Histone acetylation regulates intracellular pH.

Differences in global levels of histone acetylation occur in normal and cancer cells, although the reason why cells regulate these levels has been unclear. Here we demonstrate a role for histone acetylation in regulating intracellular pH (pH(i)). As pH(i) decreases, histones are globally deacetylated by histone deacetylases (HDACs), and the released acetate anions are coexported with protons out of the cell by monocarboxylate transporters (MCTs), preventing further reductions in pH(i). Conversely, global histone acetylation increases as pH(i) rises, such as when resting cells are induced to proliferate. Inhibition of HDACs or MCTs decreases acetate export and lowers pH(i), particularly compromising pH(i) maintenance in acidic environments. Global deacetylation at low pH is reflected at a genomic level by decreased abundance and extensive redistribution of acetylation throughout the genome. Thus, acetylation of chromatin functions as a rheostat to regulate pH(i) with important implications for mechanism of action and therapeutic use of HDAC inhibitors.

Smoking negatively impacts renal cell carcinoma overall and cancer-specific survival.

BACKGROUND: Tobacco use is a leading cause of premature death, yet few studies have investigated the effect of tobacco exposure on the outcome of patients with renal cell carcinoma (RCC). The authors of this report retrospectively studied the impact of smoking on clinicopathologic factors, survival outcomes, and p53 expression status in a large cohort of patients with RCC. METHODS: Eight hundred-two patients (457 nonsmokers and 345 smokers) who had up to 232 months of follow-up were compared for differences in their clinicopathologic features and survival outcomes. Immunohistochemical differences in p53 expression were correlated with smoking status. RESULTS: Smokers presented more commonly with pulmonary comorbidities (P < .0001) and cardiac comorbidities (P = .014) and with a worse performance status (P = .031) than nonsmokers. Smoking was associated significantly with tumor multifocality (P = .022), higher pathologic tumor classification (P = .037), an increased risk of bulky lymph node metastases (P = .031), and the presence of distant metastases (P < .0001), especially lung metastases (P < .0001). Both overall survival (OS) (62.37 months vs 43.64 months; P = .001) and cancer-specific survival (CSS) (87.43 months vs 56.57 months; P = .005) were significantly worse in patients who smoked. The number of pack-years was retained as an independent predictor of CSS and OS in patients with nonmetastatic disease. Mean expression levels of p53 were significantly higher in current smokers compared with former smokers and nonsmokers (P = .012). CONCLUSIONS: In patients with RCC, a history of smoking was associated with worse pathologic features and survival outcomes and with an increased risk of having mutated p53. Further investigation of the genetic and molecular mechanisms associated with decreased CSS in patients with RCC who have a history of smoking is indicated.

Expression of thyroid transcription factor-1 in normal endometrium is associated with risk of endometrial cancer development.

Thyroid transcription factor-1 (TTF-1) is a DNA-binding protein that is mainly expressed in thyroid and lung tissue, but has also been found in gynecologic tissue. Recent studies have suggested that TTF-1 has tumor suppressor function in lung adenocarcinoma models. In the current study, we examined whether expression of TTF-1 in benign endometrium and endometrial hyperplasia might impact on the risk of developing endometrial cancer. Formalin-fixed paraffin-embedded endometrial tissues obtained from 535 cases were used to construct an endometrial tissue microarray. One hundred fifty of 207 patients had multiple serial endometrial specimens including 46 patients who progressed to endometrial cancer. The tissue microarray included a range of histopathologies including benign endometrium (n=231), simple hyperplasia (n=105), complex hyperplasia (n=36), simple atypical hyperplasia (n=10), complex atypical hyperplasia (n=44), and endometrial carcinoma (n=109). Expression of TTF-1 by immunohistochemistry in benign endometrium and endometrial hyperplasia was correlated with progression to cancer and clinical features known to be associated with increased risk of developing endometrial cancer. Carcinoma specimens showed a significantly greater expression of TTF-1 compared with benign endometrium and non-atypical hyperplasia (P=0.0007 and P=0.05). Presence of TTF-1 expression in benign endometrium was associated with a significantly decreased risk of cancer development (P=0.003, hazards ratio=0.104, 95% CI: 0.024-0.455). TTF-1 expression in hyperplasia did not significantly correlate with progression to cancer. The data from our study show that TTF-1 expression in normal endometrium is associated with a reduced risk of endometrial cancer development. This observation suggests that TTF-1 might function as a tumor suppressor in endometrial tissue. TTF-1 expression in normal endometrium could potentially provide clinically useful information as a biomarker for the risk of endometrial cancer.

Pathological, immunohistochemical and cytogenetic features of papillary renal cell carcinoma with clear cell features.

PURPOSE: Papillary renal cell carcinoma is characterized histologically by tumors with cells arranged in a papillary pattern. Typically the cells have a chromophilic appearance but areas may show cells with clear cytoplasm, similar to those in clear cell renal cell carcinoma. MATERIALS AND METHODS: We re-reviewed the histological slides of 148 patients with papillary renal cell carcinoma who underwent nephrectomy for the presence of clear cells. Results were correlated with other pathological features, immunohistochemical expression of 22 protein markers, cytogenetic analysis and overall survival. RESULTS: Papillary renal cell carcinoma with clear cells was identified in 57 patients (39%). Clear cells were associated with higher T classification and grade, vascular invasion and type 2 papillary renal cell carcinoma. On immunohistochemistry these tumors revealed higher expression of epithelial vascular endothelial growth factor receptor-2 than papillary renal cell carcinoma without clear cells. All papillary renal cell carcinomas with clear cells expressed α-methylacyl-coenzyme A racemase and 76% expressed cytokeratin 7. Six of 8 tumors (75%) with chromosome 3p loss had clear cell features. The presence of clear cells was retained as an independent prognostic factor on multivariate analysis. In cases of papillary renal cell carcinoma with clear cells the loss of 3p material and absent cytokeratin 7 expression were associated with a worse outcome. CONCLUSIONS: Papillary renal cell carcinoma with clear cells is a novel entity with a unique clinical, immunohistochemical and cytogenetic phenotype. The presence of clear cells is associated with aggressive pathological characteristics and poorer prognosis.

Global histone modification patterns predict risk of prostate cancer recurrence.

Aberrations in post-translational modifications of histones have been shown to occur in cancer cells but only at individual promoters; they have not been related to clinical outcome. Other than being targeted to promoters, modifications of histones, such as acetylation and methylation of lysine and arginine residues, also occur over large regions of chromatin including coding regions and non-promoter sequences, which are referred to as global histone modifications. Here we show that changes in global levels of individual histone modifications are also associated with cancer and that these changes are predictive of clinical outcome. Through immunohistochemical staining of primary prostatectomy tissue samples, we determined the percentage of cells that stained for the histone acetylation and dimethylation of five residues in histones H3 and H4. Grouping of samples with similar patterns of modifications identified two disease subtypes with distinct risks of tumour recurrence in patients with low-grade prostate cancer. These histone modification patterns were predictors of outcome independently of tumour stage, preoperative prostate-specific antigen levels, and capsule invasion. Thus, widespread changes in specific histone modifications indicate previously undescribed molecular heterogeneity in prostate cancer and might underlie the broad range of clinical behaviour in cancer patients.

Global levels of histone modifications predict prognosis in different cancers.

Cancer cells exhibit alterations in histone modification patterns at individual genes and globally at the level of single nuclei in individual cells. We demonstrated previously that lower global/cellular levels of histone H3 lysine 4 dimethylation (H3K4me2) and H3K18 acetylation (ac) predict a higher risk of prostate cancer recurrence. Here we show that the cellular levels of both H3K4me2 and H3K18ac also predict clinical outcome in both lung and kidney cancer patients, with lower levels predicting significantly poorer survival probabilities in both cancer groups. We also show that lower cellular levels of H3K9me2, a modification associated with both gene activity and repression, is also prognostic of poorer outcome for individuals with either prostate or kidney cancers. The predictive power of these histone modifications was independent of tissue-specific clinicopathological variables, the proliferation marker Ki-67, or a p53 tumor suppressor mutation. Chromatin immunoprecipitation experiments indicated that the lower cellular levels of histone modifications in more aggressive cancer cell lines correlated with lower levels of modifications at DNA repetitive elements but not with gene promoters across the genome. Our results suggest that lower global levels of histone modifications are predictive of a more aggressive cancer phenotype, revealing a surprising commonality in prognostic epigenetic patterns of adenocarcinomas of different tissue origins.

Absent CD44v6 expression is an independent predictor of poor urothelial bladder cancer outcome.

PURPOSE: CD44v6 is a cell surface protein involved in cell migration, cell adhesion, tumor progression and metastatic spread. We evaluated its role as a molecular marker for urothelial bladder cancer. MATERIALS AND METHODS: A tissue microarray was constructed containing 410 primary urothelial bladder cancers, each in triplicate. Immunohistochemical staining was done with a commercially available antibody. The percent of tumor cells staining positive for CD44v6 was evaluated and we assessed associations with stage, grade and survival. RESULTS: CD44v6 expression was higher in noninvasive (Ta, Tis) vs invasive (T1-T4) tumors (p <0.001). It decreased with increasing grade (p <0.001). In patients who underwent transurethral bladder resection absent CD44v6 expression was associated with a 2.3-fold increased risk of recurrence (95% CI 1.28 to 4.08). Median time to recurrence for tumors with vs without CD44v6 expression was 23 vs 9 months (p = 0.003). In a multivariate Cox model absent CD44 expression was an independent adverse prognostic factor for tumor recurrence (HR 2.33, p = 0.006). In cystectomy cases median overall survival for CD44v6 nonexpression vs expression was 30 vs 75 months (p = 0.0027) and CD44v6 expression was retained as an independent prognostic factor for overall survival (HR 1.54, p = 0.042). CONCLUSIONS: Absent CD44v6 expression is an independent adverse predictor of urothelial bladder cancer recurrence and overall survival. Routine evaluation of CD44v6 expression may allow the identification of high risk patients who require more intensive surveillance or aggressive therapy. Targeting of CD44v6 with monoclonal antibodies may provide new avenues for urothelial bladder cancer imaging and treatment.

Elevated MED28 expression predicts poor outcome in women with breast cancer.

BACKGROUND: MED28 (also known as EG-1 and magicin) has been implicated in transcriptional control, signal regulation, and cell proliferation. MED28 has also been associated with tumor progression in in vitro and in vivo models. Here we examined the association of MED28 expression with human breast cancer progression. METHODS: Expression of MED28 protein was determined on a population basis using a high-density tissue microarray consisting of 210 breast cancer patients. The association and validation of MED28 expression with histopathological subtypes, clinicopathological variables, and disease outcome was assessed. RESULTS: MED28 protein expression levels were increased in ductal carcinoma in situ and invasive ductal carcinoma of the breast compared to non-malignant glandular and ductal epithelium. Moreover, MED28 was a predictor of disease outcome in both univariate and multivariate analyses with higher expression predicting a greater risk of disease-related death. CONCLUSIONS: We have demonstrated that MED28 expression is increased in breast cancer. In addition, although the patient size was limited (88 individuals with survival information) MED28 is a novel and strong independent prognostic indicator of survival for breast cancer.

Cytogenetic and molecular tumor profiling for type 1 and type 2 papillary renal cell carcinoma.

PURPOSE: The goal of this study was to evaluate immunohistochemical and cytogenetic features and their prognostic value in papillary renal cell carcinoma (PRCC) subtypes. EXPERIMENTAL DESIGN: One hundred fifty-eight cases of PRCC were identified and reclassified by subtype. Tumoral expression of 29 molecular markers was determined by immunohistochemistry. Cytogenetic analyses were done on a prospective series of 65 patients. Associations with clinicopathologic information and disease-specific survival were assessed. RESULTS: Fifty-one patients (32%) had type 1 and 107 (68%) type 2 PRCC. Type 2 patients had worse Eastern Cooperative Oncology Group performance status, higher T stages, nodal and distant metastases, higher grades, and a higher frequency of necrosis, collecting system invasion and sarcomatoid features. Type 2 showed greater expression of vascular endothelial growth factor (VEGF)-R2 in the tumor epithelium, and of VEGF-R3 in both tumor epithelium and endothelium. Loss of chromosome 1p, loss of 3p, and gain of 5q were exclusively observed in type 2, whereas type 1 more frequently had trisomy 17. Type 2 PRCC was associated with worse survival than type 1, but type was not retained as an independent prognostic factor. Lower PTEN, lower EpCAM, lower gelsolin, higher CAIX, and higher VEGF-R2 and VEGF-R3 expression, loss of 1p, 3p, or 9p, and absence trisomy 17 were all associated with poorer prognosis. CONCLUSIONS: Type 2 PRCC is associated with more aggressive clinicopathologic features and worse outcome. Molecular and chromosomal alterations can distinguish between PRCC subtypes and influence their prognosis. The effect of 3p loss on survival in PRCC is opposite to the relationship seen in clear cell RCC.

Molecular signatures of localized clear cell renal cell carcinoma to predict disease-free survival after nephrectomy.

PURPOSE: To identify the molecular signature of localized (N0M0) clear cell renal cell carcinoma (RCC) and assess its ability to predict outcome. METHODS: Clinical characteristics and pathologic records of 170 patients with localized clear cell RCC who underwent nephrectomy were reviewed. Immunohistochemical analysis was done on a tissue microarray of all primary tumors using a kidney cancer-related panel of protein markers, which included CAIX, CAXII, CXCR3, gelsolin, Ki-67, vimentin, EpCAM, p21, p27, p53, pS6, PTEN, HIF-1alpha, pAkt, VEGF-A, VEGF-C, VEGF-D, VEGFR-1, VEGFR-2, and VEGFR-3. Associations with disease-free survival (DFS) were evaluated with Cox models, and a concordance index assessed prognostic accuracy. RESULTS: Median follow-up was 7.1 years. The final multivariate Cox model determined T classification, Eastern Cooperative Oncology Group performance status, and five molecular markers (Ki-67, p53, endothelial VEGFR-1, epithelial VEGFR-1, and epithelial VEGF-D) to be independent prognostic indicators of DFS. The molecular signature based on these markers predicted DFS with an accuracy of 0.838, an improvement over T classification of 0.746, and the University of California-Los Angeles Integrated Staging System of 0.780. A constructed nomogram combined the molecular, clinical, and pathologic factors and approached a concordance index of 0.904. CONCLUSIONS: A molecular signature consisting of five molecular markers (Ki-67, p53, endothelial VEGFR-1, epithelial VEGFR-1, and epithelial VEGF-D) can predict DFS for localized clear cell RCC. The prognostic ability of the signature and nomogram may be superior to clinical and pathologic factors alone and may identify a subset of localized patients with aggressive clinical behavior. Independent, external validation of the nomogram is required.

CA9 gene: single nucleotide polymorphism predicts metastatic renal cell carcinoma prognosis.

PURPOSE: We assessed CA9 single nucleotide polymorphisms and mutations, and their association with CAIX protein expression, overall survival and response to interleukin-2 in white patients with metastatic clear cell renal cell carcinoma. MATERIALS METHODS: Genomic DNA was extracted from frozen tumor samples of 54 metastatic clear cell renal cell carcinomas. The CA9 gene exons and flanking regions were amplified by polymerase chain reaction and sequenced. The monoclonal antibody M75 was used to evaluate CAIX protein expression in the primary tumor by immunohistochemistry. RESULTS: CA9 reference single nucleotide polymorphisms rs2071676, rs12553173, rs3829078 and rs1048638 were found in 59%, 15%, 11% and 33% of patients, respectively. The deletion c.376del393 was observed in 2 patients. CAIX expression was greater than 85% in 65% of patients. No single nucleotide polymorphisms were significantly associated with CAIX expression. Patients with the C allele variant of rs12553173 had improved median survival (27.3 vs 13.6 months, p = 0.0431) and a greater likelihood of an interleukin-2 response (57% vs 22%, p = 0.081) Likewise high CAIX expression was associated with longer median survival (25.5 vs 8.5 months, p <0.0001) and a greater interleukin-2 response rate (37% vs 8%, p = 0.070). In a multivariate Cox model the C allele variant of CA9 single nucleotide polymorphism rs12553173 and CAIX expression were retained as independent prognostic factors. CONCLUSIONS: CA9 single nucleotide polymorphisms are common in patients with metastatic clear cell renal cell carcinoma. The synonymous C allele variant of rs12553173 may be associated with improved overall survival and a greater likelihood of a response to interleukin-2. CA9 rs12553173 and CAIX are independent prognostic factors of overall survival and complementary for predicting the prognosis of metastatic clear cell renal cell carcinoma.

Development of a real-time RT-PCR assay for detecting EGFRvIII in glioblastoma samples.

PURPOSE: Epidermal growth factor receptor variant III (EGFRvIII) is an oncogenic, constitutively active mutant form of the EGFR that is commonly expressed in glioblastoma and is also detected in a number of epithelial cancers. EGFRvIII presents a unique antigenic target for anti-EGFRvIII vaccines and it has been shown to modulate response to EGFR kinase inhibitor therapy. Thus, detection in clinical samples may be warranted. Existing patents preclude the use of anti-EGFRvIII antibodies for clinical detection. Further, frozen tissue is not routinely available, particularly for patients treated in the community. Thus, detection of EGFRvIII in formalin-fixed paraffin-embedded (FFPE) clinical samples is a major challenge. EXPERIMENTAL DESIGN: We developed a real-time reverse transcription-PCR (RT-PCR) assay for detecting EGFRvIII in FFPE samples and analyzed 59 FFPE glioblastoma clinical samples with paired frozen tissue from the same surgical resection. We assessed EGFRvIII protein expression by immunohistochemistry using two distinct specific anti-EGFRvIII antibodies and examined EGFR gene amplification by fluorescence in situ hybridization. RESULTS: The FFPE RT-PCR assay detected EGFRvIII in 16 of 59 (27%) samples, exclusively in cases with EGFR amplification, consistent with the expected frequency of this alteration. The FFPE RT-PCR assay was more sensitive and specific for detecting EGFRvIII than either of the two antibodies alone, or in combination, with a sensitivity of 93% (95% confidence interval, 0.78-1.00) and a specificity of 98% (95% confidence interval, 0.93-1.00). CONCLUSION: This assay will facilitate accurate assessment of EGFRvIII in clinical samples and may aid in the development of strategies for stratifying patients for EGFRvIII-directed therapies.

The chemokine receptor CXCR3 is an independent prognostic factor in patients with localized clear cell renal cell carcinoma.

PURPOSE: Through its binding with interferon inducible angiostatic chemokines the chemokine receptor CXCR3 has an important role in regulating tumor mediating immunity, angiogenesis and metastatic spread. To evaluate its role in the biology of clear cell renal cell carcinoma we performed a tissue microarray based study. MATERIALS AND METHODS: The tissue microarray comprised 154 patients who underwent nephrectomy for localized (N0M0) clear cell renal cell carcinoma at UCLA from 1989 to 2000. Immunohistochemical staining was evaluated by 2 anatomical pathologists who were blinded to outcome. The end point of this study was disease-free survival. Median followup was 5.9 years. RESULTS: A total of 96% of the tumor specimens stained positive for CXCR3. The mean percent of cells staining positive was 68% (range 0 to 100%). CXCR3 expression was not associated with other common clinicopathological features, such as Eastern Cooperative Oncology Group performance status, T stage, Fuhrman grade, vascular invasion or sarcomatoid features. Patients with low CXCR3 expression (less than 30%) had a significantly worse prognosis than patients with high CXCR3 expression with a 5-year disease-free survival rate of 57% vs 82% (p = 0.009). Multivariate Cox regression analysis retained T stage, Eastern Cooperative Oncology Group performance status, sarcomatoid features and CXCR3 as independent prognostic factors. CONCLUSIONS: CXCR3 is a novel molecular marker in patients with clear cell renal cell carcinoma. Its higher expression is an independent predictor of improved disease-free survival following nephrectomy for localized disease. Since CXCR3 is not associated with other clinicopathological prognostic factors, it may represent an ideal complementary molecular marker for identifying patients who are at higher risk for recurrence after nephrectomy.

Na,K-adenosine triphosphatase alpha1-subunit predicts survival of renal clear cell carcinoma.

PURPOSE: Na,K-adenosine triphosphatase, which is composed of a catalytic alpha-subunit and a regulatory beta-subunit, generates an electrochemical gradient across the plasma membrane. Previous studies demonstrated altered Na,K-adenosine triphosphatase subunit expression in renal clear cell carcinoma and an association of subunit levels with the prediction of recurrent bladder cancer. We determined the clinical association of protein expression patterns of the Na,K-adenosine triphosphatase alpha1 and beta1-subunits in renal clear cell carcinoma using tissue microarrays with linked clinicopathological data. MATERIALS AND METHODS: The UCLA kidney cancer tissue microarray was used to investigate the protein expression of Na,K-adenosine triphosphatase alpha1 and beta1-subunits by immunohistochemistry in 342 patients with renal clear cell carcinoma who were treated with radical nephrectomy. Of these patients clinical outcomes studies were performed in 317. The resultant expression reactivity was correlated with clinicopathological variables. RESULTS: We found that the alpha1-subunit was a significant and independent predictor of disease specific death from renal clear cell carcinoma on multivariate Cox proportional hazards analysis that included established prognostic factors Eastern Cooperative Oncology Group performance status, pT status, metastasis status and tumor grade. Significance was found when examining all patients with clear cell renal cell carcinoma as well as patient substrata with low or high grade tumors and localized or metastatic disease, suggesting that the Na,K-adenosine triphosphatase alpha1-subunit could be used as a new prognosticator for disease specific death from renal clear cell carcinoma. CONCLUSIONS: These results suggest that Na,K-adenosine triphosphatase alpha1-subunit expression patterns may be a useful clinical prognosticator for renal clear cell carcinoma. The Na,K-adenosine triphosphatase beta1-subunit was not found to be a useful prognosticator in this setting.

Expression of arginase II in prostate cancer.

Previous reports have shown elevated arginase activity in prostate cancer patients. This study was designed to compare expression levels of arginase II (AII) in various human prostate cancer cell lines and tissues. Expression levels of AII and other enzymes involved in arginine metabolism were examined in androgen-dependent (LNCaP, LAPC-4) and androgen-independent (PC3, DU145, CL-1, CL-2) prostate cancer cell lines by real-time RT-PCR and Western blot analysis. Further expression analysis of AII was accomplished by immunohistochemical staining of a tissue microarray comprised of 246 primary prostatectomy specimens. In addition, polyamine levels were measured within the prostate cancer cell lines by HPLC. Total polyamines were significantly lower in the androgen-dependent cell lines compared to the androgen-independent cell lines. AII expression was found to be most prominent in the androgen-dependent cell lines and least prominent in the androgen-independent cell lines. Additionally, we found expression of ornithine aminotransferase (OAT), an enzyme also responsible for ornithine production, to be inversely correlated with AII expression. The tissue microarray data revealed that the highest AII expression was seen in BPH, followed by PIN and normal samples, with the lowest expression levels observed in prostate cancer tissues. Moreover, we observed an expression gradient across Gleason grades revealing stronger AII expression in low-grade tumors. The polyamine data, combined with the expression analysis studies, support a possible correlation between AII, OAT, and polyamine synthesis. Based on these results, arginase II expression may play a role in prostate cancer progression. More specifically, the elevated AII expression seen in androgen-dependent and in more differentiated prostate cancers suggests that AII could be a potentially useful marker of early stage prostate adenocarcinoma.

Hypoxia-inducible factor 1 alpha in clear cell renal cell carcinoma.

PURPOSE: Hypoxia-inducible factor-1 alpha (HIF-1 alpha) plays an important role in tumoral adaptation to hypoxic conditions by serving as a transcription factor for several crucial proteins, including vascular endothelial growth factor and carbonic anhydrase IX (CAIX). Here, we evaluated the significance of HIF-1 alpha in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: Immunohistochemical analysis was done on a tissue microarray constructed from paraffin-embedded primary tumor specimens from 357 patients treated by nephrectomy for RCC. Nuclear expression was evaluated by a single pathologist who was blinded to outcome. The expression levels were associated with pathologic variables and survival. RESULTS: HIF-1 alpha expression was greater in RCC than in benign tissue. Clear cell RCC showed the highest expression levels. In clear cell RCC, HIF-1 alpha was significantly correlated with markers of apoptosis (p21, p53), the mammalian target of rapamycin pathway (pAkt, p27), CXCR3, and proteins of the vascular endothelial growth factor family. HIF-1 alpha was correlated with CAIX and CAXII in localized, but not in metastatic RCC. HIF-1 alpha expression predicted outcome in metastatic patients: patients with high HIF-1 alpha expression (>35%) had significantly worse survival than patients with low expression (< or =35%); median survival, 13.5 versus 24.4 months, respectively (P = 0.005). Multivariate analysis retained HIF-1 alpha and CAIX expression as the strongest independent prognostic factors for patients with metastatic clear cell RCC. CONCLUSIONS: HIF-1 alpha is an important independent prognostic factor for patients with metastatic clear cell RCC. Because HIF-1 alpha and CAIX are independently and differentially regulated in metastatic clear cell RCC, both tumor markers can be complementary in predicting prognosis.

Expression of X-linked inhibitor of apoptosis protein is a strong predictor of human prostate cancer recurrence.

PURPOSE: The X-linked inhibitor of apoptosis protein (XIAP) is associated with cell survival by blocking caspase-mediated apoptosis. We examined the expression patterns of XIAP with regard to human prostate cancer, predicting that XIAP status may predict cancer recurrence and/or clinical outcome. EXPERIMENTAL DESIGN: Immunohistochemistry was done on tissue microarrays constructed from 226 primary prostate cancer specimen. The protein expression distribution was examined across the spectrum of epithelial tissues and its association with standard clinicopathologic covariates and tumor recurrence was examined in 192 outcome-informative patients. RESULTS: The mean XIAP expression was significantly higher in prostate cancer compared with prostatic intraepithelial neoplasia (PIN), normal, and benign prostatic hyperplasia. We observed that XIAP is an independent predictor of tumor recurrence in multivariate Cox proportional hazards analysis in all patients as well as after substratifying by Gleason score. Interestingly, patients with high XIAP levels had a much lower probability of tumor recurrence than those with lower XIAP expression. Even patients with high-grade tumors who had higher XIAP levels had a lower risk of recurrence compared with any patient whose tumors express lower XIAP. CONCLUSIONS: XIAP is expressed at higher levels in prostate cancers compared with matched normal tissues. High XIAP expression is strongly associated with a reduced risk of tumor recurrence and is not directly associated with Gleason score, tumor stage, capsular involvement, or preoperative prostate-specific antigen status, suggesting that it is a novel prognosticator and a potential target for prostate cancer diagnosis and therapy. Significantly, these findings provide important and extensive validation of previous results.

Epithelial cell adhesion molecule (KSA) expression: pathobiology and its role as an independent predictor of survival in renal cell carcinoma.

PURPOSE: Epithelial cell adhesion molecule (EpCAM) is a widely expressed adhesion molecule in epithelial cancers. The purpose of this study is to determine the protein expression patterns of EpCAM in renal cell carcinoma (RCC) using tissue arrays linked to a clinicopathological database to evaluate both its predictive power in patient stratification and its suitability as a potential target for immunotherapeutic treatment strategies. EXPERIMENTAL DESIGN: The University of California, Los Angeles kidney cancer tissue microarray contains specimens from 417 patients treated with nephrectomy. EpCAM protein expression in tumors and matched morphologically normal renal tissues was evaluated using anti-EpCAM immunohistochemistry. The resultant expression reactivity was correlated with clinicopathological variables. RESULTS: EpCAM is consistently expressed in the distal nephron on normal renal epithelium. Clear cell RCCs show minimal and infrequent EpCAM expression, whereas chromophobe and collecting duct RCCs both demonstrate intense and frequent expression. Of 318 clear cell carcinomas used in the analysis, 10% were EpCAM positive in > or = 50% of cells, and 8% of patients would be considered candidates for EpCAM-based therapy, based on high expression [> or = moderate intensity and frequent (> or = 50%) expression] and the need for systemic treatment. EpCAM expression was an independent prognostic factor for improved disease-specific survival, with a multivariate hazard ratio of 0.63 (P = 0.017; 95% confidence interval, 0.43-0.92). CONCLUSIONS: EpCAM is a novel prognostic molecular marker in RCC patients, and its positive expression is an independent predictor associated with improved survival. However, high expression in morphologically normal renal tissues and minimal or absent expression in clear cell carcinomas will likely limit the utility of this epithelial marker in targeted treatments of this most common RCC type.

Tissue microarrays in the study of non-neoplastic disease of the nervous system.

Tissue microarrays (TMAs), also known as "tissue chips," are a recently developed method that allows small cores or discs of tissue from dozens or hundreds of (usually paraffin-embedded) specimens to be re-embedded in a tissue block, which can then be further sectioned. The tissue cores can subsequently be studied using any combination of techniques, including immunohistochemistry, in situ hybridization (ISH). fluorescence ISH, and in situ polymerase chain reaction (PCR). To date, the technique has found greatest use in the analysis of neoplasms, including gliomas. We describe, and provide examples of, how TMAs might be utilized in investigation of autopsy (or biopsy) tissues from individuals with non-neoplastic disease, especially to address questions that require systematic review of multiple (nearly) identical brain regions across dozens or hundreds of cases. Specific questions related to patterns of protein expression (e.g. tau, Abeta, alpha-synuclein) in multiple regions of large numbers of brain specimens (from patients with neurodegenerative diseases) can be efficiently examined using TMA technology. One possible use of TMAs in the area of infectious disease might be to examine patterns of HIV-related brain injury or AIDS-related opportunistic CNS infections in the epochs before and after highly active antiretroviral therapy came into widespread use.

Poor prognosis and advanced clinicopathological features of clear cell renal cell carcinoma (ccRCC) are associated with cytoplasmic subcellular localisation of Hypoxia inducible factor-2α.

BACKGROUND: Pre-clinical studies have implicated hypoxia inducible factor (HIF)-2α as an important oncogene for clear cell renal cell carcinoma (ccRCC). Generally considered to act as a nuclear transcription factor, a recent study has also implicated HIF-2α as a protein translational initiation complex function within the cytoplasm (Uniacke et al., 2012). We hypothesised that both the absolute expression as well as the sub-cellular localisation of HIF-2α would predict clinicopathological features and cancer specific survival (CSS) in ccRCC. METHODS: A tissue microarray (TMA) study was conducted on three hundred and eight ccRCC patients. Survival differences were investigated with the log rank test and associations with CSS with uni- and multivariate Cox regression analyses. Recursive partition tree analysis was used to identify relevant cutoff values. RESULTS: High HIF-2α nuclear (N) (cutoff >32%) expression was associated with smaller tumour sizes (p=0.002) and lower Fuhrman grades (p=0.044), whereas tumours with high cytoplasmic (C) HIF-2α (>0%) more often had positive lymph nodes (p=0.004), distant metastases (p=0.021) and higher Fuhrman grades (p<0.0001). After adjustment for TNM stage, Eastern Cooperative Oncology Group performance status (ECOG PS), and Fuhrman grade, both continuous (p<0.0001) and dichotomised (p<0.0001) HIF-2α C variables remained significant predictors of CSS, while neither HIF-2α N variable was retained. CONCLUSION: Our investigation supports that HIF-2α may have a unique tumour promoter role in the cytoplasm. This preliminary finding justifies further experimental and mechanistic studies that examine the biological functions of HIF-2α when located in the cytoplasm.