Immunohistochemistry In Paraffin-embedded Tissue Research Articles

Darifenacin: a promising chitinase 3-like 1 inhibitor to tackle drug resistance in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is among the most aggressive malignancies. Our previous work revealed Chitinase 3-like 1 (CHI3L1) involvement in PDAC resistance to gemcitabine, identifying it as a promising therapeutic target. Here, we aimed to identify putative CHI3L1 inhibitors and to investigate their chemosensitizing potential in PDAC. Docking analysis for CHI3L1 identified promising CHI3L1 inhibitors, including darifenacin (muscarinic receptor antagonist). PDAC cell lines (BxPC-3, PANC-1) and primary PDAC cells were used to evaluate darifenacin's effects on cell growth (Sulforhodamine B, SRB), alone or in combination with gemcitabine or gemcitabine plus paclitaxel. Cytotoxicity against normal immortalized pancreatic ductal cells (HPNE) was assessed. Recombinant protein was used to confirm the impact of darifenacin on CHI3L1-induced PDAC cellular resistance to therapy (SRB assay). Darifenacin's effect on Akt activation was analysed by ELISA. The association between cholinergic receptor muscarinic 3 (CHRM3) expression and therapeutic response was evaluated by immunohistochemistry of paraffin-embedded tissues from surgical resections of a 68 patients' cohort. In silico screening revealed the ability of darifenacin to target CHI3L1 with high efficiency. Darifenacin inhibited PDAC cell growth, with a GI50 of 26 and 13.6 µM in BxPC-3 and PANC-1 cells, respectively. These results were confirmed in primary PDAC-3 cells, while darifenacin showed no cytotoxicity against HPNE cells. Importantly, darifenacin sensitized PDAC cells to standard chemotherapies, reverted CHI3L1-induced PDAC cellular resistance to therapy, and decreased Akt phosphorylation. Additionally, high CHMR3 expression was associated with low therapeutic response to gemcitabine. This work highlights the potential of darifenacin as a chemosensitizer for PDAC treatment.

SSTR2a is constantly expressed in lymphoepithelioma-like carcinoma with squamous differentiation other than that with glandular differentiation

AimsSomatostatin receptor 2a (SSTR2a) is an important diagnostic marker of meningioma and neuroendocrine tumours and is frequently expressed in primary and metastatic non-keratinising nasopharyngeal carcinoma (NK-NPC). Since NK-NPC cases are...

Piglet colibacillosis diagnosis based on multiplex polymerase chain reaction and immunohistochemistry of paraffin-embedded tissues.

Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in pigs, referred to as colibacillosis. The aim of this study was to optimize multiplex polymerase chain reaction (PCR) and immunohistochemistry (IHC) analyses of paraffin-embedded material to detect pathogenic E. coli strains causing colibacillosis in pigs. Multiplex PCR was optimized for fimbriae (F18, F4, F6, F5, and F41) and toxins (types A and B heat-stable toxins [STaP and STb], heat-labile toxin [LT], and type 2 Shiga toxin [STx2e]), and IHC was optimized for an anti-E. coli polyclonal antibody. Samples (132) from pigs received between 2006 and 2014 with clinical and histopathological diagnoses of colibacillosis were analyzed. E. coli was detected by IHC in 78.7%, and at least one virulence factor gene was detected in 71.2%. Pathogenic strains of ETEC with at least one fimbria and one toxin were detected in 40% of the samples in multiplex PCR. The most frequent virulence types were F18-STaP (7.5%), F18-STaP-STb (5.7%), and F4-STaP (3.8%). A statistically significant association was noted between virulence factors F4, F18, STaP, and STb and positive immunostaining results. Colibacillosis diagnosis through multiplex PCR and IHC of paraffin-embedded tissues is a practical approach, as samples can be fixed and stored for long periods before analysis.

Association of insulin-like growth factor-binding protein-3 with radiotherapy response and prognosis of esophageal squamous cell carcinoma.

BackgroundInsulin-like growth factor-binding protein-3 (IGFBP-3) is suggested to predict the radiosensitivity and/or prognosis of patients with esophageal squamous cell carcinoma (ESCC). The present study was designed to investigate the clinical and prognostic effects of IGFBP-3 on ESCC.MethodsIGFBP-3 was detected by immunohistochemistry in paraffin-embedded tissues from 70 ESCC patients treated with radiotherapy alone and further examined by western blotting analysis in 10 pairs of fresh ESCC tissues and adjacent non-malignant esophageal specimens. Receiver operating characteristic (ROC) analysis was used to determine cut-off scores for tumor positivity and to evaluate patient survival status. The χ2 test was performed to analyze the association of IGFBP-3 expression with clinical characteristics and radiotherapy response. Associations between prognostic outcomes and IGFBP-3 expression were investigated using Kaplan–Meier analysis and the Cox proportional hazards model.ResultsThe threshold for IGFBP-3 positivity was set to greater than 65% [area under the ROC curve (AUC) = 0.690, P < 0.019]. Of the 70 ESCC patient tissues tested, 32 (45.7%) were defined as having high IGFBP-3 expression. The levels of IGFBP-3 protein expression were decreased in 70.0% (7 of 10) of ESCC tissues compared with adjacent non-malignant esophageal tissue. In addition, IGFBP-3 expression was associated with pathologic classification (P < 0.05 for T, N, and M categories and clinical stage). Patients with elevated protein level of IGFBP-3 in the tumor had an improved radiotherapy response and prolonged overall survival (P < 0.001).ConclusionsHigh level of IGFBP-3 expression in ESCC associates with early clinical stages and are predictive for favorable survival of the patients treated with radiotherapy.

Placental protein tyrosine nitration and MAPK in type 1 diabetic pre-eclampsia: Impact of antioxidant vitamin supplementation

AimTo examine the role of placental protein tyrosine nitration and p38-Mitogen-Activated Protein Kinase α (p38-MAPKα), Extra Cellular-Signal Regulated Kinase (ERK) and c-Jun NH2-Terminal Kinase (JNK) activity, in the pathogenesis of type 1 diabetic pre-eclampsia, and the putative modulation of these indices by maternal vitamin C and E supplementation. MethodsPlacental samples were obtained from a sub-cohort of the DAPIT trial: a randomised placebo-controlled trial of antioxidant supplementation to reduce pre-eclampsia in type 1 diabetic pregnancy. Placenta from placebo-treated: normotensive (NT) [n=17], gestational hypertension (GH) [n=7] and pre-eclampsia (PE) [n=6] and vitamin-treated: NT (n=20), GH (n=4) and PE (n=3) was analysed. Protein tyrosine nitration was assessed by immunohistochemistry in paraffin-embedded tissue. Catalytic activities of placental p38-MAPKα, ERK and JNK were measured by enzyme-linked immunosorbent assay (ELISA). ResultsNitrotyrosine immunostaining was present in placebo-treated NT, GH and PE placentae, with no significant difference observed between the groups. There was a non-significant trend towards decreased p38-MAPKα activity in PE vs NT control placentae. ERK and JNK were similar among the three outcome placebo groups and vitamin supplementation did not significantly alter their activity. ConclusionNitrotyrosine immunopositivity in normotensive diabetic placentae indicates some degree of tyrosine nitration in uncomplicated diabetic pregnancy, possibly due to inherent oxidative stress and peroxynitrite production. Our results suggest that p38-MAPKα, ERK and JNK are not directly involved in the pathogenesis of type 1 diabetic pre-eclampsia and are not modulated by vitamin-supplementation.

Prolyl Hydroxylase Domain 2 Protein Is a Strong Prognostic Marker in Human Gastric Cancer

Objective: According to recent research, prolyl hydroxylase domain 2 protein (PHD2) plays an important role in human carcinogenesis by inducing neovascularization and tumor growth. The aim of this study was to evaluate PHD2 expression patterns in primary gastric adenocarcinoma and to test for a potential predictive value of PHD2 expression in gastric cancer patients. Methods: In a total of 121 patients, PHD2 expression was investigated by immunohistochemistry in paraffin-embedded tissue and correlated with clinicopathological parameters and patient survival. Results: 64 of 121 gastric carcinomas (52.9%) showed PHD2 expression in tumor cell cytoplasm. In univariate analysis, PHD2-negative patients had a significantly shortened survival in comparison with PHD2-postive patients (19.5 vs. 32.7 months, p = 0.02). Independent prognostic significance could be shown in multivariate analysis for PHD2 expression (p = 0.005), age at diagnosis (p = 0.012), lymph node status (p = 0.016) and R status (p = 0.026). Conclusion: Cytoplasmic PHD2 expression has a strong impact on survival in gastric cancer patients. Therefore, PHD2 represents a useful predictive biomarker in the evaluation of high-risk patients. Furthermore, these results underline the importance of PHD2 in gastric carcinogenesis and may identify PHD2 as a putative target for future gastric cancer therapy.

Altered expression of E-cadherin and β-catenin in malignant transformation of sinonasal inverted papillomas

E-cadherin and &amp;#946;-catenin are molecules that mediate cell-cell adhesion in normal epithelium. Aberrant expression of these adhesion molecules results in the loss of intercellular adhesion, with possible cell transformation and tumour progression. We determined the role of E-cadherin and &amp;#946;-catenin in the pathogenesis of sinonasal inverted papilloma (IP) and its malignant transformation. We determined the expression of E-cadherin and &amp;#946;-catenin by immunohistochemistry in paraffin-embedded tissue of 21 subjects with nasal polyps, 56 with IPs, 7 IPs with dysplasia and 18 IPs with squamous cell carcinoma (SCC). The clinicopathological variables of the IPs with SCC correlated with the degree of expression of E-cadherin and &amp;#946;-catenin. The degree of expression of E-cadherin and &amp;#946;-catenin in the cell membrane was significantly lower in IPs with SCC than in nasal polyps and IPs. The degree of expression of &amp;#946;-catenin was significantly lower in IPs with SCC with a malignant proportion &gt; 50% compared to a malignant proportion &amp;#8804; 50%. However, there was no significant association between the degree of expression of E-cadherin and &amp;#946;-catenin and clinicopathological variables, such as age, gender, T stage, tumour differentiation, or SCC type (metachronous vs. synchronous). In addition, there was no significant relationship between recurrence or survival rate in IPs with SCC and the degree of expression of E-cadherin or &amp;#946;-catenin in the cell membrane or nuclear &amp;#946;-catenin. Decreased expression of E-cadherin and &amp;#946;-catenin in the cell membrane may be associated with carcinogenesis of IPs and help predict malignant transformation in sinonasal IPs.

Study on the expression and significance of nucleolin in osteosarcoma

Objective To investigate the expression of nucleolin in osteosarcoma and its clinical significance.Methods The expression of nucleolin was evaluated by immunohistochemistry in paraffin-em bedded tissues from 35 cases of osteosarcoma and 15 cases of osteochondroma.Results Among the osteo sarcoma cases, 8.6％ were negative for nucleolin, 20％ weakly positive, 34.3％ moderate positive, 37.1％ strong positive.The positive rate of nucleolin in osteochondroma was 40％, 46.7％, 13.3％, 0％, respectively.The nucleolin expression showed significant difference in the osteosarcoma and osteochondroma (P ＜0.01).Among the conventional ostcosarcoma cases, 6.9％ were negative for nucleolin, 13.8％ weakly positive, 34.5％ moderate positive, 44.8％ strong positive.The positive rate of nucleolin in paros teal osteochondroma was 16.7％, 50％, 33.3％, 0％, respectively.The nucleolin expression showed re markable correlation with pathological and genetical classification (P ＜ 0.05).The positive rate of nucleo 1in in osteoblastic osteochondroma was 5.9％, 5.9％, 29.4％, 58.8％, while in chondroblastic osteochon droma 0％, 33.3％, 33.3％, 33.3％ and 16.7％, 16.7％, 50％, 16.7％ in fibroblastic osteochondro ma, respectively.The positive expressions of nucleolin were almost the same in each subtype of osteosarco ma (P ＞ 0.05).Conclusions The nucleolin expression had correlation with property of tumors in bone, and the positive expressions of nucleolin had correlation with pathological and genetic classification of osteo Key words: Nuclear proteins/ME; Osteosarcona/ME

Plasma membrane proteomic analysis of human osteosarcoma and osteoblastic cells: revealing NDRG1 as a marker for osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. To identify new biomarkers for early diagnosis of OS and novel therapeutic candidates, we carried out a plasma membrane proteomic study based on two-dimensional electrophoresis (2DE). The OS cell line MG-63 and the human osteoblastic cell line hFOB1.19 were adopted as the comparison model. We extracted plasma membrane by aqueous two-phase partition extraction. The proteins were separated through 2DE. We analyzed the differentially expressed proteins by Imagemaster software and then identified them by liquid chromatography-tandem mass spectrometry, and the location and function of differential proteins were searched through the Gene Ontology database. In total, 220 protein spots were separated by 2DE. Seven proteins with more than 2.0-folds of difference were successfully identified from 13 gel spots, with 6 up-regulated and 1 down-regulated. Gene Ontology analysis of the differentially expressed proteins indicated that these proteins were involved in seven kinds of functions including binding, structural, cell motility, receptor activity, electron carrier activity, NADH dehydrogenase (ubiquinone) activity, and transcription repressor activity. The up-regulation of NDRG1 was verified in osteosarcoma through Western blotting and by immunohistochemistry in paraffin-embedded tissues. The plasma membrane proteins identified in this study may provide new insights into osteosarcoma cancer biology and potential diagnostic and therapeutic biomarkers.

Low expression of Mel-18 predicts poor prognosis in patients with breast cancer

BackgroundOur previous study suggested that melanoma nuclear protein 18 (Mel-18) acted as a tumor suppressor in human breast cancer. This study was designed to investigate the clinical and prognostic significance of Mel-18 in breast cancer patients. Patients and methodsMel-18 was detected by immunohistochemistry in paraffin-embedded tissues from 287 breast cancer patients, of which 287 were from primary cancer sites, 63 from matched adjacent noncancerous sites, and 35 from metastatic lymph nodes. Differences in Mel-18 expression and clinical characteristics were compared by χ2 test. Prognostic outcomes correlated with Mel-18 were examined using Kaplan–Meier analysis and Cox proportional hazards model. ResultsThe decreased Mel-18 expression is incremental depending upon the magnitude of cancer progression (P < 0.001). Mel-18 was conversely correlated with the pathological classifications (P < 0.001 for T, N, and M classifications, respectively), clinical staging (P < 0.001), and progesterone receptor (P = 0.030). Furthermore, patients with higher level of Mel-18 showed prolonged overall survivals (P < 0.001). The diminished Mel-18 expression may be a risk factor for the patients’ survival (P < 0.001). ConclusionsLower Mel-18 expression is correlated with advanced clinicopathologic classifications and a poor overall survival in breast cancer patients. These findings suggest that Mel-18 may serve as a useful marker in prognostic evaluation for patients.

EMMPRIN and fascin expression in non-small cell lung carcinoma

Abstract Fascin and EMMPRIN (CD 147) have a demonstrated relationship with the invasion and progression of many tumors. The aim of this study was to analyze fascin and EMMPRIN expression in non-small cell lung carcinoma and their relationship with clinicopathologic features. Fascin and EMMPRIN expression levels were investigated via the immunohistochemistry of paraffin-embedded tissues of 64 patients with non-small cell lung carcinoma, including 46 squamous cell carcinoma and 18 adenocarcinoma patients. The patients were scored on the basis of staining extent and intensity, and were then assigned a combined score. Fascin expression was present in 44 of 46 (95.6%) patients with SCC and 16 of 18 (88.8%) patients with adenocarcinoma. There was a significant correlation between fascin expression and tumor stage in the SCC and adenocarcinoma groups. EMMPRIN expression was observed in all patients with SCC (46 of 46, 100%) and 16 of 18 (88.8%) patients with adenocarcinoma. There was significant correlation between EMMPRIN expression and both tumor stage and diameter in the SCC group, but not in the adenocarcinoma group. This study revealed that high levels of fascin and EMMPRIN expression may indicate the importance of their roles in the progression of non-small cell lung carcinoma and they could be used as prognostic marker for these tumors.

The expression of prostacyclin in lungs from patients with chronic obstructive pulmonary disease

to investigate the expression of prostacyclin in lungs from patients with chronic obstructive pulmonary disease (COPD). the lung tissues were obtained from 12 patients with COPD and 10 patients without COPD. The apoptosis of pulmonary vascular endothelial cells was analyzed quantitatively using TdT-mediated dUTP nick end labeling (TUNEL). The expression of PGI2-S protein was assessed by immunohistochemistry of paraffin-embedded tissues. 6-keto Prostaglandin F1a, the stable metabolite of PGI2, was measured by enzyme-linked immunosorbent assay in whole-lung tissue extracts. The data distributed normally were expressed as x(-) +/- s, and the independent-samples t test was used for comparison of means. the apoptotic index (AI) of endothelial cells of medium and small-sized vessels in patients with COPD group [(12.9 +/- 2.0)%, (11.4 +/- 1.4)%] were significantly higher than that of patients without COPD [(6.1 +/- 1.2)%, (5.9 +/- 0.4)%]. In patients without COPD, PGI2-S protein expression in medium vessels and small-sized vessels was (95.4 +/- 2.1)% and (82.3 +/- 7.4)% respectively, and the value was (95.5 +/- 2.2)% in airway epithelial cells. In patients with COPD, PGI2-S expression in medium vessels and small-sized vessels decreased remarkably [(55.2 +/- 9.8)% and (42.3 +/- 5.1)% respectively], and exhibited a marked reduction in airway epithelial cells (31.8 +/- 5.2)%. The level of 6-keto Prostaglandin F1a was significantly lower in patients with COPD (2.6 +/- 0.4)microg/L compared with patients without COPD (16.2 +/- 2.8)microg/L. abnormal apoptosis exists in pulmonary vascular endothelial cells in patients with COPD. In patients with COPD, the expression of PGI2-S and the level of 6-keto Prostaglandin F1a in lung tissues were decreased. The results suggest that abnormal apoptosis, reduction of PGI2-S expression and PGI2 may be important histological markers for pulmonary endothelial cell dysfunction in COPD and may be involved in the pathogenesis of the disease.

CD33 Detection by Immunohistochemistry in Paraffin-Embedded Tissues: A New Antibody Shows Excellent Specificity and Sensitivity for Cells of Myelomonocytic Lineage

CD33 Detection by Immunohistochemistry in Paraffin-Embedded Tissues: A New Antibody Shows Excellent Specificity and Sensitivity for Cells of Myelomonocytic Lineage

Fascin Expression in Uterine Smooth Muscle Tumors

The diagnosis of malignant, uncertain malignant potential, and benign uterine smooth muscle tumors is derived from histologic criteria such as tumor cell necrosis, mitotic activity, and cytologic atypia. Morphologically, some variants of leiomyoma can be confused with leiomyosarcoma (LMS). In this study, we compared fascin expression in cases of leiomyoma, leiomyoma variants (LVs), uterine smooth muscle tumor of uncertain malignant potential (STUMP), and LMS, and sought to determine the potential role of fascin in differential diagnosis. Fascin expression was investigated through the immunohistochemistry of paraffin-embedded tissue in 79 cases of uterine smooth muscle tumor including 22 usual leiomyoma, 31 LV, 4 STUMP, and 22 LMS cases. The cases were scored on the basis of staining extent (from 0 to 4) and intensity (from 1 to 3), and were assigned a combined score. Fascin expression was present in 20 of 22 (90.9%) LMS, 2 of 4 (50%) STUMP, 1 of 31 (3.2%) LV, and 1 of 22 (4.5%) usual leiomyoma cases. There was a statistically significant difference in fascin extent and intensity between the LMS and benign groups, but no difference between the LMS and STUMP groups. The results of this study indicate that more distinct fascin expression exists in LMS than in the benign groups. Fascin can serve as a reliable immunohistochemical marker in distinguishing uterine LMS from LVs and usual leiomyoma, and it may usefully be used with histologic criteria in diagnosing problematic cases.

Fascin expression in melanocytic lesions of the skin

Fascin is a globular actin cross-linking protein that is important in carcinogenesis. It shows differential staining in various tumors, dependent on grade and stage. The purpose of this study was to compare fascin expression in benign, dysplastic and malignant (metastatic and non-metastatic) melanocytic lesions of the skin, and also to investigate the potential role of fascin in their differential diagnosis. Fascin expression was investigated through the immunohistochemistry of paraffin-embedded tissue in 73 cases of melanocytic lesions of the skin, including 20 benign nevi, 12 dysplastic nevi, 4 lentigo malignas, 25 malignant melanomas and 12 metastatic melanomas. The cases were scored on the basis of staining extension (from 0 to 4) and intensity (from 1 to 3), and were assigned a combined score. Fascin expression was present in 19/20 (95%) benign nevi, 8/12 (67%) dysplastic nevi, 1/4 (25%) lentigo malignas, 7/25 (28%) malignant melanomas and 3/12 (25%) metastatic melanomas. There was significantly less frequent expression of fascin in malignant melanoma than in benign nevi (p < 0.001) and dysplastic nevi (p = 0.036). The results of this study indicate that differential fascin expression exists between benign nevi and malignant melanomas. Fascin can therefore serve as a reliable immunohistochemical marker in distinguishing malignant melanomas from melanocytic nevi and dysplastic nevi, and it may be used with histological criteria for differential diagnosis.

Significance of nuclear hTra2‐beta1 expression in cervical cancer

Human Tra2-beta1, a member of the serine/arginine-rich splicing factors, is involved in C/A-dependent mRNA processing and regulation of gene expression. Since several genes involved in cervical carcinogenesis are alternatively spliced and contain C/A rich elements, we aimed to analyze hTra2-beta1 expression and subcellular localization in tumor tissue of women with cervical cancer and to determine its clinical significance. Retrospective study. Tertiary-care academic medical center. One hundred and five patients with cervical cancer and a mean follow up time of 73.1 months. Immunohistochemistry of paraffin-embedded tissues was performed and hTra2-beta1 expression was correlated with clinico-pathological variables including patient outcome. Cytoplasmic hTra2-beta1 protein expression was found in 20% of cases, while all tumors revealed nuclear immunoreactivity with strong expression in 54.3% of cases. There was a significant inverse correlation between nuclear and cytoplasmic protein expression, suggesting a potentially relevant shuttle process of hTra2-beta1 between both cellular compartments. Patients with weak expressing hTra2-beta1 tumors showed an improved survival with a tumor-related death rate of 8.3% compared to 23.7% in patients with moderate and high intranuclear hTra2-beta1 expression, respectively. Our data support the hypothesis of a biological relevance for hTra2-beta1 expression in cervical cancer. The observed shuttle process of this splicing factor with higher concentrations in the nucleus should have pronounced effects on the cellular function and tumor biology of the affected tumors, leading to the worse patient outcome.

CD33 Detection by Immunohistochemistry in Paraffin-Embedded Tissues: A New Antibody Shows Excellent Specificity and Sensitivity for Cells of Myelomonocytic Lineage.

CD33 Detection by Immunohistochemistry in Paraffin-Embedded Tissues: A New Antibody Shows Excellent Specificity and Sensitivity for Cells of Myelomonocytic Lineage.

High expression of 90K (Mac‐2 BP) is associated with poor survival in node‐negative breast cancer patients not receiving adjuvant systemic therapies

90K (Mac-2 BP) expression was evaluated by immunohistochemistry in paraffin-embedded tissue from a consecutive series of lymph-node negative breast cancer patients who did not receive adjuvant systemic treatment. An independent series of patients served as validation set. The association of 90K expression with risk of recurrence and death was examined in survival analyses together with known prognostic factors. High levels of 90K expression (IHC score>8) were observed in 43 (25.3%) of 170 tumors examined. We found elevated risks of distant recurrence and overall mortality in patients with high 90K expression compared with patients with low 90K expression in their tumors. This increase persisted after adjusting for other prognostic factors in multivariate analysis (hazard ratio=4.084; p<0.001 for recurrence; hazard ratio=4.298; p<0.001 for death). These findings were confirmed in the validation set. Therefore, evaluation of 90K expression may be beneficial to identify lymph-node negative breast cancer patients at lower risk of disease recurrence and death.

Human prion diseases: from antibody screening to a standardized fast immunodiagnosis using automation

Demonstration of pathological prion protein accumulation in the central nervous system is required to establish the diagnosis of transmissible subacute encephalopathies. In humans, this is frequently achieved using prion protein immunohistochemistry in paraffin-embedded tissue, a technique that requires multiple epitope retrieval and denaturing pretreatments. In addition to being time-consuming, this procedure induces tissue alterations that preclude accurate morphological examination. The aim of this study was to simplify prion protein immunohistochemistry procedure in human tissue, together with increased sensitivity and specificity. We screened a panel of 50 monoclonal antibodies produced using various immunogens (human and ovine recombinant prion protein, prion protein peptides, denatured scrapie-associated fibrils from 263K-infected Syrian hamsters) and directed against different epitopes along the human prion protein sequence. A panel of different forms of genetic, infectious and sporadic transmissible subacute encephalopathies was assessed. The monoclonal 12F10 antibody provided a high specificity and fast immunodiagnosis with very limited denaturing pretreatments. A standardized and reliable fast immunostaining procedure was established using an automated diagnostic system (Nexes, Ventana Medical Systems) and allowed prion protein detection in the central nervous system and in tonsil biopsies. It was evaluated in a series of 300 patients with a suspected diagnosis of transmissible subacute encephalopathies and showed high sensitivity and specificity.

CD33 Detection by Immunohistochemistry in Paraffin-Embedded Tissues

A new monoclonal antibody to CD33 that reacts in paraffin-embedded tissue samples was evaluated. The expected reactivity in granulocytic and monocytic cells was found in a tissue microarray composed of multiple tissue sites. There was no unexpected reactivity found in a wide variety of hematolymphoid and nonhematolymphoid disorders. In cases of acute leukemia, the CD33 antibody showed equivalent results by immunohistochemical analysis compared with flow cytometric analysis. The CD33 antibody was also found to be a useful marker in the workup of myeloid sarcomas. This anti-CD33 antibody will be a useful marker in the workup of acute leukemias and myeloid sarcomas on paraffin-embedded tissue samples.