Labeling of polypeptides with technetium-99m using a dextran spacer.

Radioimmunoscintigraphy and other forms of scintigraphy are becoming increasingly important as tools in detection and evaluation of cancer diseases. Several radionuclides can be considered as radiolabel; however, 99mTc may be the most suitable because of easy availability and near ideal physical properties. This study describes how dextran is coupled to a monoclonal anticytokeratin antibody, epidermal growth factor, and somatostatin through stable amine bonds. The dextran moiety could then be labeled with 40-62 MBq of 99mTc. The labeling efficiency was 60-94%, determined by gel filtration or TLC. The specific binding could be considerably preserved after the dextranation, the antibody retained > 90% of its activity, epidermal growth factor bound with > 90% specificity to receptor-expressing tumor cells, and somatostatin showed approximately 40% specific binding to rat adrenal homogenates. Because somatostatin only has a transient half-like in vivo, the in vivo plasma half-life of somatostatin-dextran was tested in normal female Sprague-Dawley rats. The result showed a strong enhancement of the plasma half-life that was dependent on two compartments, 4 and 8 h.

Expression of an estramustine-binding associated protein in human lung cancer cell lines.

Estramustine-binding protein has previously been demonstrated in normal rat prostatic tissue, in normal human prostate epithelium, and in prostatic carcinomas. It binds specifically estramustine and estromustine, the cytotoxic metabolites of estramustine phosphate (Estracyt), a drug which is used in the treatment of prostatic carcinoma. In this study we have examined the presence of an estramustine-binding associated protein in a panel of human cell lines, representing the major histopathological types of lung cancer. A mouse (murine) monoclonal antiserum developed against rat estramustine-binding protein was used for immunohistochemical detection. Fast protein liquid chromatography was used for biochemical characterization. As judged from the immunohistochemical investigation, estramustine-binding protein was present in large amounts in five of six non-small cell carcinoma cell lines, while seven of eight small cell carcinoma cell lines were essentially negative. Fast protein liquid chromatography analyses of lysated cells from the lung cancer cell lines, incubated with [3H]estromustine, concurred with the results from the immunohistochemical stainings. These data strongly indicate a convincing connection between the immunoreactivity and ligand-binding properties of estramustine-binding protein in the cell lines examined. The presence of an estramustine-binding associated protein in human lung cancer cell lines has implications for further investigations into the biological relevance and the potential for eventual therapeutic applications.

Determination of somatostatin receptor subtype 2 in carcinoid tumors by immunohistochemical investigation with somatostatin receptor subtype 2 antibodies.

We have shown previously that expression of mRNA for somatostatin receptor subtype 2 (sst2) detected by in situ hybridization correlates to therapeutic outcome in patients with carcinoid tumors treated with somatostatin analogues. However, in situ hybridization is laborious and not practical in clinical routine work. We have, therefore, developed polyclonal antibodies directed against sst2 that may be used for immunohistochemistry on tissue specimens. The staining is specific and is highly correlated to expression of mRNA for sst2 (P < 0.01) as well as to tracer uptake at somatostatin receptor scintigraphy (P < 0.01). There is also a good correlation to the therapeutic response in carcinoid patients treated with somatostatin analogues (P < 0.05). Of 35 patients with carcinoid tumors included in this investigation, 25 stained positive with the antibodies. Twenty-two of these were investigated by somatostatin receptor scintigraphy and showed tracer uptake in metastases. An additional two patients that did not stain with the antibodies showed pathological uptake of the tracer in metastases, which might indicate binding to somatostatin receptor subtype 5. None of the 10 patients without positive immunostaining responded to somatostatin analogue treatment, whereas patients with a positive stain had a biochemical response or remained stable during treatment. Thus, these antibodies may be used to determine the presence of sst2 in carcinoid tumors and to select patients suitable for somatostatin analogue treatment. The method is easily applicable in clinical practice.

Human biodistribution of [111In]diethylenetriaminepentaacetic acid-(DTPA)-D-[Phe1]-octreotide and peroperative detection of endocrine tumors.

Requisites for preoperative and intraoperative tumor localization with [111In]diethylenetriaminepentaacetic acid-D-[Phe1]-octreotide scanning were explored in 23 patients with endocrine tumors (15 carcinoids, 4 insulinomas, and single cases of gastrinoma, medullary thyroid carcinoma, aldosteronoma, and paraganglioma). The patients were subjected to Octreoscan single photon emission computed tomographic examination prior to surgery and well counter investigation of nuclide uptake in tumors and normal tissues sampled at surgery. Somatostatin receptor-positive tumors demonstrated efficient nuclide accumulation with mean tumor:blood radioactivity ratios of 180-370 (for carcinoids and insulinoma), compared with tissue:blood ratios of 302 for spleen, 42 for liver, and < 10-15 in other normal tissues (pancreas, small intestine, and mesenteric fat). Inefficient preoperative visualization of lesions was related to inconspicuous size, as for primary intestinal carcinoids, tiny liver metastases, and a single small insulinoma. High background activity, pronounced tumor fibrosis, and meager accumulation of tracer also interfered with visualization. Tumor deposits in organs with low background activity (such as carcinoid mesenteric metastases and endocrine pancreatic tumors) were generally most readily detected. Intraoperative investigations with hand-held gamma detector probes were disturbed by obvious high background activity. These investigations revealed two preoperatively unrecognized primary intestinal carcinoids, which, however, were both palpable during surgery. These studies, therefore, had little impact on the surgical strategy.

Somatostatin receptor scintigraphy in patients with carcinoid tumors: comparison between radioligand uptake and tumor markers.

We have performed 100 scintigraphic investigations using [111In-diethylenetriaminepentaacetic acid-D-Phe1]octreotide (111In-octreotide) single photon emission tomography (SPECT) in patients with carcinoid tumors. One or several lesions could be detected in 77 cases, and true negative results were obtained in 11 cases. There were false-negative results in 12 cases compared with results from conventional radiological methods. The ratio between the SPECT signals from the area with the highest uptake and normal lung was used as a tumor:background ratio. An attenuation correction was made in all investigations. We found that lesions in untreated patients had lower tumor:background ratios compared with those in patients treated with somatostatin analogues (medians, 10 and 40, respectively; P < 0.001) or IFN (median, 23; P = 0.03). In untreated patients, there was a correlation between the tumor:background ratio and the levels of urinary 5-hydroxyindoleacetic acid (U-5HIAA) and p-chromogranin A. The data obtained in the present investigation indicate that somatostatin receptor expression might be influenced by the treatment; i.e., a higher tumor:background ratio is found in patients treated with either somatostatin analogues or IFN. Furthermore, it was found that somatostatin receptor expression correlates with the levels of U-5HIAA and p-chromogranin A in untreated patients, and that 111In-octreotide SPECT scintigraphy is more likely positive in patients with elevated U-5HIAA values. This indicates that somatostatin receptor expression and elevated U-5HIAA are more likely present in patients with highly differentiated tumors and, thus, could be of prognostic value.

Metastatic hormone-refractory prostatic adenocarcinoma expresses somatostatin receptors and is visualized in vivo by [111In]-labeled DTPA-D-[Phe1]-octreotide scintigraphy.

Thirty-one patients with metastatic hormone-refractory prostatic adenocarcinoma were investigated scintigraphically with the 111In-labeled somatostatin analogue [DTPA-D-Phe1]-octreotide (OctreoScan) and with 99mTc-labeled HDP. In vitro somatostatin receptor autoradiography was performed on biopsies obtained from eight patients with hormone-refractory prostatic adenocarcinoma. In 30 of 31 patients (94%), at least one metastasis was positive at OctreoScan scintigraphy. Of the 346 lesions detected with 99mTc-labeled HDP bone scintigraphy, 128 were visualized with the OctreoScan technique, thus accounting for a 37% detection rate. Two uptakes on OctreoScan could not be identified on bone scintigraphy and were, thus, assessed as false positive. The biopsies of the eight patients disclosed a low density of receptors, localized on the tumor cells, as demonstrated with receptor autoradiography. Two patients with untreated metastatic prostatic adenocarcinoma were investigated in vivo before the start of endocrine therapy. However, none of the lesions detected by bone scintigraphy in these patients could be visualized with the OctreoScan technique. Positron emission tomography using [11C] methionine showed a decreased uptake in a metastatic index lesion in a patient treated with octreotide. It is concluded that hormone-refractory prostatic adenocarcinoma expresses somatostain receptors both in vitro and in vivo. The results obtained form the basis for the development of a new tool for in vivo characterization and of a new treatment strategy in patients with hormone-refractory prostatic adenocarcinoma.

Positron emission tomography studies in patients with locally advanced and/or metastatic breast cancer: a method for early therapy evaluation?

PURPOSE: To investigate if sequential positron emission tomographic (PET) scans with the glucose analog 18F-2-fluoro-2-deoxy-D-glucose (18FDG) and/or L-methyl-11C-methionine (11C-methionine) in patients with breast cancer could provide early information on the efficacy of polychemotherapy. PATIENTS AND METHODS: Sixteen patients with breast cancer (11 with locally advanced tumors, three with recurrent disease in the contralateral breast, two of them with distant and regional metastases, and two with distant metastases) underwent a baseline and two follow-up PET scans after the first and third/fourth polychemotherapy course. Tumor response was determined clinically/radiographically after three/four polychemotherapy courses. RESULTS: Five patients were investigated with 18FDG, seven with both 11C-methionine and 18FDG, and four with only 11C-methionine before polychemotherapy. 11C-methionine presented a more distinct visualization of primary/contralateral breast cancers in five of seven patients when compared with 18FDG. Twelve of 16 patients demonstrated a response using conventional methods after the third/fourth course of polychemotherapy. Eight of these 12 clinical responders had a significant decrease in tracer uptake at the first PET scan performed 6 to 13 days after the first polychemotherapy course, and these reductions were further augmented after the third/fourth course and corresponded to the conventional therapy evaluation (clinical examination, computed tomography [CT], ultrasonography, and mammography). CONCLUSION: Our data indicate that PET may be of clinical value in predicting response to chemotherapy in patients with locally advanced breast cancer and/or metastatic disease earlier than any other method used.

Ion exchange tumor targeting: a new approach.

Connective tissues are distinguished by the types, concentrations, and organizations of material in the extracellular matrix. Many physiological functions are determined largely by the nature and organization of the extracellular components. The components are characterized by their content and distribution of charged, mostly anionic groups. The distinct roles played by the charges are sometimes modeled by analogy to the transport theory of ion exchange resins. The intent of this study was to investigate whether the properties of the tumor matrix could be used for selective, charge-dependent accumulation of charge-modified dextran. Ten patients with diagnosed superficial urinary bladder carcinoma were included in the study. They received intravesical instillations of technetium-99m-labeled charge-modified dextran derivatives (approximately 0.1-1 mg; approximately 50 MBq in saline; 30-min incubation). After treatment and resection, samples were taken from normal and diseased tissue. The result clearly demonstrated a charge-dependent difference in the quotient of radioactive uptake in tumor tissue: normal tissue. Instillations of cationic dextran yielded a high quotient, up to 3000. Normal tissue had background activity. Anionic dextran yielded a low quotient, 1.8-2, with increased background (i.e. uptake in normal tissue). Neutral dextran gave a quotient of up to 90. No radioactivity could be detected in blood. The tumors in this study apparently displayed cation-exchanging properties. We will continue this investigation and determine whether this is a general property of bladder carcinomas and whether other carcinomas display ion exchange properties. If this is the case, the finding could have important implications for the local treatment of several cancers.

Radiation doses to the cell nucleus in single cells and cells in micrometastases in targeted therapy with (131)I labeled ligands or antibodies.

PURPOSE: The aim of this study was to theoretically investigate how the radiation dose to cell nuclei depends on the subcellular position of (131)I. The influence of the size of the cells and crossfire irradiation in clusters of cells was also studied. METHODS AND MATERIAL: Using data describing the dose rate around a point source of (131)I, we calculated the dose distributions inside and around cell models of different sizes. The assumed positions of (131)I were on the cellular or nuclear membrane, in the cytoplasm, in the nucleus, or spread in the whole cell. The mean doses to the nucleus of the targeted cell and to the nuclei of its neighbors were calculated using the dose distributions. RESULTS: The dose distributions inside a single targeted cell showed very different distribution profiles depending on the subcellular position of the (131)I. Targeting the nucleus instead of the cellular membrane could increase the dose to the nucleus 10-fold. Crossfire irradiation can be the major contributor to the nuclear dose in clusters of more than six cells. CONCLUSIONS: Dosimetry without microscopic considerations is inadequate for targeted radionuclide therapy of disseminated or clustering tumor cells exposed to (131)I. Therapeutic doses could be achieved, even in single cells, when (131)I was positioned near, or inside the cell nucleus, or when the clusters were large enough.

Nuclear localization of 111In after intravenous injection of [111In-DTPA-D-Phe1]-octreotide in patients with neuroendocrine tumors.

UNLABELLED: Treatment with tumor-targeting substances is currently being evaluated in clinical trials. For patients with neuroendocrine tumors expressing somatostatin receptors, the 111In-labeled somatostatin analog [diethylenetriaminepentaacetic acid (DTPA)-DPhe1]-octreotide has been used with promising results. To further investigate the clinical effect of the injected conjugate, we analyzed the cellular distribution of 111In by ultrastructural autoradiography. METHODS: Seven patients with somatostatin receptor-expressing midgut carcinoid tumors scheduled for abdominal surgery were investigated by somatostatin receptor scintigraphy. During operation, tumor tissue samples and samples of normal intestine were collected, fixed, and processed for electron microscopy. A thin layer of film emulsion was applied on sections and after the exposure film was developed. The cellular distribution of silver precipitations indicating the presence of isotope was evaluated. RESULTS: Cell surface receptor binding and internalization of [111In-DTPA-D-Phe1]-octreotide in the tumor cells was easily revealed by silver precipitations in the film. Multiple silver grains were seen at the plasma membrane, in the cytoplasmic area among secretory granules and vesicular compartments, and in the perinuclear area. Silver grains were also regularly located in the nucleus. For all patients, the silver precipitation patterns from 111In decay were identical in all examined cells from removed tumors, and in most cells 111In could be seen in the nucleus. The specificity of the silver reaction products is supported by the observation that enterocytes in intestinal tissue specimens from near the tumor did not show any silver grains and no background labeling was seen in the plastic. CONCLUSION: After internalization through the somatostatin receptor system, 111In is translocated to the perinuclear area and into the nucleus. Whether the nuclide is still conjugated to the intact somatostatin analog or to part of it cannot be evaluated in this study. Despite the short irradiation range of 111In, the nuclear localization can explain its clinical effectiveness. The results from this study suggest that [111In-DTPA-D-Phe1]-octreotide may act as a powerful tumor cell-targeting substance.

[111In-DTPA-D-Phe1]octreotide scintigraphy in patients with carcinoid tumours: the predictive value for somatostatin analogue treatment.

This study was performed to evaluate whether the presence or absence of somatostatin receptors in malignant carcinoid tumours detected by [111In-DTPA-D-Phe1]octreotide scintigraphy can be used to predict response to somatostatin analogue treatment. Thirty patients were investigated, 28 with midgut carcinoid tumours and two with foregut carcinoid tumours. Twenty-seven patients showed pathological uptake in tumour lesions at scintigraphy; of these, 22 responded to somatostatin analogue treatment using octreotide, somatuline or octastatin, while five patients failed to respond. None of the three patients displaying negative scintigraphic investigations responded to treatment with somatostatin analogues. These results show a good correlation between the somatostatin receptor status and the patients' ability to respond to somatostatin analogue treatment (p = 0.014). We conclude that somatostatin receptor scintigraphy using [111In-DTPA-D-Phe1]octreotide can be used to select patients with malignant carcinoid tumours suitable for somatostatin analogue treatment and exclude those that will not benefit from such medication.

Scintigraphy and biodistribution of monoclonal adrenocortical antibody in mice grafted with human adrenocortical carcinoma.

BACKGROUND: A murine monoclonal antibody recognizing normal and neoplastic human adrenocortical cells has been evaluated for scintigraphic localization and biodistribution in 53 nude mice grafted subcutaneously with human adrenocortical cell lines SW-13 and T-CAR 1. METHODS: The immunoglobulin G1 antibody and its Fab'2 fragment were purified and labeled with 125I. The tumor grafts exhibited diameters of 5 to 15 mm at 4 to 6 weeks after transplantation, when mice received a single subcutaneous or intraperitoneal injection of 50 micrograms iodinated intact or fragmented antibody, respectively. RESULTS: Examination up to 8 days after immunoglobulin G administration showed mean radioactivity ratios less than 1.0 for tumor to blood and corresponding ratios in tumor to lung, liver, spleen, and kidney from 0.6 to 5.3 at the time of peak tumor to blood ratio. A high background activity was noted on scintigraphic tumor visualization with the iodinated immunoglobulin G. In contrast, the radiolabeled Fab'2 fragment displayed gradually rising tumor to blood ratios, which, 4 days after injection, averaged 10.5 for T-CAR1 and 5.3 for SW-13. Tumor transplants were scintigraphically visualized without substantial background activity 3 days after Fab'2 injection, when the ratio of radioactivity in the tumor to the investigated murine organs was 0.5 to 7.3. CONCLUSIONS: The findings substantiate that immunoscintigraphy with the Fab'2 fragment of the antiadrenocortical Ac5 antibody may become a tool to localize human adrenocortical carcinoma.

Somatostatin receptor scintigraphy during treatment with lanreotide in patients with neuroendocrine tumors.

To investigate possible changes in somatostatin receptor expression during treatment with high dose lanreotide, eight patients with neuroendocrine tumors were investigated by [(111)In-DTPA-D-Phe1]-octreotide scintigraphy before and during treatment. The spleen-to-background ratio decreased in all patients, whereas tumor-to-background ratio revealed a heterogeneous pattern with an average increase of 50% (-79% to +1,087%). This finding indicates that lanreotide treatment may influence the binding of radioactively labeled somatostatin to the spleen, while changes in the binding to functioning somatostatin receptors in tumor cells are more complex and not clearly related to treatment.

Positron emission tomography (PET) with 11C-5-hydroxytryptophan (5-HTP) in patients with metastatic hormone-refractory prostatic adenocarcinoma.

The discovery of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma has opened a potentially new therapeutic approach in this group of patients with a poor prognosis and few effective therapy modalities. Based on previous findings of increased uptake of 11C-5-hydroxytryptophan (11C-5-HTP) in neuroendocrine tumours using the PET technique, this tracer was applied in the study of 10 patients with metastatic hormone-refractory prostatic adenocarcinoma. In three patients, the study was repeated after treatment. An increased uptake of 11C-5-HTP was observed in all investigated skeletal lesions, although the magnitude of the uptake was moderate. The difference between the standard uptake values (SUV) in normal bone and metastatic lesions was significant (p < 0.001). A kinetic analysis of the uptake of 11C-5-HTP demonstrates an increase during the first minutes followed by a wash-out and a stabilization of the tissue/blood ratio at about 2. The Patlak plots demonstrated a gradual increase in the transport rate during the first 20 to 30 min, after which a constant level was observed. The SUV varied between patients and between lesions over time and treatment. The uptake of 11C-5-HTP discriminates metastatic lesions from normal bone and may thus aid in the diagnosis and, potentially, in treatment monitoring of metastatic hormone-refractory prostatic adenocarcinoma. Uptake kinetics are characterized by a wash-out and cannot alone be used as proof of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma.

Synthesis, in vivo rhesus monkey biodistribution and in vitro evaluation of a 11C-labelled potent aromatase inhibitor: [N-methyl-11C]vorozole.

[N-methyl-11C]Vorozole, a high-affinity aromatase-binding radiotracer, was synthesized through N-methylation of the corresponding nor-vorozole derivative using [11C]methyl iodide. [N-methyl-11C]Vorozole was obtained in 53-56% radiochemical yield based on [11C]methyl iodide within 40 min of the end of radionuclide production. The final formulation was >98% radiochemically pure and had a specific radioactivity of 10-143 GBq/micromol. In vitro, [N-methyl-11C]vorozole displayed high and specific binding to aromatase-rich human placenta. [N-methyl-11C]Vorozole binding to other tissues was lower and less specific. The dissociation constant measured was in the low nM range (Kd 1.7 nM), consistent with published Ki values for vorozole. Biodistribution studies in rhesus monkeys showed high liver uptake, which reached a constant level of 20% of the injected dose after 10 min, and an otherwise relatively even distribution of radioactivity. Pretreatment with vorozole only caused minor alterations of the biodistribution of the tracer.

89Strontium in the management of painful sceletal metastases.

PURPOSE: To make a review of the literature of 89strontium-chloride and a retrospective study of time to palliative intended external irradiation, number of portals and overall-survival after 89strontium-chloride therapy. RESULTS: In total 93 patients were treated 116 times with 89strontium. The patients with prostatic carcinoma received 91% of all 89strontium therapies. Median over-all survival was 10 months after injection. In those cases when 89strontium was given before palliative radiotherapy, the average of total number of local fields was significantly lower (1.1 versus 4.1) compared to those cases where local fields preceded 89strontium therapy. However, time to 89new external irradiation after 89strontium injection was equal between these groups (3.8 versus 2.9 months). CONCLUSION: A review of literature conclude that 89strontium is effective for the reduction of pain originating from osteoblastic metastases. It also reduce the need for external radiotherapy and therefore is cost-effective. However, 89strontium is more effective in an early phase of the metastatic disease and preferably as an adjuvance to external radiotherapy.

[111In-DTPA-D-Phe1]-octreotide scintigraphy in patients with hormone-refractory prostatic adenocarcinoma can predict therapy outcome with octreotide treatment: a pilot study.

A pilot study to evaluate the predictive value of Indium-111-labelled somatostatin analogue [DTPA-D-Phe1]-octreotide scintigraphy (OctreoScan111) in the Octreotide treatment of hormone-refractory prostatic adenocarcinoma was initiated. Ten patients were investigated with OctreoScan111 with regard to disease extension and tumor-to-background ratio. Subsequently, the patients were treated with Octreotide (Sandoz, Basel, Schweiz) at a dose of 100 micrograms twice a day subcutaneously. Three patients experienced symptomatic relief, and two of these responded with a decrease in PSA. Three patients did not notice any difference after 6 months of treatment and two of them developed an increase in their PSA value. One patient progressed after five months as regards both PSA and symptoms. Three patients were not able to complete treatment. Of the seven evaluable patients, the three with the highest tumour-to-background ratios at OctreoScan111 were those patients with reduced or stable PSA levels, and none of these progressed during treatment. Previous reports along with this study demonstrate that only a minority of patients with hormone-refractory prostatic adenocarcinoma benefit from Octreotide treatment. However, OctreoScan111 investigations may identify patients who will respond to Octreotide therapy.

Pain figures are unsuitable for determination of palliative radiotherapy portals in patients with hormone refractory prostatic cancer.

We aimed to compare bone scintigraphy with pain extension and other quality of life (QoL) factors in order to evaluate QoL and the appropriateness of using pain figures and a subjective pain description as the basis for palliative radiotherapy (RT) portals. Twenty-three patients with progressive hormone-refractory prostatic adenocarcinoma were investigated with bone scintigraphy and completed pain figures, VAS (visual analogue scales) and a comprehensive self-questionnaire concerning QoL. The Soloway score was significantly correlated with Impaired overall QoL (p = 0.05), and especially with questions regarding restriction of movements (p = 0.001). Weight bearing regions were significantly more often affected at bone scintigraphy than other locations in the group of patients reporting incidental pain during exercise. Surprisingly, a poor level of correlation existed when comparing location of pain with location of uptake on bone scintigraphy, even if an adjacent region was included in the comparison. The subjective description of pain extension in pain figures correlates poorly with the uptake patterns at bone scintigraphy--an interesting finding since pain extensions is regularly used for the definition of palliative RT portals. Furthermore, it appears that the tumour burden itself is not and indicator of the pain score at rest, but affects aspects of QoL. Moreover, it would appears as though the location of metastases in the skeleton significantly affects physical quality of life aspects. It is probably more important to irradiate weight bearing regions of skeleton in order to increase QoL.

Biological characteristics of adrenocortical carcinoma: a study of p53, IGF, EGF-r, Ki-67 and PCNA in 17 adrenocortical carcinomas.

Adrenocortical carcinoma (ACC) is a rare neoplasm with a poor prognosis. Prognostic factors are needed to identify patients who should be treated aggressively and those for which a less aggressive approach is warranted. As a result of advances within the field of immunohistochemistry, investigations of Ki-67, PCNA, IGF, EGF-r and p53 were performed in 17 ACC. The aim of this study was to clarify the role of Ki-67, PCNA, EGF-r, IGF and p53 in correlation to tumour behaviour and outcome. This retrospective study includes 16 patients, 10 women and 6 men, with a median age of 46 years. Nine tumours were hormonally functioning and 7 were non-functioning. The results obtained revealed that all tumours expressed PCNA and Ki-67 with median values of 59% and 14%, respectively, while p53 was negative in 88%, IGF negative in 82% and EGF-r positive in 94% of the tumours. No correlation was found between p53, IGF, EGF-r and survival rate. There was no interdependence between PCNA and Ki-67, or between PCNA, Ki-67 and the survival rate.

Human milk fat globule antigen 1 (HMFG1) expression in prostatic carcinoma and immunotargeting with a radiolabelled monoclonal anti-HMFG1 antibody.

BACKGROUND: Prostatic cancer is the leading cause of death in Swedish men. Approximately 50% have disseminated disease at diagnosis. Radiolabelled antibodies could possibly be a treatment modality for disseminated prostatic cancer, so that in this study the expression of the human milk fat globulin 1 (HMFG1) antigen in prostate cancer was examined. MATERIALS AND METHODS: An immunohistochemistry technique with a murine monoclonal antibody was used, as well as the human prostate cancer cell line DU-145, which expresses this cell surface antigen. TUR specimens from patients with prostate cancer were also examined. RESULTS: Eighteen out of 22 (82%) patients exhibited an HMFG1-positive tumour. An inhomogenity in the immunostaining could occasionally be seen, with smaller apparently negative areas. The immunolocalisation properties of the antibody were investigated using a radiolabelled antibody injection into nude mice bearing heterotransplants of the DU-145 cell line. The highest accumulation of the antibody was seen in the tumour tissue and the liver. CONCLUSION: The results obtained form a basis for further investigations with the goal of using the antibodies for staging and therapy for prostate cancer.