The cytoskeleton actin binding protein filamin A impairs both IGF2 mitogenic effects and the efficacy of IGF1R inhibitors in adrenocortical cancer cells.

Adrenocortical carcinomas (ACCs) overexpress insulin-like growth factor 2 (IGF2), that drives a proliferative autocrine loop by binding to IGF1R and IR, but IGF1R/IR-targeted therapies failed in ACC patients. The cytoskeleton actin-binding protein filamin A (FLNA) impairs IR signalling in melanoma cells. Aims of this study were to test FLNA involvement in regulating IGF1R and IR responsiveness to both IGF2 and inhibitors in ACC. In ACC cells H295R and SW13 and primary cultures (1ACC, 4 adenomas) we found that IGF1R and IR interacted with FLNA, and FLNA silencing increased IGF1R and reduced IR expression, with a downstream effect of increased cell proliferation and ERK phosphorylation. In addition, FLNA knockdown potentiated antiproliferative effects of IGF1R/IR inhibitor Linsitinib and IGF1R inhibitor NVP-ADW742 in H295R. Finally, Western blot showed lower FLNA expression in ACCs (n = 10) than in ACAs (n = 10) and an inverse correlation of FLNA/IGF1R ratio with ERK phosphorylation in ACCs only. In conclusion, we demonstrated that low FLNA levels enhance both IGF2 proliferative effects and IGF1R/IR inhibitors efficacy in ACC cells, suggesting FLNA as a new factor influencing tumor clinical behavior and the response to the therapy with IGF1R/IR-targeted drugs.

Octreotide and pasireotide effects on medullary thyroid carcinoma (MTC) cells growth, migration and invasion.

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine neoplasm of the parafollicular thyroid C cells. Although somatostatin receptors are expressed by MTCs, treatment with octreotide has shown poor efficacy, whereas recently pasireotide has demonstrated antiproliferative effects in persistent postoperative MTCs. Aim of this study was to test the effects of octreotide and pasireotide on MTC cells proliferation, cell cycle proteins expression, MAPK activation, apoptosis, calcitonin secretion, migration and invasion in TT cell line as well as in primary MTC cultured cells. Our results showed that both octreotide and pasireotide reduced TT cell proliferation (-35.2 ± 12.1%, p < 0.001, and -25.3 ± 24.8%, p < 0.05, at 10-8 M, respectively), with concomitant inhibition of ERK phosphorylation and cyclin D1 expression. This cytostatic effect was accompanied by a proapoptotic action, with an increase of caspase3/7 activity of 1.5-fold. Moreover, both octreotide and pasireotide inhibited cell migration (-50.9 ± 11.3%, p < 0.01, and -40.5 ± 17%, p < 0.05, respectively) and invasion (-61.3 ± 35.1%, p < 0.05, and -49.7 ± 18%, p < 0.01, respectively). No effect was observed on calcitonin secretion. We then tried to extend these observations to primary cultures (n = 5). Octreotide and/or pasireotide were effective in reducing cells proliferation in 3 out of 5 tumors, and to induce cell apoptosis in 1 out of 3 MTCs. Both octreotide and pasireotide were able to reduce cell migration in all MTC tested. SST2, SST3 and SST5 were expressed in all MTC, with a tendency to increased expression of SST2 in RET mutated vs wild type MTCs. In agreement, inhibition of mutated RET in TT cells reduced SST2 expression. In conclusion, we demonstrated that octreotide and pasireotide inhibited cell proliferation and invasiveness in a subset of MTC, supporting their potential use in the control of tumor growth.

Cofilin is a mediator of RET-promoted medullary thyroid carcinoma cell migration, invasion and proliferation.

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor that originates from parafollicular thyroid C cells and accounts for 5% of thyroid cancers. In inherited cases of MTC, and in about 40% of sporadic cases, activating mutations of the receptor tyrosine kinase proto-oncogene RET are found. Constitutively active RET triggers signaling pathways involved in cell proliferation, survival and motility, but the mechanisms underlying malignant transformation of C-cells have been only partially elucidated. Cofilin is a key regulator of actin cytoskeleton dynamics. A crucial role of cofilin in tumor development, progression, invasion and metastasis has been demonstrated in different human cancers, but no data are available in MTC. Interestingly, RET activation upregulates cofilin gene expression. The aim of this study was to investigate cofilin contribution in invasiveness and growth of MTC cells, and its relevance in the context of mutant RET signaling. We found that cofilin transfection in human MTC cell line TT significantly increased migration (178 ±â€¯44%, p < 0.001), invasion (165 ±â€¯28%, p < 0.01) and proliferation (146 ±â€¯18%, p < 0.001), accompanied by an increase of ERK1/2 phosphorylation (2.23-fold) and cyclin D1 levels (1.43-fold). Accordingly, all these responses were significantly reduced after genetic silencing of cofilin (-55 ±â€¯10% migration, p < 0.001, -41 ±â€¯8% invasion, p < 0.001, -17 ±â€¯3% proliferation, p < 0.001). These results have been confirmed in primary cells cultures obtained from human MTCs. The inhibition of constitutively active RET in TT cells by both the RET pharmacological inhibitor RPI-1 and the transfection of dominant negative RET mutant (RETΔTK) resulted in a reduction of cofilin expression (-37 ±â€¯8%, p < 0.001 and -31 ±â€¯16%, p < 0.01, respectively). Furthermore, RPI-1 inhibitory effects on TT cell migration (-57 ±â€¯13%, p < 0.01), but not on cell proliferation, were completely abolished in cells transfected with cofilin. In conclusion, these data indicate that an unbalanced cofilin expression, induced by oncogenic RET, contributes to promote MTC invasiveness and growth, suggesting the possibility of targeting cofilin pathway for more effective treatment of MTC.

Cytoskeleton actin-binding proteins in clinical behavior of pituitary tumors.

Although generally benign, pituitary tumors are frequently locally invasive, with reduced success of neurosurgery and unresponsive to pharmacological treatment with somatostatin or dopamine analogues. The molecular basis of the different biological behavior of pituitary tumors are still poorly identified, but a body of work now suggests that the activity of specific cytoskeleton proteins is a key factor regulating both the invasiveness and drug resistance of these tumors. This review recapitulates the experimental evidence supporting a role for the actin-binding protein filamin A (FLNA) in the regulation of somatostatin and dopamine receptors expression and signaling in pituitary tumors, thus in determining the responsiveness to currently used drugs, somatostatin analogues and dopamine receptor type 2 agonists. Regarding the regulation of invasive behavior of pituitary tumoral cells, we bring evidence to the role of the actin-severing protein cofilin, whose activation status may be modulated by dopaminergic and somatostatinergic drugs, through FLNA involvement. Molecular mechanisms involved in the regulation of FLNA expression and function in pituitary tumors will also be discussed.

cAMP/PKA-induced filamin A (FLNA) phosphorylation inhibits SST2 signal transduction in GH-secreting pituitary tumor cells.

An efficient intracellular response to somatostatin analogs (SSA) in pituitary tumors requires filamin A (FLNA). Since cAMP pathway plays an important role in GH-secreting pituitary tumors pathogenesis and FLNA is phosphorylated by PKA on S2152, aim of this study was to investigate in tumoral somatotrophs the impact of cAMP pathway activation and SSA stimulation on FLNA phosphorylation and the consequences on SST2 function. We found a PKA-mediated increase (2-fold) and SST2 agonist-induced decrease (-50%) of FLNA phosphorylation in GH3, GH4C1 and primary somatotroph tumor cells. This modification regulates FLNA function. Indeed, phosphomimetic S2152D FLNA mutant, but not phosphodeficient S2152A, abolished the known SSA antitumoral effects, namely: 1) inhibition of cell proliferation, reduction of cyclin D3 and increase of p27; 2) increase of cell apoptosis; 3) inhibition of cell migration via RhoA activation and cofilin phosphorylation. Coimmunoprecipitation and immunofluorescence assays showed that S2152A FLNA was recruited to activated SST2, whereas S2152D FLNA constitutively bound SST2 on the plasma membrane, but prevented Gαi proteins recruitment to SST2. In conclusion, we demonstrated that FLNA phosphorylation, promoted by cAMP pathway activation and inhibited by SSA, prevented SST2 signaling in GH-secreting tumoral pituitary cells.

A novel pathway activated by somatostatin receptor type 2 (SST2): Inhibition of pituitary tumor cell migration and invasion through cytoskeleton protein recruitment.

The pharmacological therapy of GH-secreting pituitary tumors is based on somatostatin (SS) analogs that reduce GH secretion and cell proliferation by binding mainly SS receptors type 2 (SST2). Antimigratory effects of SS have been demonstrated in different cell models, but no data on pituitary tumors are available. Aims of our study were to evaluate SST2 effects on migration and invasion of human and rat tumoral somatotrophs, and to elucidate the molecular mechanism involved focusing on the role of cofilin and filamin A (FLNA). Our data revealed that SST2 agonist BIM23120 significantly reduced GH3 cells migration (-22% ± 3.6%, p < 0.001) and invasion on collagen IV (-31.3% ± 12.2%, p < 0.01), both these effects being reproduced by octreotide and pasireotide. Similar results were obtained in primary cultured cells from human GH-secreting tumors. These inhibitory actions were accompanied by a marked increase in RhoA/ROCK-dependent cofilin phosphorylation (about 2.7-fold in GH3 and 2.1-fold in human primary cells). Accordingly, the anti-invasive effect of the SS analog was mimicked by the overexpression in GH3 cells of the S3D phosphomimetic cofilin mutant, and abolished by both phosphodeficient S3A cofilin and a specific ROCK inhibitor that prevented cofilin phosphorylation. Moreover, FLNA silencing and FLNA dominant-negative mutants FLNA19-20 and FLNA21-24 transfection demonstrated that FLNA plays a scaffold function for SST2-mediated cofilin phosphorylation. Accordingly, cofilin recruitment to agonist-activated SST2 was completely lost in FLNA silenced cells. In conclusion, we demonstrated that SST2 inhibits rat and human tumoral somatotrophs migration and invasion through a molecular mechanism that involves FLNA-dependent cofilin recruitment and phosphorylation.

Correlation between clinical characteristics and proliferative activity in patients with craniopharyngioma.

OBJECTIVES: The aim of the study was to correlate the Ki-67 and cyclin A labelling index (LI) with clinical characteristics and risk of recurrence of craniopharyngiomas. METHODS: 47 consecutive patients were studied, 21 female and 26 male, aged 34.3 (2.8) years. Immunohistochemical analysis was performed on paraffin wax embedded material using monoclonal antibodies directed against the proliferation associated nuclear antigen Ki-67 and cyclin A. RESULTS: The median Ki-67 LI was 8.6% (interquartile range, 4.4%-14.0%). Ki-67 LI was significantly higher in tumours with a heavy inflammatory reaction and diabetes insipidus at presentation, whereas other clinical and histological features were not associated with the proliferation index. There was a strong linear correlation between Ki-67 LI and cyclin A LI (r = 0.77; p<0.0001); therefore, cyclin A LI showed the same clinical and histological relations described for Ki-67 LI. Recurrence of craniopharyngioma occurred in 13 of 46 patients (28.3%). The median Ki-67 LI in the 13 recurrent craniopharyngiomas (9.0%) was not significantly different from that of non-recurring tumours (7.9%). Cyclin A LI was also not associated with the risk of relapse. CONCLUSIONS: This study confirms the great variability of proliferative activity in craniopharyngiomas. Ki-67 and cyclin A LIs were associated with the presence of a heavy inflammatory reaction and diabetes insipidus, but did not correlate with the long term risk of tumour regrowth.

Effects of octreotide treatment on the proliferation and apoptotic index of GH-secreting pituitary adenomas.

To investigate the effects of octreotide administration on the growth rate of GH-secreting pituitary adenomas, we measured both the Ki-67 labeling index (LI) and the apoptotic index in tumor specimens from octreotide-treated or matched untreated acromegalic patients. Thirty-nine patients who received octreotide until the day of or the day before surgery and 39 untreated patients matched for sex, age, tumor size, extension, and invasiveness were studied. Immunocytochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick endlabeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. The Ki-67 LI and apoptosis were counted on separate slides in at least 1000 evaluable cells. Octreotide-treated patients showed a lower Ki-67 LI (1.8 +/- 0.3%) than untreated controls (3.8 +/- 0.7%; P < 0.02). Overall, the mean Ki-67 LI of treated patients was 53% lower than that in untreated patients. The antiproliferative effect of octreotide occurred independently of tumor extension and invasiveness. Octreotide-treated and untreated patients showed similar apoptotic indexes (0.6 +/- 0.2% and 0.8 +/- 0.3%, respectively). There was a positive correlation between the Ki-67 LI and the apoptotic index (r = 0.29; P < 0.03). Our study demonstrates that acromegalic patients receiving chronic octreotide treatment have a lower value of the proliferation marker Ki-67, but no significant difference in the apoptotic index compared with matched untreated patients. The antiproliferative effect of octreotide on GH-secreting adenomas should imply a lower risk of tumor growth during long-term chronic treatment with the drug.

Proliferation index of nonfunctioning pituitary adenomas: correlations with clinical characteristics and long-term follow-up results.

OBJECTIVE: The recurrence of nonfunctioning pituitary adenomas (NFPAs) after surgical removal is common. The aim of our study was to investigate and correlate the growth fraction of NFPAs with clinical characteristics and long-term follow-up results. METHODS: Tumor specimens were obtained from 101 consecutive patients with NFPAs (48 female patients and 53 male patients; mean age, 52.0 +/- 1.5 yr). Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immunocytochemical analysis using the monoclonal antibody MIB-1. The Ki-67 antigen labeling index (LI) was determined by counting a total of at least 1,000 neoplastic nuclei. RESULTS: The mean Ki-67 LI for the 101 patients was 2.4 +/- 0.3% (range, 0-23.0%). Only age at surgery was inversely correlated with the Ki-67 LI; sex, maximal tumor diameter, and invasiveness into the cavernous sinuses did not significantly affect the Ki-67 LI. The mean follow-up period was 39.7 +/- 2.1 months. During follow-up monitoring, 23 patients experienced tumor recurrence, after a mean period of 28.6 +/- 4.8 months. Invasiveness of the tumor on preoperative magnetic resonance imaging scans was the strongest predictor of late tumor recurrence, followed by previous pituitary surgery, younger age, and lack of postoperative radiotherapy. The Ki-67 LI had no independent prognostic value. CONCLUSION: Our study suggests that the clinical characteristics of patients with NFPAs, except for age at surgery, are not correlated with the Ki-67 LI. Moreover, the Ki-67 LI does not seem to provide independent information to identify patients at high risk for tumor recurrence.

Determination of the proliferation and apoptotic index in adrenocorticotropin-secreting pituitary tumors : comparison between micro- and macroadenomas.

We investigated the growth fraction and cell loss fraction in a large group of patients with Cushing's disease subdivided according to tumor size. Fifty-one patients, 8 males and 43 females, aged 12 through 61 years (mean age 34.6 +/- 1.5 years), were studied. Thirty-six patients had a microadenoma and the remaining 15 a macroadenoma. Immunohistochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. Ki-67 labeling index and apoptosis were counted on separate slides in at least 1000 evaluable cells. Patients with a macroadenoma had a significantly higher value of Ki-67 index (9.3 +/- 2.7%) than patients with microadenoma (2.8 +/- 0.5%; P < 0.002), whereas the apoptotic index was not significantly different in the two groups (1.7 +/- 0.8% in macroadenomas versus 0.8 +/- 0.3% in microadenomas). Our study shows that ACTH-secreting macroadenomas are characterized by a higher cell growth fraction than microadenomas, whereas the cell loss fraction is not different. A high proliferation rate seems to play a major role in determining the progression from small to large pituitary tumors in Cushing's disease.

Staining apoptosis in paraffin sections. Advantages and limits.

OBJECTIVE: To describe the advantages and limits of apoptosis detection on paraffin sections by TdT-mediated dUTP nick end labeling (TUNEL). STUDY DESIGN: Two hundred sixty-five paraffin-embedded samples from malignant and benign human tissue were analyzed by TUNEL. Also, biparametric analysis of apoptosis and proliferation index (MIB-1), apoptosis, cytokeratin or leukocyte common antigen was performed. RESULTS: Our preliminary conclusions are as follows. The limits are that this labelling method might detect cells that have not shown DNA fragmentation specific for apoptosis only. The technique is extremely sensitive to the degree of proteolytic digestion. TUNEL identifies nuclei in areas of necrosis. Indeed, the staining of necrotic areas of tissue with the in situ labelling method should not cause confusion since simple morphologic examination of tissues will suffice to identify areas of necrotic cells. The advantages are that TUNEL is a method of simplifying the identification of apoptotic nuclei in routinely processed tissue sections, maintaining topography. It allows retrospective studies and biparametric analysis of cell death and proliferation on the same sample. Furthermore, with biparametric stain, it could better identify the origin (epithelial, mesenchymal, and so on) of apoptotic cells. CONCLUSION: TUNEL is a good method of detecting apoptotic nuclei in fixed, embedded tissue sections, but, because of the limits of the method, the results should be interpreted in conjunction with apoptosis assessment by routine light microscopy.

Usefulness of markers of cell proliferation in the management of pituitary adenomas.

1. Pituitary adenomas are benign and slow-growing tumours whose clinical manifestations depend mainly on the secretory activity of the adenomatous cells. Except for prolactinomas, surgical removal of the tumour is the therapy of choice. 2. Despite extensive research on their clinical and pathophysiological aspects, few studies have explored the oncological characteristics of these rare lesions. Among these, the growth fraction of pituitary adenomas has been determined by different methods, of which the most useful are those performed in archival material. 3. The results reported in the literature show that adrenocorticotropic hormone-secreting tumours seem to be characterized by a higher proliferation index than the other types of pituitary adenomas, despite their usually small tumour size. 4. In small series of patients radiotherapy and medical treatment with dopaminergic drugs and octreotide were associated with a lower proliferation index than untreated tumours. Tumour size was not correlated with the growth fraction of the pituitary tumours, whereas invasiveness was correlated in most studies. 5. From a clinical point of view, however, the more promising utilization of the proliferation index seems to be in predicting the potential of recurrence of the tumour, thus allowing a more rational approach to follow-up and further treatment of patients with pituitary adenomas.

Cell loss and proliferation in non-small cell lung carcinoma: correlation with histological subtype.

BACKGROUND: Cell kinetic data are important indicators of the aggressiveness of tumor and treatment response. The size of a neoplasm depends on the balance between cell proliferation and death. Thus, the analysis of the kinetics of cell proliferation and death may explain differences in the rates of tumour progression. METHODS: We studied apoptosis and proliferative indices in 95 cases of non-small cell lung carcinomas. The analysis was performed on paraffin-embedded tissue, by both MIB-1 immunocytochemical detection to establish the proliferation index and the in-situ end labelling method for the apoptosis index. The two indices were related. RESULTS: Our results showed a high proliferative index and cell loss rate in squamous cell carcinoma, and a low proliferative index and cell loss rate in adenocarcinoma, suggesting two different growth patterns. CONCLUSION: These findings could explain the different biological behaviour and treatment response of the tumours. The tendency of a cancer cell to undergo apoptosis may be especially important for the chemotherapy of malignant tumours with a low growth rate, which are typically resistant to cytostatic agents.

Heterogeneity and susceptibility to apoptosis of human renal carcinoma cells in vitro.

Tumors are heterogeneous in terms of morphology and susceptibility to drugs or radiation. Among primary and metastatic cells of a human renal carcinoma, a population (type II) of larger cells with prominent nucleoli, eosinophilic globules of intermediate filaments in paranuclear bundles, margination of subcellular organelles and peripheral pools of glycogen was evident. Paranuclear structures were recognized by monoclonal antibodies specific for cytokeratin 8, 18 and 19, but not by vimentin specific antibodies. We propagated a cell line in vitro (referred to as BKR cells), and observed culture in vitro, the almost complete disappearance of the type II cells. Pharmacological agents that influence cell differentiation, such as retinoic acid, rescued the expression of type II cells in vitro. Long-term treatments with insulin or alpha-interferon, but not with the epithelial growth factor (EGF), similarly differentiated BKR cells and abated their susceptibility to spontaneous and actinomycin-D induced apoptosis. These data support the contention that differentiation of tumor cells is actively maintained in vivo and further strengthen the caveat on tumor lines stabilized in vitro, that poorly represent the morphologic and antigenic heterogeneity of neoplasms in vivo.

[Biparametric analysis of the apoptotic index and the proliferation index (KI-67) in solid tumors]. / Analisi biparametrica di indice apoptotico e indice di proliferazione (KI-67) nei tumori solidi.

INTRODUCTION: Cell kinetic data are important indicators of the aggressiveness of tumor and treatment response. In this study biparametric analysis of proliferation and apoptotic index was performed on paraffin-embedded tissue from certain neoplasia. MATERIAL AND METHODS: We studied 107 cases of neoplastic and non neoplastic lesions. For each case, on the same section, TUNEL reaction and immunohistochemical protein Ki67 expression analysis were performed. RESULTS: On 102 out of 107 cases (95.3%) we obtained valid results both about apoptotic and proliferative indices. CONCLUSIONS: This method could supply, at the same time, interesting information about the two possible different patterns of neoplastic growth: one related to an increase fraction of proliferating cells, the other to decrease in apoptotic cell death. Cell kinetic data may have interesting implications on therapeutic choice.

Adjuvant role of MIB1 index in differentiating serous ovarian tumors-preliminary report.

Atypically proliferating serous tumors (APST) account for 15% of all ovarian serous epithelial neoplasms. The differences between benign, borderline and malignant ovarian tumors is principally due to their cellular proliferative potential. By means of MIB1 expression we could recognize differences in proliferation among serous ovarian tumors, overcoming interobserver variability. Thirty-three patients with serous ovarian tumors, treated at S. Raffaele Hospital, University of Milan between November 1, 1992 and July 31, 1994 were used as study the population: 9 patients had serous cystoadenocarcinoma, 14 patients had APST and 10 patients had serous cystoadenoma. Pathological slides of all the cases were reviewed and immunohistochemical analysis was performed on formalin fixed, paraffin was embedded tissue. Pearson's Chi-square test and Fisher's exact test were performed for statistical evaluation. The percentage of MIB1 positive neoplastic cells ranged from, 0% to 2.1% (median 0.45%; mean 0.69%) in cystoadenomas, 1.3% to 7% (median 2.9%; mean 3.98%) in APSTs and 4.7% to 20.3% (median 6.95%; mean 9.51%) in cystoadenocarcinomas (p < 0.0001; F = 47.7). A High percentage expression of MIB1 in a serous tumor, initially diagnosed as APST, promoted a wider sampling of the surgical specimen confirming the presence of a carcinomatous component. MIB1 index is reported as representative of cellular proliferative potential. The analysis of MIB1 index provided valuable information in addition to that gained by conventional microscopic study in all cases where diagnostic difficulties arose in assessing APST.

Combination of monoclonal antibodies for radioimmunoguided surgery.

The use of a cocktail of monoclonal antibodies in intraoperative radioimmunodetection of colorectal tumour has been evaluated in 14 patients. Eight patients had primary and six recurrent colorectal cancer. Three different monoclonal antibodies were used included B72.3, recognizing TAG72 antigen, FO23C3 and FO23C5 directed against two epitopes of CEA. The antibodies were labeled with 125I. During surgery the radioactive emission of tumour and normal tissue was evaluated by a gamma detecting probe. Ten patients showed positive intraoperative results and in particular 6 (75%) of the 8 patients with primary tumour and 4 (67%) of the 6 patients with recurrence, with a mean tumour to normal tissue ratio of 2.2. Intraoperative radioimmunodetection was instrumental in modifying the therapeutic approach in two patients with recurrent cancer but in none of the patients with a primary presentation. Immunohistochemical analysis, to evaluate TAG72 and CEA antigen expression, was performed in 13 cases. CEA antigen was expressed in 8/13 cases and TAG72 in 5/13. Thus the sensitivity was 38.5% and 61.5% with B72.3 and anti-CEA monoclonal antibodies respectively, while in combination the sensitivity was 71.4%. The use of a cocktail of different antibodies improved the sensitivity of intraoperative radioimmunodetection of colorectal tumours, when compared with a single antibody injection. This approach might improve the clinical use of radioimmunodetection.

Breast carcinoma detection with a combination of radiolabeled monoclonal antibodies. Promising results from immunohistochemistry studies.

BACKGROUND: Recent studies have demonstrated that the use of radiolabeled monoclonal antibodies (MoAbs) directed against tumor-associated antigens could help in the recognition of primary tumors, their extent, and their metastases by external scintigraphy (used preoperatively) or by hand-held gamma-detecting probe (GDP) (used intraoperatively). METHODS: The authors evaluated carcinoembryonic antigen (CEA), c-erb B-2 protein, and TAG-72 expression in 100 cases of breast carcinoma using F023C5 (anti-CEA), B72.3, and anti-c-erb B-2 protein MoAbs that were previously investigated for their usefulness in radioimmunoguided surgery and external scintigraphy. The goal of this study was to examine the biodistribution of each antibody in primary, multifocal, and metastatic lesions to evaluate the suitability of their simultaneous use in GDP and external scintigraphy. RESULTS: Results showed immunoreactivity for c-erb B-2 protein in 39 of 99 cases, for B72.3 in 41 of 100 cases, and for CEA in 15 of 100 cases. Multifocal lesions demonstrated positivity for c-erb B-2 protein in 37.4% of cases (6 of 16), for B72.3 in 68.8% of cases (11 of 16), and for CEA in 6.2% of cases (1 of 16). In lymph node metastases, immunoreactivity was found for c-erb B-2 protein in 36.4% of cases (12 of 33), for B72.3 in 63.7% of cases (21 of 33), and for CEA in 24.3% of cases (8 of 33). When the authors considered the immunoreactivity of all three MoAbs, the percentage of positive cases they observed was 60% in primary tumors (60 cases), 78% in lymph node metastases, and 81.2% in multifocal lesions. CONCLUSIONS: These results suggest that in vivo tumor radioimmunodetection could be improved by the use of more antibodies directed against different tumor-associated antigens.