Somatostatin and dopamine receptor expression in neuroendocrine neoplasms: correlation of immunohistochemical findings with somatostatin receptor scintigraphy visual scores

CONTEXT

The expression of somatostatin (sstr1-5) and dopamine (DR) receptors in neuroendocrine neoplasms (NENs) facilitates diagnosis by tumour visualization with somatostatin receptor scintigraphy (SRS) and directs towards specific treatment with peptide receptor radionuclide therapy (PRRT) with radiolabelled somatostatin analogues.

OBJECTIVE

To investigate the co-expression of sstrs, D2R in relation to pre-operative SRSs in NENs.

DESIGN

Prospective two-centre study.

PATIENTS AND MEASUREMENTS

We analysed pre-operative SRS of 60 patients [44 with gastrointestinal (GI) NENs and 16 with lung NENs] and compared SRS results with immunohistochemical (IHC) reactivity for sstr2, sstr3, sstr5 in sample tissues from primary (n = 54) and metastatic (n = 27) lesions and IHC reactivity for D2R in 23 samples from primary GI-NENs lesions.

RESULTS

Sstr2 was the commonest sstr expressed (65·4%) and was co-expressed with sstr3 and sstr5 in 32·1% and 24·7% of the specimens, respectively. In 67 of 81 specimens (82·7%), there was concordance of sstr2 immunohistochemistry with SRS findings (P < 0·001). D2R was expressed in only 8 of 23 (34·8%) GI-NENs while was co-expressed with sstr2 in all cases. SRS grade, as per Krenning scale, was higher in metastatic foci, large-size (>2 cm) tumours and GI-NENs, whereas sstr2 intensity was greater in GI compared to lung NENs. SRS grade showed higher correlation with sstr2 (r = 0·6, P < 0·001) and D2R (r = 0·5, P < 0·001) IHC intensity scores than tumour size (r = 0·4, P < 0·001) and sstr3 (r = 0·4, P < 0·001) intensity score.

CONCLUSIONS

Sstr2 IHC expression and SRS are useful tools for the diagnosis and management of NENs because they display a high concordance. IHC expression of DR2 seems to be of potential clinical significance in GI-NENs tumours.

Etiology of anemia in patients with advanced heart failure

OBJECTIVES

We prospectively investigated the causes of anemia in patients with advanced congestive heart failure (CHF).

BACKGROUND

Anemia is common in patients with advanced CHF, and its etiology is generally considered to be multifactorial. However, despite its importance, precise information is lacking regarding the prevalence of putative etiologic factors.

METHODS

Patients who were hospitalized for decompensated advanced CHF and who were stabilized after their initial treatment underwent evaluation of "clinically significant" anemia, defined as a hemoglobin content <12 g/dl for men and <11.5 g/dl for women. Patients with a serum creatinine concentration >3 mg/dl or patients with concurrent diseases that are known to cause anemia were not included. The initial evaluation included measurements of vitamin B(12), folic acid, thyroid-stimulating hormone, erythropoietin, lactate dehydrogenase, Coombs test, multiple fecal occult tests, and bone marrow aspiration. Patients without diagnosis by these methods underwent red cell mass measurement with (51)Cr assay.

RESULTS

The mean age of the 37 patients was 57.9 +/- 10.9 years and mean left ventricular ejection fraction 22.5 +/- 5.9%. Iron deficiency anemia was confirmed by bone marrow aspiration in 27 patients (73%), 2 patients (5.4%) had dilutional anemia, and 1 patient (2.7%) had drug-induced anemia. No specific cause was identified in 7 patients (18.9%) who were considered to have "anemia of chronic disease." Serum ferritin for the iron-deficient patients was not a reliable marker of iron deficiency in this population.

CONCLUSIONS

In this group of patients, iron deficiency was the most common cause of anemia. The iron status of patients with end-stage chronic CHF should be thoroughly evaluated and corrected before considering other therapeutic interventions.

Synthesis, chemical, radiochemical and radiobiological evaluation of a new 99mTc-labelled bombesin-like peptide

A new pentadecapeptide bombesin analogue was prepared by Fmoc synthesis, purified by HPLC and identified by electron ionization mass spectrometry. The biological activity of the new peptide was tested on isolated human colonic muscle cells and compared to native bombesin. Labelling of the new biomolecule with Tc-99m yielded a single radioactive species which remained stable at room temperature for eight hours. In a binding assay, the radiolabelled peptide showed high affinity for oat-cell carcinoma (Kd = 9.8 nM) and colorectal adenocarcinoma (Kd = 27.2 nM). Biodistribution studies, performed in normal rodents, indicated uptake by organs that normally express bombesin receptors, such as liver, intestines and kidneys. Scintigraphic studies, performed in nude mice transplanted with small cell lung carcinoma and colon cancer cells, showed significant tumor uptake two hours p.i. The new synthetic pentadecapeptide appears to have promise for several malignancies, including oat-cell lung carcinoma, colorectal cancer and gastroenteropancreatic (GEP) tumors.

Comparative study of RIS with the 131I-OC 125 F(ab')2 Mab and CT scan prior to second look operation for ovarian cancer

A tumour-associated radiolabelled monoclonal antibody (Mab) 131I-OC 125 F(ab')2 was used to investigate 27 patients 2 weeks after their last chemotherapy regimen and prior to second-look surgery for ovarian cancer. We did compare the radioimmunoscintigraphy (RIS) findings with the CT scan results and the second-look operation data. In 23 out of 27 cases the RIS results correlated with the operation findings, while there were four false-negative results. Computed tomography (CT) scans correlated in 17 out of 23 cases with the operative findings, while there were six false-negative results. We concluded that RIS is more specific in detecting the tumour site within the pelvis, while CT scan is superior in detecting liver metastases.