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At least 721 records · Page 40Linked to original sources
PubMed1997

Detection of Epstein-Barr virus in transformations of low-grade B-cell lymphomas after fludarabine treatment.

Fludarabine is a highly effective chemotherapeutic agent for chronic lymphocytic leukemia/small lymphocytic lymphoma and is also active in other B-cell lymphoproliferative disorders. Although highly efficacious in destroying the malignant B-cells, fludarabine also causes T-cell lymphopenia and immunosuppression. We present five patients given fludarabine for low-grade B-cell lymphoproliferative disorders who showed transformation of the primary neoplasm to a higher grade tumor. Immunohistologic antibody studies were performed on paraffin-embedded tissue sections of the initial tissue (when available) and on the follow-up biopsy specimens for CD20, CD3, CD45RO, CD43, CD30, CD15, and latent membrane protein (LMP-1) for Epstein-Barr virus (EBV). The initial diagnoses in these five patients included chronic lymphocytic leukemia/small lymphocytic lymphoma (three cases), follicle center lymphoma (one case), and Waldenstrom's macroglobulinemia (one case). All of the follow-up biopsy specimens showed scattered Hodgkin's-like cells, and two of the five also showed foci of large-cell transformation. The Hodgkin's-like cells showed CD30 immunoreactivity in four of the five cases and CD15 immunoreactivity in three of the five. Strong immunoreactivity of the large, atypical, Hodgkin's-like cells for LMP-1 of EBV was noted in four cases; in the remaining case, this finding was equivocal. In situ hybridization for EBV-encoded RNA was positive in four of the five cases. Molecular studies by polymerase chain reaction (PCR) showed the presence of EBV in three of the five cases. PCR for detection of immunoglobulin heavy chain demonstrated identical monoclonal rearrangements in the original lymphoma and transformation in one case with available material. The CD4 lymphocyte count in each patient was less than 550/microL, indicating cellular dysfunction. Transformation of low-grade non-Hodgkin's lymphomas after fludarabine therapy might be associated with EBV and severe immunosuppression.

Adult↗
PubMedDate not supplied

Are endothelial cell patterns of astrocytomas indicative of grade?

BACKGROUND: The most common primary brain tumors in children and adults are of astrocytic origin. Classic histologic grading schemes for astrocytomas have included evaluating the presence or absence of nuclear abnormalities, mitoses, vascular endothelial proliferation, and tumor necrosis. MATERIALS AND METHODS: We evaluated the vascular pattern of 17 astrocytoma surgical specimens (seven from children and 10 from adults), and four normal brains obtained at autopsy, utilizing antibody to glial fibrillary acidic protein (GFAP) and von Willebrand factor (vWF) utilizing confocal microscopy. A modified WHO classification was used. RESULTS: All tumor cases showed cells positive for GFAP. Control tissues showed a few, widely separated vessels. Pilocytic astrocytomas (four cases) showed lacy clusters of small-to-medium sized vessels, with intact vessel wall integrity. Diffuse, low grade astrocytoma (three cases) showed a staining pattern similar to control tissue; intermediate grade (one case), anaplastic astrocytoma (three cases) and gliobastoma multiforme (six cases) showed an increased vessel density with multiple small vessels (glomeruloid clusters), some with prominent intimal hyperplasia, loss of vessel wall integrity, and with numerous vWF-positive single cells/microvessels within the tumor substance. CONCLUSIONS: Evaluation of astrocytomas utilizing antibody to vWF and confocal microscopy aids in the grading of these neoplasms.

Adolescent↗
PubMed1987

Bronchial sleeve resection with and without pulmonary resection.

Sleeve resection with and without pulmonary resection is safe, effective, and appropriate treatment for a wide range of endobronchial lesions including neoplasms of low-grade malignant potential and selected cases of bronchogenic carcinoma. Sixty-three patients underwent 64 sleeve resection procedures (47 with concomitant pulmonary resection and 17 without) at the Massachusetts General Hospital between 1962 in 1986 with a 30 day mortality rate of 4.7%. Applicability of the technique for bronchial lesions which do not require concomitant pulmonary resection is emphasized. Types of disease included a heterogeneous collection of 31 benign tumors, neoplasms of low-grade malignant potential, and bronchostenosis and 33 bronchogenic carcinomas. Actuarial disease-free survival rate for the former group was 100% at 5 years. Quality of life was excellent for this group. Five-year survival rates for bronchogenic carcinoma (24 squamous cell, seven adenocarcinoma, two undifferentiated) were 58% +/- 25% (+/- standard error), 69 +/- 18%, and 38% +/- 13% in Stages I, II, and III, respectively. The 5 year survival rate of 31% +/- 16% in 14 patients selected because of decreased respiratory reserve compared with 60% +/- 14% in 19 patients for whom sleeve was the operation of choice on the sole basis of anatomic suitability. Sleeve resection is the ideal form of excisional therapy for benign endobronchial tumors, bronchostenosis, tumors of low-grade malignant potential, and for selected cases of carcinoma.

Adult↗
PubMed1989

High-grade malignancies of the parotid gland: identification with MR imaging.

Most tumors in the parotid gland are either benign neoplasms or low-grade malignancies. The magnetic resonance (MR) images of 29 patients with such tumors were reviewed. These masses typically have low T1-weighted and high T2-weighted signal intensities and have clearly defined margins. The signal characteristics presumably reflect the serous and mucinous products that are characteristic of these lesions. The MR images of six patients with aggressive parotid tumors were reviewed and correlated with operative and pathologic findings. These high-grade parotid lesions are uncommon, usually have poorly defined margins, and have low T1- and T2-weighted signal intensities. These signal characteristics presumably reflect the lack of serous and mucinous products, the high mitotic ratio, and the high nuclear to cytoplasmic ratios that are characteristic of these lesions. The authors conclude that the findings of these tumors on MR images are characteristic and should be suggestive of their diagnosis. The preoperative diagnosis of these high-grade tumors allows a more radical surgical treatment to be well planned before surgery. The primary differential diagnoses of these aggressive tumors with MR imaging include fibrosis and sialolithiasis.

Humans↗
PubMed1999

Recurrence and progression in low grade papillary urothelial tumors.

PURPOSE: We report long-term followup data on patients with World Health Organization (WHO) grade I bladder tumors, and determine whether histopathological subgrouping as papillary neoplasm of low malignant potential and low grade papillary carcinoma is of clinical value. MATERIALS AND METHODS: All 680 patients in western Sweden with first diagnosis of bladder carcinoma in 1987 to 1988 were registered and followed for at least 5 years. Of the tumors 255 (37.5%) were stage Ta, WHO grade I. Tumors were further classified as papillary neoplasm of low malignant potential in 95 patients and low grade papillary carcinoma in 160 according to WHO and the International Society of Urological Pathology consensus classification of urothelial (transitional cell) neoplasms of the bladder. RESULTS: Mean age of patients at first diagnosis of low grade papillary carcinoma was 69.2 years, which was 4.6 years higher than those with papillary neoplasm of low malignant potential (p<0.005). During a mean observation time of 60 months our 255 patients underwent 577 operations for recurrences and had 1,858 negative cystoscopies. The risk of recurrence was significantly lower in patients with papillary neoplasm of low malignant potential compared to those with low grade papillary carcinoma (35 versus 71%, p<0.001). The risk of recurrence was higher in patients with multiple tumors at first diagnosis as well as those with recurrence at the first followup after 3 to 4 months. Stage progressed in 6 patients (2.4%), all with low grade papillary carcinoma at diagnosis. CONCLUSIONS: More than 90% of patients with stage Ta, WHO grade I have a benign form of bladder neoplasm, and few have truly malignant tumors. Future research should focus on reducing the number of recurrences and followup cystoscopies, and finding methods to identify malignant tumors so that pertinent treatment can be instituted. Subgrouping of WHO grade I bladder tumors as papillary neoplasm of low malignant potential and low grade papillary carcinoma seems to add valuable prognostic information.

Carcinoma, Papillary↗
PubMed2003

Expression of fascin, an actin-bundling protein, in astrocytomas of varying grades.

Malignant astrocytomas are highly infiltrative neoplasms that invade readily into regions of normal brain. On a cellular basis, the motility and invasiveness of human cancers can be ascribed in part to complex rearrangements of the actin cytoskeleton that are governed by several actinbinding proteins. One such actin-binding protein that has been linked to the invasive behavior of carcinomas is fascin, which serves to aggregate F actin into bundles. In this study, we examined the expression of fascin in a series of human malignant astrocytomas (WHO grades I-IV). Five grade I, 5 grade II, 10 grade III, and 26 grade IV human astrocytomas were examined for fascin and glial fibrillary acidic protein (GFAP) expression by double immunofluorescence confocal microscopy. Expression of fascin and GFAP was also determined by Western blot analysis. Fascin expression increased with increasing WHO grade of astrocytoma. This is in marked contrast to GFAP expression, which decreased with increasing WHO grade. In grades I and II neoplasms, and within non-neoplastic brain, fascin and GFAP were expressed diffusely within regions examined. However, in the higher-grade astrocytomas (grades III and IV), fascin and GFAP were expressed regionally in distinctly separate tumor cell populations. This is the first study to demonstrate the expression of fascin in human astrocytic neoplasms. The role that fascin plays in contributing to the invasive phenotype of anaplastic astrocytomas awaits further study and investigation.

Actins↗
PubMed1997

Disparities in mean age and histopathologic grade between human papillomavirus type-specific early cervical neoplasms.

Noninvasive squamous and glandular precursor lesions associated with human papillomavirus (HPV) types 16 and 18 have been reported to vary in morphology. HPV 16 is associated predominantly with high-grade squamous intraepithelial lesions (HSIL; cervical intraepithelial neoplasia (CIN 2 and 3), and HPV 18 is associated with low-grade squamous intraepithelial lesions (condyloma/CIN 1) and CIN 3/adenocarcinoma in situ (ACIS). This study explored the relationship of morphologic growth pattern in these precursor groups with age of presentation. One hundred fourteen CIN lesions (including those with ACIS), associated with HPV 16 or 18, were subdivided into well-differentiated low- and high-grade SIL (CIN 1 and 2, respectively), poorly differentiated HSIL (CIN 3) with or without ACIS. HPV was detected by polymerase chain reaction (PCR) amplification with L1 consensus or type-specific E7 primers and typed by restriction fragment length polymorphism (RFLP) analysis. Age of the patient was obtained from the pathology report. Mean age for each group was as follows: Low-risk HPVs, 25 years; HPV 18 CIN 1-2, 21.6 yrs; HPV 18 CIN 3/ACIS, 35.2 yrs; HPV 16 CIN 1,2, 25.9 yrs; and HPV 16 CIN 3, 29.8 yrs. There were significant differences in mean ages between HPV 18 CIN 1 and 2 and HPV 16 CIN 1 to 2 (P = .04), HPV 16 CIN 1-2 and CIN 3 (P = .01) and HPV 18 CIN 1 to 2 and HPV 18 CIN 3/ACIS (P = .00001). None of the cases of HPV 18-associated CIN3/ACIS was associated with a CINI lesion. The disparity in mean ages between well and poorly differentiated HPV 16/18 related that precursor lesions could reflect factors such as morphologic progression with increasing age, different rates of lesion persistence, depending on grade, or efficiency of detection between the two groups. The marked difference in mean age between HPV 18-associated CIN 1-2 and CIN 3/ACIS, combined with their lack of coexistence in the same cervix, raises alternate possibilities that specific viral or host factors may determine the morphological phenotype associated with some HPV 18 infections. In the latter, the possibility that age independently confers an increased risk for higher-grade lesions should be considered.

Adenocarcinoma↗
PubMed1997

Primary low-grade endometrial B-cell lymphoma.

We describe three cases of primary low-grade B-cell lymphoma of the endometrium and contrast the histological, immunohistochemical, and molecular features with two examples of benign endometrial lymphoid infiltrates. The first case was an incidental finding in a curettage specimen, confirmed on a subsequent hysterectomy. The other two cases of lymphoma were incidental findings on hysterectomy procedures performed for prolapse and cervical dysplasia, respectively. All three lymphomas occurred in patients in their sixties; none formed gross tumors. Histologic examination revealed lymphoid nodules adjacent to endometrial glands. The lymphoid cells showed mild nuclear enlargement and slight irregularities of the nuclear contour. None of the three patients had evidence of disease outside the endometrium by physical examination, bone marrow biopsy, or sampling of pelvic lymph nodes. Immunohistochemistry demonstrated a B-cell phenotype of the lymphoid cells (CD20 positive, CD79a positive) with aberrant coexpression of the T-cell-associated marker CD43. Polymerase chain reaction (PCR) amplification of the VDJ region of the immunoglobulin heavy-chain was performed on DNA isolated from paraffin sections. These studies demonstrated a clonal proliferation of B-lymphocytes in two cases. In the third case, a faint band was found superimposed on a background smear, suggesting the presence of a B-cell clone. In contrast, the two examples of histologically benign lymphoid aggregates of the endometrium consisted predominantly of T cells with rare B-lymphocytes; there was no evidence of coexpression of CD43 by B-cells. The PCR amplification from the benign lymphoid aggregates did not support a clonal process. Primary lymphoid neoplasms of the endometrium are rare, and all cases described so far have been high-stage, high-grade neoplasms. To our knowledge, this is the first report of primary low-grade B-cell lymphoma of the endometrium, presumably arising from endometrial lymphoid tissue.

Aged↗
PubMed2004

Protein profiling in brain tumors using mass spectrometry: feasibility of a new technique for the analysis of protein expression.

PURPOSE: The purpose of this research was to perform a preliminary assessment of protein patterns in primary brain tumors using a direct-tissue mass spectrometric technique to profile and map biomolecules. EXPERIMENTAL DESIGN: We examined 20 prospectively collected, snap-frozen normal brain and brain tumor specimens using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), and compared peptide and protein expression in primary brain tumor and nontumor brain tissues. RESULTS: MS can be used to identify protein expression patterns in human brain tissue and tumor specimens. The mass spectral patterns can reliably identify glial neoplasms of similar histological grade and differentiate them from tumors of different histological grades as well as from nontumor brain tissues. Initial bioinformatics cluster analysis algorithms classified tumor and nontumor tissues into similar groups comparable with their histological grade. CONCLUSIONS: We describe a novel tool for the analysis of protein expression patterns in human glial neoplasms. Initial results demonstrate that MALDI-MS technology can significantly aid in the process of unraveling and understanding the molecular complexities of gliomas. MALDI-MS accurately and reliably identified normal and neoplastic tissues, and could be used to discriminate between tumors of increasing grades.

Adult↗
PubMed2001

Biologic differences between noninvasive papillary urothelial neoplasms of low malignant potential and low-grade (grade 1) papillary carcinomas of the bladder.

We investigated the expression of oncogenes p53, c-erbB-2, and bcl-2 and cell proliferative activity in 62 newly diagnosed superficial pTa papillary bladder tumors. Based on the 1998 World Health Organization/International Society of Urological Pathology (WHO/ISUP) and 1999 WHO classifications, 19 were urothelial neoplasias of low malignant potential (LMP) and 43 low-grade (grade 1) papillary carcinomas. All the patients underwent transurethral resection and were followed up to 97 months; 42 had recurrences. Initial biopsies were tested for p53, c-erbB-2, and bcl-2 proteins using DO7, CB11, and bcl-2 124 monoclonal antibodies. Cell proliferation was assessed by MIB-1 mAb and mitotic count. LMP had significantly lower MIB-1 (p = 0.002) and p53 immunopositivity (p = 0.03), mitotic count (p = 0.006), and recurrence rates (p = 0.04) than did grade 1 cases, whereas no difference was observed for c-erbB-2 and bcl-2 expression. The median disease-free survival for LMP was 76 months but only 15 months for grade 1 cases (p = 0.002). Although the cohort is small, the results indicate that the distinction between LMP and low-grade (grade 1) papillary urothelial neoplasias, as proposed by the 1998 WHO/ISUP and 1999 WHO classifications, reflects different biologic activity and clinical behavior; however, a long-term follow-up is advisable also for patients with LMP.

Adult↗
PubMed1991

bcl-1 rearrangement. Frequency and clinical significance among B-cell chronic lymphocytic leukemias and non-Hodgkin's lymphomas.

The authors investigated the structural organization of the bcl-1 locus, a putative oncogene associated with reciprocal chromosomal translocation t(11;14), by Southern blot hybridization analysis and its frequency, distribution, and prognostic significance in a panel of 156 clinically and pathologically well-defined B-cell chronic lymphocytic leukemias (CLLs) and non-Hodgkin's lymphomas (NHLs). The authors detected bcl-1 rearrangements in only 2 of 42 CLLs and 4 of 114 NHLs, specifically 3 of 29 diffuse small lymphocytic and 1 of 10 diffuse small cleaved cell and none of 5 diffuse intermediate lymphocytic, 13 follicular predominantly small cleaved, 17 follicular mixed small cleaved and large cell, 4 diffuse mixed small and large cell, 26 diffuse large cell, and 10 diffuse small noncleaved cell lymphomas. None of seven cases of Rai stage III or IV CLL or seven diffuse large cell lymphomas occurring as Richter's syndrome exhibited bcl-1 rearrangements. In conclusion, the bcl-1 locus rearranges in only about 4% of B-cell CLLs and NHLs, is predominantly rearranged in low-grade B-cell neoplasms, and does not appear to be preferentially associated with those occasional CLLs and low-grade NHLs displaying clinical aggressiveness, advanced clinical stage, or large cell transformation (Richter's syndrome). Therefore the demonstration of bcl-1 rearrangement does not appear to have clinically useful prognostic significance.

Blotting, Southern↗
PubMed1986

Immunocytochemical characterisation of cutaneous lymphomas other than mycosis fungoides.

The immunophenotypic properties of 25 cutaneous non-Hodgkin lymphomas other than mycosis fungoides or Sezary syndrome were investigated and correlated with clinical and histopathological data. The 11 low grade lymphomas were all of B cell origin, whereas the 14 high grade lymphomas comprised B and T cell tumours, true histiocytic proliferations, and one "nul" cell lymphoid neoplasm. For the high grade lymphomas correct prediction of the immunological phenotype based on morphological criteria was only possible in three cases. In contrast, all of the low grade lymphomas showed the non-epidermotropic infiltration pattern considered to be characteristic of cutaneous B cell tumours. For these conditions, however, immunophenotypic investigations provided a convenient means of improving discrimination between benign (polyclonal) and malignant (monoclonal) lesions, and also showed similarities with nodal lymphomas in terms of expression of lymphoid subset markers and composition of the non-neoplastic white cell infiltrate. No differences were identified between primary and secondary or concurrent cutaneous and extracutaneous lymphomas. Cutaneous non-Hodgkin lymphomas other than mycosis fungoides or Sezary syndrome constitute a heterogeneous group of neoplasms and most of these disorders are likely to represent cutaneous equivalents of nodal malignancies. Immunophenotypic investigations form a useful supplement to their histogenetic characterisation and may provide a common conceptual basis for their classification.

Adolescent↗
PubMed2000

Thalamic astrocytomas: surgical anatomy and results of a pilot series using maximum microsurgical removal.

Deep-seated astrocytomas within the basal ganglia and the thalamus are considered unfavourable for microsurgical removal since the circumferential neighbourhood of critical structures limits radical resection. On closer assessment, the thalamus has a unique configuration within the basal ganglia. Its tetrahedric shape has 3 free surfaces and only the ventrolateral border is in contact with vital and critical functional structures, e.g. the subthalamic nuclei and the internal capsule. The purpose of the present study was to investigate the feasibility of maximum microsurgical removal in a series of intrinsic thalamic astrocytomas. 14 patients with intrathalamic astrocytomas grades I to 4 as diagnosed by previous stereotactic biopsy or intra-operative frozen section were selected for maximum microsurgical removal. The infratentorial supracerebellar approach from the contralateral side was used for 4 limited neoplasms of the pulvinar. For the other 10 larger and more extensive processes a parieto-occipital transventricular approach was chosen. Final histology gave the result of astrocytoma grade 1 or 2 in 4 patients, and of astrocytoma grade 3 or 4 in 10 patients. Postoperative MRI confirmed reduction of the tumor mass by 80 to 100% in 11 of 14 cases. Regional ancillary radiotherapy with 60 Gy was administered postoperatively for astrocytomas grades 3 and 4. Two patients operated on via the posterior transventricular approach had new postoperative partial hemianopia. Five of the 14 patients finally needed a ventriculo-peritoneal shunt. During the follow-up time of 6 to 52 months, tumor progression/recurrence was observed in 6 of the 10 high grade and none of the low grade neoplasms. The present pilot series demonstrates the feasibility of the microsurgical concept. Comparison with other treatment modalities, such as brachytherapy, requires future consideration.

Adolescent↗
PubMed1988

An immunoperoxidase study of renal cell carcinomas: correlation with nuclear grade, cell type, and histologic pattern.

We applied a panel of antibodies to formalin-fixed, paraffin-embedded sections of 55 renal cell carcinomas using a three-stage immunoperoxidase technique. The antibody panel included two anti-keratins, AE1 and CAM5.2, anti-epithelial membrane antigen (EMA), anti-vimentin, anti-S100 protein, and the anti-leukocyte marker PD7/26. Forty-eight of 55 renal cell carcinomas expressed keratins. CAM5.2 stained 46 tumors (84%) and AE1 stained 37 neoplasms (67%). AE1 reacted with two CAM5.2-negative tumors. EMA was expressed by 35 carcinomas (64%), including three of the CAM5.2-negative neoplasms. Therefore, using all three antibodies, 50 neoplasms (91%) expressed antigens of epithelial differentiation. Anti-EMA and AE1 were complementary to each other; the combination stained 46 of the carcinomas, comparable with CAM5.2 alone. Vimentin was expressed by 26 tumors (47%), and S100 was expressed by one. PD7/26 did not stain any of the cases. Vimentin expression correlated with nuclear grade; low nuclear grade neoplasms infrequently expressed vimentin, while the converse was true for high nuclear grade tumors. Keratin expression was related to tumor cell type and histologic pattern, as fewer neoplasms of clear cell type and with a solid pattern expressed keratins. In contrast, all papillary and eight of nine (89%) spindled carcinomas expressed keratins.

Adult↗
PubMed1980

The effect of thio-TEPA on developing and established mammalian bladder tumors.

The inhibitory effect of thio-TEPA on both developing and established mammalian bladder cancer was tested in the FANFT model system using female C3H/He mice. This model allows the histologic evaluation of the entire target organ, a major advantage over clinical trials, which have relied largely on endoscopic appearance for determination of response. A powerful carcinogen, FANFT is known to cause bladder carcinoma in at least 90% of these animals within 12 months. The tumors develop through a spectrum of morphologic changes including hyperplasia, dysplasia, and carcinoma in situ. Animals were divided into equally sized control and test groups and either thio-TEPA or saline was administered on a schedule designed to correspond to that used in clinical trials. Bladders from 159 mice were evaluated grossly, microscopically and in some instances, ultrastructurally, for the presence of tumor or other intraepithelial lesions. When compared to controls, thio-TEPA had no statistically significant inhibitory effect on either developing or established bladder tumors. The drug did, however, cause a statistically significant decrease in the frequency of high-grade, high-stage lesions when given during tumor development and may retard the evolution of such neoplasms from low-grade noninvasive carcinomas. The correlation of these experimental findings with the reportedly beneficial results of clinical trials is discussed.

Animals↗
PubMed2003

Promoter hypermethylation of the DNA repair gene O6-methylguanine-DNA methyltransferase is an independent predictor of shortened progression free survival in patients with low-grade diffuse astrocytomas.

The O6-methylguanine-DNA methyltransferase (MGMT) plays a major role in repairing DNA damage from alkylating agents. In several human neoplasms including low-grade diffuse astrocytomas, promoter hypermethylation of MGMT has been shown to correlate with an increased frequency of p53 mutation. In the present study, we analyzed MGMT promoter methylation by the methylation-specific PCR in 49 newly diagnosed WHO grade II astrocytomas and evaluated its clinical usefulness. MGMT promoter methylation was found in 21 (43%) of the 49 tumors. A tight correlation existed between MGMT methylation and p53 protein accumulation (P=0.0424). The presence of MGMT methylation was significantly associated with a shorter progression free survival (PFS) on both univariate analysis (P=0.0014) and multivariate analysis (P=0.0081). It was a more powerful determinant of the PFS than age, sex, performance status, proliferative activity, or p53 expression, and was independent of the extent of surgery. In terms of the overall survival, MGMT methylation demonstrated a prognostic utility in the univariate analysis but not in the multivariate analysis. The present findings indicate that aberrant methylation of the MGMT promoter independently augurs for an unfavorable clinical course in patients with low-grade diffuse astrocytomas. Since the presence of MGMT methylation is expected to predict an increased sensitivity to alkylating chemotherapeutic agents, earlier chemotherapy could serve to improve an unfavorable natural history in tumors with MGMT methylation.

Adult↗
PubMed2004

Quantitation of angiogenesis and its correlation with vascular endothelial growth factor expression in astrocytic tumors.

OBJECTIVE: To quantitate tumor angiogenesis by establishing intratumoral microvessel density (IMD), to study vascular endothelial growth factor (VEGF) expression in different grades of astrocytomas and to correlate VEGF expression with tumor angiogenesis. STUDY DESIGN: Forty cases of astrocytic neoplasms (10 of each grade) were assessed for tumor angiogenesis and VEGF expression. The panendothelial marker CD31 was used to highlight microvessels. Tumor angiogenesis was quantitated as IMD count per square millimeter in areas of high vascularity, or "hot spots," using an image analyzer. VEGF expression was studied in sections of the tumors. IMD counts per square millimeter and VEGF expression were correlated with histologic grade. The angiogenic potential of tumors as reflected by IMD counts per square millimeter was correlated with the intensity of VEGF expression. RESULTS: Vascular proliferation in high grade gliomas was significantly higher as compared to that in low grade gliomas. IMD count per square millimeter revealed a positive correlation with histologic grade in high grade gliomas. Pilocytic astrocytoma and low grade astrocytoma as a group had comparable IMD counts per square millimeter. VEGF expression paralleled IMD counts in rare high grade gliomas only. CONCLUSION: Malignant progression in astrocytoma is heralded and accompanied by increased angiogenesis. VEGF is an important angiogenic factor in high grade gliomas since its expression parallels the increased IMD counts in these tumors. In contrast, in low grade gliomas, angiogenic factors other than VEGF may contribute to vascular proliferation. The results emphasize the role of antiangiogenic therapy as an optimal tool in therapeutic strategies as they become available.

Astrocytoma↗