as well as secreted through the endosomal route from hematopoietic cells, serving as a late mediator of sepsis. It interacts with high-affinity RAGE (receptor for advanced glycation end products) and TLR2 receptors. Here we show that HMGB1 enhances interferon gamma release from macrophage (but not dendritic cell)-stimulated NK cells. This is effective only when coupled with other pro-inflammatory cytokines particularly with IL-2 in combination with IL-1 or IL-12. We have used this information to suggest that HMGB1, which also promotes epithelial migration and proliferation, drives repair in the absence or inhibition of other factors but enhances inflammation in their presence. The implications for tumorigenesis and tumor progression are quite important as they may be for other states of chronic inflammation.

Utility of CD10 and RCCma in the diagnosis of metastatic conventional renal-cell adenocarcinoma by fine-needle aspiration biopsy

The cytologic diagnosis of primary conventional renal-cell adenocarcinoma (cRCC) is usually straightforward; however, metastatic cRCC must be distinguished from a variety of neoplasms with clear-cell features. CD10, a cell membrane-associated neutral endopeptidase, and renal-cell carcinoma marker (RCCma), an antibody against human proximal tubular brush border antigen, have recently been shown to be useful in the diagnosis of cRCC. We compared CD10 and RCCma in cell block material from fine-needle aspiration biopsies (FNABs) to assess their utility in the diagnosis of metastatic cRCC, in cytologic specimens. Seven primary and sixteen metastatic cRCCs were immunostained with CD10 and RCCma. The immunoreactivity results were compared with those of a variety of neoplasms originating from other sites such as the liver, lungs, breast, and the gastrointestinal tract. The sensitivity and specificity of CD10 for cRCC were 100% and 59%, respectively. The sensitivity and specificity of RCCma for cRCC were 35% and 100%, respectively. We conclude that CD10 has limited value in confirming the diagnosis of cRCC because of its low specificity. RCCma, when positive, is highly specific for cRCC, but its low sensitivity hinders its diagnostic usefulness.