Summary Epidermal growth factor receptors (EGFr) were measured using a radioligand binding assay, in membrane preparations from 51 human non-small cell lung cancers and in normal tissue of the same patients.The binding characteristics of EGFr were similar in tumour and normal lung membranes (range of dissociation constant of high affinity sites: 0.1-0.6 nM). However, the concentrations in tumours (median, 16.4 fmol mgI of protein; range, 1.5-176) were significantly higher than in normal tissues (median, 7.4 fmol mg-' of protein; range, 1.9-13.4).The receptor levels in normal tissue were normally distributed. It was therefore possible to define a normal/pathologic cut-off level (12.9 fmol mg-' of protein). In 57% of cases EGFr in cancer was higher than the cut-off. No relationships were found between receptor concentrations and positivity rates of EGFr and histology, stage, lymph node positivity and pT. A trend for a direct relation between receptor positivity and grading was found.

An exaggerated response of 17- hydroxyprogesterone (17-OHP) to exogenous ACTH stimulation has been found in 30 to 70% of patients with incidentally discovered adrenal tumors, supporting the concept that congenital 21- hydroxylase deficiency may be a predisposing factor for adrenocortical tumorigenesis. Decreased expression of 21-hydroxylase gene has been observed in sporadic non-functioning adrenocortical adenomas and adrenocortical carcinomas, in agreement with the reduced steroidogenic activity found in these types of tumors. Screening studies for the presence of mutations in CYP21A2 gene, encoding 21-hydroxylase, in patients with sporadic adrenocortical tumors yielded discordant results. Overall, a higher frequency of germline 21-hydroxylase mutation carriers has been found among patients with adrenal tumors, including incidentalomas, than in the general population. However, the presence of mutations did not correlate with endocrine test results and tumor mass features, suggesting that 21-hydroxylase deficiency does not represent a relevant mechanism in adrenal tumorigenesis. Mechanisms leading to reduced 21-hydroxylase expression and activity are still unknown.

The study of tumor markers in breast cancer tissue may supply information on the tumor's biological features and its clinical behaviour. Forty-nine primary breast cancer patients are evaluable to date. CEA, ferritin, TPA and CA15/3 were measured with radioimmunometric methods in the cytosol of carcinoma and normal tissue from the same breast. The concentrations of the four markers were higher in the tumor than in normal tissue in 42/49 cases for CEA, 47/49 for ferritin, 42/49 for TPA and in 24/29 for CA15/3. However, an overlap was found between carcinoma and normal tissue levels, particularly for CEA and TPA. We can conclude that the four substances studied may be markers of malignancy in breast carcinoma when non-malignant breast tissue from the same patient is determined at the same time, whereas assays within a single, unknown breast tissue sample may be useful only in the case of ferritin and, partly, CA15/3.

Injure 1991 a 62-year-old retired man, from Udine (northern Italy), was suddenly affected by dyspnoea. X-ray and CT control

Since 1983 we have studied the relationship, in the same patient, between receptor status in breast carcinoma and in nonmalignant breast tissue. Fifty patients have been evaluated to date. The total unoccupied cytosol estrogen and progesterone receptors were determined by a dextran-coated charcoal method. In nonmalignant breast tissue we found a measurable receptor concentration above the sensitivity of the method in 62% of cases for estrogen receptors and in 44% of cases for progesterone receptors. No relationships were found between the receptor level of each tumor and that of the corresponding benign tissue. The data suggest that the levels of the receptors in the tumor and in the nonmalignant tissue are totally independent.