Somatostatin receptor subtype specificity and in vivo binding of a novel tumor tracer, 99mTc-P829

Recent data suggest that somatostatin receptors (SSTRs) are expressed on various tumor cells. High-level expression of SSTR on the tumor cell surface provides the basis for the successful clinical use of radiolabeled ligands for the in vivo localization of tumor sites. We have characterized the in vitro binding properties of the novel SSTR ligand 99mTc-P829 using primary human tumors (carcinoids, breast cancers, intestinal adenocarcinomas, pheochromocytomas, small cell and non-small cell lung cancer, and melanomas; n = 28), various tumor cell lines, and COS7 cells transfected with the human SSTR (hSSTR) subtypes 1, 2, 3, 4, and 5. 99mTc-P829 bound to primary tumor cells and tumor cell lines with high affinity and high capacity. The dissociation constants (Kd) ranged between 1 and 20 nM. 99mTc-P829 also bound with high affinity to the transfected hSSTR2 (Kd, 2.5 nM), hSSTR5 (Kd, 2 nM), and hSSTR3 (Kd, 1.5 nM). Binding of 99mTc-P829 to hSSTR3 was found to be displaceable by unlabeled P829/([ReO]-P829), SST-14, and vasoactive intestinal peptide (VIP; IC50, 2 nM) and, less effectively, by Tyr3-octreotide (IC50, 20 nM). In contrast, the binding of 99mTc-P829 to hSSTR2 and hSSTR5 could be displaced by P829/([ReO]-P829) and Tyr3-octreotide but not by VIP. 99mTc-P829 scintigraphy revealed in vivo binding to primary or metastatic tumor sites in seven of eight patients with breast cancer and six of six patients with melanoma. In summary, our data show that 99mTc-P829 binds with high affinity to many different types of primary and cloned tumor cells. Furthermore, our data identify hSSTR2, the VIP acceptor hSSTR3, and hSSTR5 as the respective target receptors. Because these receptors are frequently expressed at high levels on primary tumor cells, 99mTc-P829 appears to be a promising novel peptide tracer for tumor imaging.     

Spasskyellina mandi n. sp. (Proteocephalidea:Monticelliidae), parasite of Pimelodus ornatus Kner, 1857 (Pisces:Pimelodidae) of the Paraná River, Paraná, Brazil

Indium-111 pentetreotide scintigraphy was performed in two patients for the localization of recurrent medullary thyroid carcinoma treated by surgery and external radiotherapy 1 and 10 years earlier. A marked uptake of the radiopharmaceutical was demonstrated in the lung areas that had been irradiated. These cases strongly suggest that this uptake is related to pulmonary fibrosis, a well-known complication of radiotherapy, even long after the irradiation. Therefore, attention must be paid to the avoidance of false-positive interpretation of somatostatin receptor scintigraphy in patients previously treated by radiotherapy.     

Solitary fibrous tumor of the pleura: a report of five cases diagnosed by transthoracic cutting needle biopsy

Five patients had a solitary fibrous tumor of the pleura; a well-known but rare entity. In all cases, biopsy by a transthoracic cutting needle (Tru-Cut; Travenol; Deerfield, IL) yielded specimens adequate for histologic analysis and gave the clue to the diagnosis. In four patients, surgical resection confirmed the diagnosis. The opportunity for and interest in diagnosing these tumors by transthoracic cutting needle biopsy before surgery are discussed. An accurate diagnosis of solitary fibrous tumors of the pleura can be made by a minimally invasive procedure; this allows for a more informed allocation of surgical resources.     

Radiolabeled somatostatin analog scintigraphy in oncology and immune diseases: an overview

[111In-DTPA-D-Phe1]-octreotide is a new radiopharmaceutical with a great potential for the visualization of somatostatin receptor-positive tumors, granulomas, and diseases in which activated leukocytes play a role. The overall sensitivity of [111In-DTPA-D-Phe1]-octreotide scintigraphy to localize neuroendocrine tumors is high. In several neuroendocrine tumor types, inclusion of somatostatin receptor imaging in the localization or staging procedure may be very rewarding, either in terms of cost-effectiveness, patient management, or quality of life. In our opinion, this holds true for patients with carcinoids, gastrinomas, paragangliomas, small-cell lung carcinoma, and selected cases of patients with insulinomas. The value of [111In-DTPA-D-Phe1]-octreotide scintigraphy in patients with other tumors, such as breast cancer, malignant lymphomas, or in patients with granulomatous diseases, has to be established.     

Gastrointestinal hemorrhage and small cell carcinoma

Despite widespread dissemination of primary lung carcinoma by lymphangitic and hematogenous routes, acute gastrointestinal signs and symptoms are rarely presenting symptoms for bronchogenic carcinoma. We present a patient with small cell carcinoma of the lung who came to medical attention because of a lower gastrointestinal hemorrhage. In the absence of radiographically apparent pulmonary disease, the correct diagnosis was suggested by the biopsy specimens of the colon.     

Molecular damage in the bronchial epithelium of current and former smokers

BACKGROUND: Most lung cancers are attributed to smoking. These cancers have been associated with multiple genetic alterations and with the presence of preneoplastic bronchial lesions. In view of such associations, we evaluated the status of specific chromosomal loci in histologically normal and abnormal bronchial biopsy specimens from current and former smokers and specimens from nonsmokers. METHODS: Multiple biopsy specimens were obtained from 18 current smokers, 24 former smokers, and 21 nonsmokers. Polymerase chain reaction-based assays involving 15 polymorphic microsatellite DNA markers were used to examine eight chromosomal regions for genetic changes (loss of heterozygosity [LOH] and microsatellite alterations). RESULTS: LOH and microsatellite alterations were observed in biopsy specimens from both current and former smokers, but no statistically significant differences were observed between the two groups. Among individuals with a history of smoking, 86% demonstrated LOH in one or more biopsy specimens, and 24% showed LOH in all biopsy specimens. About half of the histologically normal specimens from smokers showed LOH, but the frequency of LOH and the severity of histologic change did not correspond until the carcinoma in situ stage. A subset of biopsy specimens from smokers that exhibited either normal or preneoplastic histology showed LOH at multiple chromosomal sites, a phenomenon frequently observed in carcinoma in situ and invasive cancer. LOH on chromosomes 3p and 9p was more frequent than LOH on chromosomes 5q, 17p (17p13; TP53 gene), and 13q (13q14; retinoblastoma gene). Microsatellite alterations were detected in 64% of the smokers. No genetic alterations were detected in nonsmokers. CONCLUSIONS: Genetic changes similar to those found in lung cancers can be detected in the nonmalignant bronchial epithelium of current and former smokers and may persist for many years after smoking cessation.     

Immunohistochemically detected p53 and P-glycoprotein predict the response to chemotherapy in lung cancer

While resistance to chemotherapy is a major problem in lung cancer treatment, there is no useful predictor of treatment response. We thus designed this study to determine the utility of p53 and P-glycoprotein expression in predicting the response to chemotherapy in patients with primary lung cancer, retrospectively. We evaluated transbronchial biopsy (TBB) specimens from 60 patients with lung cancer, who were previously untreated. Formalin-fixed, paraffin-embedded TBB specimens were immunostained using anti-p53 antibody (DO-1) and anti-P-glycoprotein antibody (JSB-1). The positivity of p53 was 63%, and that of P-glycoprotein was 17%. No correlation was observed between p53 and P-glycoprotein immunostaining. Positivity of p53 correlated significantly (P = 0.004) with a lack of response to chemotherapy in non-small cell lung cancer (NSCLC), but not in small cell lung cancer (SCLC). In contrast, positivity of P-glycoprotein was correlated with chemotherapy resistance in SCLC (P = 0.003), but not in NSCLC. Multiple logistic regression analysis revealed that positive immunostaining for p53 was a significant risk factor for chemotherapy resistance in NSCLC. These results suggest that immunostaining of p53 and P-glycoprotein for TBB specimens may help to predict response to chemotherapy in NSCLC and SCLC, although the results should be confirmed in a larger, more homogeneous series.     

Expression of P-cadherin identifies prostate-specific-antigen-negative cells in epithelial tissues of male sexual accessory organs and in prostatic carcinomas. Implications for prostate cancer biology

PURPOSE: To evaluate the efficacy of dynamic computed tomography (CT) for differentiating benign from malignant solitary pulmonary nodules (SPNs). MATERIALS AND METHODS: Sixty-five patients with noncalcified SPNs (diameter, < or = 30 mm; 42 malignant, 16 benign, seven inflammatory) underwent single-location dynamic contrast material-enhanced (100 mL, 4 mL/sec) serial CT. Peak height of time-attenuation curves and ratio of peak height of the SPN to that of the aorta were measured. Precontrast attenuation and enhancement pattern were recorded. Perfusion was calculated from the maximum gradient of the time-attenuation curve and the peak height of the aorta. RESULTS: Peak heights of malignant (41.9 HU +/- 2.8) and inflammatory (43.6 HU +/- 7.7) SPNs were significantly higher than that (13.4 HU +/- 2.2) of benign SPNs (P < .001; P < .01). SPN-to-aorta ratios in malignant and inflammatory SPNs were significantly higher than that in benign SPNs (P < .001, P < .05). No statistically significant differences in the peak height and SPN-to-aorta ratio were found between malignant and inflammatory SPNs. Precontrast attenuation of inflammatory SPNs was lower than that of malignant SPNs (P < .05). Perfusion values in malignant and inflammatory SPNs were significantly higher than that of the benign SPNs (P < .01). CONCLUSION: Dynamic CT provides quantitative information about blood flow patterns of SPNs and is an applicable diagnostic method for differentiating SPNs.     

A novel tumor suppressor locus on chromosome 18q involved in the development of human lung cancer

The high incidence of loss of heterozygosity (LOH) on chromosome 18q in advanced non-small cell lung carcinomas indicates the presence of tumor suppressor gene(s) on this chromosome arm, which plays an important role in the acquisition of malignant phenotypes in lung cancers. In the present study, we examined 62 lung cancer specimens and 54 lung cancer cell lines for allelic imbalance at 11 microsatellite loci to define common regions of 18q deletions. Allelic imbalance of 18q was detected in 24 (55.8%) non-small cell lung carcinoma specimens and in 6 (31.6%) small cell lung carcinoma specimens, whereas a similar frequency of LOH was statistically inferred to occur in cell lines by analyzing marker homozygosity as an indirect measure of LOH. Five specimens and 11 cell lines showed partial or interstitial deletions of chromosome 18q, and 2 of them had homozygous deletions at the 18q21.1 region. A commonly deleted region was assigned between the D18S46 and y953G12R loci. The size of this region is less than 1 Mb, and the coding exons of three candidate tumor suppressor genes, Smad2, Smad4, and DCC, were mapped outside the region. This result suggests that the common region harbors a novel tumor suppressor gene involved in the progression of lung cancer.     

Absence of Fhit protein in primary lung tumors and cell lines with FHIT gene abnormalities

Genomic alterations and abnormal expression of the FHIT gene at 3p14.2 have been observed in cell lines and primary tumors of the lung. To correlate FHIT locus DNA and RNA lesions with effects on Fhit protein expression, we have analyzed 11 lung cancer cell lines, 15 small cell lung carcinomas, and 38 pairs of non-small cell primary tumors and bronchial mucosa specimens by molecular genetic and immunocytochemical methods. Using specific antibodies against the Fhit protein, we observed concordance between RNA abnormalities and lack of Fhit protein expression in lung tumors and cell lines. In addition, absence of Fhit protein in some precancerous dysplastic lesions suggested that FHIT inactivation may occur at an early phase of lung carcinogenesis.     

A relentless focus on performance

The examination of 51 children with lung diseases revealed a great variety of their forms. While choosing the optimum method of early diagnosis of interstitial lung disease in children, it is necessary to use all currently available techniques: X-ray, tomography, scintigraphy, lung function tests, laboratory analyses, and morphological study of specimens of transbronchial lung biopsy and alveolar lavage (AL). In the authors' opinion, fibroscopy with transbronchial lung biopsy and lung are major techniques of differential diagnosis of pediatric pulmonology.     

Ethylene-mediated phenotypic plasticity in root nodule development on Sesbania rostrata

Leguminous plants in symbiosis with rhizobia form either indeterminate nodules with a persistent meristem or determinate nodules with a transient meristematic region. Sesbania rostrata was thought to possess determinate stem and root nodules. However, the nature of nodule development is hybrid, and the early stages resemble those of indeterminate nodules. Here we show that, depending on the environmental conditions, mature root nodules can be of the indeterminate type. In situ hybridizations with molecular markers for plant cell division, as well as the patterns of bacterial nod and nif gene expression, confirmed the indeterminate nature of 30-day-old functional root nodules. Experimental data provide evidence that the switch in nodule type is mediated by the plant hormone ethylene.     

Apoptosis in labial salivary glands from Sj?gren''s syndrome (SS) patients: comparison with human T lymphotropic virus-I (HTLV-I)-seronegative and -seropositive SS patients

Patients with solitary rectal ulcer syndrome (SRUS) frequently present with a mass that can be misinterpreted as cancer. In contrast, the occurrence and characteristics of SRUS-like histopathology produced by underlying malignancy have not been reported in detail. We report seven patients whose rectal mass that was induced by infiltrating carcinoma showed only histopathologic changes of SRUS on initial mucosal biopsy specimens. Carcinoma was evident in subsequent specimens after one to five repeat biopsies with delay in diagnosis from 1 week to 18 months in six patients. In one patient, infiltrating carcinoma was suggested on the first biopsy specimen by immunohistochemistry for cytokeratin. Three of the patients had primary rectal adenocarcinoma, two had metastatic carcinoma from stomach or ovary, and two had direct invasion of anal squamous cell carcinoma or prostatic adenocarcinoma. We conclude that the histopathology of SRUS may occasionally represent a characteristic but nonspecific mucosal reactive change to a deeper seated malignancy. The terminology "solitary rectal ulcer syndrome/mucosal prolapse changes" with a cautionary note may be useful for reporting biopsy results to emphasize the possibility of underlying primary or metastatic malignancy in the differential diagnosis.     

Prognostic role of the cyclin-dependent kinase inhibitor p27 in non-small cell lung cancer

Despite its potential role as a tumor suppressor, p27 gene, a member of the Cip/Kip family of cyclin-dependent kinase inhibitor genes, has never been found mutated in human tumors. We investigated p27 protein expression in a series of 108 non-small cell lung cancers (57.4% stage 1, 16.7% stage 2, and 25.9% stage 3) to determine whether the lack or altered expression of this protein correlates with neoplastic transformation and/or progression. We performed immunohistochemistry and Western blot analysis of each specimen. We found that tumors expressing low to undetectable levels of p27 contained high p27 degradation activity. When we evaluated the outcome of the patients in relationship to p27 expression, we found p27 to be a prognostic factor correlating with the overall survival times (P = 0.0012). The possibility of a simple assay, such as the immunohistochemical analysis of p27 expression on routinely formalin-fixed, paraffin-embedded specimens, has considerable value for the prognosis of patients who undergo surgical resection. In addition, confirmation of the involvement of the proteasome-mediated proteolysis in p27 degradation should stimulate new strategies of nonsurgical treatments of non-small cell lung cancer.     

Effects of arginine, growth hormone-releasing hormone (GHRH) and neostigmine administered singly or in paired combinations on growth hormone (GH) release in pigs

OBJECTIVE: A multicentre study was undertaken to determine the value of somatostatin receptor (sst) scintigraphy in predicting hormonal and visual responses to octreotide treatment in GH-secreting and non-functioning pituitary adenomas. SUBJECTS AND METHODS: Somatostatin receptor scintigraphy was performed in 48 patients (19 acromegaly, 29 non-functioning pituitary adenomas with ophthalmological defects). Results were expressed as an uptake index of the pituitary area. A threshold for positivity was determined in 23 subjects considered as controls. Thirty-five patients were treated for 1 month with octreotide (300 micrograms daily). The therapeutic response was assessed on GH and IGF-I suppression or evolution of the ophthalmological defects. The relationships between the somatostatin receptor scintigraphy result, the therapeutic effect of octreotide and in vitro studies performed in 12 tumours were studied. RESULTS: From the results of control subjects the uptake index threshold for positivity was 2. In patients, somatostatin receptor scintigraphy was positive in 64% and there was no relationship between uptake index and tumour size. In GH tumours, somatostatin receptor scintigraphy was positive in 68%; uptake index was related to octreotide-induced GH and IGF I suppression. The positive predictive value was 100% and the negative predictive value was 50%. In vitro studies showed detectable binding sites for somatostatin with sst2 and sst5 expression in the 4 GH tumours studied although somatostatin receptor scintigraphy was negative in 2 cases. In non-functioning pituitary adenomas somatostatin receptor scintigraphy was positive in 62%. Based on visual effects, the positive predictive value was 61% and the negative predictive value was 100%. A wide distribution of somatostatin binding sites was found in 8 non-functioning pituitary adenomas with expression of sst2 only. CONCLUSION: In the conditions of the study, in patients with acromegaly, positive somatostatin receptor scintigraphy predicts a hormonal response but the value of somatostatin receptor scintigraphy is limited by its low negative predictive value. In patients with non-functioning pituitary adenomas, negative somatostatin receptor scintigraphy predicts that there will be no visual improvement during octreotide treatment.     

Capillary electrophoresis of the collagen crosslinks HP and LP utilizing absorbance, wavelength-resolved laser-induced fluorescence and conventional fluorescence detection

In the etiological diagnosis of ACTH-dependent Cushing's syndrome, it may be difficult to distinguish pituitary disease from ectopic ACTH production, specially when this is due to a benign neuroendocrine tumor. We describe a patient with partial dexamethasone suppression consistent with Cushing's disease, an absent response to CRH suggesting ectopic ACTH production and an atypical, apparent circadian rhythm. Bilateral cavernous sinus catheterization suggested a nonpituitary source of ACTH and, in the search of an ectopic tumor, somatostatin receptor scintigraphy, abdominal CT scan, and duodenopancreatic endoscopic echography were performed and failed to reveal any abnormality. Thoracic CT scan disclosed a tiny right lung nodule that showed a definite tracer uptake on MIBG scintigraphy. After resection, the nodule proved to be an 8-mm typical pulmonary carcinoid, with positive immunostaining for the classical neuroendocrine markers and for ACTH, and showing tissue expression of the POMC gene. However, the CRH receptor gene was not expressed, explaining the absent CRH response in vivo, whereas the V3 vasopressin receptor gene was expressed in the tumor tissue. The latter feature appears to be characteristic of benign carcinoids and may contribute to explaining the CRH-independent circadian rhythm observed in this case.     

Refined use of scintigraphy in the evaluation of nodular thyroid disease

BACKGROUND: Scintigraphy has been advocated in patients with a thyroid nodule when fine needle aspiration biopsy (FNAB) is not definitive. The purpose of this study was to determine the incidence of hyperfunctioning nodules in patients without a definitive FNAB, the correlation of serum thyrotropin (TSH) levels with the functional status of a nodule, and whether a sensitive TSH assay can be used in lieu of scintigraphy. METHODS: From 1990 to 1996, patients with a thyroid nodule were evaluated with FNAB and serum TSH measurement. Iodine-123 scintigraphy was reserved for patients without a definitive FNAB and was correlated with TSH levels. RESULTS: Of 356 patients with a thyroid nodule, 102 did not have a definitive FNAB. A hyperfunctioning nodule was diagnosed in 14 of the 102 patients. A low TSH level was detected in 12 (86%) of 14 patients with a hyperfunctioning nodule (mean = 0.04 +/- 0.38 microIU/mL) and only 20 (23%) of 88 patients with a hypofunctioning nodule (mean = 0.87 +/- 4.11 microIU/mL) (P < .05). Only 2 of 70 (2.8%) patients with a normal or increased TSH level had a hyperfunctioning nodule. CONCLUSIONS: A 14% incidence of hyperfunctioning nodules in patients without a definitive FNAB warrants the use of scintigraphy but only when serum TSH levels are low, thus avoiding unnecessary scans in 91% of patients with a thyroid nodule.     

Autologous transplantation of peripheral hematopoietic cells in a patient with multiple myeloma and renal insufficiency

A 28-year-old man had recurrent episodes of headache, ophthalmoplegia, and ptosis. MR imaging showed a mass within the sphenoid sinus. TI-201 imaging showed intense uptake in the region of the sphenoid sinus and right middle fossa with moderate retention of activity, suggesting the diagnosis of a viable tumor. A biopsy specimen from the sphenoid sinus revealed dense inflammatory infiltrate dominated by plasma cells, consistent with inflammatory pseudotumor. After radiation therapy, the mass showed no significant change on MR imaging, but regressed in size and uptake on the follow-up TI-201 scan. TI-201 may accumulate in nonmalignant inflammatory lesions and could mimic a viable tumor. It is, therefore, suggested that before surgery and histologic diagnosis, any abnormal intracranial accumulation of TI-201 should be interpreted with caution.     

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.     

The food-service industry, dietary guidelines and change

This study was aimed at assessing the clinical usefulness of measuring the contrast enhancement (CE) of solitary pulmonary nodules (SPN) in distinguishing benign from malignant lesions. We used spiral CT to study prospectively 35 pulmonary lesions presenting as SPNs < 30 mm phi; we evaluated the CE of the nodules 120 minutes after the administration of 100 mL of nonionic contrast material (= 30 grams of iodine), at 2 mL/s. The final diagnosis of the 35 SPNs was made at surgery (27 cases); positive sputum cytology (2 cases), 12 months' follow-up (5 cases) or fine-needle aspiration biopsy and 6 months' follow-up (1 case). Thus, 25 of 35 SPNs proved malignant (11 adenocarcinomas, 5 squamous cell carcinoma, 2 large cell carcinomas, 2 carcinoids, 1 small cell carcinoma, 2 cases with positive sputum cytology, 2 metastases) and the extant 10 of 35 proved benign. Malignant nodules enhanced markedly more (mean value: 36.8 HU) more than benign lesions (mean value: 18.6 HU). CE exceeded 20 HU in 23/25 malignant nodules and did not in 2/25; it did not exceed 20 HU in 6/10 benign nodules and did in 4/10. With 20 HU as the threshold value for a positive test (malignancy), sensitivity was 92%, specificity 60% and accuracy 83%; positive and negative predictive values were 85% and 75%, respectively. In conclusion, CE evaluation is a sensitive, although not very specific, indicator of malignancy in SPNs.