ProACTH: use for early detection of lung cancer

Plasma ACTH in patients with bronchogenic carcinoma

Immunoreactive ACTH before and five hours after administration of 2 mg of dexamethasone was determined in patients examined in hospital for abnormalities on chest X-ray. Thirty patients had primary bronchial cancer, 15 had other lung conditions, mostly inflammatory infiltrations. The mean total ACTH and ACTH after dexamethasone suppression were significantly higher in the patients with bronchial cancer than in patients with other lung lesions or healthy controls. ACTH in plasma after administration of glucocorticoids was predominantly big ACTH. Several of the cancer patients had, however, ACTH levels within the same range as the other subjects. These results indicate that plasma ACTH determinations are of limited value as tumour markers for the detection of lung cancer although it is still possible that repeated sampling in patients with elevated ACTH levels may be of value when monitoring the therapy.

Processing-independent analysis in the diagnosis of gastrinomas

BACKGROUND

This study evaluates whether a new analytic principle, processing-independent analysis (PIA), offers better specificity and sensitivity than the conventional gastrin radioimmunoassay in the diagnosis of gastrinomas.

METHODS

Plasma concentrations of alpha-amidated gastrins and the total progastrin product were measured with radioimmunoassay and with PIA, respectively, in 512 samples taken for gastrin measurement and in a selected group of gastrinoma patients (n=10).

RESULTS

Among the 512 patients were 9 with gastrinomas. In plasma from these patients the median degree of amidation (ratio of alpha-amidated gastrins to total progastrin product) was 75% (range, 25-98%), whereas in the other groups the medians varied from 41% to 86%. In the second group of gastrinoma patients all had a degree of amidation of less than 50%.

CONCLUSIONS

In screening for gastrinomas PIA offered no diagnostic advantages in comparison with conventional gastrin radioimmunoassay. However, in selected patients who in spite of normal or slightly increased concentrations of amidated gastrins were still suspected of having gastrinoma, additional measurement of the total progastrin product showed incomplete processing of progastrin and thus proved helpful in establishing the diagnosis.

Pulmonary neuroendocrine cell system in pediatric and adult lung disease

In humans lungs affected by naturally occurring pulmonary disease, the pulmonary neuroendocrine cell system, which is normally arranged in a sparse but even distribution throughout the respiratory tract, increases in size. It is likely that the stimulus for this is pulmonary injury and that its purpose is the paracrine regulation of the restoration of pulmonary tissues to their normal state, an hypothesis supported by studies of animal lungs subjected to experimental injury as well as of the development of human and animal lungs in utero. Initially, this increase involves the development of interrupted rows of neuroendocrine cells. In the later stages, however, development of more disorderly intraepithelial aggregates can occur and the small, locally invasive neuroendocrine cell lesions known as tumourlets may occasionally result. Both of these latter structures often contain secretory products not found in the neuroendocrine cells of normal human lungs, probably indicating a derangement of what appears to be a fundamentally physiological response. It is likely that, in some circumstances, this disorderly change may contribute to pulmonary disease as well as being the result of it.

Measurements of hormonal peptides in the bronchoalveolar fluid as tumor markers of lung cancer

A large number of lung cancers contains and releases a variety of neuropeptides such as adrenocorticotropic hormone (ACTH) and beta-endorphin (beta-EP). Although the plasma levels of these peptides have been extensively investigated as possible markers that may help in the early diagnosis of the disease, the data collected have shown their limited clinical usefulness. The present study was undertaken to evaluate whether corticotropin-releasing hormone (CRH), ACTH or beta-EP levels in the bronchoalveolar lavage (BAL) fluid of patients with lung cancer might have been more helpful. To accomplish this, bronchial lavages were carried out in 25 patients affected by lung cancer (17 squamous carcinomas, 4 adenocarcinomas, 2 small cell carcinomas, and 2 not classified) and 18 controls. After centrifugation, BAL fluid was extracted using cartridges of SepPak C-18 and CRH, ACTH and beta-EP levels were measured by radioimmunoassay. CRH and ACTH BAL levels in patients with lung cancer were not significantly different from those of controls. beta-EP concentrations in the BAL fluid were about 200-fold higher than those of ACTH and showed a downward trend (p = 0.08, Mann-Whitney test) in patients with cancer. No histologic tumor type was associated with particularly elevated levels of any of the peptides measured, not even the two patients with small cell carcinoma, a tumor type which tends to release higher peptide levels. Therefore we conclude that measurements of CRH, ACTH and/or beta-EP in the BAL fluid are not useful diagnostic tumor markers of lung cancer.

The cellular and molecular basis of the ectopic ACTH syndrome

In recent years the techniques of molecular and cellular biology have made it possible to begin to dissect the origins and behaviour of the ACTH-secreting tumour cell. It is becoming apparent that these tumours represent undifferentiated neuroendocrine cells, and it may be that their peptide-secreting properties may have no more sinister oncological significance. However, an autocrine role for beta-endorphin may confer a selective growth advantage on the POMC-expressing cell. It is still not clear why glucocorticoids fail to inhibit the POMC gene in these extra-pituitary tumours despite the presence of glucocorticoid receptors. This may not be resolved until the mechanism for inhibition of POMC by glucocorticoids in the normal pituitary is understood, although it is tempting to speculate that a mutation in the glucocorticoid receptor or a tissue specific interaction is responsible for the resistance of POMC observed in the ectopic ACTH syndrome. In studying the peptides secreted by the extra-pituitary tumours responsible for the ectopic ACTH syndrome it would appear that direct measurement of ACTH precursors and comparison with the circulating concentrations of ACTH can give valuable information on the percentage of tumours which do not effectively process the ACTH precursors. However, far more data have to be collected on patients with occult tumours in order to identify whether this type of processing is tissue specific. Nevertheless, these studies provide useful insights into the mechanisms of intracellular signalling and regulation in such tumours which may identify unique pharmacological tools to inhibit ACTH secretion or more importantly tumour growth.

Limited clinical usefulness of plasma corticotropin-releasing hormone, adrenocorticotropin and beta-endorphin measurements as markers of lung cancer

We measured plasma corticotropin-releasing hormone (CRH), ACTH, beta-endorphin (beta-EP), and cortisol levels as possible tumor markers in a sequence of 103, randomly selected, patients with lung cancer but without the ectopic Cushing's syndrome and in 72 age- and sex-matched controls. Plasma CRH levels of cancer patients were similar to those of controls both in patients sampled in the morning or in the afternoon. On the other hand, plasma ACTH levels of cancer patients were significantly higher than control patients both in the morning and in the afternoon and showed a preserved circadian rhythm. However, about 35% of cancer patients sampled in the morning and about 60% of those sampled in the afternoon had ACTH levels within the 95% confidence interval (CI) of controls. Also plasma beta-EP levels were more elevated in cancer patients than controls in the morning but about 33% of them and about 80% of those sampled in the afternoon had beta-EP levels within the 95% CI of controls. Despite the higher plasma ACTH levels, cancer patients had cortisol plasma levels similar to controls with preserved circadian rhythm. In conclusion, although mean plasma ACTH and beta-EP were higher in patients affected by lung cancer, their measurements, as well as those of CRH, have practically no diagnostic value. Perhaps measurement of ACTH levels in the bronchial lavage may be more helpful.

Immunohistochemical characterization of endocrine cells in experimental exocrine pancreatic cancer in the Syrian golden hamster

Fifty exocrine pancreatic adenocarcinomas and 57 benign tumors induced in Syrian hamsters by N-nitrosobis(2-oxopropyl)amine (BOP) were examined for the presence of argyrophil cells antiinsulin, -glucagon, -somatostatin, -pancreatic polypeptide (PP), -gastrin/CCK, -vasoactive intestinal polypeptide (VIP), and - neuron-specific enolase (NSE) reactive cells. Argyrophil - and antihormone-reactive cells were found in the normal pancreatic ducts and in the acini, as well as in hyperplastic and atypical ducts/ductules, tubular complexes, benign lesions, and in 80% of ductal adenocarcinomas. Insulin and antiNSE-reactive cells were the most common, followed in decreasing frequency by glucagon, somatostatin, and PP cells. Antigastrin-/CCK-and -VIP-reactive cells were found in two cases. Argyrophil cells were present in about 60% of the tumors with Grimelius staining and in 55% of those with Churukian-Schenk staining. Insulin cells were seen in ductal cancer that had grown into a lymph node and in the lymph node metastases of another cancer. A novel finding was the presence of argyrophil and insulin cells within the lumen of some malignant glandular structures. Coexistence of several peptide cells was found in 52% of the cancers. The presence of argyrophil and hormone-producing cells in induced pancreatic ductal/ductular lesions further strengthens the existence of a close developmental relationship between exocrine and endocrine cells of the pancreas.

Ectopic production of prolactin in uterine cervical carcinoma

Sera from 743 patients with uterine cervical carcinoma were assayed for levels of circulating prolactin (PRL). Markedly abnormal serum prolactin levels were observed in 30.8% (229/743) of patients. During the early stages of cancer, the degree of PRL elevation in serum and incidence of abnormal PRL levels are much greater than those found for carcinoembryonic antigen, which is generally considered to be a circulating cervical tumor marker. Surgical removal of cervical carcinoma resulted in normalization of serum PRL concentrations. Immunohistochemical staining techniques and primary tissue culture of cervical carcinoma were used to verify the presence of PRL in the uterine cervical carcinoma cells. Twenty-two of forty-nine cervical carcinoma tissue sections showed cytoplasmic staining for prolactin, while normal cervix tissues tested were negative. Production of prolactin was directly demonstrated in the early tissue cultures of cervical carcinoma. These studies show ectopic production of PRL by uterine cervical carcinoma. Prolactin production may be a potential marker for detecting early occult tumors or for gauging the effectiveness of therapy for human cervical carcinoma.

Non-small cell lung cancer. Part I: Biology, diagnosis, and staging

Squamous, large cell, and adenocarcinoma, collectively termed non-small cell lung cancer (NSCLC), are diagnosed in approximately 75% of patients with lung cancer in the United States. The treatment of these three tumor cell types is approached in virtually identical fashion because, in contrast to small cell carcinoma of the lung, NSCLC more frequently presents with localized disease at the time of diagnosis and is thus more often amenable to surgical resection but less frequently responds to chemotherapy and irradiation. Cigarette smoking is etiologically related to the development of NSCLC in the great majority of cases. Genetic mutations in dominant oncogenes such as K-ras, loss of genetic material on chromosomes 3p, 11p, and 17p, and deletions or mutations in tumor suppressor genes such as rb and p53 have been documented in NSCLC tumors and tumor cell lines. NSCLC is diagnosed because of symptoms related to the primary tumor or regional or distant metastases, as an incidental finding on chest radiograph, or rarely because of a paraneoplastic syndrome such as hypercalcemia or hypertrophic pulmonary osteoarthropathy. Screening smokers with periodic chest radiographs and sputum cytologic examination has not been shown to reduce mortality. The diagnosis of NSCLC is usually established by fiberoptic bronchoscopy or percutaneous fine-needle aspiration, by biopsy of a regional or distant metastatic site, or at the time of thoracotomy. Pathologically, NSCLC arises in a setting of bronchial mucosal metaplasia and dysplasia that progressively increase over time. Squamous carcinoma more often presents as a central endobronchial lesion, while large cell and adenocarcinoma have a tendency to arise in the lung periphery and invade the pleura. Once the diagnosis is made, the extent of tumor dissemination is determined. Since most NSCLC patients who survive 5 years or longer have undergone surgical resection of their cancers, the focus of the staging process is to determine whether the patient is a candidate for thoracotomy with curative intent. The dominant prognostic factors in NSCLC are extent of tumor dissemination, ambulatory or performance status, and degree of weight loss. Stages I and II NSCLC, which are confined within the pleural reflection, are managed by surgical resection whenever possible, with approximate 5-year survival of 45% and 25%, respectively. Patients with stage IIIa cancers, in which the primary tumor has extended through the pleura or metastasized to ipsilateral or subcarinal lymph nodes, can occasionally be surgically resected but are often managed with definitive thoracic irradiation and have 5-year survival of approximately 15%.(ABSTRACT TRUNCATED AT 400 WORDS)

The expression of peptide hormones in normal cells and tumour cells

Insight in the mechanisms of peptide hormone expression has grown explosively by elucidation of gene, mRNA and preprohormone structures for most hormone systems during the 1980s. In addition, information about the structure and substrate specificity of many prohormone processing enzymes is rapidly accumulating in these years. The preprohormones vary considerably in size and organization from poly- to monoprotein structures. According to the structural organization and sequence homology the hormones are grouped in families. The prohormones are processed to bioactive peptides by multiple enzymatic modifications during the intracellular transport from the rough endoplasmatic reticulum to the mature secretory granules. The modifications comprise different proteolytic cleavages and amino acid derivatizations. The same prohormone may be expressed in several different cell types that process the precursor in entirely different ways. Awareness of such cell-specific processing patterns is important for the understanding of ectopic synthesis in neuroendocrine tumours.

Neuroendocrine alterations in nude mice with a human lung carcinoma producing pro-opiomelanocortin, corticotrophin-releasing hormone and arginine vasopressin

A mucoepidermoid carcinoma of the lung (ICD classification 8430/3) resected from a patient with no clinical signs of pituitary-adrenal alterations was transplanted into 2-month-old athymic nu/nu nude mice, with the purpose of studying the effects exerted by the human tumour on the host hypothalamo-pituitary-adrenal axis. The tumour produces peptides derived from different regions of pro-opiomelanocortin (POMC: ACTH, 7.6 +/- 0.7; N-terminal POMC, 6.6 +/- 0.6; beta-LPH/endorphin, 7.3 +/- 0.7; and alpha-MSH;3.8 +/- 0.5 pmol/g wet tissue) and the neuropeptides corticotrophin-releasing hormone and arginine vasopressin (CRH: 3.6 +/- 0.4 and AVP: 1.1 +/- 0.2 pmol/g wet tissue). Immunohistochemical staining of consecutive sections of the tumour indicated that staining of tumour cells for the different peptides was not uniform and although some cells co-stained with CRH and AVP, POMC-positive cells appeared to be distinct from CRH and AVP cells. Tumour extracts were chromatographed on Sephadex G-75 and fractions monitored for POMC-derived peptides. A single peak with characteristics of alpha-MSH was detected. The ACTH, N-POMC and beta-LPH/endorphin radioimmunoassays (RIA) detected a peak at large molecular weight, eluting at the position expected for POMC. These RIA systems also revealed an ACTH(1-39) peak and another peak which probably correspond to 13 kDa ACTH, a peak eluting at the position of hN-POMC(1-48), a beta-LPH-like peak, and a smaller sized peak which may represent alpha- or gamma-endorphin. The ACTH, N-POMC and beta-LPH/endorphin contents of anterior lobe (AL) extracts, but not neutrointermediate lobe (NIL) extracts, showed a striking decrease in tumour-bearing (TB) nude mice. However, while no difference was seen in the alpha-MSH content of AL extract between TB and control (C) nude mice, it decreased in NIL extracts of TB animals. The contents of CRH and AVP in stalk-median eminence extracts of TB nude mice was significantly lower than that of C nude mice. Basal plasma corticosteroids were raised in TB nude mice at levels comparable to those in stressed C nude mice, and although adrenal weights did not vary between TB and C nude mice, morphological changes indicating hypertrophy were found in the adrenal glands of the host animals. It was concluded that the tumour dramatically alters the hypothalamo-pituitary-adrenal axis of the host, and that it may be a useful model for studying tumour-host interactions in ectopic hormone-producing tumours.

The synthesis of ACTH and related peptides by tumours

Despite all we have learned, the reason why certain tumours and particularly non-pituitary tumours synthesize ACTH remains an enigma. There is no clear theory which links the neoplastic process with the expression of peptide hormones but it is interesting to speculate that the amplification of certain oncogenes may be linked to de-repression of hormone genes. Once the gene has been switched on, there should be some mechanism for preventing continuous expression and in the pituitary the POMC gene is normally inhibited by glucocorticoids. Therefore it is crucial to investigate the role of glucocorticoids in non-pituitary tumours and this requires an understanding of the molecular mechanisms involved in glucocorticoid inhibition of the normal POMC gene in the pituitary. The evidence presented in this chapter describing the glucocorticoid receptor binding site in the promoter region of the POMC gene in rat pituitary gives an exciting insight into the regulatory mechanisms and their potential for aberrant control. Taken with the presence of pituitary-specific regions regulating the POMC gene promoter there appear to be multiple approaches to dissecting out the differences in non-pituitary tumours. Thus in a relatively short period of time there has been a marked increase in our understanding of the molecular mechanisms underlying POMC gene expression. At the level of the peptides, progress has been slower. We are now aware that secretion of ACTH implies that a number of other peptides will be found in the circulation, even though there is limited evidence for a specific role for any of the co-secreted peptides. However, it is hard to understand the conflicting reports that N-POC is synthesized by non-small cell and small cell carcinoma of the lung when ACTH, which we assume to be co-secreted, is thought to be synthesized only by small cell carcinoma. The most likely explanation for this is the difficult nature of the radio-immunoassays for these hormones and the problems associated with studying large groups of clearly defined patients. Development of very simple methods for measuring the ACTH precursors has demonstrated that they are released into the circulation in normal subjects and that the levels are markedly elevated in non-pituitary tumours, suggesting that they are the major circulating forms in the ectopic ACTH syndrome. This implies that these tumours cannot process the precursor molecules suggesting that the processing enzymes are lacking.(ABSTRACT TRUNCATED AT 400 WORDS)

Peptide hormone expression and precursor processing

Insight in the mechanisms of peptide hormone expression has grown explosively by elucidation of gene, mRNA and preprohormone structures for most hormone systems during the 1980s. The preprohormones vary considerably in size and organization from poly- to mono-protein structures. According to the structural organization and sequence homology the hormones are grouped in families. The prohormones are processed to bioactive peptides by multiple enzymatic modifications during the intracellular transport from the rough endoplasmatic reticulum to the mature secretory granules. The modifications comprise different proteolytic cleavages and amino acid derivatizations. The same prohormone may be expressed in several different cell-types that process the precursor in entirely different ways. Awareness of such cell-specific processing patterns is important for the understanding of ectopic synthesis in neuroendocrine tumours.

Proopiomelanocortin gene expression in a pheochromocytoma using upstream transcription initiation sites

The proopiomelanocortin (POMC) gene is expressed in many normal nonpituitary tissues, in addition to the pituitary. POMC-derived peptides have also been detected in many pheochromocytomas. We examined poly(A)+ RNA from 5 pheochromocytomas with a POMC exon 3 riboprobe and show that 3 tumors contained POMC-like mRNAs that were 50 to 350 bases longer than pituitary POMC mRNA. S1 nuclease analyses of tumor poly(A)+ RNA demonstrate that some of the POMC-like mRNAs contain additional segments of 238, 318 or 374 nucleotides derived from the region immediately upstream from the normal transcription initiation site. We conclude that pheochromocytomas express the POMC gene and that the long POMC-like mRNAs in these tumors and, probably, those in normal adrenal and testis arise from transcription initiating at sites upstream from the normal site used in pituitary.

Leukocyte concentrations in discrimination of benign from malignant lung lesions

Malignant lung lesions are associated with significant changes in leukocyte concentrations. However, overlap of values between normal subjects and patients with cancer has limited the clinical utility of this determination. To decrease the overlap, 2,000 cells per differential determination were counted, and replicate automated cell counts were performed in blood samples obtained on different mornings between 7 and 9 A.M. Seventy-five patients who presented with undiagnosed lung lesions were analyzed. Benign and malignant lung lesions could be accurately distinguished by either relative granulocyte or lymphocyte counts. With 65.5 percent granulocytes as the cutoff, 86 percent of patients (38 of 44) proved to have lung cancer had higher values, and 97 percent of patients (30 of 31) with benign lesions had lower values. Likewise, with 28 percent lymphocytes as the cutoff, 87 percent of patients with lung cancer (39 of 44) had lower values, and 94 percent of patients (29 of 31) with benign disease had higher values. Relative monocyte counts were not different. Absolute leukocyte concentrations, although different for each group, had considerable overlap and thus were poor discriminators. These data suggest that precise analytical techniques and the use of relative leukocyte concentrations can improve the clinical utility of the leukocyte count as a discriminator of benign and malignant lung lesions.

Circulating Levels of Immunoreactive Peptides and Steroid Hormones in Bronchogenic Carcinoma

Plasma levels of immunoreactive parathormone (iPTH), immunoreactive calcitonin (iCT) and prostaglandins (PGE2) were measured by RIA in 115 patients with bronchogenic carcinoma. In 37 of these cases the following hormones were also assayed: adrenocorticotropic hormone (ACTH), cortisol, plasma renin activity (PRA), aldosterone, prolactin, human growth hormone (HGH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH) human chorionic gonadotropin (HCG), progesterone (P), an-drostenedoone (A), testosterone (T), estradiol (E2) and dehydropiandrosterone sulphate (DHAS). High serum levels of many hormone-like substances and hormones were found and the levels of certain hormones varied in some cases according to the clinical evolution of the disease and the response to therapy.

Tumor markers in patients with lung cancer

The most examined tumor markers in lung cancer patients are CEA, hormonal peptides, and some neurogenic enzymes in small cell carcinoma. Calcitonin, ACTH, ADH, CEA, neurophysin, oxytocin, beta-endorphin, neuron-specific enolase, and CK BB are elevated in serum specimens in 25-75% of cases of small cell carcinoma. The level of these markers is related to the stage of the disease in groups of patients; elevated pretreatment levels decrease with tumor regression. Marker levels are not valid in defining the tumor load and the presence of disease in the individual patient. It has not yet been documented that the markers can be used for clinical decisions on antineoplastic therapy. A recent development is the finding that measurement of CSF and plasma concentrations of ADH, calcitonin, CK BB, bombesin, and neuron-specific enolase may contribute in the diagnosis of CNS metastases including meningeal carcinomatosis.

Somatostatin and adrenocorticotrophic hormone like immunoreactivity in small cell carcinoma of the lung

The immunocytological detection of adrenocorticotrophic hormone (ACTH) and somatotropin release inhibitor factor (SRIF) like immunoreactivity was carried out on tumour cells from bronchial brush smears in 39 cases of lung tumours. Results obtained were compared with the cytological and histological diagnosis and confirmed the high incidence of ACTH synthesis by malignant bronchial carcinoma cells: the same phenomenon also seems to occur for somatostatin. The concomitant detection of ACTH and SRIF like immunoreactivity seems to be highly suggestive of small cell carcinoma and indicates that the immunocytological detection of hormones carried out at the same time as cytological examination can improve the accuracy of the diagnosis.

Tumor markers: value and limitations in the management of cancer patients

Sixteen tumor markers are reviewed, and measured to the ideal: produced by the tumor cell alone absent in health and in benign disease present in all patients with a given malignancy level in the blood representative of tumor mass detectable in occult disease. The only marker that approaches the ideal is human chorionic gonadotropin (HCG) in gestational trophoblastic tumors. In this malignancy, the HCG level suggests the diagnosis and stage, confirms response to therapy, and predicts relapse. The three most widely used and intensely studied tumor markers are carcinoembryonic antigen (CEA), alphafetoprotein (AFP), and HCG. CEA cannot be used in screening for cancer, but in carcinoma of the colon its elevation preoperatively increases the likelihood of advanced disease and postoperative recurrence. Postoperatively, elevated titers are often but not invariably associated with recurrent disease. AFP and HCG are useful in the management of nonseminomatous germ cell testicular tumors. Like CEA, they cannot be used for screening. They are more likely to be increased with advancing stage, and after therapy rising levels almost always mean recurrent disease. Some markers are valuable in specific circumstances, such as calcitonin in screening for familial medullary carcinoma of the thyroid. In multiple myeloma, immunoglobulins are useful in determining the tumor mass and response to therapy. In neuroblastoma, catecholamine metabolites are useful primarily in making the diagnosis. In some malignancies, the absence of effective therapy lowers the value of the marker, as for AFP in hepatoma. The remaining markers are too unreliable or too little studied to be useful in the management of an individual patient with cancer. The purpose of this paper is to provide the clinician with an understanding of the limitations of the present tumor markers that will lead to wiser use of the tests, and to provide standards to which future tumor markers should be measured.

Lung tumour cell lines synthesizing peptide hormones established from tumours of four histological types: characterization of the cell lines and analysis of their peptide hormone production

Thirty permanent and more than 60 primary tumour cell lines were established from pleural and pericardial exudates or wedge biopsies from human bronchial carcinoma. The permanent cell lines have their origin in 6 small cell, 5 large cell, 9 squamous and 5 adeno carcinomas of the lung. Tumour cells were purified from non tumour cells by direct cloning in fluid cultures or by soft agar cloning. In vitro secretion of ACTH, bombesin, calcitonin, and neurotensin was demonstrated for lung tumour cells belonging to the four major histological types. Cell suspensions of peptide hormone secreting permanent cell cultures were grown to solid tumours after xenotransplantation into nude mice. Comparative ultrastructural examination of the primary tumour and of cells grown in tissue culture and in xenografts demonstrated the preservation of most tumour type specific structural criteria in the ex vivo/in vitro systems. The present data show that not only tumour cells from small cell carcinoma but also from other histological types are capable of synthesizing a broad spectrum of immunoreactive peptide hormones. This result might be interpreted as indicating a common expression of hormone biosynthesis and secretion by all lung tumours.

Adrenocorticotropin, calcitonin, and antidiuretic hormone as tumor markers in patients with bronchogenic carcinoma of various histological types

We measured basal and dexamethasone-suppressed plasma ACTH in 246 patients with bronchogenic carcinoma (105 with small-cell carcinoma); in 138 of these patients (67 with small-cell carcinoma) basal and pentagastrin-stimulated serum calcitonin was also determined. In addition, in a subgroup of 120 patients (58 with small-cell carcinoma) plasma ADH with reference to plasma osmolality was also assayed. Non-suppressible plasma ACTH was found in 45% of patients with small-cell carcinoma but only in isolated cases of large-cell carcinoma, adenocarcinoma, and squamous-cell carcinoma. Serum calcitonin was increased in 28% of patients with small-cell carcinoma but only in few patients with other tumor types. Stimulation of calcitonin by pentagastrin was ineffective. Plasma ADH was inappropriately high in 47% of patients with small-cell carcinoma. Strikingly high also was the incidence of increased ADH concentrations in patients with large-cell (40%), adenocarcinoma (46%), and squamous-cell carcinoma (29%). By measuring plasma ACTH after dexamethasone suppression and ADH with reference to osmolality, the sensitivity of these tumor markers in detecting pathological hormone secretion is markedly increased. In small-cell carcinoma the simultaneous measurement of ACTH, ADH, and calcitonin gives a high yield of positive results (74%), indicating that this set of tumor markers is a promising aid in diagnosis and therapy control.

The society of Surgical Oncology Lucy Wortham James Research Award 1983. Radioimmunoassay in oncology

The role of radioimmunoassay (RIA) in the diagnosis and management of endocrine tumors, such as pituitary tumors, insulinomas, and gastrinomas, has long been well established. A variety of nonendocrine tumors are capable of elaborating one or more humoral substances that resemble immunologically well-known, well-characterized biologically active hormones or their prohormone precursors or metabolic products. The possible value of mass screening for carcinoma of the lung by the detection of precursor adrenocorticotropic hormone (ACTH) in plasma was tested. However, the usefulness was limited by the potential for false-positive, i.e., elevation of marker concentration in the plasma of heavy smokers even in the absence of invasive carcinoma. Although on occasion a dramatic decrease of plasma ACTH after surgical resection or on some chemotherapeutic schedules has been observed, this does not occur with sufficient regularity to serve definitely as an objective measure of efficacy of therapy. The limitations of nonhormonal tumor markers, such as carcinoembryonic antigen (CEA), are also considered.

Metastatic small cell carcinoma of the lung presenting as pituitary apoplexy and Cushing's syndrome

We describe a woman with metastatic small cell carcinoma of the lung who presented with pituitary apoplexy and hyperprolactinemia. Within seventeen months she developed florid Cushing's syndrome with anasarca, hyperpigmentation, hypertension with marked hypercortisolemia (not suppressible with 8 mg dexamethasone), elevated serum ACTH, hypokalemic metabolic alkalosis, and multiple hepatic metastases. This picture suggested the presence of ectopic ACTH syndrome. She died 26 months after the episode of pituitary apoplexy. Primary small cell carcinoma of the lung was diagnosed post-mortem. Metastases were present in the left lung, regional lymph nodes, heart, liver, bone marrow, sphenoid bone, anterior pituitary and pituitary capsule. Posterior pituitary was normal. There was no evidence of pituitary hyperplasia, of adenoma or of primary pituitary carcinoma. The results suggest the presence of a primary ACTH-producing small cell carcinoma of the lung that metastasized to the parasellar sphenoid bone and then extended to the anterior pituitary and dura to mimic a primary intrasellar cause of pituitary apoplexy and Cushing's syndrome. The case demonstrates how difficult it may be to diagnose the etiology of Cushing's syndrome and it emphasizes a unique variation in the presentation of small cell carcinoma of the lung.

Corticotropin/lipotropin common precursor-like material in normal rat extrapituitary tissues

A Mr 26,000 corticotropin (ACTH)-like material is present in glacial acetic acid extracts of all normal rat extrapituitary tissues. In the present study, beta-melanotropin (beta-MSH) immunoactivity was detected in glacial acetic acid extracts of normal rat extrapituitary tissues. beta-MSH immunoactivity was also present in all extracts (mean +/- SEM, fmol/mg of protein): brain, 71.0 +/- 16.3; stomach, 11.5 +/- 1.6; kidney, 8.9 +/- 0.8; colon, 8.2 +/- 1.1; small intestine, 6.5 +/- 1.1; liver, 4.3 +/- 0.5; and heart, 3.2 +/- 0.5. Except in brain extracts, beta-MSH and ACTH immunoactivities of tissue extracts were strongly correlated to each other (r = 0.79; n = 42). When tissue extracts (except brain) were passed through a Sephadex G-75 (superfine) column, ACTH and beta-MSH immunoactivities were eluted in a single peak corresponding to Mr 26,000. In contrast, for brain extracts, the MrS of major peaks of ACTH and beta-MSH immunoactivities were 4,500 and 8,000, respectively; a smaller peak of Mr 26,000 ACTH/beta-MSH-like material was also eluted. Specific anti-ACTH immunocolumns, which did not bind purified synthetic beta-MSH, adsorbed both ACTH and beta-MSH immunoactivities of all tissue extracts except those of brain. One-third of the beta-MSH immunoactivity in brain extracts adsorbed to the anti-ACTH immunocolumn, but two-thirds of beta-MSH immunoactivity passed through the column. We conclude that ACTH and beta-MSH immunoactivities are present in all normal rat extrapituitary tissues and exist in most tissues on the same molecule. This Mr 26,000 molecule is closely related to the pituitary ACTH/beta-lipotropin common precursor.

Primary empty sella syndrome, ACTH hypersecretion, and normal adrenocortical function. Report of two cases

Although the primary empty sella syndrome (PESS) is associated with normal endocrine function or subtle pituitary insufficiency, pituitary hormone hypersecretion associated with PESS has also been recognized. ACTH hypersecretion and primary empty sella syndrome have previously been reported in patients with either Cushing's disease or Addison's disease. This report describes two unique patients with ACTH hypersecretion, primary empty sella syndrome, and normal cortisol dynamics. The investigators speculate that this association may have resulted from infarction of hyperplastic adenohypophyseal corticotrophes due to production of an ACTH peptide with reduced biologic activity. These two cases emphasize that primary empty sella syndrome may be associated with ACTH hypersecretion and normal adrenocortical function.

Circulating ACTH and related peptides in lung cancer

The prevalence of high levels of circulating ACTH-like immunoactivity was determined in 134 patients with lung cancer, using reference ranges from 52 age- and sex-matched patients with non-malignant lung disease. Two studies used ACTH radioimmunoassays with different specificities. Study A used an unextracted plasma or serum assay for total ACTH immunoactivity. High serum ACTH levels occurred in 24% of patients with small-cell carcinoma and 3% of patients with non-small-cell cancer. In patients with small-cell carcinoma, levels were high in 12% with limited disease and 32% with extensive disease. Study B used an ACTH assay after plasma extraction by porous glass, which measured mainly regular 1-39 ACTH. Here no lung-cancer patient had levels above the reference range, suggesting that the high levels in Study A may be due to plasma ACTH components which are poorly extracted by porous glass. It is concluded that high circulating ACTH immunoactivity occurs in a minority of patients with lung cancer, particularly those with extensive small-cell carcinoma. Indirect evidence suggests that the high ACTH levels detected with assays for total ACTH are due to molecular forms other than 1-39 ACTH, probably high-mol.-wt species.

Infrequent elevation of plasma ACTH in patients with bronchogenic carcinoma

Older methods for radioimmunoassay of ACTH in human plasma have detected a high frequency of plasma ACTH elevation in patients with lung cancer, even in the absence of Cushing's syndrome. It now appears evident that these assay systems measure biologically inactive forms and fragments of ACTH. Since ectopic Cushing's syndrome may be clinically atypical, a radioimmunoassay for ACTH that correlates with the clinical state would be of value. Accordingly, circulating plasma corticotropin (ACTH) levels were measured in 39 consecutive patients with biopsy-proven, untreated lung cancer, all without evidence of Cushing's syndrome. In only one instance was ACTH found to be elevated by the method of assay used. Two interpretations are justified: (1) elevated plasma ACTH levels are infrequent in patients with lung cancer, or (2) ACTH measurements vary according to the assay system used.

Ectopic adrenocorticotrophic (ACTH) syndrome and small cell carcinoma of the lung-assessment of clinical implications in patients on combination chemotherapy

Small cell carcinoma of the lung is the tumor most commonly associated with ectopic ACTH production and hypercortisolism. The relationship between this paraneoplastic endocrine syndrome and the clinical course of the tumor is examined in this review of patients with the ectopic ACTH syndrome and small cell carcinoma seen at The Johns Hopkins Oncology Center between 1973 and 1979. Five of 157 (3.2%) patients with small cell carcinoma were clinically diagnosed as having the ectopic ACTH syndrome. The onset of this endocrine syndrome appeared to coincide with a more aggressive phase of the course of small cell carcinoma. Further analysis of these cases suggests that the development of the ectopic ACTH syndrome may reflect changes in cell populations within the tumor and/or alterations in tumor behavior with time and perhaps with the effects of drug therapy.

Is prolactin secreted ectopically?

The ectopic secretion of prolactin by neoplasms has been reported only rarely although in one preliminary report it has been found to be present commonly in tumor extracts. To ascertain whether this is due to a true rarity of prolactin-secreting tumors or to the fact that prolactin hypersecretion causes few notable clinical symptoms in patients with cancer, we measured prolactin levels by radioimmunoassay in the serums of 215 patients who had a variety of malignancies. Prolactin levels were elevated (greater than 25 ng/ml) in 15 patients. In 12 of these 15 patients, the elevations could be explained by the use of phenothiazine or opiates, or prior irradiation to the chest wall or head. Additional serum samples showed clearly normal prolactin levels in one of the patients. Of the entire series of 215 patients, therefore, only two patients (1 percent) had modestly elevated prolactin levels without having known causes for hyperprolactinemia: one patient with squamous cell carcinoma of the lung (prolactin 34.1 ng/ml) and one patient with breast cancer (prolactin 45.4 ng/ml). Even in these two patients the hyperprolactinemia could as likely be due to stimulation of afferent nerves in the chest wall as to ectopic secretion by the tumors. There is no clear evidence in our study or in the literature that prolactin is secreted ectopically; this is in sharp contrast to many studies showing the high frequencies of the ectopic secretion of a number of other hormones. Why this is so is unknown.

Persistent lymphocytopenia as a diagnostic feature of bronchogenic carcinoma

Patients with abnormalities due to bronchogenic carcinoma, noted on chest films, have decreased peripheral blood lymphocytes and increased total white cells compared to patients with benign lesions. Precision studies of 40 patients revealed that a low percentage of lymphocytes averaged over a three-week period distinguished bronchogenic carcinoma patients from patients with benign lesions with 95 percent overall accuracy. Lesions as small as 1.0 cm were correctly predicted to be malignant. Mean 8 AM plasma cortisol levels were elevated in patients with bronchogenic carcinoma and there was a negative correlation of 8 AM plasma cortisol levels with precentage of lymphocytes. Increased levels of endogenous cortisol may account for lymphocytopenia in bronchogenic carcinoma patients.

Ectopic hormones--biochemical aspects

Biochemical evidence suggests that ectopic hormone production is much more common than suspected clinically. The majority of lung carcinomas of oat cell or carcinoid type appear to synthesise ACTH and related peptides, calcitonin and less frequently, chorionic gonadotrophin and vasopressin. The primary amino acid sequences of ectopic hormones closely resemble their normal counterparts but ectopic hormone producing tumours contain greater proportions of high molecular weight, subunit and fragment forms than the normal gland of origin. Assays for ectopic hormones are clinically useful in diagnosis, tumour localisation, and monitoring patients with ectopic hormonal syndromes. Currently the clinical value of hormone assays in the routine management of common forms of malignancy in the absence of overt ectopic hormonal syndromes is unproven. However, better characterisation of hormonal forms relatively specific for neoplasia together with improved assay specificity and sensitivity may enhance the clinical value of ectopic hormones as tumour markers, particularly in malignancies which are commonly associated with ectopic hormone production (e.g. lung cancer).

Plasma immunoreactive calcitonin in lung cancer

We have measured plasma calcitonin in 135 untreated eucalemic men with lung cancer and a control/smoker population. Calcitonin levels were determined by radioimmunoassay and validated by immunoextraction. Plasma immunoreactive calcitonin moieties were purified by immunoadsorbent chromatography, treated with mercaptoethanol and urea, and characterized by gel filtration. Artifacts in human calcitonin radioimmunoassays of cancer-patient plasmas were detected by parallel plasma incubations in a salmon calcitonin radioimmunoassay system which does not detect human calcitonin and by immunoprecipitation of tracer at the end of radioimmunoassay incubations. Heating fresh plasmas to 65 degrees C for 1.5 hours reduced radioimmunoassay artifacts without loss of calcitonin moieties. Such characterization of hypercalcitoninemia in each of the histopathological types of lung cancer has raised some important questions about the interpretation of plasma calcitonin radioimmunoassay measurements in lung cancer. Based on inhibition of tracer-antibody binding, plasma calcitonin seemed to be elevated in 18% (14/80) of basal plasma samples obtained from patients with epidermoid or with anaplastic lung cancer. Unequivocal hypercalcitoninemia (heat stable, causing no inhibition of antibody-tracer binding in the salmon calcitonin radioimmunoassays, and immunoextractable with human calcitonin antibodies) was not found in any of the apparently hypercalcitoninemic plasmas from persons with epidermoid or anaplastic lung cancer. By contrast, unequivocal hypercalcitoninemia was found in 27% (15/55) of plasmas from patients with small cell carcinoma or adenocarcinoma. Most of the immunoreactive calcitonin recovered from small cell and adenocarcinoma lung cancer plasmas with unequivocally elevated calcitonin is much larger than calcitonin monomer.