Hemoglobin F Only Syndrome at Birth: A Case of Maternal HbA2' Complicating the Diagnosis of ß-Thalassemia.

An asymptomatic infant of Ghanaian descent had hemoglobin F only detected on newborn screening. ß-globin gene sequencing identified the intervening sequence (IVS)-II-849 (A → G) mutation with no normal ß-globin gene. ß-globin/δ-globin gene sequencing showed that both parents were heterozygous for the IVS-II-849 (A → G) mutation. The mother was heterozygous for the HbA2' δ-globin mutation (δ16 (A13) Gly → Arg), thus ß-thalassemia trait was unrecognized due to coinheritance of HbA2'. The infant developed anemia, splenomegaly, and began transfusion therapy by the age 6 of months. This is the first report of ß-thalassemia major with homozygous IVS-II-849 (A → G) mutations. This case highlights the importance of δ-globin gene mutations in prenatal testing.

Chromosome instability in diffuse large B cell lymphomas is suppressed by activation of the noncanonical NF-κB pathway.

Diffuse large B cell lymphoma (DLBCL) is the most common form of lymphoma in the United States. DLBCL comprises biologically distinct subtypes including germinal center-like (GCB) and activated-B-cell-like DLBCL (ABC). The most aggressive type, ABC-DLBCL, displays dysregulation of both canonical and noncanonical NF-κB pathway as well as genomic instability. Although, much is known about the tumorigenic roles of the canonical NF-kB pathway, the precise role of the noncanonical NF-kB pathway remains unknown. Here we show that activation of the noncanonical NF-κB pathway regulates chromosome stability, DNA damage response and centrosome duplication in DLBCL. Analysis of 92 DLBCL samples revealed that activation of the noncanonical NF-κB pathway is associated with low levels of DNA damage and centrosome amplification. Inhibiting the noncanonical pathway in lymphoma cells uncovered baseline DNA damage and prevented doxorubicin-induced DNA damage repair. In addition, it triggered centrosome amplification and chromosome instability, indicated by anaphase bridges, multipolar spindles and chromosome missegregation. We determined that the noncanonical NF-κB pathway execute these functions through the regulation of GADD45α and REDD1 in a p53-independent manner, while it collaborates with p53 to regulate cyclin G2 expression. Furthermore, this pathway regulates GADD45α, REDD1 and cyclin G2 through direct binding of NF-κB sites to their promoter region. Overall, these results indicate that the noncanonical NF-κB pathway plays a central role in maintaining genome integrity in DLBCL. Our data suggests that inhibition of the noncanonical NF-kB pathway should be considered as an important component in DLBCL therapeutic approach.

Gene expression profiling of clear cell papillary renal cell carcinoma: comparison with clear cell renal cell carcinoma and papillary renal cell carcinoma.

Clear cell papillary renal cell carcinoma is a distinct variant of renal cell carcinoma that shares some overlapping histological and immunohistochemical features of clear cell renal cell carcinoma and papillary renal cell carcinoma. Although the clear cell papillary renal cell carcinoma immunohistochemical profile is well described, clear cell papillary renal cell carcinoma mRNA expression has not been well characterized. We investigated the clear cell papillary renal cell carcinoma gene expression profile using previously identified candidate genes. We selected 17 clear cell papillary renal cell carcinoma, 15 clear cell renal cell carcinoma, and 13 papillary renal cell carcinoma cases for molecular analysis following histological review. cDNA from formalin-fixed paraffin-embedded tissue was prepared. Quantitative real-time PCR targeting alpha-methylacyl coenzyme-A racemase (AMACR), BMP and activin membrane-bound inhibitor homolog (BAMBI), carbonic anhydrase IX (CA9), ceruloplasmin (CP), nicotinamide N-methyltransferase (NNMT), schwannomin-interacting protein 1 (SCHIP1), solute carrier family 34 (sodium phosphate) member 2 (SLC34A2), and vimentin (VIM) was performed. Gene expression data were normalized relative to 28S ribosomal RNA. Clear cell papillary renal cell carcinoma expressed all eight genes at variable levels. Compared with papillary renal cell carcinoma, clear cell papillary renal cell carcinoma expressed more CA9, CP, NNMT, and VIM, less AMACR, BAMBI, and SLC34A2, and similar levels of SCHIP1. Compared with clear cell renal cell carcinoma, clear cell papillary renal cell carcinoma expressed slightly less NNMT, but similar levels of the other seven genes. Although clear cell papillary renal cell carcinoma exhibits a unique molecular signature, it expresses several genes at comparable levels to clear cell renal cell carcinoma relative to papillary renal cell carcinoma. Understanding the molecular pathogenesis of clear cell papillary renal cell carcinoma will have a key role in future sub-classifications of this unique tumor.

Histological image classification using biologically interpretable shape-based features.

BACKGROUND: Automatic cancer diagnostic systems based on histological image classification are important for improving therapeutic decisions. Previous studies propose textural and morphological features for such systems. These features capture patterns in histological images that are useful for both cancer grading and subtyping. However, because many of these features lack a clear biological interpretation, pathologists may be reluctant to adopt these features for clinical diagnosis. METHODS: We examine the utility of biologically interpretable shape-based features for classification of histological renal tumor images. Using Fourier shape descriptors, we extract shape-based features that capture the distribution of stain-enhanced cellular and tissue structures in each image and evaluate these features using a multi-class prediction model. We compare the predictive performance of the shape-based diagnostic model to that of traditional models, i.e., using textural, morphological and topological features. RESULTS: The shape-based model, with an average accuracy of 77%, outperforms or complements traditional models. We identify the most informative shapes for each renal tumor subtype from the top-selected features. Results suggest that these shapes are not only accurate diagnostic features, but also correlate with known biological characteristics of renal tumors. CONCLUSIONS: Shape-based analysis of histological renal tumor images accurately classifies disease subtypes and reveals biologically insightful discriminatory features. This method for shape-based analysis can be extended to other histological datasets to aid pathologists in diagnostic and therapeutic decisions.

Hb Fulton-Georgia [α20(B1)His→Pro; HBA1: c.62A>C]: a new α-globin variant coinherited with α-thalassemia-2 (3.7 kb deletion) and Hb SC disease.

We report a novel hemoglobin (Hb) variant that we named Hb Fulton-Georgia, caused by a point mutation in exon 1/codon 20 of the α-globin gene [α20(B1)His→Pro; HBA1: c.62A>C]. This α chain variant was identified in an adult African-American female with Hb SC disease who was also heterozygous for the α-thalassemia-2 (α-thal-2) (3.7 kb deletion or αα/-α(3.7)). The Hb Fulton-Georgia mutation was located on the intact α1-globin gene not involved by α-thal-2. Molecular models indicated that the α20 residue of Hb Fulton-Georgia was the first amino acid of the B helix, and was not involved in α1/ß1 or α1/ß2 contacts in Hb S [ß6(A3)Glu→Val; HBB: c.20A>T] or Hb C [ß6(A3)Glu→Lys; HBB: c.19G>A] tetramers. Furthermore, the histidine→proline substitution at α20 did not disrupt the helical structure. High performance liquid chromatography (HPLC) detected Hb Fulton-Georgia in 16.0% of total Hb, consistent with inheritance on the α1 gene. Coinheritance of Hb Fulton-Georgia, heterozygous α-thal-2 and Hb SC disease was associated with a mild phenotype, consisting of microcytosis and anisocytosis, but no anemia or other hematological abnormality.

Frequency and determinants of disagreement and error in gleason scores: a population-based study of prostate cancer.

BACKGROUND: To examine factors that affect accuracy and reliability of prostate cancer grade we compared Gleason scores documented in pathology reports and those assigned by urologic pathologists in a population-based study. METHODS: A stratified random sample of 318 prostate cancer cases was selected to ensure representation of whites and African-Americans and to include facilities of various types. The slides borrowed from reporting facilities were scanned and the resulting digital images were re-reviewed by two urologic pathologists. If the two urologic pathologists disagreed, a third urologic pathologist was asked to help arrive at a final "gold standard" result. The agreements between reviewers and between the pathology reports and the "gold standard" were examined by calculating kappa statistics. The determinants of discordance in Gleason scores were evaluated using multivariate models with results expressed as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The kappa values (95% CI) reflecting agreement between the pathology reports and the "gold standard," were 0.61 (95% CI: 0.54, 0.68) for biopsies, and 0.37 (0.23, 0.51) for prostatectomies. Sixty three percent of discordant biopsies and 72% of discordant prostatectomies showed only minimal differences. Using freestanding laboratories as reference, the likelihood of discordance between pathology reports and expert-assigned biopsy Gleason scores was particularly elevated for small community hospitals (OR = 2.98; 95% CI: 1.73, 5.14). CONCLUSIONS: The level of agreement between pathology reports and expert review depends on the type of diagnosing facility, but may also depend on the level of expertise and specialization of individual pathologists.

Robust microarray meta-analysis identifies differentially expressed genes for clinical prediction.

Combining multiple microarray datasets increases sample size and leads to improved reproducibility in identification of informative genes and subsequent clinical prediction. Although microarrays have increased the rate of genomic data collection, sample size is still a major issue when identifying informative genetic biomarkers. Because of this, feature selection methods often suffer from false discoveries, resulting in poorly performing predictive models. We develop a simple meta-analysis-based feature selection method that captures the knowledge in each individual dataset and combines the results using a simple rank average. In a comprehensive study that measures robustness in terms of clinical application (i.e., breast, renal, and pancreatic cancer), microarray platform heterogeneity, and classifier (i.e., logistic regression, diagonal LDA, and linear SVM), we compare the rank average meta-analysis method to five other meta-analysis methods. Results indicate that rank average meta-analysis consistently performs well compared to five other meta-analysis methods.

caCORRECT2: Improving the accuracy and reliability of microarray data in the presence of artifacts.

BACKGROUND: In previous work, we reported the development of caCORRECT, a novel microarray quality control system built to identify and correct spatial artifacts commonly found on Affymetrix arrays. We have made recent improvements to caCORRECT, including the development of a model-based data-replacement strategy and integration with typical microarray workflows via caCORRECT's web portal and caBIG grid services. In this report, we demonstrate that caCORRECT improves the reproducibility and reliability of experimental results across several common Affymetrix microarray platforms. caCORRECT represents an advance over state-of-art quality control methods such as Harshlighting, and acts to improve gene expression calculation techniques such as PLIER, RMA and MAS5.0, because it incorporates spatial information into outlier detection as well as outlier information into probe normalization. The ability of caCORRECT to recover accurate gene expressions from low quality probe intensity data is assessed using a combination of real and synthetic artifacts with PCR follow-up confirmation and the affycomp spike in data. The caCORRECT tool can be accessed at the website: http://cacorrect.bme.gatech.edu. RESULTS: We demonstrate that (1) caCORRECT's artifact-aware normalization avoids the undesirable global data warping that happens when any damaged chips are processed without caCORRECT; (2) When used upstream of RMA, PLIER, or MAS5.0, the data imputation of caCORRECT generally improves the accuracy of microarray gene expression in the presence of artifacts more than using Harshlighting or not using any quality control; (3) Biomarkers selected from artifactual microarray data which have undergone the quality control procedures of caCORRECT are more likely to be reliable, as shown by both spike in and PCR validation experiments. Finally, we present a case study of the use of caCORRECT to reliably identify biomarkers for renal cell carcinoma, yielding two diagnostic biomarkers with potential clinical utility, PRKAB1 and NNMT. CONCLUSIONS: caCORRECT is shown to improve the accuracy of gene expression, and the reproducibility of experimental results in clinical application. This study suggests that caCORRECT will be useful to clean up possible artifacts in new as well as archived microarray data.

Expression of C-reactive protein and cyclooxygenase enzyme-2 in clear cell renal cell carcinoma: correlation with pathological parameters in 110 patients.

C-reactive protein is produced in response to cytokines such as interleukin (IL)-6. It is known that increased plasma IL-6 levels induce increased hepatic and intratumoral production of C-reactive protein. Cyclooxygenase enzyme-2 is induced by various stimuli, including inflammation and various growth factors. Expression of these two markers has not been well studied in clear cell renal cell carcinoma. The objective of this study is to correlate the expression of C-reactive protein and cyclooxygenase enzyme-2 in clear cell renal cell carcinoma with pathologic parameters. A search of the surgical pathology and consultation files at our institution was performed for nephrectomy specimens with clear cell renal cell carcinoma from 2007 to 2008. Immunohistochemical stains for C-reactive protein and cyclooxygenase enzyme-2 were performed. Staining intensity was graded as 0, 1+, 2+, and 3+. The staining intensity was then correlated with pathologic stage and Fuhrman nuclear grade for each case. A total of 110 cases were identified. Strong expression of C-reactive protein was associated with higher Fuhrman nuclear grade and pathologic stage, and the strength of correlation was statistically significant (p = 0.01 and p = 0.001), respectively. However, cyclooxygenase enzyme-2 expression did not show statistically significant correlation with both pathologic stage and Fuhrman nuclear grade (p = 0.1 and p = 0.15), respectively. To our knowledge, this is the largest study to date correlating the expression of both C-reactive protein and cyclooxygenase enzyme-2 in tissue with pathologic parameters in patients with clear cell renal cell carcinoma, which could have significant prognostic and therapeutic implications.

C-reactive protein may represent sensitive measure of renal cell carcinoma metastasis.

A patient with localized kidney cancer underwent potentially curative nephrectomy. Routinely post-operative serum C-Reactive Protein (CRP) values were measured. At 25 months post-operatively, lung imaging suggested possible metastasis. However, CRP levels remained at baseline. Subsequent resection revealed a benign mass. CRP values have been shown to carry prognostic significance for overall and disease free survival. This case suggests a novel use for CRP: a sensitive biomarker of disease recurrence and metastasis.

Increased number of coagulation products in relationship to red blood cell products transfused improves mortality in trauma patients.

BACKGROUND: Recent data from military and civilian centers suggest that mortality is decreased in massive transfusion patients by increasing the transfusion ratio of plasma and platelet (PLT) products, and fibrinogen in relationship to red blood cell (RBC) products during damage control resuscitation and surgery. This study investigates the relationship of plasma:RBC, PLT:RBC, and cryoprecipitate:RBC transfusion ratios to mortality in massively transfused patients at a civilian Level 1 trauma center. STUDY DESIGN AND METHODS: Demographic, laboratory, transfusion, and outcome data were collected prospectively from February 1, 2007, to January 31, 2009, and retrospectively from February 1, 2005, to January 31, 2007, on all injured patients who underwent massive transfusion (defined as >or=10 RBC products within 24 hr). Mortality was analyzed in relation to the plasma:RBC, PLT:RBC, and cryoprecipitate:RBC transfusion ratios using both univariate and multivariate analyses. RESULTS: A total of 214 patients received massive transfusion secondary to traumatic injury. High versus low transfusion ratios were associated with improved 30-day survival: plasma:RBC 59% versus 44%, p = 0.03; PLT:RBC 63% versus 33%, p < 0.01; and cryoprecipitate:RBC 66% versus 41%, p < 0.01. By multivariable stepwise logistic regression analysis, increased plasma:RBC (p = 0.02) and PLT:RBC (p = 0.02), and decreased age (p = 0.02), ISS (p < 0.01) and total RBCs (p = 0.03) were statistically associated with improved 30-day survival. CONCLUSIONS: In the civilian setting, plasma, PLT, and cryoprecipitate products significantly increased 30-day survival in trauma patients. Future prospective randomized clinical trials are required to determine the optimal transfusion ratios.

Convergence of biomarkers, bioinformatics and nanotechnology for individualized cancer treatment.

Recent advances in biomarker discovery, biocomputing and nanotechnology have raised new opportunities in the emerging fields of personalized medicine (in which disease detection, diagnosis and therapy are tailored to each individual's molecular profile) and predictive medicine (in which genetic and molecular information is used to predict disease development, progression and clinical outcome). Here, we discuss advanced biocomputing tools for cancer biomarker discovery and multiplexed nanoparticle probes for cancer biomarker profiling, in addition to the prospects for and challenges involved in correlating biomolecular signatures with clinical outcome. This bio-nano-info convergence holds great promise for molecular diagnosis and individualized therapy of cancer and other human diseases.

Compound heterozygosity for hemoglobin S [beta6(A3)Glu6Val] and hemoglobin Korle-Bu [beta73(E17)Asp73Asn].

We report a case of compound heterozygous hemoglobins S [beta6(A3)Glu6Val] and Korle-Bu [beta73(E17)Asp73Asn] in a 2-year-old girl. This hemoglobin genotype is associated with a benign clinical course, much like the sickle cell trait; however, its laboratory characteristics are very similar to compound heterozygous hemoglobin S and hemoglobin D-Los Angeles [beta121(GH4)Glu121Gln], which produces severe sickling hemolytic anemia. We describe laboratory data used to resolve this important differential diagnosis and review the interactions between hemoglobin S and the variant hemoglobins that may account for the different clinical phenotypes in compound heterozygotes.

C/EBP and C-Myb sites are important for the functional activity of the human myeloperoxidase upstream enhancer.

Myeloperoxidase (MPO), an enzyme active against bacterial and fungal infections, is expressed specifically in myeloblasts and promyelocytes and minimal in other cell types. We recently identified and partially characterized an upstream enhancer located between -4100 and -3844 bp of the MPO gene. We showed that an AML1 site contributes to enhancer activity and specificity. We now demonstrate three additional footprints within the MPO enhancer and provide evidence that C/EBP and c-Myb sites contribute to its functional, tissue-specific activity. This distal enhancer appears to play an important role in the control of MPO transcription during differentiation of myeloid cells.

Prognostic role of CD44 cell adhesion molecule expression in primary and metastatic renal cell carcinoma: a clinicopathologic study of 125 cases.

Possible prognostic utility of CD44 in renal cell carcinoma (RCC) prompted a comparison of its expression in primary and metastatic RCC. A total of 164 paraffin-embedded tissues of primary RCC and metastatic RCCs from 125 patients were immunostained with CD44 (standard form) antibody. It consisted of 86 primary RCCs (50 with subsequent metastasis [MET+] and 36 with no known metastasis [MET-]) during follow up and 78 metastatic RCCs (39 metastatic RCCs only and 39 with matched RCC primary from RCC MET + category). Immunoreactivity for CD44 was scored semiquantitatively as 0, 1, or 2 (0, <5%; 1, 5-50%; 2, > or =50%). Expression of CD44 was significantly higher in metastatic RCCs compared to primary RCCs (p = 0.036). CD44 immunoreactivity in the primary RCC (MET- and MET+) correlated with progression-free survival (p = 0.027). In metastatic RCCs, CD44 immunoreactivity also correlated with survival after detection of first metastasis (p = 0.011). In multivariate analysis, stage (p = 0.0001) and CD44 immunoreactivity (p = 0.03) in primary RCC were independent predictors of progression-free survival. Our study suggests that CD44 status in RCC provides useful prognostic information both in primary and metastatic RCCs and may have applicability in stratifying patients for therapeutic decisions.

Compound heterozygosity for hemoglobin C and hemoglobin Korle-Bu.

We describe a case of compound heterozygosity for hemoglobin C (beta6 Glu-->Lys) and hemoglobin Korle-Bu (beta73 Asp-->Asn). To our knowledge, this is the third case report of this unusual hemoglobin genotype, and the first to integrate data from cation exchange high-performance liquid chromatography, hemoglobin electrophoresis, and beta-globin gene sequencing. The principal hematological finding in our case was microcytosis without significant anemia. The previous case reports of this hemoglobinopathy also describe microcytosis, with varying degrees of hemolytic anemia. Given the relative gene frequencies of hemoglobins C and Korle-Bu, the occurrence of this compound-heterozygous genotype should be anticipated in people of African ancestry.

Expression analysis of kidney-specific cadherin in a wide spectrum of traditional and newly recognized renal epithelial neoplasms: diagnostic and histogenetic implications.

Kidney-specific cadherin (Ksp-cad) is a membrane-associated cell adhesion glycoprotein expressed by the distal nephron tubular cells in its later developmental stages. Chromophobe renal cell carcinoma and renal oncocytoma are reported to be variably positive for Ksp-cad with some studies suggesting a discriminatory role for Ksp-cad. Immunoreactivity in other tumors with granular eosinophilic cytoplasm including clear cell and papillary renal cell carcinomas needs to be clearly elucidated and its expression in emerging novel and other unusual renal epithelial neoplasm subtypes including tumors with uncertain histogenesis is not yet known. In this study, we performed a detailed immunohistochemical analysis for Ksp-cad in a broad range of 136 renal epithelial neoplasms. Reactivity with Ksp-cad was observed in the following tumors: chromophobe renal cell carcinoma [23/25 (92%), diffuse (>50% of tumor cells)] positivity and membranous characteristically accentuating the "plant cell-like" histomorphology of the typical (clear) type, renal oncocytoma [15/20 (75%), usually diffuse staining with predominantly membranous accentuation], papillary renal cell carcinoma [5/17 (29%) all focal to moderate, eosinophilic type or type 2-3/7 (43%), basophilic type or type 1-2/10 (20%)], Xp11 translocation carcinoma [1/4 (25%), diffuse positivity] and clear cell renal cell carcinoma [6/36 (17%) all focal, clear cell renal cell carcinoma with prominent eosinophilic cells 1/7 (14%)]. Immunoreactivity was higher when evaluating whole histologic sections than with tissue microarrays for both chromophobe renal cell carcinoma (100% vs. 60%) and renal oncocytoma (100% vs. 55%). No immunoreactivity was observed in mucinous tubular and spindle cell carcinomas (0/23), high-grade collecting duct carcinomas (of Bellini) (0/3), renal medullary carcinomas (0/2), and urothelial carcinomas (0/6). Our study documents the immunoreactivity of Ksp-cad in the range of contemporarily classified renal epithelial neoplasms. The findings argue against the use of Ksp-cad in differentiating chromophobe renal cell carcinoma and renal oncocytomas and further support their relationship to the distal nephron. Ksp-cad may be helpful in distinguishing these two tumor types from clear cell renal cell carcinoma with prominent eosinophilic cells particularly in cases with limited tissue samples (ie, needle core biopsy). In the similar diagnostic setting, caution must be exercised, however, in differentiating chromophobe renal cell carcinoma and renal oncocytoma from the eosinophilic variant of papillary renal cell carcinoma as moderate expression of Ksp-cad may be observed in papillary renal cell carcinoma. The histogenesis of mucinous tubular and spindle cell carcinoma remains debatable as this tumor does not express Ksp-cad, which is highly expressed normally in the thick ascending loop of Henle and the distal convoluted tubules. In conclusion, Ksp-cad is a useful tumor type associated marker for distinguishing chromophobe renal cell carcinoma and renal oncocytoma from the wide range of nonintercalated cell-related adult renal epithelial neoplasms; addition of this marker to a panel comprised of other histologic subtype-associated markers may greatly facilitate histologic subclassification of adult renal epithelial neoplasms.

Beta2-microglobulin promotes the growth of human renal cell carcinoma through the activation of the protein kinase A, cyclic AMP-responsive element-binding protein, and vascular endothelial growth factor axis.

PURPOSE: Beta(2)-microglobulin (beta2M), a soluble protein secreted by cancer and host inflammatory cells, has various biological functions, including antigen presentation. Because aberrant expression of beta2M has been reported in human renal cell carcinoma, we investigated the effects of beta2M overexpression on cancer cell growth and analyzed its molecular signaling pathway. EXPERIMENTAL DESIGN: We established clonal cell lines that overexpressed beta2M in human renal cell carcinoma (SN12C) cells and then examined cell growth in vitro and in vivo and studied the beta2M-mediated downstream cell signaling pathway. RESULTS: Our results showed that beta2M expression positively correlates with (a) in vitro growth on plastic dishes and as Matrigel colonies, (b) cell invasion and migration in Boyden chambers, and (c) vascular endothelial growth factor (VEGF) expression and secretion by cells. We found, in addition, that beta2M mediates its action through increased phosphorylation of cyclic AMP-responsive element-binding protein (CREB) via the protein kinase A-CREB axis, resulting in increased VEGF expression and secretion. In convergence with this signal axis, beta2M overexpression also activated both phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase pathways. Beta2M overexpression induced accelerated growth of SN12C in mouse subcutis and bone. Interrupting the beta2M signaling pathway using small interfering RNA led to apoptosis with increased activation of caspase-3 and caspase-9 and cleaved poly(ADP-ribose) polymerase. CONCLUSIONS: Our results showed for the first time that the beta2M-protein kinase A-CREB-VEGF signaling axis plays a crucial role in support of renal cell carcinoma growth and progression and reveals a novel therapeutic target.

Loss of HOXC6 expression induces apoptosis in prostate cancer cells.

We have performed whole genome expression profiling of 28 patient prostate tumor samples and 12 normal prostate samples and identified 55 upregulated and 60 downregulated genes significantly changed in prostate tumor samples compared to normal prostate tissues. Among the members of the upregulated gene set was the developmental transcription factor Homeobox C6 (HOXC6). Silencing of HOXC6 expression using small-interfering RNA (siRNA) resulted in decreased proliferation rates for both androgen-dependent LnCaP cells and the LnCaP-derived androgen-independent C4-2 cell line. Flow cytometry and immunoblotting for the caspase-cleaved form of poly-ADP ribose polymerase (PARP) determined that the decrease in cell numbers was due to increased apoptosis. To validate the specificity of the siRNA-induced apoptosis, LnCaP cells were cotransfected with siRNA specific to the HOXC6 3'UTR and a mammalian expression vector containing the HOXC6 open reading frame, but lacking the 3'UTR. Overexpression of HOXC6 rescued the LnCaP cells from HOXC6 siRNA-induced apoptosis, and increased growth of control GFP siRNA-transfected cells. Expression profiling of HOXC6 siRNA transfections and HOXC6 overexpression identified neutral endopeptidase (NEP) and insulin-like growth factor binding protein-3 (IGFBP-3) as potential proapoptotic repression targets of HOXC6. Our data suggest that HOXC6 may be a novel potential therapeutic target for prostate cancer.

Immunohistochemical analysis of mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma of the kidney: significant immunophenotypic overlap warrants diagnostic caution.

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of alpha-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.