The predictive value of immunohistochemical markers in untreated Wilms' tumour: are they useful?

PURPOSE: This study reevaluates the potential role of different tumour markers as prognostic indicators in untreated nephroblastoma. METHODS: Expression of a broad panel of tumour markers was investigated by means of immunohistochemical analysis in 43 WT patients. Patients were treated by radical nephrectomy and had a mean follow-up of 11.9 years. RESULTS: Generally, all the tumour markers studied were expressed in normal kidney tissue and at variable levels in the three cell types of WT (blastema, epithelium and stroma). Immunoreactive blastemal (Bcl-X, Bcl-2 and CD44s) and epithelial (Bcl-X, Bcl-2 and MIB-1) cells were present in the majority of tumours. No correlation was found between their expression and pathological stages. Univariate analysis showed that blastemal WT-1, TGF-α, VEGF, MIB-1 and p27 Kip1 were indicative for clinical progression. In a multivariate analysis, WT-1 protein expression by blastemal cells was an independent prognostic marker for clinical progression. CONCLUSIONS: The blastemal WT-1, TGF-α, VEGF, MIB-1 and p27Kip1 expression correlate with clinical progression in untreated nephroblastoma. Therefore, their expression may be of value in identifying patients with a high propensity to develop distant metastases.

A framework of teaching competencies across the medical education continuum.

BACKGROUND: The quality of teachers in higher education is subject of increasing attention, as exemplified by the development and implementation of guidelines for teacher qualifications at Universities in The Netherlands. AIM: Because medical education takes a special position in higher education the Council of Deans of Medical Schools in The Netherlands installed a national task force to explore a method to weigh criteria for teacher qualifications of medical teachers. METHODS: A framework was developed covering competencies of teachers throughout the medical education continuum and including medicine, dentistry and veterinary medicine. RESULTS: The framework distinguishes 3 dimensions: (a) six domains of teaching (development - organization - execution - coaching - assessment - evaluation); (b) three levels in the organization at which teachers perform (micro, meso and macro level) and (c) competencies as integration of knowledge, skills and attitude and described as behaviour in specific context. The current framework is the result of several cycles of descriptions, feedback from the field and adaptations. It is meant as a guideline, leaving room for local detailing. CONCLUSION: The framework provides a common language that may be used not only by teachers and teacher trainers, but also by quality assurance committees, human resource managers and institutional boards.

Sublocalization of the synovial sarcoma-associated t(X;18) chromosomal breakpoint in Xp11.2 using cosmid cloning and fluorescence in situ hybridization.

In a previous study we localized the synovial sarcoma-associated t(X;18)(p11;q11) breakpoint within the ornithine aminotransferase-like 1 (OATL1) cluster on the X chromosome. This localization was delineated from both somatic cell hybrid and fluorescence in situ hybridization (FISH) analysis of patient material, using OAT-specific cDNA and YAC probes. Simultaneously, Knight et al. (1992, Mol. Hum. Genet, in press) mapped this same breakpoint in their patient material adjacent to the more proximal OATL2 region on the X chromosome. Here we report the analysis of two additional tumors and demonstrate that again in these cases the chromosomal break occurs within the OATL1 cluster. In order to further specify the breakpoint, we subcloned the OATL1 YAC (no. 2) into cosmids. At least one of these cosmids (0.38) hybridizes to sequences that bracket the translocation breakpoint, as demonstrated by both Southern blot and FISH analysis. These observations confirm and substantiate our previous findings. In addition, cosmid 0.38 should be a valuable instrument for the ultimate isolation and identification of the gene(s) involved in the development of synovial sarcoma.

Detection of recurrence in patients with clinical stage I nonseminomatous testicular germ cell tumors and consequences for further follow-up: a single-center 10-year experience.

PURPOSE: A wait-and-see policy for patients with stage I nonseminomatous testicular germ cell tumors (NSTGCT) was evaluated in a prospective study. The frequency and time of recurrence, detection of recurrence, and presence of unfavorable prognostic factors were investigated. PATIENTS AND METHODS: During the period 1982 to 1992, 154 patients with stage I NSTGCT (median age, 29 years) underwent orchidectomy and were monitored at follow-up evaluation with physical examinations, alfafetoprotein (AFP) and beta-human choriogonadotropin (hCG) levels, chest x-rays (CXR), and computed tomographic (CT) scans of the abdomen and chest. Multivariate logistic regression analyses were performed to identify prognostic factors. RESULTS: During a median follow-up period of 7 years (range, 2 to 12), recurrence was found in 42 patients (27.3%). All cases of recurrence were detected within 2 years, 90% in the first year after orchidectomy. In 29 patients (69.0%), recurrence was detected in the abdominal lymph nodes. Nine patients (21.4%) had metastases in the retroperitoneum and mediastinum and/or lungs, and four patients (9.6%) had metastases only in the mediastinum or lungs. The majority of recurrences (97.6%) were detected by tumor markers and CT scans. Recurrence was related to the presence of vascular invasion, embryonal carcinoma (E), elevated preoperative hCG level, and absence of mature teratoma (M). Only vascular invasion was an independent risk factor. After polychemotherapy treatment for recurrence, the survival rate for the total group was 98.7%. CONCLUSION: The wait-and-see policy is a reliable method for follow-up monitoring of patients with stage I NSTGCT. Even in patients with unfavorable prognostic factors, it is justified to await the possible appearance of metastases. For the future, it is recommended that CXR be omitted from the schedule, and it might be feasible to discontinue follow-up evaluations after 5 years.

The value of high-dose methotrexate-based neoadjuvant chemotherapy in malignant fibrous histiocytoma of bone.

PURPOSE: The value of high-dose methotrexate (HD-MTX)-based neoadjuvant chemotherapy was evaluated in patients with malignant fibrous histiocytoma (MFH) of bone. PATIENTS AND METHODS: Since 1977, MFH of bone was diagnosed in 17 patients (12 males and five females). Ten patients (59%), completed treatment with four courses of neoadjuvant chemotherapy as follows: HD-MTX, vincristine, doxorubicin, cyclophosphamide, bleomycin, and dactinomycin, or HD-MTX, 4(1)-epidoxorubicin, and carboplatin followed by local tumor resection (n = 3), curettage-cryosurgery (n = 2), amputation (n = 2), or tumor resection-endoprosthetic replacement or allograft (n = 3). After recovery from surgery, an additional six courses of polychemotherapy, including HD-MTX in nine patients, were administered. One patient changed to cisplatin- instead of HD-MTX-containing chemotherapy postoperatively. One additional patient received only adjuvant HD-MTX-containing polychemotherapy. Neoadjuvant MTX-containing chemotherapy was contraindicated in five patients (29%) due to age, cardiac insufficiency, or mental disorder. In one patient, neoadjuvant chemotherapy was cancelled after one course due to renal failure. Treatment consisted of amputation (n = 2), one course of chemotherapy and amputation (n = 1), hyperthermic isolated limb perfusion (HILP; n = 1), intraarterial chemotherapy, radiotherapy, and endoprosthetic replacement (n = 1), and a combination of chemotherapy and radiation treatment (n = 1). RESULTS: Five of six patients who received no HD-MTX-based neoadjuvant chemotherapy developed metastatic disease (83%); the median time to metastatic disease was 17 months (range, 3 to 44). In contrast, in 10 patients who completed treatment with HD-MTX-based neoadjuvant chemotherapy, with a mean follow-up time of 9.8 years (range, 2.3 to 15.7) and a median follow-up time of 10.8 years (range, 2.3 to 15.7) after diagnosis, no local recurrence or distant metastases were diagnosed (P < .005). CONCLUSION: Neoadjuvant HD-MTX-containing chemotherapy in addition to surgery has dramatically improved the prognosis of patients with MFH of bone.

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.

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.

Imaging of soft-tissue tumors using L-3-[iodine-123]iodo-alpha-methyl-tyrosine single photon emission computed tomography: comparison with proliferative and mitotic activity, cellularity, and vascularity.

The radiolabeled amino acid L-3-[123I]-iodo-alpha-methyltyrosine (IMT) is a new tumor tracer that accumulates in many tumors and is suitable for single photon emission computed tomography (SPECT) imaging. Using IMT SPECT, we studied 32 patients with a soft-tissue tumor suspected to be a soft-tissue sarcoma to determine whether: (a) tumors can be visualized; (b) benign and malignant lesions can be distinguished; and (c) IMT uptake is related to tumor grade and proliferation. Whole-body imaging was performed 15 min after administration of 300 MBq IMT, biopsy, or resection 1-2 weeks later. IMT uptake was quantified using a region-of-interest method resulting in tumor:background (T:B) ratios. These were compared with tumor grade, mitotic index, tumor cellularity, vascularity, and the Ki-67 proliferation index. Eleven patients had a benign tumor, and 21 patients had a soft-tissue sarcoma. Six benign tumors demonstrated minor IMT uptake, and five lipomas had no uptake. All malignant tumors had high uptake and were clearly visualized. T:B ratios in malignant tumors (3.83 +/- 1.16) were higher (P < 0.001) than in benign tumors (1.52 +/- 0.60). Small (<5 mm) metastases in two patients were not detected. Taking the T:B ratio 2.0 as the cutoff level, the sensitivity for detection of malignancy was 100%, and specificity was 88%. IMT uptake correlated with histological grade (r = 0.82; P < 0.001), mitotic index (r = 0.75; P < 0.001), tumor cellularity (r = 0.73; P < 0.01), and with the Ki-67 proliferation index (r = 0.63; P < 0.01). In conclusion, IMT SPECT visualized all soft-tissue sarcomas. Uptake in sarcomas was clearly higher than in benign lesions, yielding 100% sensitivity for detection of malignancy at 88% specificity. Uptake increased with higher tumor grade and higher proliferation rate.

[Practice guideline 'Diagnostic techniques for soft tissue tumours and treatment of soft tissue sarcomas (revision)']. / Richtlijn 'Diagnostiek bij wekedelentumoren en behandeling van wekedelensarcomen (herziening)'.

Members of the Dutch working group on soft tissue tumours developed an up-to-standard evidence-based multidisciplinary clinical practice guideline for the diagnosis of soft tissue tumours and the treatment and follow-up of soft tissue sarcomas, in cooperation with the Dutch Association of Comprehensive Cancer Centres and the Dutch Institute for Healthcare Improvement. A soft tissue sarcoma is defined as every non-epithelial tumour that does not originate in haematopoietic or lymphatic system, central nervous system or bone. The guideline lists 'alarm signals' to raise awareness of malignancy and recommends consulting a multidisciplinary team. Non-invasive imaging has to be completed before proceeding to any invasive (diagnostic) procedure or assessment of dissemination. Aspiration cytology can be useful for differentiating between sarcoma and other malignancies. A definite diagnosis is obtained by means of image-guided needle biopsy. Tumours will be classified according to the World Health Organization and graded according to the Federation Nationale des Centres de Lutte Contre le Cancer. Surgical excision with a tumour free margin of 2 cm is the core of therapy, taking into account vital structures when necessary. In case of small superficial tumours (diameter < or = 3 cm) excision biopsy may be justified. Radiotherapy is almost always necessary and certainly indicated when wide margins are impossible even after re-resection. In the case of primary metastatic disease, an individual decision should be taken after multi-disciplinary consultation concerning the possibility of curative or palliative treatment. Neither neo-adjuvant nor adjuvant chemotherapy is standard. Chemotherapy may be useful in metastatic disease. The guideline advises referring patients who are eligible for chemotherapy to a centre and that they should be included in a study protocol.

[Electives at the dental school in Groningen]. / Keuzeonderwijs binnen de opleiding Tandheelkunde Groningen.

To offer a more comprehensive curriculum in various dental topics, the dental school of the University of Groningen developed electives. This article gives an overview of the learning objectives of the different electives, the program and the way in which students are examined. Attention is also paid to some experiences of students and teachers with this kind of education. The electives seem to effectively prepare students for specific parts of dentistry, and they give an orientation on the scientific aspects of dentistry. Students and teachers are positive about the electives. The electives give good opportunities to the assessment of professional behavior.

High frequency of TP53 mutations in juvenile pilocytic astrocytomas indicates role of TP53 in the development of these tumors.

In adults, the TP53 tumor suppressor gene is frequently mutated in astrocytic brain tumors which is supposed to represent an early event in their development. In juvenile pilocytic and low-grade astrocytomas, however, TP53 mutations have until now been reported as rare, which has led to the suggestion that these tumors may follow a different molecular pathogenesis with an involvement of genes other than TP53. Our analysis of 20 pilocytic and two low-grade astrocytomas of childhood, based on a comprehensive denaturing gradient gel electrophoresis (DGGE) mutation detection assay of the entire coding region, including all splice site junctions of TP53, showed mutations considered as causative in 7 of the 20 (35%) pilocytic astrocytomas and in one of the two low-grade astrocytomas. Our finding is significantly different from the mutation frequency of 1.3% (2/155) previously reported for these tumor types. This may be attributed to the mutation detection system used, which also detects mutations occurring outside the evolutionary conserved region of TP53. Our results suggest that, contrary to the present notion, TP53 mutations may well play a role in the development of juvenile astrocytomas. Furthermore, no mutations were found in tumors of patients with progression of residual tumor after postoperative follow-up. This suggests that TP53 mutations may be associated with less aggressive forms of juvenile astrocytomas, analogous to the situation in adult astrocytomas.

Extensive mutation scanning of RET in sporadic medullary thyroid carcinoma and of RET and VHL in sporadic pheochromocytoma reveals involvement of these genes in only a minority of cases.

Sporadic medullary thyroid carcinoma (MTC) and pheochromocytoma (PC) have been reported to be associated with some specific RET gene mutations. To assess the role of RET in the development of MTC and PC, we screened 14 sporadic MTC, two MTC-derived cell lines, and 5 sporatic PC cases of RET mutations by a systematic analysis of the whole coding sequence, including all intron-exon junctions. In only 6 of the 14 sporadic MTC we were able to detect a RET mutation. Apart from the MET918-->Thr mutation in 5 of the MTC cases, we found a 3-bp deletion in exon 11, only present in the tumor, in another case. Analysis of 2 cell lines revealed the Met918-->Thr mutation in 1 and a Cys634-->Trp mutation in the other cell line. A possible somatic nature of these mutations could not be confirmed because in neither case was constitutive DNA available. We conclude that a large proportion of sporadic MTC must be due to mutations in an unidentified gene(s) other than RET. In none of the sporadic PC cases was a RET mutation found. As PC is a frequent complication in families suffering from von Hippel Lindau disease, for which mutations of the VHL gene are responsible, we also screened the 5 sporadic PC cases for VHL mutations. This revealed a Gly164-->Ser mutation in a single specimen. Thus, in PC, a large majority of tumors are due to mutations in an unidentified gene(s) other than RET and VHL.

Recurrent astrocytoma in a child: a report of cytogenetics and TP53 gene mutation screening.

An 8-year-old girl presented with a cerebral tumor and 3 recurrences within 15 months. The primary tumor was a low-grade astrocytoma, but the recurrences showed progressively malignant phenotypes with increasing mitotic activity and MIB-1 labeling indices. Radiotherapy was given between the first and the second recurrences. Cytogenetic analysis of the first and the second recurrences showed abnormal karyotypes. There seemed to be 2 common breakpoints in these 2 recurrences. TP53 gene mutation screening, using comprehensive denaturing gradient gel electrophoresis, revealed among others a possibly causative mutation of exon 5 in 3 of 4 tumor samples. The meaning of TP53 mutations in low-grade astrocytomas is still unclear, but the highly abnormal karyotypes, which are unusual in these tumors, probably provide genetic evidence for the unexpected aggressive behavior of the tumor in this patient.

Epidemiological aspects of soft tissue sarcomas (STS)--consequences for the design of clinical STS trials.

The purpose of the study was to gain insight into epidemiological aspects of soft tissue sarcomas (STS), based on the population-based cancer registry of the Comprehensive Cancer Center North-Netherlands (CCCN), and to provide data for the development of future STS clinical trials. 456 primary STS (Kaposi, urogenital and gastro-intestinal STS excluded), registered from 1989 to 1995 by the cancer registration of the Comprehensive Cancer Center North-Netherlands (CCCN), were analysed. The annual, age-adjusted, STS incidence was 3.6 per 100,000. Incidence increased with age. Half of the patients were over the age of 65 years. Malignant fibrous histiocytomas and liposarcomas were most frequently encountered. At presentation, nodal involvement was rare (3-8%). Distant metastases were more frequently encountered (9-14%), and appeared to be related to tumour size and site. Above 70 years of age, 16% of patients received no treatment at all, especially for metastatic disease.

Expression of multidrug resistance proteins, P-gp, MRP1 and LRP, in soft tissue sarcomas analysed according to their histological type and grade.

The biological behaviour of different histological types and grades of soft tissue sarcomas (STS) varies. This might result in a differing sensitivity to cytotoxic drugs. Cross-resistance to functionally and structurally distinct natural-product drugs, known as multidrug resistance (MDR), is associated with the overexpression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and lung resistance-related protein (LRP). The purpose of this study was to evaluate the expression of P-gp, MRP1 and LRP in STS according to their histological type and grade. In 141 chemotherapy-naive STS patients, the expression of the three MDR proteins was detected by immunohistochemistry. Nine histological types were documented. These were 19% grade 1, 34% grade 2 and 47% grade 3 tumours. Expression of P-gp and LRP was observed more frequently than the expression of MRP1 (P<0.0001). P-gp expression was most pronounced in malignant fibrous histiocytoma (MFH), but was low in leiomyosarcomas. MRP1 was expressed in most malignant peripheral nerve sheath tumours (MPNST). LRP was strongly expressed in MFH and unspecified sarcomas, but was low in liposarcomas. MRP1 and LRP expression was significantly more common in grades 2 and 3 compared with grade 1 tumours. P-gp expression was correlated with MRP1, especially in grade 3 STS. In conclusion, P-gp, MRP1 and LRP are expressed in the majority of STS, but this expression varies according to the histological type. MRP1 and LRP, but not P-gp expression, were found to be correlated to tumour grade. MDR might contribute to the observed differences in clinical behaviour within the heterogeneous group of STS.

Feasibility and efficacy of external beam radiotherapy after hyperthermic isolated limb perfusion with TNF-alpha and melphalan for limb-saving treatment in locally advanced extremity soft-tissue sarcoma.

PURPOSE: Hyperthermic isolated limb perfusion (HILP) with tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and melphalan is associated with a dramatic antitumor effect in locally advanced extremity soft-tissue sarcomas (STS). The aim of this study was to demonstrate the feasibility and efficacy of adjuvant radiotherapy after HILP with TNF-alpha, IFN-gamma, and melphalan and delayed surgical resection. METHODS AND MATERIALS: Between 1991 and 1995, 34 patients--16 males and 18 females, median age 50 (range 18-80) years--underwent HILP for locally advanced extremity STS. Resection of the residual tumor mass was performed in most patients after 6-8 weeks. Fifteen patients with histopathological viable tumor after resection received adjuvant 60-70 Gy external beam radiotherapy (EBRT) (44%, HILP + EBRT group). Nineteen patients received HILP without adjuvant EBRT (56%, HILP-only group). Five patients in the HILP-only group had also distant metastases (15%) and received HILP as a palliative treatment. Treatment morbidity, local recurrences, and regional and distant metastases were scored. RESULTS: During a median follow-up of 34 months (range 8-54), limb salvage was achieved in 29 patients (85%): 14 patients after HILP + EBRT and 15 patients after HILP only. None of the patients from the HILP + EBRT group developed local recurrences; however, five patients from the HILP-only did (26%) (p < 0.05). Regional metastases were observed in one patient from the HILP + EBRT group (7%) and in two patients from the HILP-only group who were treated with curative intent (14%). Distant metastases occurred in four patients after HILP + EBRT (27%) and in four patients after HILP only with curative intent (29%). The mean morbidity (subjective, objective, medical management, and analytical evaluation) score in both groups was, respectively, 0.33 for skin and subcutaneous tissue and for muscle and soft tissue, 0.34 (HILP + EBRT group) and 0.33 (HILP-only group). CONCLUSION: Adjuvant EBRT after HILP with TNF-alpha, IFN-gamma, and melphalan and delayed tumor resection of locally advanced extremity STS is feasible and may increase local tumor control without increasing treatment morbidity.

FDG and L-[1-11C]-tyrosine imaging of soft-tissue tumors before and after therapy.

UNLABELLED: This study was undertaken to investigate the relationship of PET using fluorodeoxyglucose (FDG) or L-[1-11C]-tyrosine (TYR) with histopathologic findings in soft-tissue tumors, before and after therapy. Histopathologic parameters that were studied were tumor grade, mitotic rate, proliferation activity and amount of necrosis. METHODS: PET with either FDG or TYR was performed in 55 patients with a lesion suspected to be a malignant soft-tissue tumor. In 28 patients, a second PET study was performed after therapy. Metabolic rate of glucose consumption (MRglc) and protein synthesis rate (PSR) were calculated. Histologic parameters were obtained from a biopsy specimen that was taken just after the first PET study and from the tumor remnant that was resected after therapy. RESULTS: MRglc correlated with tumor grade (r = 0.71) and mitotic rate (r = 0.68) but not with proliferation or necrosis. After therapy, there was no longer a correlation with mitotic rate. PSR correlated with tumor grade (r = 0.53), mitotic rate (r = 0.73) and proliferation (r = 0.66). After therapy, correlation with mitosis and proliferation had improved, and a negative correlation was found between PSR and necrosis (r = -0.74). CONCLUSION: These results validate the use of both FDG and TYR to give an in vivo indication of histologic tumor parameters. However, FDG gives a better indication of tumor grade, whereas TYR is more accurate in predicting mitotic rate and proliferation, especially after therapy. FDG may therefore not be the most suited tracer for monitoring therapy. TYR might be more appropriate for that purpose.

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.

L-[1-11C]-tyrosine PET to evaluate response to hyperthermic isolated limb perfusion for locally advanced soft-tissue sarcoma and skin cancer.

UNLABELLED: PET with L-[1-11C]-tyrosine (TYR) was investigated in patients undergoing hyperthermic isolated limb perfusion (HILP) with recombinant tumor necrosis factor alpha (rTNF-alpha) and melphalan for locally advanced soft-tissue sarcoma and skin cancer of the lower limb. METHODS: Seventeen patients (5 women, 12 men; age range 24-75 y; mean age 52 y) were studied. TYR PET studies were performed before HILP and 2 and 8 wk afterwards. The protein synthesis rates (PSRs) in nanomoles per milliliter per minute were calculated. After final PET studies, tumors were resected and pathologically examined. Patients with pathologically complete responses (pCR) showed no viable tumors after treatment. Those with pathologically partial responses (pPR) showed various amounts of viable tumors in the resected tumor specimens. RESULTS: Six patients (35%) showed a pCR and 11 patients (65%) showed a pPR. All tumors were depicted as hot spots on PET studies before HILP. The PSR in the pCR group at 2 and 8 wk after perfusion had decreased significantly (P < 0.05) in comparison to the PSR before HILP. A significant difference was found in PSR between the pCR and pPR groups at 2 and at 8 wk (P < 0.05). Median PSR in nonviable tumor tissue was 0.62 and ranged from 0.22 to 0.91. With a threshold PSR of 0.91, sensitivity and specificity of TYR PET were 82% and 100%, respectively. The predictive value of a PSR > 0.91 for having viable tumor after HILP was 100%, whereas the predictive value of a PSR < or = 0.91 for having nonviable tumor tissue after HILP was 75%. The 2 patients in the pPR groups with a PSR < 0.91 showed microscopic islets of tumor cells surrounded by extensive necrosis on pathological examination. CONCLUSION: Based on the calculated PSR after HILP, TYR PET gave a good indication of the pathological outcome. Inflammatory tissue after treatment did not interfere with viable tumor on the images, suggesting that it may be worthwhile to pursue TYR PET in other therapy evaluation settings.

Fluorine-18-fluorodeoxyglucose PET imaging of soft-tissue sarcoma.

UNLABELLED: PET with 18F-fluoro-2-deoxy-D-glucose (FDG) was used to study soft-tissue lesions. The goals of the study were to establish FDG uptake in soft-tissue sarcoma, to determine the sensitivity of this technique, to investigate the correlation between histologic grade and glucose consumption and to determine whether FDG-PET can discriminate between benign and malignant lesions. METHODS: PET imaging was performed in 18 patients with soft-tissue sarcoma and 4 patients with a benign soft-tissue lesion. Glucose consumption in the tumors was calculated using Patlak's graphical analysis with an assumption made for the lumped constant. Standardized uptake values also were calculated. RESULTS: All soft-tissue sarcomas were clearly depicted. The median glucose consumption was 13.0 mumole/100 g/min (range 2.9-41.8 mumole/100 g/min). A correlation was found between glucose metabolism and the histopathologic malignancy grade. Such a correlation was not demonstrated for the standardized uptake values. One benign lesion was also visualized. Benign lesions were not visualized in two patients and in the remaining patient an equivocal scan was obtained. Benign lesions could be distinguished from high-grade malignant lesions but not consistently from lesions with low or intermediate malignancy grades. CONCLUSION: PET with FDG is an effective technique to visualize soft-tissue sarcomas. We found a sensitivity of 100%. There is a correlation between glucose metabolic rate and tumor malignancy grade. FDG appears to be unsuitable for discriminating benign lesions from soft-tissue sarcomas with low or intermediate malignancy grades.