Dichotomous ALK-IHC Is a Better Predictor for ALK Inhibition Outcome than Traditional ALK-FISH in Advanced Non-Small Cell Lung Cancer.

Purpose: ALK rearrangement detection using FISH is the standard test to identify patients with non-small cell lung carcinoma (NSCLC) eligible for treatment with ALK inhibitors. Recently, ALK protein expression in resectable NSCLC showed predictive value. We evaluated tumor response rate and survival after crizotinib treatment of patients with advanced NSCLC with ALK activation using both dichotomous immunohistochemical (IHC) staining and FISH.Experimental Design: Patients with stage IV NSCLC treated with crizotinib were selected. Tumor response was assessed. ALK rearrangements were detected by FISH (Vysis ALK-break-apart FISH-Probe KIT) and IHC [Ventana ALK (D5F3) CDx assay]. Cohorts of patients with ALK-FISH-positive advanced NSCLC from four other hospitals were used for validation.Results: Twenty-nine consecutive patients with ALK-positive advanced NSCLC diagnosed by FISH and/or IHC on small biopsies or fine-needle aspirations (FNA) were treated with ALK inhibitors. All ALK-IHC-positive patients responded to crizotinib except three with primary resistance. No tumor response was observed in 13 ALK-FISH-positive but ALK-IHC-negative patients. This was confirmed in an external cohort of 16 patients. Receiver operator characteristic (ROC) curves for ALK-IHC and ALK-FISH compared with treatment outcome showed that dichotomous ALK-IHC outperforms ALK-FISH [tumor response area under the curve: (AUC), 0.86 vs. 0.64, P = 0.03; progression-free survival (PFS): AUC 0.86 vs. 0.36, P = 0.005; overall survival (OS): AUC, 0.78 vs. 0.41, P = 0.01, respectively].Conclusions: Dichotomous ALK-IHC is superior to ALK-FISH on small biopsies and FNA to predict tumor response and survival to crizotinib for patients with advanced NSCLC. Our data strongly suggest adapting the guidelines and using dichotomous ALK-IHC as standard companion diagnostic test to select patients with NSCLC who benefit from ALK-targeting therapy. Clin Cancer Res; 23(15); 4251-8. ©2017 AACR.

RAB25 expression is epigenetically downregulated in oral and oropharyngeal squamous cell carcinoma with lymph node metastasis.

Oral and oropharyngeal squamous cell carcinoma (OOSCC) have a low survival rate, mainly due to metastasis to the regional lymph nodes. For optimal treatment of these metastases, a neck dissection is required; however, inaccurate detection methods results in under- and over-treatment. New DNA prognostic methylation biomarkers might improve lymph node metastases detection. To identify epigenetically regulated genes associated with lymph node metastases, genome-wide methylation analysis was performed on 6 OOSCC with (pN+) and 6 OOSCC without (pN0) lymph node metastases and combined with a gene expression signature predictive for pN+ status in OOSCC. Selected genes were validated using an independent OOSCC cohort by immunohistochemistry and pyrosequencing, and on data retrieved from The Cancer Genome Atlas. A two-step statistical selection of differentially methylated sequences revealed 14 genes with increased methylation status and mRNA downregulation in pN+ OOSCC. RAB25, a known tumor suppressor gene, was the highest-ranking gene in the discovery set. In the validation sets, both RAB25 mRNA (P = 0.015) and protein levels (P = 0.012) were lower in pN+ OOSCC. RAB25 mRNA levels were negatively correlated with RAB25 methylation levels (P < 0.001) but RAB25 protein expression was not. Our data revealed that promoter methylation is a mechanism resulting in downregulation of RAB25 expression in pN+ OOSCC and decreased expression is associated with lymph node metastasis. Detection of RAB25 methylation might contribute to lymph node metastasis diagnosis and serve as a potential new therapeutic target in OOSCC.

Identification of methylation markers for the prediction of nodal metastasis in oral and oropharyngeal squamous cell carcinoma.

Hypermethylation is an important mechanism for the dynamic regulation of gene expression, necessary for metastasizing tumour cells. Our aim is to identify methylation tumour markers that have a predictive value for the presence of regional lymph node metastases in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). Significantly differentially expressed genes were retrieved from four reported microarray expression profiles comparing pN0 and pN+ head-neck tumours, and one expression array identifying functionally hypermethylated genes. Additional metastasis-associated genes were included from the literature. Thus genes were selected that influence the development of nodal metastases and might be regulated by methylation. Methylation-specific PCR (MSP) primers were designed and tested on 8 head-neck squamous cell carcinoma cell lines and technically validated on 10 formalin-fixed paraffin-embedded (FFPE) OOSCC cases. Predictive value was assessed in a clinical series of 70 FFPE OOSCC with pathologically determined nodal status. Five out of 28 methylation markers (OCLN, CDKN2A, MGMT, MLH1 and DAPK1) were frequently differentially methylated in OOSCC. Of these, MGMT methylation was associated with pN0 status (P = 0.02) and with lower immunoexpression (P = 0.02). DAPK1 methylation was associated with pN+ status (P = 0.008) but did not associate with protein expression. In conclusion, out of 28 candidate genes, two (7%) showed a predictive value for the pN status. Both genes, DAPK1 and MGMT, have predictive value for nodal metastasis in a clinical group of OOSCC. Therefore DNA methylation markers are capable of contributing to diagnosis and treatment selection in OOSCC. To efficiently identify additional new methylation markers, genome-wide methods are needed.

Detection of HPV-associated oropharyngeal tumours in a 16-year cohort: more than meets the eye.

BACKGROUND: Accurate assessment of the prevalence of the human papilloma virus (HPV) in oropharyngeal tumours (OpSCC) is important because HPV-positive OpSCC are consistently associated with an improved overall survival. Recently, an algorithm has become available that reliably detects clinically relevant HPV in tumour tissue, however, no complete cohorts have been tested. The aim was to determine the prevalence of active high-risk HPV infection in a complete cohort of OpSCC collected over a 16-year period. METHODS: Using a triple algorithm of p16 immunohistochemistry, HPV-BRISH and HPV-PCR, we assessed the prevalence of active HPV infection in all OpSCC diagnosed in our hospital from 1997 to 2012 (n=193) and a random selection of 200 oral tumours (OSCC). RESULTS: Forty-seven OpSCC (24%) were HPVGP PCR-positive; 42 cases were HPV16+, 1 HPV18+, 3 HPV33+ and 1 HPV35+. Brightfield in situ hybridisation did not identify additional HPV-positive cases. Human papilloma virus-associated tumour proportion increased from 13% (1997-2004) to 30% (2005-2012). Human papilloma virus-positivity was an independent predictor for longer disease-specific survival (HR=0.22; 95%CI:0.10-0.47). Only one OSCC was HPV+. CONCLUSIONS: In our cohort, the incidence of HPV-associated OpSCC is low but increasing rapidly. The strict detection algorithm, analysis of disease-specific survival and the complete cohort, including palliatively treated patients, may influence the reported prevalence and prognostic value of HPV in OpSCC.

Lack of claudin-7 is a strong predictor of regional recurrence in oral and oropharyngeal squamous cell carcinoma.

OBJECTIVES: Adequate treatment of oral and oropharyngeal squamous cell carcinoma (OSCC) is dependent on correctly predicting the presence of lymph node metastases. Current methods to diagnose nodal metastases partly result in overtreatment with associated morbidity and undertreatment with decreased disease-free survival. E-cadherin has been studied extensively as potential marker for lymph node metastases. EpCAM and claudin-7 have a functional relationship with E-cadherin, forming a complex that promotes tumourigenicity in vitro. We hypothesize that the co-expression patterns of these related molecules is a better prognostic marker for nodal status and regional recurrences. MATERIALS AND METHODS: We constructed separate tissue microarrays of tumour centre and tumour invasive front of 227 OSCC with complete clinicopathological and follow-up data, including HPV status, and performed immunohistochemistry for these molecules. RESULTS: Lack of E-cadherin and presence of cytoplasmic EpCAM expression in the tumour front were predictive for nodal metastasis, but no co-expression pattern was found clinically relevant. Lack of claudin-7 in the tumour centre was highly and independently predictive for shorter regional disease-free survival (HR=0.19; 95%CI: 0.06-0.62) and disease-specific survival (HR=0.43; 95%CI: 0.21-0.87). High-risk HPV was not associated with any marker. CONCLUSIONS: The expression of E-cadherin and EpCAM, depending on the specific tumour sublocalization, is predictive for nodal status. However, co-expression did not improve the prediction of nodal status, indicating that the proposed in vitro complex is not functional in clinical samples. Additionally, lack of claudin-7 expression in the tumour centre may be used to identify patients with increased risk for regional recurrence.

FADD expression is associated with regional and distant metastasis in squamous cell carcinoma of the head and neck.

AIMS: The Fas-associated death domain gene (FADD) is often overexpressed in squamous cell carcinoma of the head and neck (HNSCC), and is considered to be a driver gene in amplification of the chromosomal 11q13.3 region. Amplification of 11q13.3 is associated with increased metastasis in HNSCC and breast cancer. The aim of this study was to investigate the association between FADD protein expression in advanced-stage HNSCC and clinicopathological features and outcome. METHODS AND RESULTS: Tumour tissues of 177 HNSCC patients uniformly treated with primary surgery and postoperative radiotherapy were collected. FADD expression was assessed on pretreatment tumour biopsies using immunohistochemistry. High FADD expression was detected in 44% of the HNSCC patients. High expression was associated with an increased rate of lymph node metastasis (P = 0.001) and with a shorter distant metastasis-free interval (DMFI) (HR 2.6, 95% CI 1.0-6.7, P = 0.046) when lymph node metastases were present. CONCLUSIONS: Our data show that an increase in FADD expression is associated with a higher incidence of lymph node metastasis at presentation, and with shorter DMFI when lymph node metastases are present. High FADD expression in the primary tumour could be a useful marker to select patients for systemic treatment strategies that reduce the risk of distant metastases.

The phosphatase and tensin homologue deleted on chromosome 10 mediates radiosensitivity in head and neck cancer.

BACKGROUND: For locally advanced squamous cell carcinoma of the head and neck (HNSCC), the recurrence rate after surgery and postoperative radiotherapy is between 20 and 40%, and the 5-year overall survival rate is approximately 50%. Presently, no markers exist to accurately predict treatment outcome. Expression of proteins in the human epidermal growth factor receptor (EGFR) pathway has been reported as a prognostic marker in several types of cancer. METHODS: The aim of this study was to investigate the prognostic value of proteins in the EGFR pathway in HNSCC. For this purpose, we collected surgically resected tissue of 140 locally advanced head and neck cancer patients, all treated with surgery and postoperative radiotherapy. RESULTS: In a multivariate analysis, expression of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was significantly related to worse locoregional control (LRC; HR: 2.2, 95% CI: 1.1-4.6; P=0.03), independent of lymph node metastases (HR: 5.6, 95% CI: 1.2-27.4; P=0.03) and extranodal spread (HR: 2.7; 95% CI: 1.2-6.5; P=0.02). In vitro clonogenic radiosensitivity assays confirmed that overexpression of PTEN resulted in increased radioresistance. CONCLUSION: Our study is the first report showing that expression of PTEN mediates radiosensitivity in vitro and that increased expression in advanced HNSCC predicts worse LRC.

Overexpression of intrinsic hypoxia markers HIF1alpha and CA-IX predict for local recurrence in stage T1-T2 glottic laryngeal carcinoma treated with radiotherapy.

PURPOSE: To examine the prognostic value of three endogenous hypoxia markers (hypoxia inducible factor 1 alpha subunit [HIF1 alpha], carbonic anhydrase IX [CA-IX], and glucose transporter type 1 [GLUT-1]) on the clinical outcome in patients with early-stage glottic carcinoma primarily treated with radiotherapy (RT) and to determine the predictive hypoxic profile to choose the optimal treatment of early-stage laryngeal carcinoma. METHODS AND MATERIALS: Immunohistochemistry for HIF1 alpha, CA-IX, and GLUT-1 was performed on formalin-fixed, paraffin-embedded, pretreatment tissue samples of 91 glottic squamous cell carcinoma specimens. The patient group consisted only of those with early-stage (T1-T2) glottic carcinoma, and all patients were treated with RT only. Relative tumor staining was scored on the tissue samples. Receiver operating curve analysis was performed to determine the optimal cutoff value for each tumor marker. Cox regression analyses for the variables HIF1 alpha, CA-IX, GLUT-1, gender, age, hemoglobin level, T category, N category, tobacco use, and alcohol use were performed with local control and overall survival as endpoints. RESULTS: HIF1 alpha overexpression in early-stage glottic carcinoma correlated significantly with worse local control (hazard ratio [HR], 3.05; p = 0.021) and overall survival (HR, 2.92; p = 0.016). CA-IX overexpression correlated significantly with worse local control (HR, 2.93; p = 0.020). GLUT-1 overexpression did not show any correlation with the clinical outcome parameters. Tumors with a nonhypoxic profile (defined as low HIF1 alpha and low CA-IX expression) had significantly better local control (HR, 6.32; p = 0.013). CONCLUSION: The results of our study have shown that early-stage glottic laryngeal carcinomas with low HIF1 alpha and CA-IX expression are highly curable with RT. For this group, RT is a good treatment option. For tumors with HIF1 alpha or CA-IX overexpression, hypoxic modification before RT or primary surgical treatment should be considered.

Cortactin expression predicts poor survival in laryngeal carcinoma.

Amplification of the 11q13 region is one of the most frequent aberrations in squamous cell carcinomas of the head and neck region (HNSCC). Amplification of 11q13 has been shown to correlate with the presence of lymph node metastases and decreased survival. The 11q13.3 amplicon carries numerous genes including cyclin D1 and cortactin. Recently, we reported that FADD becomes overexpressed upon amplification and that FADD protein expression predicts for lymph node positivity and disease-specific mortality. However, the gene within the 11q13.3 amplicon responsible for this correlation is yet to be identified. In this paper, we compared, using immunohistochemical analysis for cyclin D1, FADD and cortactin in a series of 106 laryngeal carcinomas which gene correlates best with lymph node metastases and increased disease-specific mortality. Univariate Cox regression analysis revealed that high expression of cyclin D1 (P=0.016), FADD (P=0.003) and cortactin (P=0.0006) predict for increased risk to disease-specific mortality. Multivariate Cox analysis revealed that only high cortactin expression correlates with disease-specific mortality independent of cyclin D1 and/or FADD. Of genes located in the 11q13 amplicon, cortactin expression is the best predictor for shorter disease-specific survival in late stage laryngeal carcinomas.

Expression of P-glycoprotein, multidrug resistance-associated protein 1, and lung resistance-related protein in human soft tissue sarcomas before and after hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan.

BACKGROUND: Multidrug resistance (MDR) is associated with expression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and lung resistance-related protein (LRP). Tumor necrosis factor (TNF-alpha) is able to modify the expression of these three proteins in different cell types. The effect of TNF-alpha in the clinical situation on patients with soft tissue sarcomas (STS) is indeterminate. METHODS: Thirty-seven patients with a locally advanced extremity STS underwent hyperthermic isolated limb perfusion (HILP) with TNF-alpha and melphalan; 15 patients received additional interferon gamma. Clinical and histologic responses were documented and used to define the overall response. Samples before and after HILP were analyzed immunohistochemically for P-gp, MRP1, and LRP. Samples were scored as negative or positive (< or = 5% or > 5% positive tumor cells). RESULTS: Six patients had an overall complete response, 25 patients had a partial response, and 4 patients with STS revealed no change; in 2 patients, the response remained unclear. The percentage STS samples that were positive for all three proteins dropped from 92% before HILP to 85% after HILP. P-gp positive samples were encountered more often than MRP1 positive samples (P < 0.05). The percentage of samples that were negative for all three MDR proteins increased after HILP from 6% to 16%. MDR status had no significant correlation with tumor response. CONCLUSIONS: HILP with TNF-alpha and melphalan results in excellent overall tumor response in patients with locally advanced STS. STS more often are positive for P-gp than for MRP1. MDR status in patients with STS is not predictive for tumor response after HILP. Data from the current study suggest that the combination of TNF-alpha and melphalan does not induce MDR positive STS: a result with clinical importance when consecutive, adjuvant, doxorubicin-containing chemotherapy is considered.

Soft tissue leiomyosarcomas and malignant gastrointestinal stromal tumors: differences in clinical outcome and expression of multidrug resistance proteins.

PURPOSE: Several studies have reported clinical behavior and chemotherapy resistance in leiomyosarcomas, but these studies did not differentiate between soft tissue leiomyosarcomas (LMS) and malignant gastrointestinal stromal tumors (GIST). Multidrug resistance (MDR) has been associated with the expression of P-glycoprotein (P-gp), multidrug resistance protein (MRP(1)), and lung resistance protein (LRP). The aim of the present study was to compare LMS and GIST with respect to clinical outcome and MDR parameters. PATIENTS AND METHODS: Clinical outcome was evaluated in 29 patients with a primary deep-seated LMS and 26 patients with a primary malignant GIST. Paraffin-embedded material, available for 26 patients with LMS and 25 with GIST, was used for immunohistochemical detection of P-gp, MRP(1), LRP, and c-kit. RESULTS: Mean overall survival (OS) was 72 months for LMS patients and 31 months for GIST patients (P: <.05). Metastases occurred in 16 (59%) of 27 assessable LMS patients and in 10 (56%) of 18 assessable GIST patients. LMS predominantly metastasized to the lungs (14 of 16 patients), whereas GIST tended to spread to the liver (five of 10 patients) and the abdominal cavity (three of 10 patients; P: <.001). P-gp and MRP(1) expression was more pronounced in GIST than in LMS (P: <.05): the mean percentage of P-gp expressing cells was 13.4% in patients with LMS and 38.4% in patients with GIST, and the mean percentage MRP(1) expressing cells was 13.3% in patients with LMS and 35.4% in patients with GIST. LRP expression did not differ between LMS and GIST. c-kit was expressed in 5% of the LMS patients and in 68% of the GIST patients. CONCLUSION: LMS patients have a better survival than GIST patients, and the metastatic pattern is different. Expression of MDR proteins in LMS is less pronounced than in GIST.

The 16p11 breakpoint in myxoid liposarcomas might affect the expression of the LRP gene on 16p11.2 encoding the multidrug resistance associated major vault protein.

BACKGROUND: Chromosome breakage could influence the expression of genes. This has been noticed in specific cases of acute myeloid leukaemia, where the 16p13 breakpoint affects the expression of the multidrug resistance related protein (MRP). Myxoid liposarcomas (LPS) are characterized by the t(12; 16)(q13; p11), which leads to the formation of a FUS-CHOP fusion transcript. This study investigates the relationship between the cytogenetically detected breakpoint 16p11 in myxoid LPS, the presence of the FUS-CHOP fusion transcript in nonmyxoid LPS and the expression of the lung resistance major vault protein (LRP) gene on 16p11.2. MATERIALS AND METHODS: Of 16 cases with a diagnosis of a (possible) liposarcoma with an abnormal karyotype, fresh frozen tumour material was available for immunohistological detection of LRP. Cases without a cytogenetically detected t(12; 16)(q13; p11), were analyzed for the presence of a FUS-CHOP fusion transcript by RT-PCR. RESULTS: In all 9 myxoid LPS a t(12; 16)(q13; p11) was found and LRP expression was absent or low. In none of the remaining 7 cases was a FUS-CHOP fusion transcript found, and four tumours were LRP positive (P = 0. 02). LRP expression in myxoid LPS (mean: 1.3%) was lower (P = 0.07) than in the nonmyxoid tumours (mean: 35.7%). CONCLUSIONS: These observations indicate a relation between the t(12; 16)(q13; p11), leading to a FUS-CHOP fusion transcript in myxoid LPS, and the low or absent expression of the LRP-gene located on 16p11.2.

Computer-assisted cytogenetic analysis of 51 malignant peripheral-nerve-sheath tumors: sporadic vs. neurofibromatosis-type-1-associated malignant schwannomas.

Cytogenetic studies in small groups of patients with malignant peripheral-nerve-sheath tumors (MPNST) revealed complex karyotypes with no consistent changes. A computer-assisted cytogenetic analysis using a cytogenetic database was performed to determine recurrent cytogenetic alterations in 51 MPNSTs (44 from the literature and 7 new cases) and to allow direct cytogenetic comparison between NF-1-associated and sporadic MPNSTs. Significant loss (p < 0.05) was observed in the chromosomal regions 9p2, 11p1, 11q2 and 18p1. Also, loss in 1p3, 9p1, 11q1, 12q2, 17p1, 18q1-q2, 19p1, 22q1, X and Y was detected. Gain of chromosomal material was found in chromosome 7, especially 7q1 (p < 0.05). Most involved breakpoints were: 1p13, 1q21, 7p22, 9p11, 17p11, 17q11, 22q11. Cytogenetic differences between NF-1-associated and sporadic MPNSTs included a relative loss of chromosomal material in NF-1-associated MPNSTs in 1p3, 4p1 and 21p1-q2 and a relative gain in 15p1-q1. Differences in breakpoints between the NF-1 associated and the sporadic MPNST group were observed in 1p21-22 (28% of NF-1 vs. 0% of sporadic MPNSTs), 1p32-34 (17% vs. 0%), 8p11-12 (7% vs. 27%) and 17q10-12 (24% vs. 7%). This approach, in which the cytogenetic results of various reports are combined, shows that losses in 9p2 and gains in 7q1 could be of oncogenetic importance in MPNSTs. Loss of 17q1, on which the NF-1 gene has been located (17q11.2), is not a common cytogenetic finding in NF-1-associated MPNSTs. The observed differences between NF-1-associated and sporadic MPNSTs might reflect different oncogenetic pathways.

Hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan in patients with locally advanced soft tissue sarcomas: treatment response and clinical outcome related to changes in proliferation and apoptosis.

Hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan (HILP-TM) with or without IFN-gamma is a promising local treatment in patients with locally advanced extremity soft tissue sarcomas (STSs), with response rates of up to 84%. The mechanisms of the treatment response are poorly understood. Here, we determined the HILP-TM-induced changes in mitotic activity, proliferation, and apoptosis in 37 STSs; the additional effect of IFN-gamma; and the association of HILP-TM with treatment response and clinical outcome. On archival material, obtained before and 6-8 weeks after HILP-TM with (n = 15) or without (n = 22) IFN-gamma, the number of mitoses was counted, and the proliferation fraction was determined by immunohistological staining for the proliferation associated Ki-67 antigen (MIB1). Apoptosis was visualized by enzymatic detection of DNA fragmentation (terminal deoxynucleotidyl transferase-mediated nick end labeling method). Clinical and histological response, follow-up status, and survival were recorded. The number of mitoses dropped 57% and proliferation rate decreased with 40% after HILP-TM, whereas the amount of apoptosis after HILP-TM more than doubled as before HILP-TM. The addition of IFN-gamma to HILP-TM did not influence the changes in tumor parameters and did not affect treatment response. A better clinical response to HILP-TM was correlated with high mitotic activity and low amount of apoptosis in tumor samples before HILP-TM. Patients with highly proliferative STS before and after HILP-TM had a relatively poor prognosis. Furthermore, patients who developed distant metastases after HILP-TM had a relatively high number of dividing cells in the tumor remnants after treatment.

Translocation (11;22)(q24;q12) in a small cell tumor of the thigh in a 2-year-old boy: immunohistology, cytogenetics, molecular genetics, and review of the literature.

A case of a 2-year-old boy with a palpable mass in the left thigh is presented. Incisional biopsy was performed and subsequent histopathological examination revealed an infiltrative tumor composed of relatively large cells. The tumor cells were immunoreactive for vimentin and keratin, but not for desmin or smooth muscle actin. Cytogenetic analysis showed a 46,XY,t(11;22)(q24;q12) karyotype. The translocation (11;22)(q24;q12) is said to be characteristic for the family of Ewing's sarcoma and related tumors. As a result of the t(11;22)(q24;q12) the EWS gene on chromosome 22q12 joins the 3' part of FLI-1 gene on chromosome 11q24, which encodes a member of the ets family of transcriptional regulators. Using reverse transcription polymerase chain reaction (RT-PCR) a corresponding EWS-FLI-1 fusion product was detected. Additional immunohistological staining for p30/p32MIC2, which is suggestive, but not specific for Ewing's sarcoma, appeared to be weakly positive. In the current case a diagnosis of Ewing's sarcoma was considered unlikely, because of the location of the tumor and the immunohistological profile. Nevertheless it was decided to treat the patient according to a Ewing's sarcoma protocol based on the genotype of the tumor. The findings were compared with other extraosseous pediatric small cell tumors showing the t(11;22)(q24;q12) described in the literature.

Proliferative activity in human brain tumors: comparison of histopathology and L-[1-(11)C]tyrosine PET.

UNLABELLED: To validate the protein synthesis rate (PSR) measured in human brain tumors using L-[1-(11)C]tyrosine (TYR) PET, the PSR was compared to histopathological parameters that reflect proliferation and protein synthesis. METHODS: We studied 20 patients who had a brain biopsy and who also underwent a PET study with TYR. Paraffin sections were stained with the monoclonal antibody MIB 1, targeted against the core antigen Ki-67, and nucleolar organizer regions (NORs) were measured as argyrophilic NORs (AgNORs). The TYR uptake was measured by PET, and with a kinetic model, the PSR was determined. RESULTS: PSR (nmol/ml/min) ranged from 0.44 to 1.99 (mean, 0.97), Ki-67 labeling indices (%) ranged from 0.9 to 33.5 (mean, 9.5) and AgNOR area (mm2/cm2) ranged from 0.13 to 0.85. No relationship was found between PSR and Ki-67 labeling index or AgNOR area. CONCLUSION: It seems that the PSR and proliferation, as measured by Ki-67, are independent processes. The role of the PSR is uncertain, but it is likely that it can be seen as a marker for the homeostasis of the cell.