Expression of tachykinins by ileal and lung carcinoid tumors assessed by combined in situ hybridization, immunocytochemistry, and radioimmunoassay.

Mid-gut carcinoid tumors have been shown to produce substance P, a tachykinin. A recent addition to this family of peptides is neurokinin A which is cleaved from the same precursor as substance P; beta-pre-pro-tachykinin. The authors have examined mid-gut and pulmonary carcinoid tumors for the presence of the two tachykinins, using immunocytochemical study and radioimmunoassay, and have applied the techniques of in situ hybridization and Northern blot analysis to investigate the expression of mRNA for beta-pre-pro-tachykinin. All gut tumors (n = 8) and three of the six lung tumors examined were found by immunocytochemical study to contain both tachykinins or neurokinin A alone. Chromatographic analysis of tumor extracts suggests that this peptide is being detected as a separate molecule and/or as the C-terminal portion of a larger, uncleaved form. Three of the cases positive for tachykinins showed no detectable serotonin immunoreactivity. Strong hybridization signals for beta-pre-pro-tachykinin mRNA were seen in all but one of the cases studied which contained tachykinin immunoreactivity. Intact mRNA and positive hybridization was found by Northern blot analysis in two mid-gut tumors. Concentrations of tachykinins were found by radioimmunoassay to be higher in mid-gut tumors (substance P 27.2 +/- 19.7 pmol/g; neurokinin A 31.8 +/- 24.2 pmol/g; mean +/- SEM, n = 5) than in lung cases (substance P mean 0.8, range 0.5-1.0 pmol/g; neurokinin A mean 11.0, range 10.0-12.0 pmol/g; n = 3). These results show that mid-gut and pulmonary carcinoid tumors produce tachykinins, which are detected, in some cases, where no serotonin immunoreactivity can be found, possibly because of a high rate of amine secretion. Screening for tachykinins may prove to be a useful diagnostic adjunct for these tumors.

Ectopic production of renin by ileal carcinoma.

A 54-yr-old woman with the symptoms of primary reninism, i.e. hypertension, metabolic alkalosis and elevated levels of plasma renin activity (PRA) and aldosterone, is described. She had an ileal cancer secreting active and inactive renin. The symptoms markedly improved after resection of the tumor. In the tumor active and inactive renin were proved to be present by an assay of angiotensin I formation in the presence and absence of renin antibody, and renin immunoreactivity was found immunohistochemically. The mRNA coding for the renin precursor was identified in the RNA-rich extract of the tumor by blot hybridization analysis with the human renin cDNA as a probe. The mRNA from the tumor was shown to be identical in molecular size to that from the human kidney by agarose gel electrophoresis. This is the first description of an ectopic renin-producing ileal carcinoma and the first demonstration of renin mRNA in the tumor tissue.

[Primary ileal adenocarcinoma, showing squamous differentiation and ossification].

A 55-year-old man underwent an ileocecal resection because of an intestinal obstruction. The resected specimen contained a sessile tumor near the ileal end. This tumor was 9 x 7 cm in size, with a nodular surface of brown tint. Microscopically, it was a well-differentiated adenocarcinoma, the tumor tissue extending into the muscularis propria. The malignant tissue was associated partially with adenomatous areas and, in malignant nests, with foci of lamellar and intracellular cornification. Further, there was focal ossification in the fibrous stroma. Stains for argyrophil and argentaffin cells revealed strong positive reactions, and immunohistochemical studies were positive for calcitonin and CEA. These findings suggest the multi-potentiality of a small intestinal carcinoma.

Cytometric study of carcinoid tumors and their metastases.

A series of 5 lung and 11 gastro-entero-pancreatic carcinoid tumors has been studied microspectrophotometrically. All lung carcinoids and the majority of gut-derived tumors had near-diploid stemlines. The DNA absorption profile of metastases was similar to that of primary tumors. There was no difference in DNA patterns of tumors with and without metastases and it is suggested that cytophotometry cannot predict the metastasizing capacity of carcinoid tumors.

Isolation and characterization of neurokinin A, neurokinin A(3-10) and neurokinin A(4-10) from a neutral water extract of a metastatic ileal carcinoid tumour.

A metastasis to the right liver lobe of an argyrophil/argentaffin midgut carcinoid tumour in a patient with the classical carcinoid syndrome was examined for the presence of tachykinins other than substance P, using a specific antiserum. The extract was initially purified using SepPak cartridges, and subsequently subjected to cation-exchange chromatography on SP Sephadex C-25 which separated the immunoreactive material into two main components (components I and II). Both were further purified by anion-exchange chromatography on DEAE-Sephadex A-25, and by reverse-phase fast protein liquid chromatography. Component II was identified as neurokinin A by its immunochemical and chromatographic properties and amino acid sequence analysis. Component I consisted of two molecular forms which were identified as neurokinin A(3-10) and neurokinin A(4-10) by amino acid sequence analysis. The tumour tissue contained only small amounts of the eledoisin-like peptide that has earlier been demonstrated in mammalian tissues. Although this component behaved like the nonmammalian peptide eledoisin on reverse-phase HPLC and on reverse-phase ion-pair chromatography, eledoisin-specific antiserum E2 indicated that eledoisin-like peptide is not identical to eledoisin. Neurokinin A in carcinoid tumours has an N-terminal heterogeneity; this multiplicity constitutes a further support for the hypothesis that carcinoid tumours produce a number of tachykinins which may be present in different relative amounts in individual patients and may contribute to the individual differences in symptomatology.

Isolation and characterization of substance P, substance P 5-11, and substance K from two metastatic ileal carcinoids.

Using an antiserum directed at the COOH-terminus of tachykinins, we have examined postmortem tissue from two cases of metastatic ileal carcinoid for the presence of tachykinin-like immunoreactivity. The vast majority of the immunoreactive tachykinin-like material eluted from a Sephadex G-50 column as two peaks at positions corresponding to molecular weights of 1300 and 850. The 1300 dalton peak was resolved by reverse-phase-HPLC into two components which by Edman sequencing, amino acid analysis, and fast atom bombardment (FAB)-mass spectrometry criteria, were identified as substance P and substance K. The 850 dalton peak was also resolved on RP-HPLC into two peaks which were resistant to Edman degradation but from amino acid analysis and FAB-mass spectrometry criteria were identified as pyro-Glu-substance P 5-11 and oxidized pyro-Glu-substance P 5-11. In control experiments substance P 5-11 was converted to pyro-Glu-substance P 5-11 during the extraction procedure. Both tumors also contained a minor immunoreactive peak which eluted from a Sephadex G-50 sizing column at a position corresponding to a molecular weight of 4000 which probably represents neuropeptide K. These results suggest that beta-preprotachykinin is preferentially expressed in carcinoid tumors and that substance K may also play a role in the carcinoid syndrome.

Chemical and immunochemical characterisation of substance P-like immunoreactivity and physalaemin-like immunoreactivity in a carcinoid tumour.

Extracts of a carcinoid tumour, resected from the mid-portion of the ileum of a patient with no symptoms of endocrine disorder, were associated with a high concentration of substance P-like immunoreactivity. Using reverse-phase high performance liquid chromatography and antisera specifically directed against the C-terminal and N-terminal regions of substance P and against the N-terminal region of physalaemin, the following components were isolated and identified: substance P and its oxidised form, [pGlu5]substance P-(5-11) peptide and its oxidised form, and the oxidised form of physalaemin. The identity of tumour substance P with the undecapeptide was confirmed by amino acid analysis and high performance ion-exchange chromatography. In vitro incubation of tumour tissue from a lymph node metastasis from the same patient with [3H]leucine resulted in incorporation of radioactivity into newly synthesised substance P.

Adenosquamous carcinoma of the ileum. Report of a case and review of the literature.

Adenosquamous carcinomas of the intestine are rare tumours, especially those occurring in the small bowel. We report the first case of a metastasizing adenosquamous carcinoma of the ileum in a 74 year old male. The tumour mainly consisted of squamous cells, many of which reacted with antikeratin antibody. A review of the pertinent literature is given.

Carcinoid syndrome from gastrointestinal carcinoids without liver metastasis.

Although patients with bronchial and ovarian carcinoid tumors can develop the carcinoid syndrome (diarrhea and/or flushing) in the absence of hepatic metastasis, it is believed that development of the carcinoid syndrome in patients with carcinoid tumors of gastrointestinal origin occurs only after the patient has hepatic metastasis. This is explained by hepatic inactivation of most of the serotonin in the portal circulation or by the fact that hepatic metastases are larger than the primary tumor in the gastrointestinal tract. Three patients with ileal and jejunal carcinoid tumors who developed the carcinoid syndrome without obvious hepatic metastasis are described. Two of the patients had intra-abdominal, but extrahepatic, metastasis that probably drained directly into the systemic circulation. The third patient had an ileal carcinoid with clinical involvement limited to adjacent mesenteric lymph nodes. Following resection of her tumor, her urinary 5-HIAA excretion and platelet serotonin level returned to normal, and her attacks of carcinoid flushing virtually ceased. She has occasional spells of "blushing" that are thought to be benign; however, further close follow-up study will be needed to be certain that she is free of disease. It is suggested that each patient with the carcinoid syndrome be evaluated with CT and technetium-99 pertechnetate liver scans. If there is no liver involvement detected with these studies, one should consider hepatic arteriogram or laparotomy to determine if the patient's tumor might be totally resectable.