Identification of proliferating human anterior pituitary adenoma cells in vitro.

A method to determine whether dispersed human anterior pituitary adenoma cells proliferate in mixed culture was developed. Fifteen pituitary adenomas were dispersed enzymatically to single cells, following which twelve were double immunostained after eight days. Proliferating cells were identified immunologically following one hour of bromo-deoxyuridine incorporation. Adenoma cells were subsequently identified with an anti-neuron-specific enolase antibody system. A time course of bromo-deoxyuridine labelling was performed on three nonfunctional adenomas over a four day period, with bromo-deoxyuridine being added to cultures at one hour, 24 hours and four days prior to immunostaining. Double immunolabelled cells were unambiguously identified by a dark brown nucleus surrounded by red cytoplasm. Eight out of 12 pituitary adenomas (two prolactinomas, three nonfunctional, three growth hormone secreting) showed an increased bromo-deoxyuridine labelling index (range 0.1%-1.4%). Bromo-deoxyuridine incorporation over four days showed an increase in bromo-deoxyuridine from 0.02%, 0.03% and 3.3% at one hour to 10.1%, 1.3% and 5.0% at four days, respectively, but evidence of mitosis was scant. This study shows that pituitary adenomas may proliferate in vitro and that this double immunostaining method may be used as an in vitro proliferation assay in a mixed cell population.

Expression of the transferrin receptor in human anterior pituitary adenomas is confined to gonadotrophinomas.

OBJECTIVE: The human pituitary gland is affected selectively by conditions associated with iron deposition, but the mechanisms for this are unknown. In this study we have determined whether the transferrin receptor, which mediates iron uptake by cells, could be detected immunocytochemically in human pituitary adenomas in vitro. PATIENTS: Data were derived from 35 patients undergoing transsphenoidal surgery and included 13 with clinically non-functioning adenomas, 15 with acromegaly, 4 prolactinomas, 2 patients with Cushing's disease and one patient with Nelson's syndrome. MEASUREMENTS: Transferrin receptor immunopositivity was determined for each adenoma in dispersed cell culture using a specific monoclonal antibody. RESULTS: Eight of 13 clinically functionless adenomas showed immunopositive transferrin receptor expression, whilst adenomas from 15 patients with acromegaly, 4 prolactinomas, 2 Cushing's syndrome and one patient with Nelson's syndrome were negative. The eight transferrin receptor positive tumours were gonadotrophinomas and accounted for eight of the nine tumours which secreted and immunostained for FSH; all eight also secreted and immunostained for LH. CONCLUSIONS: These findings may reflect a special requirement for iron by gonadotrophin secreting cells in comparison to other pituitary cell types and this could underlie the reasons why in the normal pituitary these cells are especially susceptible to malfunction in iron overload syndromes such as genetic haemochromatosis and beta-thalassaemia.

Expression of proliferating cell nuclear antigen (PCNA) in dysplasia of the bronchial epithelium.

Proliferating cell nuclear antigen (PCNA) is expressed in cells in the cell cycle and has been studied as a marker of proliferation in lung and other tumours. We have noted immunocytochemical differences in PCNA expression between normal and neoplastic bronchial cells. As bronchial dysplasia is considered preneoplastic, we have examined PCNA expression in this condition. PCNA staining in 47 cases of bronchial dysplasia and 32 samples of normal bronchial epithelium was compared. Of the dysplasias, three were mild, 11 moderate, and 33 severe. A significant increase in PCNA counts over normal epithelium was seen only in moderate and severe dysplasias. In dysplasia, mitotic indices showed a significant positive correlation with the percentage of PCNA-positive cells. We conclude that in moderate and severe dysplasias there is an increase in the number of cells expressing PCNA and undergoing division, indicating abnormal growth control.

Neuroendocrine and epithelial markers in diagnostic bronchial lung cancer biopsy specimens.

The incidence of neuroendocrine and epithelial markers was investigated by immunocytochemistry in archival, lung cancer, bronchial biopsy specimens (n = 48). No correlation of antigenicity with histological type was observed. 79% non-small cell lung carcinoma (NSCLC) and 61% small cell lung carcinoma (SCLC) were positive for epithelial markers. HuTu-m3 did not discriminate adenocarcinomas and squamous cell carcinomas from SCLC. 83% SCLC and 93% NSCLC were positive for one or more neuroendocrine marker. Multiple neuroendocrine markers were found in 61% SCLC, 83% NSCLC and 83% squamous cell carcinomas, this incidence being greater in the NSCLC group, and in the squamous carcinomas in particular, than previously reported.

Immunocytochemical investigation of the tissue of origin of two lung cancer cell lines.

The constitutive cell types of the two lung cancer cell lines CaLu1 and CaLu3 have been investigated by immunocytochemical staining with markers for cytokeratins, vimentin, carcinoembryonic antigen and the epithelial cell epitope recognized by the monoclonal antibody Ber-EP4. The cells of both lines reacted with vimentin, with CAM 5.2, which is a marker for cytokeratins 8, 18 and 19, and with a specific marker for cytokeratin 19. CaLu3 cultures showed patchy staining, and CaLu1 none, when treated with a monoclonal antibody reactive with cytokeratins 13, 14 and 17. CaLu3 cells all reacted strongly with Ber-EP4 and the antibody to carcinoembryonic antigen, whereas CaLu1 gave a negative reaction with both these reagents. These results indicate that the CaLu3 line has retained antigens characteristic of some bronchial adenocarcinomata, and that the CaLu1 line was derived from a mesothelioma rather than a pleural metastasis of a squamous carcinoma.